Academic literature on the topic 'Trusses Design and construction Mathematical models'
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Journal articles on the topic "Trusses Design and construction Mathematical models"
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DUNAI, LÁSZLÓ, and GÁBOR JAKAB. "STABILITY BEHAVIOR AND DESIGN OF NONCONVENTIONAL COLD-FORMED STEEL STRUCTURES — RESEARCH REVIEW." International Journal of Structural Stability and Dynamics 11, no. 05 (October 2011): 903–27. http://dx.doi.org/10.1142/s0219455411004397.
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In the paper, the methodology and main results of two research projects on nonconventional cold-formed thin-walled steel structures are presented. Laboratory tests, standard-based calculations, numerical models, and the connection of these to design method development are summarized. The implementation of the methodology is presented on two areas in detail: CompressionC-section members and a truss made of C-section members. The studied CompressionC-section members are of various cross-sectional arrangement and end- and lateral-supporting conditions. They consist of single or double asymmetric C-section members; in the latter case, either a back-to-back arrangement is applied or two sections are stuck in each other, forming a box-like closed section. The applied load is in each case compression with different eccentricities. Test arrangement, program, and results are presented; measured load-bearing capacities are compared to resistances calculated according to Eurocode 3, Part 1–3 where applicable, design rules for the cases not covered by the code are proposed. Trusses made of C-sections from the same product line are analyzed in the light of full-scale laboratory tests. EC3-based design formulae are derived for the failure modes obtained in the tests either by modifying existing application rules or by deriving new ones from these. Advanced numerical models of both structures are presented with focus on modeling imperfections, bolted connections, and joint rigidities.
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Abakumov, R., and A. Al-Sabaeei. "ASSESSMENT OF THE RELIABILITY LEVEL OF STRENGTHENING OPTIONS FOR BUILDING STEEL STRUCTURES USING THE MATHEMATICAL MODEL OF THEIR UNINTERRUPTED OPERATION." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 6, no. 7 (July 10, 2021): 44–50. http://dx.doi.org/10.34031/2071-7318-2021-6-7-44-50.
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The article is devoted to the issues of assessing the level of reliability of options for strengthening building metal structures using mathematical models of the probability of their uninterrupted operation. The increasing requirements for the structural safety of building metal structures, the need to use justified mathematical calculations confirming their performance and safety, taking into account various reinforcement options determine the relevance of this study. The content of the article is based on the platform of the theoretical basis for the design of reinforcement of metal structures. It is predetermined by the subsequent synthesis of innovative solutions in assessing the level of reliability building structures taking into account the use of mathematical modeling of the probability of uninterrupted operation. The article presents an analysis of the problem points of using the probabilistic method for calculating the level of reliability of building metal structures. This allows to assess the compliance of the existing loads with standard values and guarantee the reliable operation of building metal structures. The characteristics that influence the assessment of the level of reliability of options for strengthening building metal structures using mathematical modeling are highlighted. A critical review of the amplification options from the point of view of the use of mathematical models of the probability of the operation of a metal structure is presented. Attention is focused on the construction of an optimization mathematical model of the bearing capacity of a metal structure using probability theory, Gram-Charlier series, Gumbel's law, Weibull's law. An example of strengthening of a load-bearing truss using a mathematical model for assessing the level of reliability of a metal structure is described. The proposed option will improve the safety, bearing capacity of the structure while ensuring the perception of the maximum possible load and at the same time will reduce the cost of this type of structure in construction.
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Hamidavi, Tofigh, Sepehr Abrishami, Pasquale Ponterosso, David Begg, and Nikos Nanos. "OSD." Construction Innovation 20, no. 2 (March 14, 2020): 149–69. http://dx.doi.org/10.1108/ci-11-2019-0126.
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Purpose The paper aims to leverage the importance of the integrated automatic structural design for tall buildings at the early stage. It proposes to use an automatic prototype to perform the structural design, analysis and optimisation in a building information modelling (BIM)-based platform. This process starts with extracting the required information from the architectural model in Revit Autodesk, such as boundary conditions and designs different options of the structural models in Robot Autodesk. In this process, Dynamo for Revit is used to define the mathematical functions to use different variables and generate various structural models. The paper aims to expand the domain of automation in the BIM platform to reduce the iterative process in different areas such as conceptual structural design and collaboration between architects and structural engineers to reduce the time and cost at the early stages. Design/methodology/approach The paper begins with an exploratory research by adopting a qualitative methodology and using open-ended questions to achieve more information about the phenomenon of automation and interoperability between structural engineers and architects and gain new insight into this area. Furthermore, correlation research is used by adopting quantitative and short questions to compare the proposed prototype with the traditional process of the structural design and optimisation and the interoperability between architects and engineers and consequently, validate the research. Findings As an outcome of the research, a structural design optimisation (SDO) prototype was developed to semi-automate the structural design process of tall buildings at the early stages. Moreover, the proposed prototype can be used during the early stage of structural design in different areas such as residential buildings, bridges, truss, reinforced concrete detailing, etc. Moreover, comprehensive literature regarding using automation in structural design, optimisation process and interoperability between architects and engineers is conducted that provides a new insight to contribute to future research and development. Research limitations/implications Due to the time limit, the paper results may lack in a comprehensive automatic structural design process. Therefore, the researchers are encouraged to expand the workability of the prototype for a comprehensive automatic design check such as automatic design for the minimum deflection, displacement of different types of buildings. Practical implications The prototype includes implications for the development of different automatic designs. Originality/value The focus of this paper is the optimisation of the structural design in the BIM platform by using automation. This combination is one of the novelties of this paper, and the existing literature has a very limited amount of information and similar work in this area, especially interoperability between architects and engineers.
