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1
Davis, Allen G. „Assessing Reliability of Drilled Shaft Integrity Testing“. Transportation Research Record: Journal of the Transportation Research Board 1633, Nr. 1 (Januar 1998): 108–16. http://dx.doi.org/10.3141/1633-14.
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The reliability of an engineering system can be described as the degree of confidence in the system performing as it is designed or intended to do. This can be assessed by a purely subjective, “gut feeling” reaction from the engineer making judgments based on the test results, or it can be expressed mathematically by considering the reliability of individual system components, together with their relative effects on the performance of the total system. Nondestructive testing (NDT), when used in the quality control of drilled shafts, can be viewed from two extremes: either NDT helps engineers confirm that their design and intended performance criteria are being met, or NDT checks that the contractor has supplied the owner with the product for which the owner has paid (material quality, minimal geometric requirements, etc.). NDT methods currently available are more suited to the first scenario (performance specification). This is supported by analysis of the parameters controlling NDT results and by experience in the United States and in the rest of the world.
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Muñiz-Calvente, Miguel, und Alfonso Fernández-Canteli. „Special Issue: Probabilistic Mechanical Fatigue and Fracture of Materials“. Materials 13, Nr. 21 (31.10.2020): 4901. http://dx.doi.org/10.3390/ma13214901.
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When designing structural and mechanical components, general structural integrity criteria must be met in order to ensure a valid performance according to its designed function, that is, supporting loads or resisting any kind of action causing stress and strains to the material without catastrophic failure. For these reasons, the development of solutions to manage the test conditions, failure mechanism, damage evolution, component functionalities and loading types should be implemented. The aim of this Special Issue “Probabilistic Mechanical Fatigue and Fracture of Materials” is to contribute to updating current and future state-of-the-art methodologies that promote an objective material characterization and the development of advanced damage models that ensure a feasible transferability from the experimental results to the design of real components. This is imbricated in some probabilistic background related to theoretical and applied fracture and fatigue theories, and advanced numerical models applied to some real application examples.
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Haffke, Marcin, Matthias Pahn, Catherina Thiele und Szymon Grzesiak. „Experimental Investigation of Concrete Sandwich Walls with Glass-Fiber-Composite Connectors Exposed to Fire and Mechanical Loading“. Applied Sciences 12, Nr. 8 (12.04.2022): 3872. http://dx.doi.org/10.3390/app12083872.
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Precast concrete sandwich panels (PCSPs) are known for their good thermal, acoustic and structural properties. Severe environmental demands can be met by PCSPs due to their use of highly thermally insulating materials and non-metallic connectors. One of the main issues limiting the wider use of sandwich walls in construction is their unknown fire resistance. Furthermore, the actual behaviour of connectors and insulation in fire in terms of their mechanical performance and their impact on fire spread and the fire resistance of walls is not fully understood. This paper presents an experimental investigation on the structural and thermal behaviour of PCSPs with mineral-wool insulation and glass-fiber-reinforced polymeric bar connectors coupling two concrete wythes. Three full-size walls were tested following the REI certification test procedure for fire walls under fire and vertical eccentric and post-fire mechanical impact load. The three test configurations were adopted for the assessment of the connectors’ fire behaviour and its impact on the general fire resistance of the walls. All the specimens met the REI 120-M criteria. The connectors did not contribute to the fire’s spread and the integrity of the walls was maintained throughout the testing time. This was also confirmed in the most unfavourable test configuration, in which some of the connectors in the inner area of the wall were significantly damaged, and yet the structural connection of the concrete wythes was maintained. The walls experienced heavy heat-induced thermal bowing. The significant contribution of connectors to the stiffness of the wall during fire was observed and discussed.
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Li, Qiong, und Carol A. Rubin. „Virtual Prototype Design and Test-Simplifying the CAD/Analysis Interface“. Applied Mechanics and Materials 284-287 (Januar 2013): 3473–76. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.3473.
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The design of mechanical structural parts is now predominantly a digital process. As an important element of the virtual design cycle, these parts must be tested for their structural integrity using finite element analysis (FEA) software. However, the interface between CAD and FEA is imperfect. The process of preparing CAD models for FEA consumes a great deal of the stress analyst’s time. Existing “automatic” CAD to FEA translators tend to treat all part features as “solid”; this leads to longer computation times and less accurate results for features that can be better characterized as “thin” or “long.” In addition, many features of CAD parts (e.g. fillets and chamfers) are important for their size and shape in the manufactured product, but have relatively little impact on the strength of the part and needlessly complicate the stress analysis—these features are usually removed by the analyst prior to FEA; they may need to be evaluated with additional analyses to test if it is safe to remove them. The Automatic CAD-FEA Interface Project (ACFI), is developing algorithms to make the translation from CAD to FEA seamless and automatic; these algorithms are based on mathematical theory and the principles of theoretical mechanics. This paper presents the latest ACFI advances for (i) automatically evaluating and reworking three dimensional CAD part geometries to prepare them for finite element meshing, (ii) exporting the revised geometries to a preprocessor, and (iii) identifying element type to be associated with each feature geometry. The algorithms used in this work approximate the medial axis transform (MAT) of the CAD part, a “power shape” that represents the three-dimensional solid part. This part can then be evaluated for its geometric properties. This approach has been shown to be a robust method for shape interrogation of three dimensional geometries.
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Karolak-Michalska, Magdalena. „Byłe republiki ZSRR wobec aneksji Krymu do Rosji – analiza porównawcza reakcji państw“. Studia Gdańskie. Wizje i rzeczywistość XIV (03.06.2018): 333–48. http://dx.doi.org/10.5604/01.3001.0015.5411.
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The aim of the article is to analyze the reaction of the former USSR towards the annexation of the Crimea to Russia. The author points out that the crisis Ukrainian-Russian met a series of reactions, which were particularly important response to those located in the immediate vicinity of Russia. Violation of the integrity of the borders of Ukraine provoked a wave of unrest in the region of the former republics of the communist empire, which faced a need to respond to the rapidly changing political reality. Analyzing the responses of individual countries, the author concludes that either option of the conflicting parties, it was the first test for the condition of the political and economic policies of particular countries, and secondly verified relations with Russia, revealing interdependencies and concerns, and also gave Kremlin authorities with information on how much they can afford to continue violating international order.
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Abbassi, Amira, Ali Trabelsi, Sofien Akrichi und Noureddine Ben Yahia. „Assessment of cylindricity and roughness tolerances of holes drilled in marble using multiple regression and artificial intelligence“. Advances in Mechanical Engineering 13, Nr. 8 (August 2021): 168781402110406. http://dx.doi.org/10.1177/16878140211040647.
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The Calacatta-Carrara marble is widely used due to its excellent physico-chemical characteristics and attractive aspect. However, the sensitivity of this materiel, when performing delicate manufacturing operations, presents for the engineers a hard challenge to overcome. This issue is mainly encountered with complex shapes of parts, for which it is difficult to preserve surface integrity and avoid geometric defects. The paper aims at finding out optimal drilling parameters of cutting in the Calacatta-Carrara white marble material, in order to minimize the holes cylindricity (HC) and surface roughness (HR) using six controlled operating factors, namely, the rotation speed ( N), the feed speed ( F), the drill bit diameter (BD), the drill bit height (BH), the number of pecking cycles ( P), and the drilling depth (DD). The experimental design uses a [Formula: see text] fractional factorial plan that is replicated once for cost consideration. The optimization process, that is, minimum cylindricity and roughness tolerances, is carried out using the Gray Relational Analysis (GRA) technique. Numerical modeling of machining parameters is performed using Multi-Layer Perceptron Artificial Neural Network (MLP ANN) and Multiple Regression Model (MR) to predict surface quality. For the sake of completeness these two models were compared in terms of fitness and predictability. The models were assessed statistically using the correlation coefficient. Results showed that either solution predicts a roughness tolerance which is in good agreement with the test data (both R-sq.(adj.) and R-sq.(pred.) >94%). However, the holes cylindricity tolerance response was shown to be superior with MLP-ANN model (R-sq.(adj.) 50.64% and R-sq.(pred.) 48.67%). The GRA analysis shows that minimum cylindricity and roughness are met when N and F are set high, BD and BH low, P high and DD low.
