Academic literature on the topic 'Microstructure impact simulation results'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Microstructure impact simulation results.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Microstructure impact simulation results"
1
Ye, Xiao Yu, Kai Hua Zhang, and Jun Zuo. "The Effects of Rolling Process on Microstructures and Properties of High Nb X80 Grade Pipeline Steel." Advanced Materials Research 641-642 (January 2013): 538–42. http://dx.doi.org/10.4028/www.scientific.net/amr.641-642.538.
Full textAbstract:
In Gleele-3500 Thermal Simulation Test Machine，conduct Thermal Simulation Experiment for High Niobium X80 Grade Pipeline Steel at Different Deformation Temperature, Deformation Extent and Coiling Temperature. Analysis the Microstructure Was Influenced by Different Rolling Process. According to the Thermal Simulation Experiments, Designed Test Scheme of Controlled Rolling and Controlled Cooling and Completed the Trial. the Results Showed that: for High Niobium X80 Grade Pipeline Steel, the Microstructures Are Acicular Ferrite and Have Good Mechanical Properties. the Low Temperature Impact Toughness Are More than 300J in -20°C and -40°C.
2
Zhi, Ying, Xiang Hua Liu, and Zhen Fan Wang. "Simulation to Static Recrystallization of Nb Micro Alloyed Steel by Cellular Automaton." Advanced Materials Research 418-420 (December 2011): 1622–28. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.1622.
Full textAbstract:
The model of cellular automaton (CA) for simulating the static recrystallization of Nb micro alloyed steel after hot deformation was established. The static precipitation of micro alloyed elements on the impact of static recrystallization was considered in the mode. The microstructure evolution of austenite static recrystallization of Nb micro alloyed steel was simulated dynamically, such as the the volume fraction, kinetics curve of static recrystallization, dislocation density and grain shape, were quantitatively, accurately and visually described. According to the simulation results by cellular automaton, the effects of the deformation temperature, strain rate, and other processing parameters on the microstructure of the austenite static recrystallization of Nb micro alloyed steel were analyzed. The simulation results could provide a theoretical reference for the control of the microstructure and property of Nb micro alloyed steel.
3
Węglowski, Marek Stanislaw, Marian Zeman, and Miroslaw Lomozik. "Physical Simulation of Weldability of Weldox 1300 Steel." Materials Science Forum 762 (July 2013): 551–55. http://dx.doi.org/10.4028/www.scientific.net/msf.762.551.
Full textAbstract:
In the present study, the investigation of weldability of new ultra-high strength - Weldox 1300 steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on the microstructure and mechanical properties of the heat affected zone (HAZ). In the frame of these investigation the microstructure was studied by the light (LM) and transmission electron microscopies (TEM). It has been shown that the microstructure of the Weldox 1300 steel is composed of tempered martensite, and inside the laths the minor precipitations mainly V(CN) and molybdenum carbide Mo2C were observed. Mechanical properties of parent material were analysed by the tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 - 300 s. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The results show that the impact toughness and hardness decrease with the increase of t8/5 under the condition of a single thermal cycle in simulated HAZ. The continuous cooling transformation diagrams (CCT-W for welding conditions) of Weldox 1300 steel for welding purposes was also elaborated. The steel Weldox 1300 for cooling time in the range of 2,5 - 4 s showed martensite microstructure, for time from 4 s to 60 s mixture of martensite and bainite, and for longer cooling time mixture of ferrite, bainite and martensite. The results indicated that the weldability of Weldox 1300 steel is limited and to avoid the cold cracking the preheating procedure or medium net linear heat input should be used.
4
Worswick, Michael J., Ryan George, Alex Bardelcik, Luke Ten Kortenaar, and Duane Detwiler. "Thermal Processing History and Resulting Impact Response of a Hot-Formed Component with Tailored Properties – Numerical Study." Applied Mechanics and Materials 566 (June 2014): 34–40. http://dx.doi.org/10.4028/www.scientific.net/amm.566.34.
Full textAbstract:
The impact modeling of a hot-formed component with tailored mechanical properties is studied to understand the influence of the thermal processing history and how the final properties of the component will affect its impact response. This paper presents a numerical study of the forming and quenching process and subsequent impact simulations. The processing simulations serve to predict the final microstructure and hardness distribution within a lab-scale B-pillar component that is processed using a tool with separate heated and cooled regions. A remapping algorithm is used to translate the results of the forming simulation to the impact simulation. A strain-rate sensitive material model is applied to model the response of these tailored microstructures during impact events. A comparison between a component that is fully hardened and a tailored component with regions of lower strength but increased ductility is presented in this work. Simulations that do not consider the onset of fracture predict superior peak impact load and energy absorption of the fully martensitic component due to its higher overall strength. However, the bainitic regions within the tailored component exhibit much higher ductility. Current work is addressing the introduction of failure criteria into simulations of tailored hot stamped components under impact loading for which the tailored component is expected to demonstrate superior resistance to cracking relative to the fully hardened component.
5
Lian, Jun, Bo Hong Gu, and Wei Dong Gao. "Microstructure Model for Finite Element Analysis of 4-Step 3-D Rectangular Braided Composites under Ballistic Impact." Key Engineering Materials 334-335 (March 2007): 485–88. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.485.
Full textAbstract:
This paper presents a real microstructure model which has the same fiber volume fraction and tows’ spatial configuration with 3D rectangular composites to simulate the ballistic impact damage of the composites struck by steel projectile. The commercial available FEM code of Ls-Dyna was employed to calculate the interaction between the composite targets and steel projectile. From the comparison of residual velocities between simulation and experiment, it is proven the microstructure model can simulate the ballistic penetration with higher precision than the continuum model. The acceleration vs. time curve reveals the complicated interaction between composite and projectile in ballistic penetration. The prominent advantage of the microstructure model is that it can simulate the local damage mode of the composites at real microstructure level and obtain vivid simulating results.
6
Vuherer, Tomaž, Fidan Smaili, Edvard Bjelajac, Mirza Manjgo, and Gorazd Lojen. "Simulation and Mechanical Properties of Fine-Grained Heat-Affected Zone Microstructure in 18CrNiMo7-6 Steel." Materials 15, no. 19 (September 30, 2022): 6782. http://dx.doi.org/10.3390/ma15196782.
Full textAbstract:
Heat-affected zones (HAZs) in real welds are usually quite narrow, and consequently most standard mechanical tests are difficult or even impossible. Therefore, simulated microstructures are often used for mechanical tests. However, the most often used weld thermal cycle simulator produces only a few millimeters wide area of simulated microstructure in the middle of specimens. Consequently, these kind of simulated specimen are not suitable for standard tensile tests, and even for Charpy impact tests, the simulated area can be too narrow. Therefore, to investigate the mechanical properties of a fine-grain heat-affected zone in 18CrNiMo7-6 steel, two methods were used for simulation of as-welded microstructures: (a) a weld thermal cycle simulator, and (b) as an alternative, though not yet verified option, austenitizing in a laboratory furnace + water quenching. The microstructures were compared and mechanical properties investigated. The grain sizes of the simulated specimens were 10.9 μm (water-quenched) and 12.6 μm (simulator), whereby the deviations from the real weld were less than 10%. Both types of simulated specimen were used for hardness measurement, Charpy impact tests, and fatigue tests. Water-quenched specimens were large enough to enable standard tensile testing. A hardness of 425 HV, yield strength Rp02 = 1121 MPa, tensile strength Rm = 1475 MPa, impact energy KV = 73.11 J, and crack propagation threshold ΔKthR = 4.33 MPa m0.5 were obtained with the water quenched specimens, and 419 HV, KV = 101.49 J, and ΔKthR = 3.4 MPa m0.5 with the specimens prepared with the simulator. Comparison of the results confirmed that the annealed and quenched specimens were suitable for mechanical tests of FG HAZs, even for standard tensile tests. Due to the use of simulated test specimens, the mechanical properties determined can be linked to the FG HAZ microstructure in 18CrNiMo7-6 steel.
7
Liu, Binchao, Rui Bao, Yamei Niu, Songsong Lu, and Kai Wang. "Peridynamic Simulation of Fatigue Crack Growth Behaviour with the Effect of Microstructure." MATEC Web of Conferences 165 (2018): 04003. http://dx.doi.org/10.1051/matecconf/201816504003.