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Hohol, Myron, and Dmytro Sydorak. "STRUCTURAL EFFICIENCY OF STEEL COMBINED TRUSSES." Theory and Building Practice 2022, no. 2 (December 20, 2022): 58–67. http://dx.doi.org/10.23939/jtbp2022.02.058.
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In this article on increasing the efficiency of steel combined structures, the tasks of rational design, regulation and control of structural parameters of elements, the use of steels with increased mechanical properties are considered. It is shown that for a six-span stiffening girder of a combined truss with elastic supports, which operates under a distributed load, the moment is 72 times smaller than the moment of a single-span beam. It is suggested to use high-strength steel for truss braces. Rationality criteria are proposed. On the basis of rationality criteria, new steel combined trusses were developed and their models were designed for stress tests. The results of experimental studies of models of combined trusses are presented. The results of experimental studies conducted on models of steel combined trusses qualitatively and quantitatively confirmed the theoretical results obtained on the basis of the proposed theory.
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Atkočiūnas, Juozas, Dalia Merkevičiūte, Artūras Venskus, and Juozas Nagevičius. "MATHEMATICAL MODELS FOR OPTIMAL SHAKEDOWN TRUSSES DESIGN PROBLEMS IN CASE OF MOVING LOAD." Technological and Economic Development of Economy 13, no. 2 (June 30, 2007): 93–99. http://dx.doi.org/10.3846/13928619.2007.9637782.
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Prisitaikomumo teorija, nagrinejanti tampriai plastiškas konstrukcijas, veikiama kintamosios kartotines apkrovos, leidžia judamaja apkrova traktuoti kaip atskira kartotinai kintančiu jegu atveji. Apkrovai leidžiama “judeti” bet kuria konstrukcijos dalimi: nuo tilto vidurio, grižti atgal, vel i prieki ‐ taip universaliai ivertinama apkrovimo istorija, kuri yra lemiamas faktorius, nagrinejant plastines deformacijas patiriančios konstrukcijos itempiu ir deformaciju būvi. Straipsnyje atskleista galimybe taikyti prisitaikomumo teorijos metodus, sudarant teorinius santvaru optimizavimo uždaviniu matematinius modelius ir juos sprendžiant. Nagrinejama idealiai tampriai plastine žinomos geometrijos santvara, veikiama judamosios apkrovos. Sudaryti minimalaus tūrio santvaros ar javeikiančios apkrovos maksimizavimo uždaviniu matematiniai modeliai. Modeliuose ivertinamos ne tik konstrukcijos stiprumo (prisitaikomumo) ir standumo salygos, bet ir stabilumo netekimo galimybe esant plastinei santvaros darbo stadijai. Pasiūlyti nauji sprendimo algoritmai, pateikti skaitiniai strypu lankstines santvaros, veikiamos judamosios apkrovos, optimizavimo uždaviniu pavyzdžiai. Tyrimai atlikti, darant mažu poslinkiu prielaida.
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Pantelides, Chris P., and Sara Ganzerli. "Design of Trusses Under Uncertain Loads Using Convex Models." Journal of Structural Engineering 124, no. 3 (March 1998): 318–29. http://dx.doi.org/10.1061/(asce)0733-9445(1998)124:3(318).
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Soloveva, Anastasia A., and Sergey A. Solovev. "Reliability analysis of planar steel trusses based on p-box models." Vestnik MGSU, no. 2 (February 2021): 153–67. http://dx.doi.org/10.22227/1997-0935.2021.2.153-167.
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Introduction. The development of probabilistic approaches to the assessment of mechanical safety of bearing structural elements is one of the most relevant areas of research in the construction industry. In this research, probabilistic methods are developed to perform the reliability analysis of steel truss elements using the p-box (probability box) approach. This approach ensures a more conservative (interval-based) reliability assessment made within the framework of attaining practical objectives of the reliability analysis of planar trusses and their elements. The truss is analyzed as a provisional sequential mechanical system (in the language of the theory of reliability) consisting of elements that represent reliability values for each individual bar and truss node in terms of all criteria of limit states.
Materials and methods. The co-authors suggest using p-blocks consisting of two boundary distribution functions designated for modeling random variables in the mathematical models of limit states performed within the framework of the truss reliability analysis instead of independent true functions of the probability distribution of random variables. Boundary distribution functions produce a probability distribution domain in which a true distribution function of a random variable is located. However this function is unknown in advance due to the aleatory and epistemic uncertainty. The choice of a p-block for modeling a random variable will depend on the type and amount of statistical information about the random variable.
Results. The probabilistic snow load model and the numerical simulation of tests of steel samples of truss rods are employed to show that p-box models are optimal for modeling random variables to solve numerous practical problems of the probabilistic assessment of reliability of structural elements. The proposed p-box snow load model is based on the Gumbel distribution. The mathematical model used to perform the reliability analysis of planar steel truss elements is proposed. The co-authors provide calculation formulas to assess the reliability of a truss element for different types of p-blocks used to describe random variables depending on the amount of statistical data available.