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Salem, Ahmed Z. „Using Glass Mat Thermoplastic as Automotive Bumper’s Material to Enhance Pedestrian Safety“. Advanced Materials Research 875-877 (Februar 2014): 455–61. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.455.
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The usage of softer systems in automotive bumper is a growing trend currently especially to serve the pedestrians safety function. The term softer here does refer to the bumper system’s dynamic behavior rather than its material’s flexure or tension modules. However, the usage of such softer systems would raise issues of structural integrity of the bumper during crash. There is a strong drive currently to adopt materials such as glass mat thermoplastic (GMT), high-strength sheet molding compound (SMC) for the bumper material and plastic polypropylene (PEP) for the bumper holders [1, 2, 3] in this regard. While both the GMT and SMC do enhance the pedestrian safety condition, they both show plastic deformation at crash, even in low-speed scenarios [2, 3]. The PEP holders react only as shock absorbers and act like mechanical fuses to be destroyed in car crash, preventing the main bumper from being damaged [4]. In this paper, we propose a remedy for this problem by changing the common system that the GMT and SMC materials are usually fitted at. We propose coating the bumper beam with a Rubber padding layer that eliminates the plastic strain at low-speed crash. We also examine the behavior of the PEP during such crash scenarios. We present here the results of a low-speed head-on automotive-pedestrian crash simulation scenario for these material models, using the explicit dynamics finite element code LS-DYNA within ANSYS integration setting. A simplified parameterized finite element model of the Ford Crown Victoria car’s bumper form is used in several crash simulations that are carried out to test the validity of this modified bumper system. Based on the results of these tests, we show that, applying the Rubber coating material for the GMT and SMC bumper beams eliminates the plastic stains at low-speed crash.
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Lee, J. H., S. K. Hong, H. C. Hur und Y. J. Choi. „Improvement of the resolution in direct membrane integrity test by controlling solution surface tension“. Water Science and Technology 59, Nr. 11 (01.06.2009): 2205–11. http://dx.doi.org/10.2166/wst.2009.251.
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Membrane-based treatment technologies have been introduced as a promising tool for the removal of water-borne pathogens. To ensure successful application of membrane processes, the integrity of the membrane system should be maintained. Related with evaluation of the membrane integrity, USEPA guidance recommends pressure-based membrane integrity (MIT). Based on the bubble point theory, the ability of detecting smallest integrity breakage during the MIT is defined as “Resolution”. However, the response to remarkably small breach demands significantly high initial test pressure of the pressure decay test. In this study, the surface tension of the test liquid was controlled to improve the resolution without increasing the corresponding test pressure. Three common chemicals were chosen to control the solution surface tension. It is concluded that 0.1 M of the citric acid can decrease the initial test pressure significantly for the same pore size. Subsequently, the improvement of the resolution with controlled surface tension was confirmed by the results of pressure decay test and marker test.
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Urbano, Jose, Andrej Golowin, Stefan Löhnert und Dieter Bestle. „Mechanical Integrity of Steel Discs with Corrosion Pits“. MATEC Web of Conferences 165 (2018): 04012. http://dx.doi.org/10.1051/matecconf/201816504012.
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Currently, prediction of crack initiation by corrosion pits is only possible by assuming regular geometrical shapes, such as semi-spheres or semi-ellipsoids. Moreover, typical fatigue life diagrams associate the crack initiation life with geometrical features, such as pit depth or aspect ratio, often leading to unsatisfactory correlations due to high pit shape variability and data scatter. In the context of blade-disc fixation in aero engine turbines, this limitation translates into highly conservative life estimations. Therefore, a new crack initiation predictor is formulated based on experimental testing and numerical analysis of 28 artificial corrosion pits. A low-cycle fatigue test campaign is conducted using three-point bending test specimens to simulate maximum takeoff operation conditions of the aero engine and the associated loading of the blade root designed as firtree. An artificial pit is located at the critical point of each test specimen, respectively. The prediction criterion is based on finite element analysis and is formulated as the lowest plastic strain of a plastic region with a certain volume in the corrosion pit. This reference volume is varied until an optimum correlation with experimental crack initiation life is obtained. The criterion shows a superior correlation with crack initiation life compared to pure geometrical parameters such as pit depth.
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Hossiep, Rüdiger, und Sabine Bräutigam. „Tests und Tools“. Zeitschrift für Personalpsychologie 6, Nr. 2 (April 2007): 85–90. http://dx.doi.org/10.1026/1617-6391.6.2.85.
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Zusammenfassung. Vorgestellt wird das IBES (Inventar berufsbezogener Einstellungen und Selbsteinschätzungen), das erste publizierte deutschsprachige Verfahren der Gattung “Integrity Test”. Ziel des Instrumentes ist die Vorhersage kontraproduktiven Verhaltens in Unternehmen (z. B. Absentismus, Diebstahl, Aggression). Die Konstruktion erfolgte in enger Anlehnung an Inhalte prominenter amerikanischer Integrity Tests. Das IBES besteht aus einem einstellungsorientierten Teil mit 60 Items, die den vier Skalen “Vertrauen”, “Geringe Verbreitung unerwünschten Verhaltens”, “Nicht-Rationalisierung” und “Verhaltensabsichten” zugeordnet sind sowie einem eigenschaftsorientierten Teil mit 55 Items, unterteilt in die fünf Skalen “Gelassenheit/Selbstwertgefühl”, “Zuverlässigkeit/Voraussicht”, “Vorsicht”, “Zurückhaltung” und “Konfliktmeidung”. Die Anwendbarkeit des Verfahrens in der Praxis wird insbesondere vor dem Hintergrund der Datenbasis und des Itemmaterials kritisch diskutiert.
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Geisler, Holm, Martin Brueckner, Petra Hofmann, Matthias U. Lehr, Michael Grillberger und Eckhard Langer. „Testing the Mechanical Integrity of On-Chip Interconnects“. EDFA Technical Articles 14, Nr. 2 (01.05.2012): 4–12. http://dx.doi.org/10.31399/asm.edfa.2012-2.p004.
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Abstract The introduction of ultralow-k dielectrics is a recent milestone in the quest for higher clock speeds and lower power consumption in ICs. One tradeoff, however, is that interconnect stacks layered with low-k materials rather than SiO2 are more vulnerable to mechanical damage. This article presents a method that makes it possible to assess the mechanical integrity of interconnect stacks at the wafer level. The new bump-assisted BEOL stability indentation (BABSI) test uses a nanoindentation tool to apply lateral and vertical forces to solder bumps and copper pillars on the wafer surface. By applying appropriate stresses, various aspects of integrity, such as the onset of failure modes or the weakest interface in the stack, can be determined by subsequent SEM/FIB analysis. The authors describe the basic principles of the measurement technique and some of the applications in which it was used.
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Hare, B. A., A. Moyse und H. J. Sue. „Evaluation of Packaging Film Mechanical Integrity Using a Standardized Scratch Test Instrument“. Packaging Technology and Science 25, Nr. 2 (06.08.2011): 85–96. http://dx.doi.org/10.1002/pts.962.
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Roberts, Laura. „The Validation of Using Assessment Tools and a Theory to Mentor Doctoral Students with Integrity and Trustworthiness“. International Journal of Doctoral Studies 15 (2020): 029–56. http://dx.doi.org/10.28945/4475.