Full textAbstract:
The purpose of this paper is to explore the influences of microstructures on crack growth behaviour in 2324-T39 aluminum alloy based on peridynamic(PD) theory. The microelastic bond-based peridynamic constitutive is modified as microplastic to describe the plasticity of aluminum alloys. A new method to establish polycrystalline models based on metallographs is adopted, and grains are reflected in simulations by setting transgranular and intergranular pairwise force in the corresponding bonds. Two kinds of microstructures are modeled according to metallographs, and a special kind of crack branch resulted from the link-up of the secondary crack with the main crack and the growth of the branched crack is successfully captured. The PD simulations reveal that microstructure orientation characteristics have an impact on crack propagation paths and crack growth modes, and it is easier for the secondary-crack resulted macroscopic crack branching to appear if grain boundaries locate not too close to the leading crack tip but within the crack tip plastic zone. The numerical results are verified by experiments and fractographic analysis.
8
Li, Jin, Liang Yi Li, and Zheng Yuan. "Study of the Impact Toughness Experiment of SiCp/Al FGM and Numerical Simulation." Applied Mechanics and Materials 268-270 (December 2012): 134–37. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.134.
Full textAbstract:
This paper by cold isostatic pressing and sintering of combining the method of preparation of silicon carbide enhance aluminum functional gradient materials, and the microstructure, density, impact toughness are analyzed, the results of experiments showed that in the aluminum gradient to join in the silicon carbide enhance particles, The impact toughness of the material has been obviously improved. Using ANSYS Numerical simulation Impact process, the simulation results anastomosis with the experimental results.
9
Schwich, Gideon, Thomas Henke, Joachim Seitz, and Gerhard Hirt. "Prediction of Microstructure and Resulting Rolling Forces by Application of a Material Model in a Hot Ring Rolling Process." Key Engineering Materials 622-623 (September 2014): 970–77. http://dx.doi.org/10.4028/www.scientific.net/kem.622-623.970.
Full textAbstract:
Ring rolling is a versatile incremental bulk forming process. Due to the incremental character of the process, it consists of a large number of deformation and dwell steps. Finite element (FE) simulations of bulk forming processes are capable of predicting loads, stresses and material flow. In recent years, the finite element analysis of ring rolling processes has become feasible both in terms of calculation time as well as regarding the closed loop control of the kinematic degrees of freedom [1]. Accordingly, the focus of interest now includes the prediction of the microstructure evolution. The accuracy of such numerical simulations strongly depends on the models characterizing the material behavior and boundary conditions. In this paper, a finite element based simulation study was conducted, in order to evaluate the impact of boundary conditions such as transfer time, radiation, heat transfer and friction on the target values of the ring rolling process. The results of the simulation study were compared to ring rolling experiments on an industrial size ring rolling device. A good accordance regarding the evolution of the outer diameter and radial force was observed. Strong contingencies of transfer time on the forces throughout the process were detected and considered in the simulation study. In a post processing step, the evolution of the microstructure considering the dynamic and static recrystallization as well as the grain growth was calculated using the FE results. The calculated grain sizes show good accordance with the experimentally observed microstructure of the ring before and after the rolling. Furthermore, the impact of process parameters on the evolution of the grain size was investigated.
10
Mitrovic, Radivoje, Dejan Momcilovic, Olivera Eric, Ivana Atanasovska, and Nenad Hut. "Study on impact properties of creep-resistant steel thermally simulated heat affected zone." Thermal Science 16, no. 2 (2012): 513–25. http://dx.doi.org/10.2298/tsci111006142m.
Full textAbstract:
The steam pipe line (SPL) and steam line material, along with its welded joints, subject to damage that accumulates during operation in coal power plants. As a result of thermal fatigue, dilatation of SPL at an operating temperature may lead to cracks initiation at the critical zones within heat affected zone (HAZ) of steam pipe line welded joints. By registration of thermal cycle during welding and subsequent HAZ simulation is possible to obtain target microstructure. For the simulation is chosen heat resisting steel, 12H1MF (designation 13CrMo44 according to DIN standard). From the viewpoint of mechanical properties, special attention is on impact toughness mostly because very small number of available references. After simulation of single run and multi run welding test on instrumented Charpy pendulum. Metallographic and fractographic analysis is also performed, on simulated 12H1MF steel from service and new, unused steel. The results and correlation between microstructure and impact toughness is discussed, too.
Dissertations / Theses on the topic "Microstructure impact simulation results"
1
Bourgin, Didier. "Lattice physics mesh refinement study and its impact on full core nodal simulation results." Thesis, KTH, Reaktorteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143031.
Full text
2
Quan, Liang. "Using FDM and FEM to simulate the decarburization in AISI 1074 during heat processing and its impact." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44769.
Full textAbstract:
The metallurgical processes and the products developed from these processes have been the cornerstone on which our civilizations have developed and flourished. Many of the new materials that have been developed over centuries were often the result of serendipitous occurrences. Because of the importance of new materials to the improvement of society, it is necessary to accelerate the way in which new alloys and processes are designed, developed and implemented.
Over the last two decades the computational side of materials science has thrived as a result of bigger and faster computers. However, the application of new computational methods to the development of new materials and structures is still in the early stages primarily because of the complexity of most metallurgical processes. One such process is the decarburization of steel. Because of the importance of the microstructure on the mechanical properties, changes in the near surface properties are affected by the loss of carbon in the alloy. The topics investigated in this thesis include a variety of alloys and microstructures that are considered to be important in the development of a unique structure necessary for a more efficient method of recovering natural gas and oil from underground reserves as well as structures for energy absorbing systems. Since both the material application and the structure are new, this research represents an ideal opportunity to combine processing, properties, microstructure and computations to accelerate the development of these new structures.
Compared to other commercially available proppants which tend to fail in demanding environments, the thin-walled hollow metal proppants are regarded more promising due to the low density and high mechanical strength. The energy-absorbing composite material manufactured by embedding said spheres in the Mg/Al matrix material is optimized by improving sphere and matrix properties at each step in the process. Ultimately the mechanical strength, fracture toughness, and energy absorption are expected to achieve a factor of 2-5 higher than previously reported.
Modeling makes it economically practical to assess the targeted materials' overall properties, behaviors and the mechanical responses in conjunction with stress environment, material properties, material dimensions among other variables, before a structure is built. Additionally, more advanced modeling can enable the quantitative descriptions of more complex metallurgical phenomena such as the effects of impurity elements and deformation under complex loading conditions.
3
Wei, Chun-Hung, and 魏鈞宏. "Impact of Correlated Activity Parameters on Computer Simulation Results." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/02268768631558317872.
Full textAbstract:
碩士淡江大學
土木工程學系碩士班
95
Using the computer simulation technology to treat the uncertainty in the scheduling of projects has already been accepted by the field of construction management. General simulation models include the following steps:(1)establish the probability distributions of simulation components.(ex: activities duration, production efficiency of machines and tools, the amount of activity.)(2)transform into computer code.(3)perform a number of simulation iterations and obtain specific management information.(ex: production efficiency, duration of cycle, total duration of project.) Previous researches attempted to address possible correlations among the parameters of simulation components. They, however, often assumed that the distributions are of the same form. This study allows different kinds of distributions, and generates correlated random variables by applying the NORmal To Anything (NORTA) method. The proposed model has been applied to a pavement rehabilitation project. This study develops a simulation model to analyze the uncertainty of project duration at the presence of correlations among simulation components. The validation of this study involves two parts. The first part is to test whether the generated samples have the specified marginal distributions. The second is to check whether the generated correlations are close to the specified ones.
4
LIANG, YU-FANG, and 梁瑜芳. "3rd Grade of Junior High School Impact Simulation Test Results of The Analysis of The Comprehensive Assessment Program for Junior High School." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/m2s23y.
Full textBooks on the topic "Microstructure impact simulation results"
1
Zaba, Basia. The demographic impact of AIDS: Some stable population simulation results. London: Centre for Population Studies, London School of Hygiene & Tropical Medicine, 1994.