Conclusions. The application of statistically unsubstantiated hypotheses for choosing the probability distribution law or assessing the parameters of the probability distribution of a random variable leads to erroneous assessments of the reliability of structural elements, including trusses. P-boxes ensure a more careful reliability assessment of a structural element, but at the same time this assessment is less informative, as it is presented in the form of an interval. A more accurate reliability interval requires interval-based assessments of distribution parameters or types of p-boxes applied to mathematical models of the limit state, which entails an increase in the economic and labor costs of the statistical data.
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Kazaryan, Ruben, Peraskovya Andreeva, and Natalya Galaeva. "Organization of planning in transport construction." E3S Web of Conferences 157 (2020): 04006. http://dx.doi.org/10.1051/e3sconf/202015704006.
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Purpose. Development of methods and models of economic efficiency of the integrated use of various modes of transport in the interests of ensuring national security of the state. Methods. System analysis, logical-mathematical modeling, systems theory, economic-visual modeling, research methods of operations, economic and mathematical methods. Results. The paper discusses the need for the application of economic and mathematical models in the design of transport construction (model of “moving the earth masses”, linear programming model, design of the “red line” on the longitudinal profile, dynamic programming model). Conclusion. The difficult stage of the transition of economic and mathematical analysis from the verbal description of the system process to the elemental base of the mathematical apparatus. Most research models of operations are designed for single criteria. Economic and mathematical modeling allows the effect of “private optimization”.
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Janušaitis, Rolandas, Valerijus Keras, and Jūratė Mockienė. "DEVELOPMENT OF METHODS FOR DESIGNING RATIONAL TRUSSES." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 9, no. 3 (September 30, 2003): 192–97. http://dx.doi.org/10.3846/13923730.2003.10531325.
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Striving for rationality and long-term reliability is seen in different periods of building activities. Application of linear programming methods has enabled to formalise this striving and to elaborate the necessary mathematical models. But later theoretical and practical investigations have disclosed that not always, when optimising in respect of one criterion, it is possible to obtain solutions rational in other aspects, and this stimulated the application of multicriteria optimization methods. It is useful in this case to apply the ideas of the game theory, game problems solving methods already applied in other building design fields. When adapting methods of the game theory to popular needs for truss designing, a criteria set involving 11 alternatives has been selected. Attempts have been made to find rational truss variants by applying different methods (method of proximity to an ideal point, Wald's and Hurwitz's methods). It has been found when using the method of proximity to an ideal point for rational truss designing that a truss with a sloping brace network and pivoted knots supported by a column and composed of rectangular box shapes is more valuable than other trusses. According to Wald's and Hurvitz's methods, among popular spans of 24 m such a truss is the truss with a lowered bottom chord.
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Wang, Haoqing, Wen Yi, and Yannick Liu. "Optimal Route Design for Construction Waste Transportation Systems: Mathematical Models and Solution Algorithms." Mathematics 10, no. 22 (November 18, 2022): 4340. http://dx.doi.org/10.3390/math10224340.
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A huge amount of construction waste is generated in construction sites every day that needs to be transported by vehicle to disposal facilities for processing. Unlike in most typical transportation problems, once these vehicles are loaded with construction waste, they must travel directly to the disposal facility. Moreover, there are different types of construction waste that may require handling by different disposal facilities. In this paper, we develop a model and algorithm for identifying the optimal transportation routes specific to construction waste transportation. Our results can not only minimize the overall costs for both the logistics company and the contractor but also minimize the distance traveled, thus reducing urban traffic emissions.
Dissertations / Theses on the topic "Trusses Design and construction Mathematical models"
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Malone, Brett. "Multidisciplinary optimization in aircraft design using analysis technology models." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-10102009-020042/.
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Law, Gordon Ki-Wai. "Decision support system for construction cycle design." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26715.
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The objective of this thesis is to develop a conceptual design of a computerized environment for detailed design of construction activities associated with projects characterized by significant repetition.
High-rise building construction is used as the example of repetitive construction projects. The construction cycle design of a typical floor structure is studied to gain an understanding of the difficulty and complexity involved in the activity design process. Modeling techniques currently used in construction planning, modeling techniques developed in the field of operations research, and assembly line balancing techniques used in industrial engineering are reviewed to determine their applicability for detailed construction cycle design.
Using the concept of decision support systems developed in the fields of management science and knowledge engineering for solving ill-structured and ill-defined problems, a conceptual design of a decision support system for construction cycle design is developed.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Mirjalili, Vahid. "Modelling the structural efficiency of cross-sections in limited torsion stiffness design." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99780.
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Most of the current optimization techniques for the design of light-weight structures are unable to generate structural alternatives at the concept stage of design. This research tackles the challenge of developing an optimization method for the early stage of design. The main goal is to propose a procedure to optimize material and shape of stiff shafts in torsion.Recently introduced for bending stiffness design, shape transformers are presented in this thesis for optimizing the design of shafts in torsion. Shape transformers are geometric parameters defined to classify shapes and to model structural efficiency. The study of shape transformers are centered on concept selection in structural design. These factors are used to formulate indices of material and shape selection for minimum mass design. An advantage of the method of shape transformers is that the contribution of the shape can be decoupled from the contribution of the size of a cross-section. This feature gives the designer insight into the effects that scaling, shape, as well as material have on the overall structural performance.