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Aim/Purpose: The primary aim of this study was to reveal the assessment tools and a theory preferred to mentor doctoral students with integrity and trustworthiness. The connection between mentors’ feelings of trustworthiness and protégé success were explored. Background: This study examines the concept presented in 1983, 1985, and 1996 by Kram of mentor relations (MR) theory, which illustrates that graduation rates can improve with effective mentoring. In the United States, doctoral programs have low graduation rates. Scholars and researchers agree that doctoral programs must develop ways and means to improve their graduation rates. This researcher examined an extension of Kram’s mentor relations theory by employing the Mentor Integrity and Trustworthiness (MIT) theory, which depicts that mentors with a strong sense of integrity and trustworthiness provide a safe haven for protégés to succeed. As supported by Daloz, a trustworthy mentor provides a safe haven for protégés to take the intellectual risks required to produce an original contribution to the canon of scholarly knowledge in the form of a doctoral dissertation. Methodology: A quantitative research methodology of data collection ensued including the researcher generated MIT scale and the mentors’ perceptions of protégés’ independence (MPPI) scale, a survey to establish acceptable levels of internal consistencies for items on the two scales, a supported evidence of the content validity of the two scales, the researcher’s analysis of the validity of the MIT theory, and a multi-stage sampling method to recruit a research sample of 50 mentors from four universities in the eastern part of the United States from several education-related doctoral programs. The doctoral programs were diverse in terms of selectivity, type of degree, and mentors’ years of experience. Contribution: This research study contributes to existing literature knowledge by generating the relationship between mentors’ feelings of trustworthiness and protégés’ success as measured by graduation rate and the number of awards won by protégés. The validation of the mentor integrity and trustworthiness (MIT) scale and the mentor perceptions of protégé independence (MPPI) scale, and the supported evidence of content validity and reliability for both scales will deepen and extend the discussion of doctoral mentoring in higher education. Findings: Results indicated that mentors’ feelings of trustworthiness were correlated with the number of dissertation awards won by protégés and with graduation rates. Graduation rates and dissertation awards rates were not measured directly, but were reported by the mentors. In addition, the researcher found that mentors perceived their protégés to be independent scholars, in general, however, minimally in the area of writing the research methods section of their dissertation. Recommendations for Practitioners: The researcher discussed the practical implications for mentors’ professional development in trustworthiness and integrity. The researcher also provided the Right Angle Research Alignment table to help protégés organize and manage the research methods section of their dissertation. Recommendation for Researchers: Researchers should continue to explore MIT theory with experimental methods to attempt to improve the internal validity of the theory. Impact on Society: The researcher encourages scholars to test the MIT theory in mentoring relationships that go beyond doctoral studies such as mentoring in business and in the arts. The researcher also encourages scholars to test whether the MIT theory is relevant in other kinds of teaching relationships such as coaching and tutoring. Future Research: Further research questions that arise from this study are as follows: What can mentors do to improve their integrity? What can mentors do to improve their feelings of trustworthiness? How can the MIT and MPPI instruments be refined and improved?
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Zhang, Xiaoyu, Lei Wang, Zhenhui Bi, Yintong Guo, Chunhe Yang, Hanzhi Yang und Xin Chang. „Mechanical analysis on cement sheath integrity under asymmetric load“. Journal of Petroleum Exploration and Production Technology 12, Nr. 1 (29.10.2021): 135–46. http://dx.doi.org/10.1007/s13202-021-01346-4.
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AbstractIn large-scale multi-section hydraulic fracturing, the stress environment of wellbore is extreme complex, often causing the unbalanced stress distribution around the wellbore. That poses great challenges to the integrity of the sheath. In this paper, firstly, triaxial compression test and triaxial cyclic test are carried out at 130 °C to study the deformation characteristics of the cement under high temperature. Then based on that, an appropriate plastic mechanics model is established. Finally, the shakedown theory is applied to analyze the model and acquires a maximum cyclic loading under asymmetric stress. The result shows that (1) the well cement, with the increase of load, shows the plastic flow characteristics and can be regarded as an ideal elastic–plastic material under high temperature. (2) During the cyclic loading and unloading process, the "hysteresis loop" becomes denser, which indicates that the accumulation rate of plastic deformation is continuously declining. The main plastic strain appears in the phase of the first loading. (3) The external pressure Pz plays a positive role in the deformation control of the sheath. With the growth of Pz, the maximum cyclic loading Pmax will also increase. (4) Asymmetric stress distribution can significantly affect the bearing capacity of the sheath. If stress difference coefficient λ = 0.3, the Pmax tends to decrease nearly by 50%. With the growth of λ, the negative influence of stress asymmetry reduces gradually. High external pressure is beneficial to reduce the negative impact of the asymmetry. With the growth of λ, the benefit tends to enhance. (5) In engineering practice, if the geology around wellhole showcases the strong asymmetry (the value of λ is large), some steps need to be adopted to reduce the stress concentration.
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Baharom, Zulkhibri, Zamratul Maisarah Mohd Ismail, Maizlinda Izwana Idris und Hasan Zuhudi Abdullah. „The Mechanical Integrity of Self-Healing Coating Embedded with Microencapsulated Vegetable Oil“. Key Engineering Materials 908 (28.01.2022): 612–17. http://dx.doi.org/10.4028/p-v7e94l.
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The challenge of self-healing coating is the mechanical integrity of the coating system embedded with microcapsules. This paper emphasis the mechanical integrity of self-healing coating embedded with microencapsulated vegetable oil (waste sunflower oil). The mechanical integrity of the coating system was determined by the bending and Vickers test. The microencapsulation of waste sunflower oil was successfully produced microcapsules with a mean diameter of 1 μm and a rough shell structure that matchable to embedded in coating matrix. The embedment of microcapsules into the coating matrix has generated self-healing performance with ability to self-heal after 5 days. The mechanical integrity of coating system was increased and demonstrated higher maximum stress (654.25 N/mm2) and higher hardness value (4.40 HV) as compared to the reference sample. It can be concluded that, the microencapsulated waste sunflower oil as an alternative natural vegetable oil to be embedded in the coating system to generate self-healing performance and induce higher mechanical integrity. This finding was able to contribute to the advancement of the future of metal coating industries.
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Zuyok, V., O. Mazurok, O. Godun, M. Chaikovskyi und M. Tretyakov. „Materials Science Analysis of RCCA Structural Materials and Calculations for Lifetime Extension“. Nuclear and Radiation Safety, Nr. 1(101) (13.03.2024): 38–48. http://dx.doi.org/10.32918/nrs.2024.1(101).04.
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The paper considers the possibility of lifetime extending of the rod control cluster assemblies in operation by determining their residual lifetime using an approach that takes into account the actual position of the rod control cluster assembly in the core. Excessive conservatism was introduced by assuming that the immersion of the 10th working group in the core during all fuel campaigns is 70 %, while the actual position is 85-90 %. Taking into account the actual position of the rod control cluster assemblies indicates much less irradiation of the lower, most loaded part of control rod cladding and much less burnup of the 10B compared to 70 % immersion of the rod control cluster assemblies, since they are in the area of lower neutron flux density.
The results of a comprehensive analysis of available studies and test results to determine the phenomena that can potentially approach the achievement of the boundary state of the structural components or limit the lifetime of control rods and rod control cluster assemblies in general are presented. Such phenomena include general corrosion of structural materials (42CrNiMo, Cr18Ni10Ti) (decrease in wall thickness, increased transfer of radioactive corrosion products the coolant); radiation resistance (degradation of mechanical characteristics) of control rod cladding materials (42CrNiMo) and other structural components of the rod control cluster assemblies (42CrNiMo, CrKh18Ni10Ti); radiation resistance of neutron-absorbing materials (B4C, Dy2O3∙TiO2); compatibility of absorbing materials with the control rod cladding.
Based on the results of post-irradiation examinations of control rods tested in research reactors as dummy rods or rod control cluster assembly rods operated in the VVER-1000 core, the following boundary values were established that can be used as criteria for maintaining the integrity of the control rod cladding: maximum fast neutron fluence in the lower, most loaded part of the control rod cladding (in the weld area of the lower end plug and the cladding) should not exceed 34×1021 n/cm2; maximum burnup of the 10B isotope should not exceed 45 %. If these two criteria are met, the possibility of other potentially damaging phenomena is too low.