Find full text
2
Ahmed, Amer S. The Impact Of Trade In Services On Factor Incomes: Results From A Global Simulation Model. The World Bank, 2009. http://dx.doi.org/10.1596/1813-9450-5155.
Full text
3
Levin, Ines, and Betsy Sinclair. Causal Inference with Complex Survey Designs. Edited by Lonna Rae Atkeson and R. Michael Alvarez. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780190213299.013.4.
Full textAbstract:
This article discusses methods that combine survey weighting and propensity score matching to estimate population average treatment effects. Beginning with an overview of causal inference techniques that incorporate data from complex surveys and the usefulness of survey weights, it then considers approaches for incorporating survey weights into three matching algorithms, along with their respective methodologies: nearest-neighbor matching, subclassification matching, and propensity score weighting. It also presents the results of a Monte Carlo simulation study that illustrates the benefits of incorporating survey weights into propensity score matching procedures, as well as the problems that arise when survey weights are ignored. Finally, it explores the differences between population-based inferences and sample-based inferences using real-world data from the 2012 panel of The American Panel Survey (TAPS). The article highlights the impact of social media usage on political participation, when such impact is not actually apparent in the target population.
4
Gao, Yanhong, and Deliang Chen. Modeling of Regional Climate over the Tibetan Plateau. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.591.
Full textAbstract:
The modeling of climate over the Tibetan Plateau (TP) started with the introduction of Global Climate Models (GCMs) in the 1950s. Since then, GCMs have been developed to simulate atmospheric dynamics and eventually the climate system. As the highest and widest international plateau, the strong orographic forcing caused by the TP and its impact on general circulation rather than regional climate was initially the focus. Later, with growing awareness of the incapability of GCMs to depict regional or local-scale atmospheric processes over the heterogeneous ground, coupled with the importance of this information for local decision-making, regional climate models (RCMs) were established in the 1970s. Dynamic and thermodynamic influences of the TP on the East and South Asia summer monsoon have since been widely investigated by model. Besides the heterogeneity in topography, impacts of land cover heterogeneity and change on regional climate were widely modeled through sensitivity experiments.In recent decades, the TP has experienced a greater warming than the global average and those for similar latitudes. GCMs project a global pattern where the wet gets wetter and the dry gets drier. The climate regime over the TP covers the extreme arid regions from the northwest to the semi-humid region in the southeast. The increased warming over the TP compared to the global average raises a number of questions. What are the regional dryness/wetness changes over the TP? What is the mechanism of the responses of regional changes to global warming? To answer these questions, several dynamical downscaling models (DDMs) using RCMs focusing on the TP have recently been conducted and high-resolution data sets generated. All DDM studies demonstrated that this process-based approach, despite its limitations, can improve understandings of the processes that lead to precipitation on the TP. Observation and global land data assimilation systems both present more wetting in the northwestern arid/semi-arid regions than the southeastern humid/semi-humid regions. The DDM was found to better capture the observed elevation dependent warming over the TP. In addition, the long-term high-resolution climate simulation was found to better capture the spatial pattern of precipitation and P-E (precipitation minus evapotranspiration) changes than the best available global reanalysis. This facilitates new and substantial findings regarding the role of dynamical, thermodynamics, and transient eddies in P-E changes reflected in observed changes in major river basins fed by runoff from the TP. The DDM was found to add value regarding snowfall retrieval, precipitation frequency, and orographic precipitation.Although these advantages in the DDM over the TP are evidenced, there are unavoidable facts to be aware of. Firstly, there are still many discrepancies that exist in the up-to-date models. Any uncertainty in the model’s physics or in the land information from remote sensing and the forcing could result in uncertainties in simulation results. Secondly, the question remains of what is the appropriate resolution for resolving the TP’s heterogeneity. Thirdly, it is a challenge to include human activities in the climate models, although this is deemed necessary for future earth science. All-embracing further efforts are expected to improve regional climate models over the TP.
5
Sobczyk, Eugeniusz Jacek. Uciążliwość eksploatacji złóż węgla kamiennego wynikająca z warunków geologicznych i górniczych. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN, 2022. http://dx.doi.org/10.33223/onermin/0222.
Full textAbstract:
Hard coal mining is characterised by features that pose numerous challenges to its current operations and cause strategic and operational problems in planning its development. The most important of these include the high capital intensity of mining investment projects and the dynamically changing environment in which the sector operates, while the long-term role of the sector is dependent on factors originating at both national and international level. At the same time, the conditions for coal mining are deteriorating, the resources more readily available in active mines are being exhausted, mining depths are increasing, temperature levels in pits are rising, transport routes for staff and materials are getting longer, effective working time is decreasing, natural hazards are increasing, and seams with an increasing content of waste rock are being mined. The mining industry is currently in a very difficult situation, both in technical (mining) and economic terms. It cannot be ignored, however, that the difficult financial situation of Polish mining companies is largely exacerbated by their high operating costs. The cost of obtaining coal and its price are two key elements that determine the level of efficiency of Polish mines. This situation could be improved by streamlining the planning processes. This would involve striving for production planning that is as predictable as possible and, on the other hand, economically efficient. In this respect, it is helpful to plan the production from operating longwalls with full awareness of the complexity of geological and mining conditions and the resulting economic consequences. The constraints on increasing the efficiency of the mining process are due to the technical potential of the mining process, organisational factors and, above all, geological and mining conditions. The main objective of the monograph is to identify relations between geological and mining parameters and the level of longwall mining costs, and their daily output. In view of the above, it was assumed that it was possible to present the relationship between the costs of longwall mining and the daily coal output from a longwall as a function of onerous geological and mining factors. The monograph presents two models of onerous geological and mining conditions, including natural hazards, deposit (seam) parameters, mining (technical) parameters and environmental factors. The models were used to calculate two onerousness indicators, Wue and WUt, which synthetically define the level of impact of onerous geological and mining conditions on the mining process in relation to: —— operating costs at longwall faces – indicator WUe, —— daily longwall mining output – indicator WUt. In the next research step, the analysis of direct relationships of selected geological and mining factors with longwall costs and the mining output level was conducted. For this purpose, two statistical models were built for the following dependent variables: unit operating cost (Model 1) and daily longwall mining output (Model 2). The models served two additional sub-objectives: interpretation of the influence of independent variables on dependent variables and point forecasting. The models were also used for forecasting purposes. Statistical models were built on the basis of historical production results of selected seven Polish mines. On the basis of variability of geological and mining conditions at 120 longwalls, the influence of individual parameters on longwall mining between 2010 and 2019 was determined. The identified relationships made it possible to formulate numerical forecast of unit production cost and daily longwall mining output in relation to the level of expected onerousness. The projection period was assumed to be 2020–2030. On this basis, an opinion was formulated on the forecast of the expected unit production costs and the output of the 259 longwalls planned to be mined at these mines. A procedure scheme was developed using the following methods: 1) Analytic Hierarchy Process (AHP) – mathematical multi-criteria decision-making method, 2) comparative multivariate analysis, 3) regression analysis, 4) Monte Carlo simulation. The utilitarian purpose of the monograph is to provide the research community with the concept of building models that can be used to solve real decision-making problems during longwall planning in hard coal mines. The layout of the monograph, consisting of an introduction, eight main sections and a conclusion, follows the objectives set out above. Section One presents the methodology used to assess the impact of onerous geological and mining conditions on the mining process. Multi-Criteria Decision Analysis (MCDA) is reviewed and basic definitions used in the following part of the paper are introduced. The section includes a description of AHP which was used in the presented analysis. Individual factors resulting from natural hazards, from the geological structure of the deposit (seam), from limitations caused by technical requirements, from the impact of mining on the environment, which affect the mining process, are described exhaustively in Section Two. Sections Three and Four present the construction of two hierarchical models of geological and mining conditions onerousness: the first in the context of extraction costs and the second in relation to daily longwall mining. The procedure for valuing the importance of their components by a group of experts (pairwise comparison of criteria and sub-criteria on the basis of Saaty’s 9-point comparison scale) is presented. The AHP method is very sensitive to even small changes in the value of the comparison matrix. In order to determine the stability of the valuation of both onerousness models, a sensitivity analysis was carried out, which is described in detail in Section Five. Section Six is devoted to the issue of constructing aggregate indices, WUe and WUt, which synthetically measure the impact of onerous geological and mining conditions on the mining process in individual longwalls and allow for a linear ordering of longwalls according to increasing levels of onerousness. Section Seven opens the research part of the work, which analyses the results of the developed models and indicators in individual mines. A detailed analysis is presented of the assessment of the impact of onerous mining conditions on mining costs in selected seams of the analysed mines, and in the case of the impact of onerous mining on daily longwall mining output, the variability of this process in individual fields (lots) of the mines is characterised. Section Eight presents the regression equations for the dependence of the costs and level of extraction on the aggregated onerousness indicators, WUe and WUt. The regression models f(KJC_N) and f(W) developed in this way are used to forecast the unit mining costs and daily output of the designed longwalls in the context of diversified geological and mining conditions. The use of regression models is of great practical importance. It makes it possible to approximate unit costs and daily output for newly designed longwall workings. The use of this knowledge may significantly improve the quality of planning processes and the effectiveness of the mining process.