Similar to the index for bending, the performance index for torsion stiffness design is a function of the relative scaling of two cross-sections. The thesis examines analytically and graphically the impact of scaling on the torsional efficiency of alternative cross-sections. The resulting maps assist the selection of the best material and shape for cross-sections subjected to dimensional constraints. It is shown that shape transformers for torsion, unlike those for bending, are generally function of the scaling direction.
The efficiency maps ease the visual contrast among the efficiency of open-walled cross-sections and that of close-walled cross-sections. As expected, the maps show the relative inefficiency of the former compared to the latter. They can also set the validity range of thin- and thick-walled theory in torsion stiffness design. The analytical results are validated with the numerical data obtained from ANSYS to guarantee the consistency of the models. The thesis concludes with three case studies that demonstrate the method.
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Mason, Brian H. "Analysis and design of composite curved frames." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06102009-063304/.
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Hon, Alan 1976. "Compressive membrane action in reinforced concrete beam-and-slab bridge decks." Monash University, Dept. of Civil Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/5629.
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Hashemolhosseini, Sepehr. "Algorithmic component and system reliability analysis of truss structures." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85710.
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Thesis (MScEng)-- Stellenbosch University, 2013.ENGLISH ABSTRACT: Most of the parameters involved in the design and analysis of structures are of stochastic nature. This is, therefore, of paramount importance to be able to perform a fully stochastic analysis of structures both in component and system level to take into account the uncertainties involved in structural analysis and design. To the contrary, in practice, the (computerised) analysis of structures is based on a deterministic analysis which fails to address the randomness of design and analysis parameters. This means that an investigation on the algorithmic methodologies for a component and system reliability analysis can help pave the way towards the implementation of fully stochastic analysis of structures in a computer environment. This study is focused on algorithm development for component and system reliability analysis based on the various proposed methodologies. Truss structures were selected for this purpose due to their simplicity as well as their wide use in the industry. Nevertheless, the algorithms developed in this study can be used for other types of structures such as moment-resisting frames with some simple modi cations. For a component level reliability analysis of structures different methods such as First Order Reliability Methods (FORM) and simulation methods are proposed. However, implementation of these methods for the statistically indeterminate structures is complex due to the implicit relation between the response of the structural system and the load effect. As a result, the algorithm developed for the purpose of component reliability analysis should be based on the concepts of Stochastic Finite Element Methods (SFEM) where a proper link between the finite element analysis of the structure and the reliability analysis methodology is ensured. In this study various algorithms are developed based on the FORM method, Monte Carlo simulation, and the Response Surface Method (RSM). Using the FORM method, two methodologies are considered: one is based on the development of a finite element code where required alterations are made to the FEM code and the other is based on the usage of a commercial FEM package. Different simulation methods are also implemented: Direct Monte Carlo Simulation (DMCS), Latin Hypercube Sampling Monte Carlo (LHCSMC), and Updated Latin Hypercube Sampling Monte Carlo (ULHCSMC). Moreover, RSM is used together with simulation methods. Throughout the thesis, the effciency of these methods was investigated. A Fully Stochastic Finite Element Method (FSFEM) with alterations to the finite element code seems the fastest approach since the linking between the FEM package and reliability analysis is avoided. Simulation methods can also be effectively used for the reliability evaluation where ULHCSMC seemed to be the most efficient method followed by LHCSMC and DMCS. The response surface method is the least straight forward method for an algorithmic component reliability analysis; however, it is useful for the system reliability evaluation. For a system level reliability analysis two methods were considered: the ß-unzipping method and the branch and bound method. The ß-unzipping method is based on a level-wise system reliability evaluation where the structure is modelled at different damaged levels according to its degree of redundancy. In each level, the so-called unzipping intervals are defined for the identification of the critical elements. The branch and bound method is based on the identification of different failure paths of the structure by the expansion of the structural failure tree. The evaluation of the damaged states for both of the methods is the same. Furthermore, both of the methods lead to the development of a parallel-series model for the structural system. The only difference between the two methods is in the search approach used for the failure sequence identification. It was shown that the ß-unzipping method provides a better algorithmic approach for evaluating the system reliability compared to the branch and bound method. Nevertheless, the branch and bound method is a more robust method in the identification of structural failure sequences. One possible way to increase the efficiency of the ß-unzipping method is to define bigger unzipping intervals in each level which can be possible through a computerised analysis. For such an analysis four major modules are required: a general intact structure module, a damaged structure module, a reliability analysis module, and a system reliability module. In this thesis different computer programs were developed for both system and component reliability analysis based on the developed algorithms. The computer programs are presented in the appendices of the thesis.