According to the calculations that use the schedule of changes in the position of the rod control cluster assemblies of the control group and the power of one of the power units during one fuel cycle, one can preliminary conclude that the proposed approach will extend the lifetime of almost all rod control cluster assemblies from 25500 to 38000 hours in the automatic control group and from 75600 to 113500 hours in the shutdown group. The residual lifetime should be assessed for a particular power unit and each rod control cluster assembly separately, since each rod control cluster assembly has its own operating history.
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Raj, Ankit, K. Anandhanarayanan, R. Krishnamurthy und Debasis Chakraborty. „Numerical simulation of fairing separation test for hypersonic air breathing vehicle“. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 231, Nr. 2 (06.08.2016): 319–25. http://dx.doi.org/10.1177/0954410016636911.
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Fairings are provided to cover hypersonic air breathing vehicle to protect it from adverse aerodynamic loading and kinetic heating. Separation dynamics of fairings is an important event in the launch of vehicle. Extensive computational fluid dynamics simulations are carried out for the design of fairings and vehicle and selection of time sequences of various separation events. A ground test of fairing separation is conducted in the sled facility to check the structural integrity and functionality of various separation mechanisms and flight hardware. Simulations have been carried out to study the separation dynamics of fairings at test conditions using grid-free Euler solver to get the aerodynamic loads and the loads are integrated to get the trajectory of fairings. The aerodynamic loads are provided to verify the structural integrity of various components and the trajectory of panels is used in the test planning. The pressure distributions on the vehicle are compared with the test results.
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Shi, Kaining, Dinghua Zhang, Junxue Ren, Changfeng Yao und Yuan Yuan. „Multiobjective Optimization of Surface Integrity in Milling TB6 Alloy Based on Taguchi-Grey Relational Analysis“. Advances in Mechanical Engineering 6 (01.01.2014): 280313. http://dx.doi.org/10.1155/2014/280313.
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This paper studied an effective method based on Taguchi's method with the grey relational analysis, focusing on the optimization of milling parameters on surface integrity in milling TB6 alloy. The grey relational grade that is derived from the grey relational analysis is mainly used to determine the optimum cutting process operations with multiple performance characteristics. Specifically, surface roughness (Ra), hardness, and residual stress were important characteristics in surface integrity of milling TB6 alloy. Based on the combination of these multiple performance characteristics, the feed per tooth, cutting speed, and depth of cut were optimized in this study. Additionally, the analysis of variance (ANOVA) was also applied to determine the most significant factor for the surface integrity of milling TB6 alloy according to the contribution of the ANOVA, and the most significant factor is the cutting speed in this paper. Based on the analysis, the experimental test results have been improved prominently through the grey relational analysis. Hence this method can be an effective approach to enhance the surface integrity of milling TB6 alloy.
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Wang, Shu Ren, Paul Hagan und Yan Cheng. „Fractal Characteristics of Sandstone Cutting Fracture under Mechanical Shock Loading Conditions“. Applied Mechanics and Materials 226-228 (November 2012): 1789–94. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.1789.
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It is the key to guide rock-breaking design and engineering practice for how to obtain a reasonable test indicator to assess the cuttability of the rock. Some sandstone samples were tested by using the linear rock cutting machine in the school of mining engineering, University of New South Wales (UNSW), Australia. The curves characteristics for the weight percent of the broken debris with the mesh size distribution were obtained through the screening statistics. Furthermore, the fractal dimension of the specimen broken debris was derived through theoretical calculations and statistical analysis. The results showed that the rock cutting fragmentation is of significant fractal features under the mechanical shock loads. The broken debris fractal dimension of the structural integrity specimens is bigger, the range of the fractal dimension is smaller and the broken debris size distribution is more even than that of the poor structural integrity specimens. The fractal dimension is the ideal test indicator to assess and analysis the rock-breaking degree.
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Sathujoda, Prabhakar, Paul Arnell und Andrew Deans. „Mechanical integrity of gas turbine enclosure doors under fire test conditions for A0 fire rating“. Journal of Structural Fire Engineering 10, Nr. 1 (28.02.2019): 76–89. http://dx.doi.org/10.1108/jsfe-12-2017-0045.
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PurposeAs fire doors are passive fire protection parts, the doors have to be certified through standard fire tests. It is usual practice to perform the standard fire testing on the components which require the fire certification. However, some gas turbine enclosure doors are too large to test at the test facility and hence the fire resistance test is practically not possible. The purpose of this paper is to develop a reliable finite element model, validate the model using the specimen door test results and extend the method to actual gas turbine enclosure doors to support the fire certification.Design/methodology/approachFirst, the standard fire testing on enclosure door test specimen was carried out. Second, the finite element analysis model was built and tuned to match the standard fire test deflections, and finally, the same modelling technique was extended to model the actual gas turbine enclosure door to verify the results for fire certification process.FindingsGap analysis, a method of post processing is suggested for result analysis. It was found suitable to verify the gap openings which are required for A0 rated fire certification according to fire test procedure code and also to check the mechanical integrity of the enclosure door frame assembly.Originality/valueThe method presented in this work could be used as support information along with the test specimen results for A0 class fire rating certification of the doors according to International Maritime Organization Resolution MSC.307 (88) Annexure 1: Part 3.
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Kuna, Meinhard, und Martin Abendroth. „Prüfung duktiler Werkstoffe mit dem Small-Punch-Test“. Materials Testing 47, Nr. 1-2 (Februar 2005): 45–54. http://dx.doi.org/10.3139/120.100637.
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Morita, N., G.-F. Fuh und P. A. Boyd. „Safety of Casing Shoe Test and Casing Shoe Integrity After Testing“. SPE Drilling & Completion 12, Nr. 04 (01.12.1997): 266–74. http://dx.doi.org/10.2118/22557-pa.
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Zhang, Min, Xiao Jian Fu, Yang Wu und Hao Sun. „Test Study on the Mechanical Behavior of Recycled Aggregate Concrete Wall-Beam“. Applied Mechanics and Materials 351-352 (August 2013): 260–63. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.260.
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A new type of wall-beam was put forward, of which the upper wall is replaced by recycled aggregate concrete whose coarse aggregate is made of the waste brick. Three recycled aggregate concrete wall-walls and three ordinary brick wall-beams were tested, and then the bearing capacity, stress-strain relationship, cracking load and failure mode were analyzed. The results show that: the structural integrity of recycled aggregate concrete wall-beam is better than ordinary brick wall-beam, and the increase of the depth of joist can improve the mechanical behavior of wall-beam structure under the condition of same depth-span ratio.
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Carpenter, Chris. „Resin-Cement Blend Enhances Wellbore Integrity“. Journal of Petroleum Technology 76, Nr. 05 (01.05.2024): 109–11. http://dx.doi.org/10.2118/0524-0109-jpt.