Book chapters on the topic "Microstructure impact simulation results"
1
Sugiura, Keisuke. "Results: Shapes of Impact Outcomes." In Development of a Numerical Simulation Method for Rocky Body Impacts and Theoretical Analysis of Asteroidal Shapes, 61–86. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-3722-6_3.
Full text
2
Schröder, Daniel. "Simulation Results and Discussions for Air-Composition Impact." In Analysis of Reaction and Transport Processes in Zinc Air Batteries, 135–71. Wiesbaden: Springer Fachmedien Wiesbaden, 2016. http://dx.doi.org/10.1007/978-3-658-12291-1_9.
Full text
3
Riedl, Reinhard. "The impact of workload on simulation results for distributed transaction processing." In High-Performance Computing and Networking, 33–42. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/bfb0100563.
Full text
4
Jančíková, Andrea, and Jan Unucka. "DTM Impact on the Results of Dam Break Simulation in 1D Hydraulic Models." In Lecture Notes in Geoinformation and Cartography, 125–36. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-18407-4_11.
Full text
5
Imanaga, S., K. Hane, and Y. Hayafuji. "Inverse Modeling of Impact Ionization Rate Formula Through Comparison Between Simulation and Experimental Results of MOS Device Characteristics." In Simulation of Semiconductor Devices and Processes, 473–76. Vienna: Springer Vienna, 1993. http://dx.doi.org/10.1007/978-3-7091-6657-4_117.
Full text
6
Tu, Nguyen Thanh, Dinh Thanh Binh, Le Thu Huyen, and An Minh Ngoc. "Impact of Congestion Charging on Traffic and Environment in Hanoi: Results from Simulation Analysis." In Lecture Notes in Civil Engineering, 1643–52. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-7160-9_166.
Full text
7
Dyja, Robert, Elzbieta Gawronska, Andrzej Grosser, Piotr Jeruszka, and Norbert Sczygiol. "Estimate the Impact of Different Heat Capacity Approximation Methods on the Numerical Results During Computer Simulation of Solidification." In Transactions on Engineering Technologies, 1–14. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-2717-8_1.
Full text
8
Jia, Zehui, Lingwei Xu, Shuangkai Huang, Haoran Xu, Zhimo Zhang, and Xu Cui. "Preparation and Impact Resistance of Carbon Fiber Reinforced Metal Laminates Modified by Carbon Nanotubes." In Lecture Notes in Civil Engineering, 306–13. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-1260-3_27.
Full textAbstract:
AbstractFiber reinforced metal laminates (FMLs) are a kind of interlaminar hybrid composites made of metal sheets and fibers alternately stacked and cured at a certain pressure and temperature. In this paper, through the simulation of ABAQUS finite element software and recording the change of projectile velocity, the energy loss of projectile is calculated and the impact resistance is judged. Through the comparison of three groups of simulation experimental results, the energy absorbed by carbon fiber reinforced metal laminate is about 300 times that of aluminum alloy plate, which fully shows that carbon fiber reinforced metal composite has excellent impact resistance compared with aluminum alloy. After adding 1 wt% carbon nanotubes to carbon fiber reinforced metal laminates, the absorbed energy is about 10 times that of the original, which shows that carbon nanotubes improve the ultimate yield stress of resin and materials in epoxy resin and enhance the weakness that the composites are easy to delamination under impact load.
9
Sontheimer, Henrik, Christiane Schlawitschek, Stefan Batzdorf, Peter Stephan, and Tatiana Gambaryan-Roisman. "Numerical Simulation of Heat Transfer and Evaporation During Impingement of Drops onto a Heated Wall." In Fluid Mechanics and Its Applications, 269–89. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-09008-0_14.
Full textAbstract:
AbstractIn this study, hydrodynamics and heat transport during the impact of single and multiple drops onto a hot wall are studied numerically. The heat transfer in the vicinity of the three-phase contact line, where solid, liquid and vapour meet, contributes significantly to the global heat transfer. The microscale processes in the region of the three-phase contact line are analysed using a lubrication approximation. The results in the form of correlations are integrated into an overall model. The impingement of drops on a macro scale is simulated using a numerical model developed within the OpenFOAM library. The influence of dimensionless parameters, i.e., the Reynolds, Weber, Bond, Prandtl and Jakob numbers, as well as the influence of pressure, on the transport phenomena is discussed. The analysis of the influence of drop frequency and substrate thickness during the vertical coalescence and the influence of the drop spacing during the horizontal coalescence of drops on the hot surface complete the study. The results contribute to a better understanding of the complex mechanisms of spray cooling.
10
Wang, Pengyu, and Zhong Chen. "Vapor Condensation Under Electric Field: A Study Using Molecular Dynamics Simulation." In Supercomputing Frontiers, 20–30. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-10419-0_2.
Full textAbstract:
AbstractThe condensation of water vapor on the substrate surface under electric field is studied by molecular dynamics simulation, and a series of behaviors of water molecules during condensation were studied, such as nucleation, growth and coalescence. In the process of condensation, there will be some small clusters, whose size increases with the increase of time, and under the action of the movement of water molecules in vapor, the clusters move irregularly on the substrate surface and coalesced into larger clusters. And the droplets will be stretched along the direction of the electric field. Interestingly, the condensation will decrease with the increase of the electric field strength under the electric field perpendicular to the surface. The results also show that the orientations of water molecule dipole are closely related to the direction of electric field, indicating that the electric field causes the realignment of water molecules. The research shows that the electric intensity will have great impact on vapor condensation, which provides guidance for reversible adjustment of vapor condensation and the design of intelligent surface.
Conference papers on the topic "Microstructure impact simulation results"
1
Li, Zhiye, and Somnath Ghosh. "Analytically derived space time-based boundary condition (STBC) to account for stress wave propagation in a heterogeneous micromechanical model at hypervelocity impact." In 2019 15th Hypervelocity Impact Symposium. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/hvis2019-090.
Full textAbstract:
Abstract Recent years have seen a surge in research on material and structural response of composites using the homogenization based hierarchical modeling method. The microstructural representative volume element (RVE) is a small micro-region for which the volume average of variables is the same as those for the entire body. Representations of the microstructure are used for micromechanical simulations in determination of effective material properties by homogenization. Conventionally, periodic boundary conditions (PBC) are applied on the RVE boundary. However, when the heterogeneous microstructure is under very high strain rate loading conditions (105s−1−107s−1), periodic boundary conditions (PBC) do not accurately represent the effect of stress wave propagation. Improper boundary conditions can lead to significant error in homogenized material properties. In order to increase the accuracy of the homogenization model, this study introduces a new space-time dependent boundary condition (STBC) for a 3D microscopic RVE subjected to high strain rate deformation in explicit FEM simulation by using the characteristics method of traveling waves. The advantages of the STBC are discussed in comparison with time-dependent averaged results of examples using PBC. The proposed STBC offers significant advantages over conventional PBC in the RVE-based analysis of heterogeneous materials.
2
Li, Chang-Jiu, Wen-Ya Li, and H. Fukanuma. "Impact Fusion Phenomenon During Cold Spraying of Zinc." In ITSC2004, edited by Basil R. Marple and Christian Moreau. ASM International, 2004. http://dx.doi.org/10.31399/asm.cp.itsc2004p0335.