AFRIKAANSE OPSOMMING: Meeste van die veranderlikes betrokke by die ontwerp en analise van strukture is stogasties in hul aard. Om die onsekerhede betrokke in ontwerp en analise in ag te neem is dit dus van groot belang om 'n ten volle stogastiese analise te kan uitvoer op beide komponent asook stelsel vlak. In teenstelling hiermee is die gerekenariseerde analise van strukture in praktyk gebaseer op deterministiese analise wat nie suksesvol is om die stogastiese aard van ontwerp veranderlikes in ag te neem nie. Dit beteken dat die ondersoek na die algoritmiese metodiek vir komponent en stelsel betroubaarheid analise kan help om die weg te baan na die implementering van ten volle rekenaarmatige stogastiese analise van strukture. Di e studie se fokus is op die ontwikkeling van algoritmes vir komponent en stelsel betroubaarheid analise soos gegrond op verskeie voorgestelde metodes. Vakwerk strukture is gekies vir die doeleinde as gevolg van hulle eenvoud asook hulle wydverspreide gebruik in industrie. Die algoritmes wat in die studie ontwikkel is kan nietemin ook vir ander tipes strukture soos moment-vaste raamwerke gebruik word, gegewe eenvoudige aanpassings. Vir 'n komponent vlak betroubaarheid analise van strukture word verskeie metodes soos die "First Order Reliability Methods" (FORM) en simulasie metodes voorgestel. Die implementering van die metodes vir staties onbepaalbare strukture is ingewikkeld as gevolg van die implisiete verband tussen die gedrag van die struktuur stelsel en die las effek. As 'n gevolg, moet die algoritme wat ontwikkel word vir die doel van komponent betroubaarheid analise gebaseer word op die konsepte van stogastiese eindige element metodes ("SFEM") waar 'n duidelike verband tussen die eindige element analise van die struktuur en die betroubaarheid analise verseker is. In hierdie studie word verskeie algoritmes ontwikkel wat gebaseer is op die FORM metode, Monte Carlo simulasie, en die sogenaamde "Response Surface Method" (RSM). Vir die gebruik van die FORM metode word twee verdere metodologieë ondersoek: een gebaseer op die ontwikkeling van 'n eindige element kode waar nodige verandering aan die eindige element kode self gemaak word en die ander waar 'n kommersiële eindige element pakket gebruik word. Verskillende simulasie metodes word ook geïmplimenteer naamlik Direkte Monte Carlo Simulasie (DMCS), "Latin Hypercube Sampling Monte Carlo" (LHCSMC) en sogenaamde "Updated Latin Hypercube Sampling Monte Carlo" (ULHCSMC). Verder, word RSM tesame met die simulasie metodes gebruik. In die tesis word die doeltreffendheid van die bostaande metodes deurgaans ondersoek. 'n Ten volle stogastiese eindige element metode ("FSFEM") met verandering aan die eindige element kode blyk die vinnigste benadering te wees omdat die koppeling tussen die eindige element metode pakket en die betroubaarheid analise verhoed word. Simulasie metodes kan ook effektief aangewend word vir die betroubaarheid evaluasie waar ULHCSMC as die mees doeltre end voorgekom het, gevolg deur LHCSMC en DMCS. The RSM metode is die mees komplekse metode vir algoritmiese komponent betroubaarheid analise. Die metode is egter nuttig vir sisteem betroubaarheid analise. Vir sisteem-vlak betroubaarheid analise is twee metodes oorweeg naamlik die "ß-unzipping" metode and die "branch-and-bound" metode. Die "ß-unzipping" metode is gebaseer op 'n sisteem-vlak betroubaarheid ontleding waar die struktuur op verskillende skade vlakke gemodelleer word soos toepaslik vir die hoeveelheid addisionele las paaie. In elke vlak word die sogenaamde "unzipping" intervalle gedefinieer vir die identifikasie van die kritiese elemente. Die "branch-and-bound" metode is gebaseer op die identifikasie van verskillende faling roetes van die struktuur deur uitbreiding van die falingsboom. The ondersoek van die skade toestande vir beide metodes is dieselfde. Verder kan beide metodes lei tot die ontwikkeling van 'n parallelserie model van die strukturele stelsel. Die enigste verskil tussen die twee metodes is in die soek-benadering vir die uitkenning van falingsmodus volgorde. Dit word getoon dat die "ß-unzipping" metode 'n beter algoritmiese benadering is vir die ontleding van sisteem betroubaarheid vergeleke met die "branch-and-bound" metode. Die "branch-and- bound" metode word nietemin as 'n meer robuuste metode vir die uitkenning van die falings volgorde beskou. Een moontlike manier om die doeltre endheid van die "ß-unzipping" metode te verhoog is om groter "unzipping" intervalle te gebruik, wat moontlik is vir rekenaarmatige analise. Vir so 'n analise word vier hoof modules benodig naamlik 'n algemene heel-struktuur module, 'n beskadigde-struktuur module, 'n betroubaarheid analise module en 'n sisteem betroubaarheid analise module. In die tesis word verskillende rekenaar programme ontwikkel vir beide sisteem en komponent betroubaarheid analise. Die rekenaar programme word in die aanhangsels van die tesis aangebied.
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Yang, Dong-Shan. "Deformation-based seismic design models for waterfront structures." Thesis, online access from Digital Dissertation Consortium access full-text, 1999. http://libweb.cityu.edu.hk/cgi-bin/er/db/ddcdiss.pl?9933214.
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Chen, Jou-Jun Robert. "Load and resistance factor design of shallow foundations for bridges." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44627.
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Load Factor Design (LFD), adopted by AASHTO in the mid-1970, is currently used for bridge superstructure design. However, the AASHTO specifications do not have any LFD provisions for foundations. In this study, a LFD format for the design of shallow foundations for bridges is developed.