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_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 213763, “Use of Innovative Resin-Cement Blend To Enhance Wellbore Integrity,” by Wajid Ali, Faisal A. Al-Turki, and Athman Abbas, SPE, TAQA Well Services, et al. The paper has not been peer reviewed. _ A major challenge occasionally faced during a well’s life cycle is the buildup of sustained casing pressure (SCP). Compromised cement-sheath integrity is one of the primary reasons for such a pressure buildup. Meeting this challenge requires development of an isolation material that can enhance the mechanical properties of cement. This paper presents the laboratory testing and application of a resin-cement system in a scenario where potential high-pressure influx was expected across a water-bearing formation. The resin-cement system was designed to be placed as a tail slurry to provide enhanced mechanical properties compared with a conventional slurry. Introduction The objectives of this study were to investigate the use of new systems at different densities with epoxy resin as an additive and to demonstrate value added in terms of improved mechanical properties and bonding. The resin used in this study is diglycidylether of bisphenol-F, a linear epoxy resin formed by reacting bisphenol-F with a suitable amount of epichlorohydrin and hydroxide. Amines are used as curing agents for epoxy resins. The curing mechanism is a step-growth polymerization. The curing is observed initially by an increase in viscosity and then by hardening. The final product’sproperties, in terms of compressive strength and viscosity, also are affected by the type and concentration of the amine. Aliphatic amines produce more-flexible types of epoxy resins compared with aromatic amine curing agents. Aromatic amines will produce a stronger, harder epoxy resin. Experimental Study Cement Slurry Preparation and Testing. The cement slurry was formulated and mixed with a maximum speed of 12,000 rev/min for 15 seconds and then at 4,000 rev/min for 35 seconds. To condition the cement slurry, an atmospheric consistometer was used. A viscometer was used to measure rheological properties. Thickening time tests also were conducted. Fluid-loss measurements (dynamic and static) were performed on the prepared cement slurry. Dynamic fluid loss can affect rheology and thickening time of cement slurries. Static fluid loss can result in reduction in cement slurry and allow formation fluids to enter the cement slurry. Separation of water is observed when a cement slurry is allowed to stand for a period before it sets. To determine the extent of water separation, a free water test was performed to determine the extent of water separation. The test was conducted by allowing cement slurry to stand in a 250-mL graduated cylinder for 2 hours. The cement slurry was poured into a cylindrical cell and lowered into a curing chamber. While maintaining pressures and temperatures, the cement slurry was cured up to 30 days. At the end of the curing period, the pressure and temperature were reduced to ambient conditions and the test specimens were removed from the curing chamber to be tested for mechanical properties.
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Goh, J. C. H., P. V. S. Lee und P. Ng. „Structural integrity of polypropylene prosthetic sockets manufactured using the polymer deposition technique“. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 216, Nr. 6 (01.06.2002): 359–68. http://dx.doi.org/10.1243/095441102321032157.
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Rapid prototyping (RP) technology has been used recently as a means for automated socket fabrication. Although the technology has proven to be promising and has truly automated the socket fabrication process, the structural integrity of RP sockets remains questionable. For the long term, unsupervised use of these ‘unconventional’ sockets, their material properties and structural integrity must be determined. This study investigated the structural integrity of polypropylene sockets manufactured using a polymer deposition technique, in which a socket is formed by a continuous strand of partially melted polypropylene that is spirally deposited according to the socket's cross-sectional contour. To investigate the problem of delamination of the socket, the tensile properties of the socket material were determined according to ASTM D638-99. The ultimate tensile strength was found to be approximately 13–23 per cent lower than that of polypropylene sheets that are at present normally used for socket fabrication. In order to improve the load-bearing capacity of the socket, it was reinforced using a double-wall arrangement at the distal region, where failure normally occurs. The structural integrity of the complete prosthesis was then investigated according to ISO 10328 (loading condition II). The prosthesis passed the static loading test registering only 12 mm permanent deformation, and it successfully completed a preliminary cyclic test of 250000 cycles with no observable failure.
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Torigoe, Ippei, Kazuya Mori und Andrea Spagnoli. „Signal processing procedure for non-destructive test of concrete structure integrity“. NDT & E International 38, Nr. 7 (Oktober 2005): 575–81. http://dx.doi.org/10.1016/j.ndteint.2005.02.006.
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Jang, Yun-Jung, Jang-Ho Lee und Ki-Weon Kang. „Structural Integrity of Small Wind Turbine Composite Blade Using Structural Test and Finite Element Analysis“. Transactions of the Korean Society of Mechanical Engineers A 36, Nr. 9 (01.09.2012): 1087–94. http://dx.doi.org/10.3795/ksme-a.2012.36.9.1087.
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Lee, Hyeong-Yeon, und Dong-Won Lee. „Evaluation of Creep-Fatigue Integrity for High Temperature Pressure Vessel in a Sodium Test Loop“. Transactions of the Korean Society of Mechanical Engineers A 38, Nr. 8 (01.08.2014): 831–36. http://dx.doi.org/10.3795/ksme-a.2014.38.8.831.
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Semitekolos, Dionisis, Panagiotis Goulis, Despoina Batsouli, Elias P. Koumoulos, Loukas Zoumpoulakis und Costas A. Charitidis. „Enhancement of mechanical integrity of advanced composites using PMAA-electropolymerised CF fabrics“. International Journal of Structural Integrity 11, Nr. 5 (23.08.2019): 645–54. http://dx.doi.org/10.1108/ijsi-08-2018-0050.
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Purpose The purpose of this paper is to develop modified composite materials that show improved mechanical and structural integrity. Design/methodology/approach To accomplish this goal, a novel functionalisation method of the carbon fibres (CFs) for the reinforcement of the composites surface was investigated. Through the electrografting of methacrylic acid (MAA) onto the surface of the CF, this treatment aims to selectively modify the surface of the carbon fabrics, in order to create active groups that can chemically react with the epoxy resin, under heat and pressure. By this way, better adhesion as mechanical interlocking between the resin and the reinforcement can be achieved. Findings The surface treatment was examined qualitatively by means of infrared spectroscopy, scanning electron microscopy and Raman spectroscopy. The CF reinforced polymers were manufactured via the hot-press technique and they were subsequently submitted to flexural, shear and nanoindentation test. Finally, the internal structural integrity was tested through micro-computing tomography. Originality/value Through this investigation, it will be determined if the electropolymerisation of MAA onto the CF surface enhances the mechanical and structural integrity of composite materials.
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Stolle, D. F. E. „Effect of mechanical model on back-calculated pavement modulus“. Canadian Journal of Civil Engineering 17, Nr. 3 (01.06.1990): 494–96. http://dx.doi.org/10.1139/l90-053.
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In recent years nondestructive testing techniques have become popular for evaluating the structural integrity of pavements. An important factor for the interpretation of the test data is the mechanical model used in the back-calculation analyses. It is demonstrated that simplifications introduced for material modelling of the subgrade can have a significant influence on the prediction of the pavement structure moduli from surface deflection data. Key words: back calculation, pavement, Winkler foundation, elastic halfspace.
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Reiff, Ellen-Christine, und Steffen Arnold. „Automatischer Test für Photonik-Komponenten“. Konstruktion 68, S2 (2016): 48–49. http://dx.doi.org/10.37544/0720-5953-2016-s2-48.
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Die Siliziumphotonik sorgt für Tempo auf der Datenautobahn aus Glasfasern. Cloud-Computing, Serverfarmen, Big Data, schnelle Internetzugänge sowie viele andere computergestützte Dienste, die hohe Übertragungsgeschwindigkeiten verlangen, profitieren von Datenraten in der Größenordnung von TBit/s. Bei Fertigung und Test von Chips mit optischer Datenübertragung gilt es jedoch, viele Herausforderungen zu meistern. Automatisierte Lösungen müssen unter industriellen Bedingungen zuverlässig funktionieren und rund um die Uhr mit großer Genauigkeit arbeiten. Gleichzeitig sind auch noch individuelle Lösungen gefragt, da die Wafer recht unterschiedliche Anforderungen an Test- und Fertigungseinrichtungen stellen können.
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Birgisson, Bjorn, Reynaldo Roque und Gale C. Page. „Ultrasonic Pulse Wave Velocity Test for Monitoring Changes in Hot-Mix Asphalt Mixture Integrity from Exposure to Moisture“. Transportation Research Record: Journal of the Transportation Research Board 1832, Nr. 1 (Januar 2003): 173–81. http://dx.doi.org/10.3141/1832-21.
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The ultrasonic pulse wave velocity test is evaluated as a possible tool for monitoring changes in the integrity of mixtures due to moisture conditioning. Two sets of mixtures were prepared. The first group involved fine-grained (above the restricted zone) and coarse-grained (below the restricted zone) limestone mixtures commonly used by the Florida Department of Transportation (FDOT) that were produced with multiple void structure and permeability configurations by varying the gradations and proportions for a common set of aggregates and asphalt cement. The second set of mixtures consisted of three granite-based mixtures commonly used by FDOT. The results presented show that the small strain modulus obtained with the ultrasonic pulse wave velocity test appears to be sensitive to changes in mixture integrity due to moisture, and therefore it may be a possible tool for the characterization of damage in both laboratory and field specimens. Additional work remains to be performed to better define the meaning of the values obtained. However, the current results indicate that the ultrasonic pulse wave velocity test may be used as an indicator of damage in specimens as well as a quick monitoring device for detecting changes in the integrity of mixtures due to exposure to moisture.