Full textAbstract:
Abstract In the present study, the zinc powder (-48 µm) was used to deposit coating by cold spraying using nitrogen as driving gas at different operating temperatures. The microstructure of the deposited coating was characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy (TEM) to reveal the occurrence of fusion during the impacting of spray particles. The selected area electron diffraction analysis was used to examine the microstructural feature at the near interface areas between the deposited particles in zinc coating. Numerical simulation was carried out to estimate the particle temperature increment during the impacting process. The simulation result suggests a possibility of the melting of zinc particles at the localized contact region on impact. The examination of the coating surface provided the evidence for the occurrence of the melting of spray particles on impact. The experimental results showed that the cold-sprayed zinc coating presented a dense microstructure. The nano-structural phase was formed at the near interface areas between deposited particles in zinc coating, while the grains in the size of micrometers similar to that in the powder were retained in the inside of the particles in the coating. Moreover, the TEM observation evidently showed that the amorphous phase was formed at the interface areas between the particles. It can be considered that the amorphous phase in the coating was formed through subsequent rapid solidification of the melted material on impact. This fact provided further evidence to the occurrence of localized melting during impacting of spray particles.
3
Owolabi, Gbadebo, Daniel Odoh, Akindele Odeshi, and Horace Whitworth. "Modeling and Simulation of Adiabatic Shear Bands in AISI 4340 Steel Under Impact Loads." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-89084.
Full textAbstract:
In this study, the effects of microstructure and strain rate on the occurrence and failure of adiabatic shear bands in AISI 4340 steel under high velocity impact loads are investigated using finite element analysis and experimental tests. The shear band generated due to impact load was divided into some set of elements separated by nodes using finite element method in ABAQUS environment with initial and boundary conditions specified. The material properties were assumed to be lower at the second element set in order to initialize the adiabatic shear bands. The strain energy density for each successive node was calculated successively starting from the first element where initial boundary condition, initial strain hardening constant, and stress resistance had been specified. As the load time is increased, its corresponding effect on the localized shear deformation and width of the adiabatic shear band was also determined. The finite element model was used to determine the maximum stress, the strain hardening, the thermal softening, and the time to reach critical strain for formation of adiabatic shear bands. Experimental results show that deformed bands were formed at low strain rates and there was a minimum strain rate required for formation of transformed band in the alloy. The experimental results also show that cracks were initiated and propagated along transformed bands leading to fragmentation under the impact loading. The susceptibility of the adiabatic shear bands to cracking was markedly influenced by strain-rates and the initial material microstructures. The numerical results obtained were compared with the experimental results obtained for the AISI 4340 steel under high strain-rate loading in compression using split impact Hopkinson bars. A good agreement between the experimental and simulation results are also obtained.
4
Dou, Yangqing, Yucheng Liu, Wilburn Whittington, and Jonathan Miller. "Experimental Calibration of ISV Damage Model Constants for Pure Copper for High-Speed Impact Simulation." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65690.
Full textAbstract:
Coefficients and constants of a microstructure-based internal state variable (ISV) plasticity damage model for pure copper have been calibrated and used for damage modeling and simulation. Experimental stress-strain curves obtained from Cu samples at different strain rate and temperature levels provide a benchmark for the calibration work. Instron quasi-static tester and split-Hopkinson pressure bar are used to obtain low-to-high strain rates. Calibration process and techniques are described in this paper. The calibrated material model is used for high-speed impact analysis to predict the impact properties of Cu. In the numerical impact scenario, a 100 mm by 100 mm Cu plate with a thickness of 10 mm will be penetrated by a 50 mm-long Ni rod with a diameter of 10mm. The thickness of 10 mm was selected for the Cu plate so that the Ni-Cu penetration through the thickness can be well observed through the simulations and the effects of the ductility of Cu on its plasticity deformation during the penetration can be displayed. Also, that thickness had been used by some researchers when investigating penetration mechanics of other materials. Therefore the penetration resistance of Cu can be compared to that of other metallic materials based on the simulation results obtained from this study. Through this study, the efficiency of this ISV model in simulating high-speed impact process is verified. Functions and roles of each of material constant in that model are also demonstrated.
5
Ghumman, Umar Farooq, Akshay Iyer, Rabindra Dulal, Aaron Wang, Joydeep Munshi, TeYu Chien, Ganesh Balasubramanian, and Wei Chen. "A Spectral Density Function Approach for Design of Organic Photovoltaic Cells." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-86154.
Full textAbstract:
Organic Photovoltaic Cells (OPVCs), having received significant attention over the last decade, are yet to be established as viable alternatives to conventional solar cells due to their low power conversion efficiency (PCE). Complex interactions of several phenomena coupled with the lack of understanding regarding the influence of fabrication conditions and nanostructure morphology have been major barriers to realizing higher PCE. To this end, we propose a computational microstructural design framework addressing the Processing–Structure–Performance (PSP) linkages for designing the active layer of P3HT:PCBM based OPVCs conforming to bulk heterojunction architecture. The framework pivots around the Spectral Density Function (SDF), a frequency space microstructure characterization and reconstruction methodology, for microstructure design representation. Nanostructure images obtained by novel Scanning Tunneling Microscopy are used to validate the applicability of SDF for representing active layer morphology in OPVCs. SDF enables a low dimensional microstructure representation that is crucial in formulating a parametrized microstructure optimization scheme. A level-cut Gaussian Random Field (governed by SDF) technique is used to generate reconstructions that serve as Representative Volume Elements (RVEs) for structure-performance simulations. A novel structure-performance simulation approach is developed using physics-based performance metric, Incident Photon to Converted Electron (IPCE) ratio, to account for the impact of microstructural features on OPVC performance. Finally, an SDF based computational IPCE optimization study using metamodels created using design of computer experiments over three design variables results in 36.75% increase in IPCE, underlining the efficacy of proposed design framework.
6
Wang, Zhuo, Pengwei Liu, Zhen Hu, and Lei Chen. "Simulation-Based Process Optimization of Metallic Additive Manufacturing Under Uncertainty." In ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/detc2019-97492.
Full textAbstract:
Abstract The presence of various uncertainty sources in metal-based additive manufacturing (AM) process prevents producing AM products with consistently high quality. Using electron beam melting (EBM) of Ti-6A1-4V as an example, this paper presents a data-driven framework for process parameters optimization using physics-informed computer simulation models. The goal is to identify a robust manufacturing condition that allows us to constantly obtain equiaxed materials microstructures under uncertainty. To overcome the computational challenge in the robust design optimization under uncertainty, a two-level data-driven surrogate model is constructed based on the simulation data of a validated high-fidelity multi-physics AM simulation model. The robust design result, indicating a combination of low preheating temperature, low beam power and intermediate scanning speed, was acquired enabling the repetitive production of equiaxed-structure products as demonstrated by physics-based simulations. Global sensitivity analysis at the optimal design point indicates that among the studied six noise factors, specific heat capacity and grain growth activation energy have largest impact on the microstructure variation.
7
Gianetto, J. A., F. Fazeli, Y. Chen, B. Shalchi-Amirkhiz, and T. Smith. "Microstructure and Toughness of Simulated Grain Coarsened Heat Affected Zones in X80 Pipe Steels." In 2014 10th International Pipeline Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/ipc2014-33254.
Full textAbstract:
The objective of this research was to gain a better understanding of the influence of essential welding variables on microstructure and properties of the grain-coarsened heat-affected zone (GCHAZ) regions formed in pipeline girth welds. In this study, thermal simulation techniques were used to provide a detailed evaluation of the GCHAZ microstructure evolution and intrinsic toughness for two different pipe steels subjected to known welding thermal cycles. The continuous cooling transformation (CCT) diagrams for the GCHAZ were determined by means of dilatometric techniques with a peak temperature (Tp) = 1350°C and a range of cooling times (Δt800–500 = ∼1 to 100 s). The transformation start and finish temperatures were used to create GCHAZ CCT diagrams for two X80 pipe steels. To further assist with the interpretation of CCT results both light optical microscopy (LOM) and microhardness surveys were used. The results revealed that transformation to predominantly low carbon lath martensite or fine bainite occurred for short cooling times, while bainite formed at intermediate cooling times and upper or granular bainite was obtained for longer cooling times. Some of the detailed features of these simulated GCHAZ microstructures were characterized by scanning electron and transmission electron microscopy (SEM and TEM) in order to better quantify the phases in selected samples. This analysis clearly indicates that despite similar carbon equivalents (CEs), the response of each steel to given GCHAZ thermal was quite different. The GCHAZ Charpy-V-notch (CVN) impact energy transition curves for the series of single thermal cycles with cooling times, Δt800–500 = 6, 15 and 30 s and were compared against those obtained for the respective pipe steels. The results showed that there were upward shifts in transition temperature for the simulated GCHAZs relative to the respective pipe steels. This overall reduction of notch toughness was attributed to variations in microstructural features for the respective GCHAZs.