Design equations for reliability analysis are formulated. Uncertainties in design parameters for ultimate and serviceability limit states are evaluated. A random field model is employed to investigate the combined inherent spatial variability and systematic error for serviceability limit state. Advanced first order second moment method is then used to compute reliability indices inherent in the current AASHTO specifications. Reliability indices for ultimate and serviceability limit states with different safety factors and dead to live load ratios are investigated. Reliability indices for ultimate limit state are found to be in the range of 2.3 to 3.4, for safety factors between 2 and 3. This is shown to be in good agreement with Meyerhof's conclusion (1970). Reliability indices for serviceability limit state are found to be in the range of 0.43 to 1.40, for ratios of allowable to actual settlement between 1.0 to 2.0. This appears to be in good agreement with what may be expected. Performance factors are then determined using target reliability indices selected on the basis of existing risk levels.
Master of Science
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Klostermeier, Christian. "Investigation into the capability of large eddy simulation for turbomachinery design." Thesis, University of Cambridge, 2008. https://www.repository.cam.ac.uk/handle/1810/252106.
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Lee, Chun-Sho. "A process simulation model for the manufacture of composite laminates from fiber-reinforced, polyimide matrix prepreg materials." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/40298.
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A numerical simulation model has been developed which describes the manufacture of composite laminates from fiber-reinforced polyimide (PMR-15) matrix prepreg materials. The simulation model is developed in two parts. The first part is the volatile formation model which simulates the production of volatiles and their transport through the composite microstructure during the imidization reaction. The volatile formation model can be used to predict the vapor pressure profile and volatile mass flux. The second part of the simulation model, the consolidation model, can be used to determine the degree of crosslinking, resin melt viscosity, temperature, and the resin pressure inside the composite during the consolidation process. Also, the model is used to predict the total resin flow, thickness change, and total process time. The simulation model was solved by a finite element analysis.
Experiments were performed to obtain data for verification of the model. Composite laminates were fabricated from ICI Fiberite HMF2474/66C carbon fabric, PMR-15 prep reg and cured with different cure cycles. The results predicted by the model correlate well with experimental data for the weight loss, thickness, and fiber volume fraction changes of the composite. An optimum processing cycle for the fabrication of PMR-15 polyimide composites was developed by combining the model generated optimal imidization and consolidation cure cycles. The optimal cure cycle was used to manufacture PMR-15 composite laminates and the mechanical and physical properties of the laminates were measured. Results showed that fabrication of PMR-15 composite laminates with the optimal cure cycle results in improved mechanical properties and a significantly reduced the processing time compared with the manufacturer's suggested cure cycle.Ph. D.
Books on the topic "Trusses Design and construction Mathematical models"
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Piotr, Osiński, ed. Modelling and design of gear pumps. Wrocław: Oficyna Wydawn. Politechniki Wrocławskiej, 2009.
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Pfeffer, Karin. Integrating spatio-temporal environmental models for planning ski runs. Utrecht: Koninklijk Nederlands Aardrijkskundig Genootschap, 2003.
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HF filter design and computer simulation. New York: McGraw-Hill, 1995.
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Workshop on Future Research Directions in Underwater Robotics (1994 Maui, Hawaii). Underwater robotic vehicles: Design and control. Edited by Yuh Junku, University of Hawaii at Manoa. Sea Grant College Program., National Science Foundation (U.S.), and Hawaii. Dept. of Business, Economic Development & Tourism. Albuquerque, NM: TSI Press, 1995.
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Unigovskiĭ, L. M. Ėkonomiko-matematicheskie modeli v truboprovodnom stroitelʹstve. Moskva: "Nedra", 1985.
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Tarczewski, Romuald. Topologia form strukturalnych: Naturalne i tworzone przez człowieka prototypy form konstrukcyjnych w architekturze = Topology of structural forms. Wrocław: Oficyna Wydawnicza Politechniki Wrocławskiej, 2011.
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Vanderplaats, Garret N. Gear optimization. [Washington, D.C.]: National Aeronautics and Space Administration, Scientific and Technical Information Division, 1988.
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Cherchali, C. Tunnel. Alger: Office des publications universitaires, 1993.
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Anita, Enmark, ed. Integrated modeling of telescopes. New York: Springer, 2011.
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A, Lianskiĭ I͡A. Matematicheskoe modelirovanie pri avtomatizat͡sii proizvodstva truboprovodov. Moskva: [s.n.], 1990.
Find full textBook chapters on the topic "Trusses Design and construction Mathematical models"
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Tounsi, Imen, Najeh Khalfi, Abdessamad Saidi, and Mohamed Hadj Kacem. "Modeling IoT Design Patterns Proven Correct by Construction." In Lecture Notes in Computer Science, 30–42. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-09593-1_3.
Full textAbstract:
AbstractFormal method techniques are used to model complex systems as mathematical entities. By building mathematical rigorous models of IoT design patterns, it is possible to verify their properties in a thorough fashion. In this paper, we propose a refinement-based approach for modeling IoT design patterns. It allows the modeling of correct by construction IoT design patterns. It takes advantage of formal methods by the specification of design pattern models with the Event-B method and checking the design correctness. Our goal is to design IoT patterns proven correct by construction to successfully apply them and promote their reuse. Our approach is experimented through pattern examples and we illustrate it with a case study in the health care domain.
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Velasco-Hernandez, Jorge X. "Modelling Epidemics: a Perspective on Mathematical Models and Their Use." In Moving From COVID-19 Mathematical Models to Vaccine Design: Theory, Practice and Experiences, 207–37. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815051902122010010.