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Liang, Dong, Peng Fei Li und Sha Li. „Test Study of Transverse Prestressed Tendons (TPTS) on the Mechanical Performance of Hollow Slab Bridge“. Advanced Materials Research 935 (Mai 2014): 220–23. http://dx.doi.org/10.4028/www.scientific.net/amr.935.220.
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Structural defects and heavy traffic make the hollow slab bridge serious diseases, such as “Single Beam Bearing”. Transverse prestressed tendons (TPTS for short) is an effective methods to solve this problem. A detailed test study of hollow slab bridge modeled by plexiglass with TPTS is done in this article. The analysis parameters include the TPTS’ layout and the value of prestress. The test results show that TPTS can effectively even the transverse load distribution, and improve the integrity of bridges.
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Soldal, Magnus, Elin Skurtveit und Jung Chan Choi. „Laboratory Evaluation of Mechanical Properties of Draupne Shale Relevant for CO2 Seal Integrity“. Geosciences 11, Nr. 6 (05.06.2021): 244. http://dx.doi.org/10.3390/geosciences11060244.
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The mechanical integrity of caprocks overlying injection formations is one of the key factors for safe storage of carbon dioxide in geological formations. Undrained effects caused by CO2 injection on strength and elastic parameters should be properly considered in the operational design to avoid fracture creation, fault reactivation and unwanted surface uplift. This study presents results from eleven undrained triaxial compression tests and one oedometer test on the Draupne shale, which is the main caprock of the Smeaheia site in the North Sea, to extract parameters relevant for seal integrity. Tests have been performed on samples oriented perpendicular to and parallel with the horizontal layering of the rock to study the effects of sample orientation relative to the loading direction. Results from undrained triaxial tests showed only minor effects of sample orientation on friction and cohesion. However, when loading during undrained shearing was parallel with layering (horizontal samples), measured Young’s modulus was roughly 1.4 times higher than for the vertical samples. Undrained shearing of vertical samples generated 30–50% more excess pore pressure than for horizontal samples with similar consolidation stress owing to more volume compaction of vertical samples. With apparent pre-consolidation stress determined from a high-stress oedometer test, the normalized undrained shear strength was found to correlate well with the overconsolidation ratio following the SHANSEP (Stress History and Normalized Soil Engineering Properties) procedure.
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Ab Rahim, S. Nю, und Mohd Amri Lajis. „Mechanical Properties and Surface Integrity of Recycling Aluminum 6061 by Hot Extrusion Process“. Materials Science Forum 894 (März 2017): 21–24. http://dx.doi.org/10.4028/www.scientific.net/msf.894.21.
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In the present work, aluminum AA6061 chip metals were extruded by hot extrusion and the effect of extrusion parameters on the mechanical properties and surface integrity were investigated. The objective of the present studies it to analyze the mechanical and structural properties of 6061 after plastic consolidation by hot extrusion. Tensile test results showed that material extruded using temperature 550°C exhibit higher ultimate tensile strength (UTS) compared with temperature of 400°C. Fracture surfaces shown that ductile fracture mode occurred at condition 500°C and 2 hours, and brittle fracture occurred at condition 400°C.
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Semitekolos, Dionysios A., Panagiotis Goulis, Despoina I. Batsouli, Elias P. Koumoulos, Loukas Zoumpoulakis und Costas A. Charitidis. „Enhancement of Mechanical Integrity of Advanced Composites using PMAA-Electropolymerised CF Fabrics“. MATEC Web of Conferences 188 (2018): 01007. http://dx.doi.org/10.1051/matecconf/201818801007.
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The aim of the present study is the development of new composite materials that show improved mechanical and structural integrity. In order to accomplish this goal, a novel functionalization method of the carbon fibers for the reinforcement of the composites surface was investigated. Through the electrografting of methacrylic acid onto the surface of the carbon fiber, this treatment aims to selectively modify the surface of the carbon fabrics, in order to create active groups that can chemically react with the epoxy resin, under heat and pressure. By this way, better adhesion as mechanical interlocking between the resin and the reinforcement can be achieved. The surface treatment was examined qualitatively by means of Infrared spectroscopy, Scanning Electron Microscopy and Raman spectroscopy. The carbon fiber reinforced polymers were manufactured via the hot-press technique and they were subsequently submitted to flexural, shear and nanoindentation test. Finally, the internal structural integrity was tested through micro-Computing Tomography.
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Bursik, Ondrej, Radim Kopřiva, Petra Petelova und Barbora Maresova. „Recent Developments in Small Punch Testing: Interlaboratory Tests and Standardization“. Key Engineering Materials 795 (März 2019): 466–72. http://dx.doi.org/10.4028/www.scientific.net/kem.795.466.
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Small specimen testing techniques are developed mainly for characterization of the structural materials with a limited volume of material. One of the most used miniature specimen testing techniques is the small punch (SP) test which is based on the testing of thin disc shaped samples. From the operational point of view SP test can be considered as a non-destructive method, because the material volume cut from industrial component is not diminishing its structural integrity. This benefit can be significant for the use in nuclear power generation sector, as many components are considered as irreplaceable and conventional testing techniques are not applicable for the determination of current mechanical properties. Although SP testing has been used for more than 40 years, there are still many research and development subjects. The article describes the SP test method as a suitable supplement to classical methods for evaluating mechanical properties that are fundamental for the nuclear power plant integrity and operational lifetime assessment processes. Main part of the article is focused on the current status of ASTM and EN standardization processes that are essential for possible usage in nuclear power plant integrity assessment and other industrial areas as well. Paper also describes results of the ongoing interlaboratory study which task is to determine repeatability and reproducibility of results obtained from material testing.
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Добродеев, А. А. „Variations in physical and mechanical properties of model fine-grained ice during experiment“. MORSKIE INTELLEKTUAL`NYE TEHNOLOGII)</msg>, Nr. 2(56) (09.06.2022): 29–36. http://dx.doi.org/10.37220/mit.2022.56.2.038.
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Определение физико-механических свойств моделированного льда является одним из важнейших этапов экспериментальных исследований в ледовом бассейне, предназначенном для изучения ходкости и управляемости судов во льдах, а также ледовых нагрузок на морские инженерные и гидротехнические сооружения. Подходы к выполнению таких измерений в ледовых бассейнах всего мира стандартизированы и соответствуют рекомендациям Международного Комитета Опытовых Бассейнов. Определённой особенностью экспериментальных исследований данного типа является то, что достаточно сложно с высокой точностью добиться требуемых значений толщины или прочности моделированного льда. В связи с этим разработаны и применяются методики корректировки результатов модельных испытаний. Но при этом остается открытым вопрос выбора времени для измерений свойств льда и частоты их выполнения, т.к. влияние длительности эксперимента на изменчивость физико-механических свойств льда изучено слабо. Данная проблема обусловлена еще и тем, что продолжительность модельных испытаний в современных ледовых бассейнах, отличающихся увеличенными размерами ледового поля, варьируется в зависимости от количества пробегов и уровня сложности исследований. В ледовом бассейне Крыловского Центра выполнены необходимые для изучения данного вопроса измерения в ровном льду, смоделированном по технологии FG, и сделаны выводы о влиянии температуры воздуха на основные характеристики ледяного покрова гранулированного типа. Полученные результаты направлены на снижение неопределённости результатов модельных испытаний в ледовом бассейне. Evaluation of physical & mechanical properties of model ice is one of the most important aspects of experimental studies in ice basins designed to investigate ship propulsion and maneuverability in ice-covered waters as well as ice loads on engineering and hydraulic structures. These measurements in ice basins follow standard procedures across the world and comply with recommendations of the ITTC Committee. A certain specific feature of these types of experimental studies is that it is quite difficult to achieve the target thickness or strength values of model ice with a high accuracy. In this connection methods for correction of model test data have been developed and implemented. However, the time and frequency of measuring the ice properties remain an open question because the influence of experiment duration on variable physical & mechanical properties has been studied poorly. This problem is also caused by the fact that the test duration in modern ice basins capable of generating larger ice sheets varies depending on the number of test runs and particulars of studies. For investigation of this issue the Ice Basin of Krylov State Research Centre has conducted measurements in level ice modeled using FG ice technology and some conclusions have been drawn regarding the impact of air temperature on the main characteristics of FG ice type. The obtained results are aimed at reducing the uncertainty of model test results gathered in the ice basin.