8
Ding, Yulong, Xiaotao T. Bi, and David P. Wilkinson. "3-D Numerical Simulation of Gas-Liquid Flow in a Minichannel With a Non-Uniform GDL Surface." In ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30341.
Full textAbstract:
Gas-liquid two-phase flow in rectangular minichannels of polymer-electrolyte membrane fuel cells (PEMFCs) has a major impact on the fuel cell performance and durability. Different from traditional two-phase flow in other applications, water in the PEMFCs is introduced into the minichannel from the gas diffusion layers (GDLs) through random pores of different sizes. Meanwhile, the four channel surfaces may have different wettabilities due to the different materials used. Thus, the microstructure of GDLs and the surface wettability should be considered in investigating the two-phase flow in PEMFC channels. One challenge in simulating PEMFCs is that, full consideration of detailed microstructure of GDL needs extremely large computational time. In this work, we simplified the microstructure of GDL to a number of representative pores on the 2D GDL surface. A 3-D minichannel with 1.0 mm × 1.0 mm square cross section and 100 mm long was used in the simulation. Operating conditions and material properties were selected according to realistic fuel cell operating conditions. Volume of fluid (VOF) method was employed to explicitly track the droplet surfaces emerging from the non-uniform GDLs. Simulation results show that, as the flow develops along the channel, the flow pattern evolves from corner flow on the bottom and side wall to corner flow on the top wall, annular flow and slug flow. The effects of liquid injection rates were studied, and it is found that the high liquid flow rate would accelerate the flow pattern development. The effect of wall surface material wettability was also studied by changing the hydrophobicity of GDL surface and side walls, separately. Simulation results show that the material wettability has a strong impact on the two-phase flow pattern, with a more hydrophilic side walls and/or a more hydrophobic GDL surface being more beneficial for expelling water out of the channel.
9
Mandal, Madhumanti, Warren J. Poole, Thomas Garcin, Matthias Militzer, and Laurie Collins. "Mechanical Behaviour of Intercritically Reheated Coarse-Grained Heat Affected Zone in High Strength Line Pipe Steels." In 2018 12th International Pipeline Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/ipc2018-78317.
Full textAbstract:
Multipass welding of high strength steels used for fabrication and joining of transmission pipelines presents a number of metallurgical challenges. A key concern is both the strength and toughness of the heat affected zone (HAZ) adjacent to both seam and girth welds. In this work, a systematic study has been conducted on regions of the heat affected zone in the base metal where the first welding pass produces a thermal excursion which results in a coarse-grained heat affected zone (CGHAZ). The subsequent weld pass involves intercritical annealing of this region, i.e. a microstructure associated with intercritically reheated coarse grain heat affected zone (ICCGHAZ). The small ICCGHAZ region is often identified as being particularly susceptible to crack initiation. This work was undertaken to understand microstructure development in this zone and how the ICCGHAZ may affect the overall performance of the HAZ. Gleeble thermomechanical simulations have been conducted to produce bulk samples representative of different welding scenarios. Charpy impact tests and tensile tests have been performed over a range of temperatures. It was found that when a continuous necklace of martensite-austenite islands form on the prior austenite grain boundaries (i.e. for a M/A fraction of ≈10%), the Charpy impact toughness energy is dramatically decreased and the ductile brittle transition temperature is significantly raised. Detailed studies on the secondary cracks have been conducted to examine the fracture mechanisms in the different microstructures. The results show that the lower bainite microstructures obtained after the 1st thermal treatment, representative of CGHAZ have excellent impact properties. The impact toughness of the microstructures typical of ICCGHAZ is strongly dependent on the composition as well as morphology and spatial distribution of the resulting martensite-austenite (M/A) islands transformed from inter-critically formed austenite. This zone can play a significant role in fracture initiation and thus needs to be considered in alloy and welding process designs.
10
Bae, G., K. Kang, H. Na, C. Lee, and H. J. Kim. "Thermally Enhanced Kinetic Sprayed Titanium Coating: Microstructure and Property Improvement for Potential Applications." In ITSC2009, edited by B. R. Marple, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima, and G. Montavon. ASM International, 2009. http://dx.doi.org/10.31399/asm.cp.itsc2009p0290.
Full textAbstract:
Abstract In the present investigation, thermally enhanced kinetic spraying of titanium onto mild steel substrates is carried out in conjunction with powder preheating to obtain a dense coating using low-cost nitrogen as the process gas. Prior to this, a prototype model was developed for process optimization based on numerically approximated adhesion factors. The simulation results show that adiabatic shear instability accelerated by thermal energy and subsequent particle impact leads to the formation of an enhanced thermal boost-up zone that closely correlates with deposition behavior and coating properties. It is thus shown that the deposition efficiency of titanium can be more than 90% and porosity less than 1% when nitrogen gas is used for cold spraying.
Reports on the topic "Microstructure impact simulation results"
1
Oliynyk, Kateryna, and Matteo Ciantia. Application of a finite deformation multiplicative plasticity model with non-local hardening to the simulation of CPTu tests in a structured soil. University of Dundee, December 2021. http://dx.doi.org/10.20933/100001230.
Full textAbstract:
In this paper an isotropic hardening elastoplastic constitutive model for structured soils is applied to the simulation of a standard CPTu test in a saturated soft structured clay. To allow for the extreme deformations experienced by the soil during the penetration process, the model is formulated in a fully geometric non-linear setting, based on: i) the multiplicative decomposition of the deformation gradient into an elastic and a plastic part; and, ii) on the existence of a free energy function to define the elastic behaviour of the soil. The model is equipped with two bonding-related internal variables which provide a macroscopic description of the effects of clay structure. Suitable hardening laws are employed to describe the structure degradation associated to plastic deformations. The strain-softening associated to bond degradation usually leads to strain localization and consequent formation of shear bands, whose thickness is dependent on the characteristics of the microstructure (e.g, the average grain size). Standard local constitutive models are incapable of correctly capturing this phenomenon due to the lack of an internal length scale. To overcome this limitation, the model is framed using a non-local approach by adopting volume averaged values for the internal state variables. The size of the neighbourhood over which the averaging is performed (characteristic length) is a material constant related to the microstructure which controls the shear band thickness. This extension of the model has proven effective in regularizing the pathological mesh dependence of classical finite element solutions in the post-localization regime. The results of numerical simulations, conducted for different soil permeabilities and bond strengths, show that the model captures the development of plastic deformations induced by the advancement of the cone tip; the destructuration of the clay associated with such plastic deformations; the space and time evolution of pore water pressure as the cone tip advances. The possibility of modelling the CPTu tests in a rational and computationally efficient way opens a promising new perspective for their interpretation in geotechnical site investigations.
2
Birchmore, Roger. Medium-density Dwellings in Auckland and the Building Regulations. Unitec ePress, July 2018. http://dx.doi.org/10.34074/ocds.0822.
Full textAbstract:
National thermal standards have historically been set to minimise winter heating energy in detached houses. It is uncertain whether these standards are optimal for the increasing number of joined, medium-density dwellings when summer and winter conditions are considered. Using freely available software, annual heating energy use and summertime peak temperatures were calculated for a number of versions of detached and joined dwellings offering the same occupied volume and window areas. Initial results indicated that, as expected, the joined dwellings required less heating energy. The detached house exhibited a higher peak summertime temperature but a lower overall average daily temperature. Interventions such as changing insulation, glazing areas and ventilation were calculated to reduce summertime temperatures in the joined dwelling. Increasing ventilation provided the greatest improvement particularly during the sensitive sleeping hours. Changes to clauses H1 Energy Efficiency, G4 ventilation and G6 Airborne and Impact Sound are recommended if these early findings are confirmed in a more complex simulation.