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In this text, we look at several mathematical models that have been constructed during the present pandemic to address different issues of importance to public health policies about epidemic scenarios and their causes. We start by briefly reviewing the most basic properties of the classic Kermack-McKendrick model and then proceed to look at some generalizations and their applications to contact structures, co-circulation of viral infections, growth patterns of epidemic curves, characterization of probability distributions and passage times necessary to parametrize the compartments that are added to the basic Kermack-McKendrick model. All of these examples revolve around the idea that a system of differential equations is constructed from a specific epidemiological problem, has as a central and main theoretical and conceptual support the epidemiological, medical, and biological context that motivates its construction and analysis. <br>
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Celikbilek, Can, and Gürsel A. Süer. "Supply Chain Design Approaches for Dual Demand Management Strategies." In Advances in Logistics, Operations, and Management Science, 161–200. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-5225-0021-6.ch009.
Full textAbstract:
Supply chain management involves efficiently integrating suppliers, manufacturers, warehouses, stores, and customers. To survive in a highly competitive business environment, manufacturing, resource planning and scheduling and distribution operations are the significant drivers that need to be optimized within supply chain management. In this chapter, we design the supply chain system considering dual demand management strategies simultaneously for the same company, both engineer-to-order (ETO) and make-to-order (MTO). This research has been inspired from the window manufacturer which manufactures and distributes vinyl windows to meet new construction and replacement/remodeling sector demand in the State of Ohio. The company manufacturers windows based on make-to-order strategy for new construction projects and at the same time builds replacement windows to individual customer specifications in very small quantities to be used for replacement in homes. In this study, a total of 174 individual customers and six big contractors are considered throughout the State of Ohio. This paper proposes to separate products based on demand management strategy and develop different supply chain networks for each group. The idea is to design bigger facilities for high volume (make-to-order products) as transportation cost per unit is reduced due to economies of scale whereas to place smaller and more facilities for low volume engineer-to-order products to be closer to the clients where it may not feasible to carry a only few products over long distances. All in all, this study provides nested models to integrate both design and operational aspects of supply chain system in the presence high-volume and low-volume of window products. Moreover, all location, design and manufacturing operations are performed by considering new mathematical models (mixed-integer and integer mathematical models) and heuristics in engineer-to-order demand management environment. Normally-distributed, probabilistic demand environment is considered in our design and operational phase of the study. Preliminary results show that, each design has its own strategic advantage and outcome and the ultimate objective has been accomplished in our design in this study. Briefly, four manufacturing facilities are established to meet the demand of replacement/remodeling sector and two manufacturing facilities are situated to meet the demand of new construction sector. The results revealed that, 29 layered-cells and a total of 200 machines are opened and utilized for replacement/remodeling sector. Additionally, 15 layered-cells and a total of 104 machines are needed to cover the entire demand of new construction sector. Also for the new construction sector, three distribution centers are needed to facilitate the products over the region. In terms of daily cell loading and scheduling phase, the results are almost doubled in replacement/remodeling sector demand compared to new construction sector demand volume due to having more cells and machines in the new construction design strategy. The supply chain work involves location and number of manufacturing facilities, number and location of distribution centers, detailed design of manufacturing systems and performing scheduling to confirm the validity of the manufacturing system design.
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Celikbilek, Can, and Gürsel A. Süer. "Supply Chain Design Approaches for Dual Demand Management Strategies." In Supply Chain and Logistics Management, 491–526. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-0945-6.ch024.
Full textAbstract:
Supply chain management involves efficiently integrating suppliers, manufacturers, warehouses, stores, and customers. To survive in a highly competitive business environment, manufacturing, resource planning and scheduling and distribution operations are the significant drivers that need to be optimized within supply chain management. In this chapter, we design the supply chain system considering dual demand management strategies simultaneously for the same company, both engineer-to-order (ETO) and make-to-order (MTO). This research has been inspired from the window manufacturer which manufactures and distributes vinyl windows to meet new construction and replacement/remodeling sector demand in the State of Ohio. The company manufacturers windows based on make-to-order strategy for new construction projects and at the same time builds replacement windows to individual customer specifications in very small quantities to be used for replacement in homes. In this study, a total of 174 individual customers and six big contractors are considered throughout the State of Ohio. This paper proposes to separate products based on demand management strategy and develop different supply chain networks for each group. The idea is to design bigger facilities for high volume (make-to-order products) as transportation cost per unit is reduced due to economies of scale whereas to place smaller and more facilities for low volume engineer-to-order products to be closer to the clients where it may not feasible to carry a only few products over long distances. All in all, this study provides nested models to integrate both design and operational aspects of supply chain system in the presence high-volume and low-volume of window products. Moreover, all location, design and manufacturing operations are performed by considering new mathematical models (mixed-integer and integer mathematical models) and heuristics in engineer-to-order demand management environment. Normally-distributed, probabilistic demand environment is considered in our design and operational phase of the study. Preliminary results show that, each design has its own strategic advantage and outcome and the ultimate objective has been accomplished in our design in this study. Briefly, four manufacturing facilities are established to meet the demand of replacement/remodeling sector and two manufacturing facilities are situated to meet the demand of new construction sector. The results revealed that, 29 layered-cells and a total of 200 machines are opened and utilized for replacement/remodeling sector. Additionally, 15 layered-cells and a total of 104 machines are needed to cover the entire demand of new construction sector. Also for the new construction sector, three distribution centers are needed to facilitate the products over the region. In terms of daily cell loading and scheduling phase, the results are almost doubled in replacement/remodeling sector demand compared to new construction sector demand volume due to having more cells and machines in the new construction design strategy. The supply chain work involves location and number of manufacturing facilities, number and location of distribution centers, detailed design of manufacturing systems and performing scheduling to confirm the validity of the manufacturing system design.