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Cacciola, Matteo, Fabio La Foresta, Francesco Carlo Morabito und Mario Versaci. „Advanced use of soft computing and eddy current test to evaluate mechanical integrity of metallic plates“. NDT & E International 40, Nr. 5 (Juli 2007): 357–62. http://dx.doi.org/10.1016/j.ndteint.2006.12.011.
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Kersten, Antje, Samuel Schabel und Pegah Aziziyanesfahani. „Wasserlinsen-Test“. Wochenblatt für Papierfabrikation 149, Nr. 7 (2021): 398–405. http://dx.doi.org/10.51202/0043-7131-2021-7-398.
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Im Rahmen des folgenden Beitrags werden Untersuchungen zur Eignung des Wasserlinsen-Tests zur Bestimmung der phytotoxischen Effekte von Papierfabriksabwässern beschrieben. Innerhalb dieser Untersuchungen wurde eine standardisierte Methode zur Durchführung des Wasserlinsen-Tests in Papierfabriksabwässern erarbeitet. Die Abwasserproben müssen nach der Entnahme entweder direkt analysiert werden oder sofort eingefroren werden. Die gefrorene Abwasserprobe kann bis zu zwei Wochen gelagert werden. Die Testdurchführung für die Endabläufe wird mit vier Verdünnungsstufen empfohlen. Proben müssen vor dem Test schwarzbandfiltriert und der pH-Wert der Proben auf 5,5 eingestellt werden. Die Darstellung der Ergebnisse der Abwasserproben erfolgt als Gw-Wert, der die nominell erste Verdünnungsstufe (höchste Konzentration an Abwasserprobe) beschreibt, bei der eine Wachstumshemmung von 10 % nicht überschritten wird. Der Wasserlinsen-Test wurde unter definierten Bedingungen in demselben Labor dreimal für die Endabläufe aus sieben Papierfabriken wiederholt und damit die Reproduzierbarkeit der Ergebnisse quantifiziert. Im Laufe dieser Untersuchung zeigten 6 von 7 untersuchten Proben einen Gw-Wert von 1 oder 2. Die innerhalb der Reproduzierbarkeitsuntersuchungen bestimmten Gw-Werte entsprechen denen einer unbedenklichen Abwasserprobe. Für die ARA-Zuläufe und die teilgereinigten Abwässer ergeben sich höhere Werte für den CSB, den AOX und die Trübung. Die höheren Belastungen dieser Abwässer sind mit höheren Wachstumshemmungen im Wasserlinsen-Test verbunden. Ob einer dieser Faktoren oder ein Zusammenspiel mehrerer Faktoren für die höhere Wachstumshemmung verantwortlich ist, konnte in dieser Untersuchung nicht geklärt werden.
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Tennyson, R. C., N. Banthia, E. Rivera, S. Huffman und I. Sturrock. „Monitoring structures using long gauge length fibre optic sensors“. Canadian Journal of Civil Engineering 34, Nr. 3 (01.03.2007): 422–29. http://dx.doi.org/10.1139/l06-155.
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Long gauge length fibre optic sensors have been installed on bridges and pipelines to monitor their long-term structural integrity. These sensors measure the average displacement or strain over their gauge length due to mechanical or thermal loading. It is shown that long gauge length sensors can provide an estimate of the maximum bending strain for beam-type structures, such as bridge girders or pipelines, subject to sag. Bending and hoop strain test results are presented for bridges with composite reinforcements bonded to concrete girders and columns that were statically loaded at various locations to assess the integrity of the bond interface. These sensors can also provide information on corrosion-induced wall thinning of pipelines based on changes in the local strain field due to internal pressure in the line. Test data are presented for measuring pipeline corrosion using different fibre optic sensor configurations.Key words: fibre optic sensors, bridges, pipelines, integrity monitoring.
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Chen, Jianxun, Qingsong Wang, Jiaqi Guo, Yanbin Luo, Yao Li, Qin Liu und Hongyu Wang. „Mechanical Properties and Acoustic Emission Characteristics of Karst Limestone under Uniaxial Compression“. Advances in Materials Science and Engineering 2018 (12.07.2018): 1–14. http://dx.doi.org/10.1155/2018/2404256.
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Firstly, I-RPT ultrasonic detector was used to test the wave velocity of karst limestone with different initial microstructure and water content. Then, RMT-150B rock testing machine and DS2-16B acoustic emission system were used to test the acoustic emission (AE) under uniaxial compression. Mechanical properties and AE characteristics were obtained during rock failure. The detailed relationship between stress-strain and AE characteristics was studied in this paper. Research results indicated the following: (1) For samples with many primary fissures and defects, wave velocity in dry state was larger than that in its natural state. From natural state to saturated state, the wave velocity tended to increase. For samples with good integrity, wave velocity increased with increasing of water content. (2) In the dry state, the samples presented tension failure. In saturated state, the samples presented tension-shear failure. For samples with cracks and good integrity, samples showed brittle failure. For samples with many corrosion pores which showed ductile damage under natural and saturated state, the spalling phenomenon was enhanced under saturated state. (3) With increasing of water content, the peak stress and AE peak reduced dramatically. In brittle failure, AE peak could be considered a sign of failure. In ductile failure, AE activity decreased gradually with the decrease of stress. (4) The mechanical properties and AE characteristics corresponding to four main fracture propagation types were also discussed.
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Colino, Enrique, Jorge Garcia-Unanue, Bas Van Hooren, Leonor Gallardo, Kenneth Meijer, Alejandro Lucia und Jose Luis Felipe. „A Proposed Method to Assess the Mechanical Properties of Treadmill Surfaces“. Sensors 20, Nr. 9 (10.05.2020): 2724. http://dx.doi.org/10.3390/s20092724.
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The aim of this study was to define a reliable and sensitive test method for assessing Shock Absorption (SA), Vertical Deformation (VD), and Energy Restitution (ER) in treadmill surfaces. A total of 42 treadmills belonging to four different models were included in the study: (a) Technogym Jog700 Excite (n = 10), (b) Technogym Artis Run (n = 12), (c) LifeFitness Integrity Series 97T (n = 11), and (d) LifeFitness Integrity Series DX (n = 9). An advanced artificial athlete (AAA) device was used to assess SA, VD, and ER at three different locations along the longitudinal axis of each treadmill and in the support area of the athletes’ feet. For each location, our results show that the error assumed when performing one impact with the AAA instead of three (SA ≤ |0.1|%, VD ≤ |0.0| mm, and ER ≤ |0.2|%) is lower than the smallest changes that can be detected by the measuring device (SA = 0.4%, VD = 0.2 mm, and ER = 0.9%). Also, our results show the ability of the test method to detect meaningful differences between locations once the one-impact criterium is adopted, since absolute minimum differences between zones (SA: |0.6|%, VD: |0.3| mm, and ER: |1.2|%) were above the uncertainty of the measuring device. Therefore, performing a single impact with the AAA in each of the three locations described in this study can be considered a representative and reliable method for assessing SA, VD, and ER in treadmill surfaces.
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Al-Ethari, Haydar Abdul Hassan, Sundus Abbas Jasim und Ekhlas Khalid Zamel. „Investigation on Biocompatibility and Mechanical Properties of Ti15Mg Alloy“. Materials Science Forum 1039 (20.07.2021): 557–64. http://dx.doi.org/10.4028/www.scientific.net/msf.1039.557.