3
Williams, Michael, Marcial Lamera, Aleksander Bauranov, Carole Voulgaris, and Anurag Pande. Safety Considerations for All Road Users on Edge Lane Roads. Mineta Transportation Institute, March 2021. http://dx.doi.org/10.31979/mti.2021.1925.
Full textAbstract:
Edge lane roads (ELRs), also known as advisory bike lanes or advisory shoulders, are a type of shared street where two-way motor vehicle (MV) traffic shares a single center lane, and edge lanes on either side are preferentially reserved for vulnerable road users (VRUs). This work comprises a literature review, an investigation of ELRs’ operational characteristics and potential road user interactions via simulation, and a study of crash data from existing American and Australian ELRs. The simulation evaluated the impact of various factors (e.g., speed, volume, directional split, etc.) on ELR operation. Results lay the foundation for a siting criterion. Current American siting guidance relies only upon daily traffic volume and speed—an approach that inaccurately models an ELR’s safety. To evaluate the safety of existing ELRs, crash data were collected from ELR installations in the US and Australia. For US installations, Empirical Bayes (EB) analysis resulted in an aggregate CMF of .56 for 11 installations observed over 8 years while serving more than 60 million vehicle trips. The data from the Australian State of Queensland involved rural one-lane, low-volume, higher-speed roads, functionally equivalent to ELRs. As motor vehicle volume grows, these roads are widened to two-lane facilities. While the authors observed low mean crash rates on the one-lane roads, analysis of recently converted (from one-lane to two-lane) facilities showed that several experienced fewer crashes than expected after conversion to two-lane roads.
4
Konstantinou, Theodora, Donghui Chen, Konstantinos Flaris, Kyubyung Kang, Dan Daehyun Koo, Jonathon Sinton, Konstantina Gkritza, and Samuel Labi. A Strategic Assessment of Needs and Opportunities for the Wider Adoption of Electric Vehicles in Indiana. Purdue University, 2022. http://dx.doi.org/10.5703/1288284317376.
Full textAbstract:
The primary objective of this study was to assess the challenges and opportunities associated with the provision of appropriate infrastructure to support electric vehicle (EV) operations and electrification across Indiana. A secondary objective of this study was to develop a strategic plan for INDOT that outlines new business opportunities for developing EV charging stations. To achieve these objectives, the project team assessed current and emerging trends in EV operations, particularly EV charging infrastructure and EV demand forecasting. They also examined opportunities for the strategic deployment of EV charging stations by identifying EV infrastructure deficit areas; investigated the impact of EV adoption on highway revenue and the feasibility of new revenue structures; and evaluated strategic partnerships and business models. The agent-based simulation model developed for future long distance EV trip scenarios enables INDOT to identify EV energy deficient areas for current and future energy charging demand scenarios, and it can support Indiana’s strategic plans for EV charging infrastructure development. The results of the revenue impact analysis can inform INDOT’s revenue model. The estimations of the recovery EV fee, the VMT fee, and pay-as-you-charge fee that break-even the fuel tax revenue loss can be used by INDOT in pilot programs to capture users’ perspectives and estimate appropriate fee rates and structures. The insights obtained from the stakeholder interviews can be used to enhance preparedness for increasing EV adoption rates across vehicle classes and to strengthen the engagement of different entities in the provision of charging infrastructure.
5
Floyd, Jason, and Daniel Madrzykowski. Analysis of a Near Miss in a Garden Apartment Fire – Georgia 2022. UL's Fire Safety Research Institute, October 2022. http://dx.doi.org/10.54206/102376/rsfd6862.
Full textAbstract:
On February 9, 2022, Cobb County Fire and Emergency Services responded to a fire in a ground floor unit in a garden apartment building. At arrival, the fire was a post-flashover fire in a bedroom. Initial fire control was attempted by an interior fire attack team which was unable to quickly locate the fire. Exterior suppression through the bedroom window was started prior to discovery of the fire by the interior team. Shortly after fire discovery by the internal team, a mayday was called. Four firefighters from the interior fire attack team received first and second degree burns. This report analyzes photographic, video, and written documentation from the incident to evaluate the timeline of the incident and to assess the fire conditions present. Computer modeling using the Fire Dynamics Simulator (FDS) was performed to provide further insight into the fire conditions and the impact of decisions and actions on the fire ground. Additionally, data from a full scale fire test of a similar fire in a similar structure was used to provide additional insight. Four FDS simulations were performed in support of the analysis. These included a simulation of the event as it unfolded and three simulations looking at the impact of alternate tactics which included: initial exterior attack prior to entry, the use of a smoke curtain to protect the building exit path, and interior only attack. FDS simulations provided insight on the heat present in the apartment during the fire and the impact of the interior and exterior suppression on conditions inside the apartment. Full scale test data of a similar fire showed similar behavior to the FDS predictions and gives credence to the FDS results. Results of the analysis suggest that injuries resulted from the length of time the interior attack team was present inside the apartment before actions were taken to reduce the severity of the fire. Six contributing factors were identified including size-up, communication and accountability, delayed exterior attack, lack of entry hall protection, the apartment layout and construction, thermal imager use, and mayday procedures and training. The last contributing factor was a positive contribution that helped avoid more serious injuries. Based on the contributing factors, five recommendations were made that include improved size-up, exterior fire control to prevent exterior spread, protection of exit pathways, basing fire ground tactics on known information, and recognizing when a change in tactics is needed.
6
Allen, Luke, Robert Haehnel, and Yonghu Wenren. South Pole Station snowdrift model. Engineer Research and Development Center (U.S.), August 2022. http://dx.doi.org/10.21079/11681/44943.
Full textAbstract:
The elevated building at Scott-Amundsen South Pole Station was designed to mitigate the effects of windblown snow on it and the surrounding infrastructure. Because the elevation of the snow surface increases annually, the station is periodically lifted on its support columns to maintain its design height above the snow surface. To assist with planning these lifts, this effort developed a computational model to simulate snowdrift formation around the elevated building. The model uses computational fluid dynamics methods and synthetic wind record generation derived from statistical analysis of meteorological data. Simulations assessed the impact of several options for the lifting operation on drifts surrounding the elevated building. Simulation results indicate that raising the eastern-most building section (Pod A), or the entire station all at once, can reduce drift accumulation rates over the nearby arches structures. Long-term analyses, spanning 5–6 years, determine whether an equilibrium drift condition may be reached after a long period of undisturbed drift development. These simulations showed that after about 6 years, the rate of growth of the upwind drift slows, appearing to approach an equilibrium condition. However, the adjacent drifts were still increasing in depth at a roughly linear rate, indicating that equilibrium for those drifts was still several seasons away.
7
Diahyleva, Olena S., Igor V. Gritsuk, Olena Y. Kononova, and Alona Y. Yurzhenko. Computerized adaptive testing in educational electronic environment of maritime higher education institutions. [б. в.], June 2021. http://dx.doi.org/10.31812/123456789/4448.
Full textAbstract:
The article is devoted to the organization of modern learning process, namely the use of innovative technologies – computerized adaptive testing in educational electronic environment of maritime higher education institutions. The example of educational electronic environment is presented in the article on LMS Moodle. The provided new technological and methodological opportunities are a priority in the developed methods of control and testing of knowledge, skills and abilities of students. Comparative characteristic of using computerized adaptive testing in educational electronic environment is given in the article according to different criteria: the role of tests in the learning process; methods of training; equipment; presence of the problems in educational process; level of its control and learning outcomes. The paper also presents examples of activities to form communicative competency of future maritime professionals. Types of adaptive tests are listed in the paper. The research activities were done by second year cadets of ship engineering department of Maritime College of Kherson State Maritime Academy. The experiment was devoted to the formation of communicative competence with the help of electronic environment of maritime higher education institution. The results of experiment proved positive impact of computerized adaptive testing on communicative competence of future ship engineers. Further investigation of adaptive testing can also be done for learning system of maritime education establishments using simulation technologies of virtual, augmented and mixed realities.