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In this research work, bioactive Ti15Mg alloy was prepared by powder metallurgy route to investigate its biocompatibility and mechanical properties. Many tests were performed including X-ray diffraction; optical microscope analysis, scanning electron microscope analysis, ultrasonic wave test, corrosion behavior test, Static immersion test, and the wet sliding wear test. The XRD result shows that the prepared alloy sample consist of (α-Ti phase) and Mg. The microstructure of the prepared alloy sample consisted of a biodegradable Mg or pore and alpha titanium. The effect of the Mg content on degradability was tested based on simulated body fluid of Ringer solutions using electrochemical corrosion. The findings indicate that an elastic modulus of 47GPa exhibits the alloy. There were low corrosion rates of the alloy. The Ti matrix remained integrity after 14 days of immersion in the Ringer solutions, and the magnesium phase dissolved in the solution, causing a layer to form on the alloy. The wear behavior of the prepared ally at wet sliding conditions was evaluated using pin on disc method. The in vitro analysis showed good biocompatibility with Ti15Mg alloy. The prepared alloy demonstrates good biocompatibility and bioactivity.
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Gul, Rizwan Mehmood, Fahad Ullah Zafar, Muhammad Ali Kamran und Muhammad Noman. „Effect of Wind Load on Performance of Photovoltaic (PV) Modules Available in Pakistan“. Mehran University Research Journal of Engineering and Technology 40, Nr. 4 (01.10.2021): 860–66. http://dx.doi.org/10.22581/muet1982.2104.15.
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Mechanical integrity of a Photovoltaic (PV) module plays a major role in its performance and electrical output. Mechanical loads which include loads produced by wind, snow, rain, and hail tend to degrade the performance of PV module by generating stresses and enhancing micro-cracks and defects. This research aims to investigate the impact of wind loads on the performance of PV modules, particularly the degradation in its power output. A load of 2400 Pa was applied as per international standards (ASTM E1830-15 and IEC-61215). A total of four PV module samples, of the same specifications with 60 W rated power, were initially subjected to solar flash testing and Electroluminescence (EL) imaging. This was followed by three cycles of mechanical load test. After the mechanical load tests, the modules were again subjected to solar flash testing and EL imaging and the results were compared. It was noted that static wind load degrades the mechanical integrity of photovoltaic modules in two ways; by aiding the propagation of existing cracks and initiating new cracks. This loss of mechanical integrity degraded the power output of PV module. Maximum drop of 2% in the power output and 0.27% in the efficiency was observed. In addition, the average increase of 3.37% in the series resistance was observed indicating decrease in performance.
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Baek, Jong Hyun, Cheol Man Kim, Young Pyo Kim und Chang Sung Seok. „Structural Integrity Evaluation of API 5L X65 Pipe Subjected to Pre-Strain up to Tensile Strain Using the API 579 Procedure“. Key Engineering Materials 345-346 (August 2007): 1353–56. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1353.
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Mechanical properties of the pre-strained material are different with those of virgin material without pre-strain. Buried pipelines for natural gas transmission may be deformed by outside force such as ground subsidence, ground liquefaction, cold bending and mechanical damage. Plastic deformation affects the tensile properties and fracture toughness. The effects of prestrain on the mechanical properties of API 5L X65 pipe were diversely investigated through the tensile test, crack tip opening displacement test and Charpy impact test. Axial tensile pre-strain of 1.5, 5 and 10% was applied to plate-type tensile specimens cut from the pipe body prior to mechanical testing. Tensile test revealed that yield strength and tensile strength were increased with increasing tensile pre-strain. However, Fracture toughness for crack initiation decreased with increasing tensile pre-strain. Structural integrity evaluation of the API 5L X65 pipe with crack-like flaws was assessed by using the level 2 in the API 579 code.
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Biglari, Farid R., Catrin Mair Davies und Kamran M. Nikbin. „Development of Simulations Models under Thermo Mechanical Loading Conditions“. Key Engineering Materials 417-418 (Oktober 2009): 69–72. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.69.
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Advanced steels are designed and produced to be used in engineering applications in which thermo-mechanical fatigue could be a main factor in causing failure in components operating at elevated temperatures. In this paper thermo-mechanical fatigue properties of these steels are studied under the influence of creep and fatigue damage evolution. Development of different models and simulation techniques are reviewed to predict material behaviour. Numerical simulations are carried out to predict experimental tests on parent material notched bar specimens. Numerical predictions are introduced in advance of experimental test to assess the experimental test procedure. This is usually done to enhance the experimental result integrity and expectations. A local ductile damage development methodology is employed using the kinematic hardening criterion and compared to previously used strain hardening material property. The modelling on notched bar geometries is extended to geometries with cracks in which a local damage criterion will be used to predict virtual crack extension in compact tension specimens.
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Sherman, Debra M. „Novel Life Science Tensile Stage Integration with Cryo Dual-Beam FIB Technology“. Microscopy Today 16, Nr. 6 (November 2008): 22–23. http://dx.doi.org/10.1017/s1551929500062337.
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Soft and hydrated samples present unique challenges when determining structural integrity. Mechanical strength may be a critical factor in evaluating the sample in question. For example, genetic manipulation can change the chemical composition of plant cell walls. One goal would be producing strong plants whose stems and leaves lend themselves to easy break down for the production of ethanol. Arabidopsis is an ideal test sample for cell wall manipulation since the genetic strains are so well documented. However, these plants are quite small and mechanically testing the integrity of the walls can be problematic in the laboratory setting.
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Čermák, Martin, Miroslav Havlíček und Martin Zouhar. „Tensile stress and penetration test of the Red Haven peaches skin“. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 59, Nr. 1 (2011): 23–28. http://dx.doi.org/10.11118/actaun201159010023.
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Skin protects fruits against changing external factors such as varying temperature, moisture, etc. The knowledge of its mechanical properties is thus of critical importance. The paper is focused on determination of selected mechanical characteristics of Red Haven peach skin. Such destructive experiments (tensile stress and penetration test) were performed, where fruit skin integrity was radically violated. In a peach, a part of the skin is subject to external mechanical action and resulting deformation is measured and it can be viewed as a function of parameters describing both the action and considered sample of the skin or vice versa. Several basic physical quantities such as Young’s modulus of elasticity, stress in failure, toughness, and maximal penetration pressure were determined. These quantities, depending e.g. on date of harvest and describing quality and maturity of peaches, were quantified and evaluated. The results obtained within this research can be used e.g. for creation of detailed mathematical model.
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Bateson, P. H., und S. E. Webster. „The Significance of Local Brittle Zones to the Integrity of Large Welded Structures“. Journal of Offshore Mechanics and Arctic Engineering 112, Nr. 3 (01.08.1990): 199–205. http://dx.doi.org/10.1115/1.2919857.
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An extensive group-sponsored research program has been carried out within the UK, which, supplemented by additional work by British Steel, was designed to study the structural significance of local brittle zones. Charpy impact, CTOD and wide plate tests have been examined in order to compare and contrast their fracture behavior under similar conditions. In order to permit this comparison, two welding conditions were studied giving nominally 30 and 10 percent of coarse-grained HAZ through the thickness of a 50-mm-thick plate. The high percentage of coarse grain condition was tested in the as-welded and PWHT state and the low percentage condition as-welded only. It was shown that low toughness (<0.1 mm CTOD) measurements could be obtained using both through thickness and surface-notched test pieces over a temperature range of −30 to +10°C. Similar minimum toughness values were obtained for all the test conditions studied, but the frequency of occurrence varied. Twenty-two wide plate tests were carried out and nine fractured, four in the as-welded condition (two each for the two welding variables studied) and five in the PWHT condition. A further plate initiated a fracture from a bevel weld procedure which arrested in the parent plate. It is postulated that the requirement for an extreme combination of stress level, defect size and coarse-grained microstructure at the crack tip plus the potential for crack arrest is the reason for the absence of fractures in offshore structures.