8
Tawfik, Aly, Deify Law, Juris Grasis, Joseph Oldham, and Moe Salem. COVID-19 Public Transportation Air Circulation and Virus Mitigation Study. Mineta Transportation Institute, June 2022. http://dx.doi.org/10.31979/mti.2021.2036.
Full textAbstract:
COVID-19 may have forever changed our world. Given the limited space and air circulation, potential infections on public transportation could be concerningly high. Accordingly, this study has two objectives: (1) to understand air circulation patterns inside the cabins of buses; and (2) to test the impact of different technologies in mitigating viruses from the air and on surfaces inside bus cabins. For the first objective, different devices, metrics and experiments (including colored smoke; videotaping; anemometers; pressure differentials; particle counts; and 3D numerical simulation models) were utilized and implemented to understand and quantify air circulation inside different buses, with different characteristics, and under different operating conditions (e.g. with windows open and shut). For the second objective, three different live prokaryotic viruses were utilized: Phi6, MS2 and T7. Various technologies (including positive pressure environment inside the cabin, HEPA filters with different MERV ratings, concentrated UV exposure with charged carbon filters in the HVAC systems, center point photocatalytic oxidation technology, ionization, and surface antiviral agents) were tested to evaluate the potential of mitigating COVID-19 infections via air and surfaces in public transportation. The effectiveness of these technologies on the three live viruses was tested in both the lab and in buses in the field. The results of the first objective experiments indicated the efficiency of HVAC system designs, where the speed of air spread was consistently much faster than the speed of air clearing. Hence, indicating the need for additional virus mitigation from the cabin. Results of the second objective experiments indicated that photocatalytic oxidation inserts and UVC lights were the most efficient in mitigating viruses from the air. On the other hand, positive pressure mitigated all viruses from surfaces; however, copper foil tape and fabrics with a high percentage of copper mitigated only the Phi6 virus from surfaces. High-temperature heating was also found to be highly effective in mitigating the different viruses from the vehicle cabin. Finally, limited exploratory experiments to test possible toxic by-products of photocatalytic oxidation and UVC lights inside the bus cabin did not detect any increase in levels of formaldehyde, ozone, or volatile organic compounds. Implementation of these findings in transit buses, in addition to the use of personal protective equipment, could be significantly valuable for protection of passengers and drivers on public transportation modes, possibly against all forms of air-borne viruses.
9
Tawfik, Aly, Deify Law, Juris Grasis, Joseph Oldham, and Moe Salem. COVID-19 Public Transportation Air Circulation and Virus Mitigation Study. Mineta Transportation Institute, June 2022. http://dx.doi.org/10.31979/mti.2022.2036.
Full textAbstract:
COVID-19 may have forever changed our world. Given the limited space and air circulation, potential infections on public transportation could be concerningly high. Accordingly, this study has two objectives: (1) to understand air circulation patterns inside the cabins of buses; and (2) to test the impact of different technologies in mitigating viruses from the air and on surfaces inside bus cabins. For the first objective, different devices, metrics and experiments (including colored smoke; videotaping; anemometers; pressure differentials; particle counts; and 3D numerical simulation models) were utilized and implemented to understand and quantify air circulation inside different buses, with different characteristics, and under different operating conditions (e.g. with windows open and shut). For the second objective, three different live prokaryotic viruses were utilized: Phi6, MS2 and T7. Various technologies (including positive pressure environment inside the cabin, HEPA filters with different MERV ratings, concentrated UV exposure with charged carbon filters in the HVAC systems, center point photocatalytic oxidation technology, ionization, and surface antiviral agents) were tested to evaluate the potential of mitigating COVID-19 infections via air and surfaces in public transportation. The effectiveness of these technologies on the three live viruses was tested in both the lab and in buses in the field. The results of the first objective experiments indicated the efficiency of HVAC system designs, where the speed of air spread was consistently much faster than the speed of air clearing. Hence, indicating the need for additional virus mitigation from the cabin. Results of the second objective experiments indicated that photocatalytic oxidation inserts and UVC lights were the most efficient in mitigating viruses from the air. On the other hand, positive pressure mitigated all viruses from surfaces; however, copper foil tape and fabrics with a high percentage of copper mitigated only the Phi6 virus from surfaces. High-temperature heating was also found to be highly effective in mitigating the different viruses from the vehicle cabin. Finally, limited exploratory experiments to test possible toxic by-products of photocatalytic oxidation and UVC lights inside the bus cabin did not detect any increase in levels of formaldehyde, ozone, or volatile organic compounds. Implementation of these findings in transit buses, in addition to the use of personal protective equipment, could be significantly valuable for protection of passengers and drivers on public transportation modes, possibly against all forms of air-borne viruses.
10
Crowley, David E., Dror Minz, and Yitzhak Hadar. Shaping Plant Beneficial Rhizosphere Communities. United States Department of Agriculture, July 2013. http://dx.doi.org/10.32747/2013.7594387.bard.
Full textAbstract:
PGPR bacteria include taxonomically diverse bacterial species that function for improving plant mineral nutrition, stress tolerance, and disease suppression. A number of PGPR are being developed and commercialized as soil and seed inoculants, but to date, their interactions with resident bacterial populations are still poorly understood, and-almost nothing is known about the effects of soil management practices on their population size and activities. To this end, the original objectives of this research project were: 1) To examine microbial community interactions with plant-growth-promoting rhizobacteria (PGPR) and their plant hosts. 2) To explore the factors that affect PGPR population size and activity on plant root surfaces. In our original proposal, we initially prqposed the use oflow-resolution methods mainly involving the use of PCR-DGGE and PLFA profiles of community structure. However, early in the project we recognized that the methods for studying soil microbial communities were undergoing an exponential leap forward to much more high resolution methods using high-throughput sequencing. The application of these methods for studies on rhizosphere ecology thus became a central theme in these research project. Other related research by the US team focused on identifying PGPR bacterial strains and examining their effective population si~es that are required to enhance plant growth and on developing a simulation model that examines the process of root colonization. As summarized in the following report, we characterized the rhizosphere microbiome of four host plant species to determine the impact of the host (host signature effect) on resident versus active communities. Results of our studies showed a distinct plant host specific signature among wheat, maize, tomato and cucumber, based on the following three parameters: (I) each plant promoted the activity of a unique suite of soil bacterial populations; (2) significant variations were observed in the number and the degree of dominance of active populations; and (3)the level of contribution of active (rRNA-based) populations to the resident (DNA-based) community profiles. In the rhizoplane of all four plants a significant reduction of diversity was observed, relative to the bulk soil. Moreover, an increase in DNA-RNA correspondence indicated higher representation of active bacterial populations in the residing rhizoplane community. This research demonstrates that the host plant determines the bacterial community composition in its immediate vicinity, especially with respect to the active populations. Based on the studies from the US team, we suggest that the effective population size PGPR should be maintained at approximately 105 cells per gram of rhizosphere soil in the zone of elongation to obtain plant growth promotion effects, but emphasize that it is critical to also consider differences in the activity based on DNA-RNA correspondence. The results ofthis research provide fundamental new insight into the composition ofthe bacterial communities associated with plant roots, and the factors that affect their abundance and activity on root surfaces. Virtually all PGPR are multifunctional and may be expected to have diverse levels of activity with respect to production of plant growth hormones (regulation of root growth and architecture), suppression of stress ethylene (increased tolerance to drought and salinity), production of siderophores and antibiotics (disease suppression), and solubilization of phosphorus. The application of transcriptome methods pioneered in our research will ultimately lead to better understanding of how management practices such as use of compost and soil inoculants can be used to improve plant yields, stress tolerance, and disease resistance. As we look to the future, the use of metagenomic techniques combined with quantitative methods including microarrays, and quantitative peR methods that target specific genes should allow us to better classify, monitor, and manage the plant rhizosphere to improve crop yields in agricultural ecosystems. In addition, expression of several genes in rhizospheres of both cucumber and whet roots were identified, including mostly housekeeping genes. Denitrification, chemotaxis and motility genes were preferentially expressed in wheat while in cucumber roots bacterial genes involved in catalase, a large set of polysaccharide degradation and assimilatory sulfate reduction genes were preferentially expressed.