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Goldberg, David E. "John H. Holland, Facetwise Models, and Economy of Thought." In Perspectives on Adaptation in Natural and Artificial Systems. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195162929.003.0008.
Full textAbstract:
Noted complex adaptive system researcher John H. Holland now receives acclaim from many quarters, but it is important to understand that this man and his ideas have been controversial since the beginning of his career. Genetic algorithms (GAs) were ignored or disparaged throughout the 1960s and 1970s, and even now, as these and his other ideas receive worldwide recognition in broad outline, the specifics of his mode of thought and insight are rejected by many who claim to embrace his key insights. This is a mistake. I have known John Holland for 23 years, and I have learned many things from him, but a critical influence has been his style of thought, in particular, his style of modeling. John has an uncanny knack of getting to the heart of a matter through the construction of what I call little models. Sometimes these models are verbal, sometimes they are mathematical, but they almost always shed a great deal of light on some nagging question in the analysis and design of complex systems. In this chapter, I propose to briefly explore John Holland's style of little modeling, and better understand its nature, its essence, and why some of those who embrace the broad outlines of his teaching have been slow to embrace the details of his modeling and the style of his thought. The exploration begins by recalling my own first impressions of John Holland and his style of thought, impressions made 23 years ago in a classroom in Ann Arbor, Michigan. It continues with a case study in Holland-style facetwise model building in constructing a takeover time model. It continues by integrating the takeover time model with a model of innovation on dimensional grounds. Finally, the Hollandian mode of model building is placed on intellectual terra firma with an economic argument, suggesting that the costs of modeling or thought must be weighed in relation to the model's benefits in understanding or designing a complex system.
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Yeomans, Julian Scott. "A Nature-Inspired Metaheuristic Approach for Generating Alternatives." In Encyclopedia of Information Science and Technology, Fourth Edition, 2178–87. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-2255-3.ch189.
Full textAbstract:
“Real world” decision-making often involves complex problems that are riddled with incompatible and inconsistent performance objectives. These problems typically possess competing design requirements which are very difficult – if not impossible – to quantify and capture at the time that any supporting decision models are constructed. There are invariably unmodelled design issues, not apparent during the time of model construction, which can greatly impact the acceptability of the model's solutions. Consequently, when solving many practical mathematical programming applications, it is generally preferable to formulate numerous quantifiably good alternatives that provide very different perspectives to the problem. This solution approach is referred to as modelling-to-generate-alternatives (MGA). This study demonstrates how the nature-inspired, Firefly Algorithm can be used to efficiently create multiple solution alternatives that both satisfy required system performance criteria and yet are maximally different in their decision spaces.
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Yeomans, Julian Scott. "A Nature-Inspired Metaheuristic Approach for Generating Alternatives." In Advanced Methodologies and Technologies in Business Operations and Management, 722–33. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7362-3.ch054.
Full textAbstract:
“Real-world” decision making often involves complex problems that are riddled with incompatible and inconsistent performance objectives. These problems typically possess competing design requirements which are very difficult—if not impossible—to quantify and capture at the time that any supporting decision models are constructed. There are invariably unmodeled design issues, not apparent during the time of model construction, which can greatly impact the acceptability of the model's solutions. Consequently, when solving many practical mathematical programming applications, it is generally preferable to formulate numerous quantifiably good alternatives that provide very different perspectives to the problem. This solution approach is referred to as modelling to generate alternatives (MGA). This study demonstrates how the nature-inspired firefly algorithm can be used to efficiently create multiple solution alternatives that both satisfy required system performance criteria and yet are maximally different in their decision spaces.
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Imanirad, Raha, and Julian Scott Yeomans. "Bio-Inspired Modelling to Generate Alternatives." In Encyclopedia of Business Analytics and Optimization, 361–71. IGI Global, 2014. http://dx.doi.org/10.4018/978-1-4666-5202-6.ch033.
Full textAbstract:
“Real world” decision-making often involves complex problems that are riddled with incompatible and inconsistent performance objectives. These problems typically possess competing design requirements which are very difficult – if not impossible – to capture and quantify at the time that any supporting decision models are constructed. There are invariably unmodelled design issues, not apparent during the time of model construction, which can greatly impact the acceptability of the model's solutions. Consequently, when solving many practical mathematical programming applications, it is generally preferable to formulate numerous quantifiably good alternatives that provide very different perspectives to the problem. These alternatives should possess near-optimal objective measures with respect to all known modelled objectives, but be fundamentally different from each other in terms of the system structures characterized by their decision variables. This solution approach is referred to as modelling-to-generate-alternatives (MGA). This study demonstrates how the nature-inspired, Firefly Algorithm can be used to efficiently create multiple solution alternatives that both satisfy required system performance criteria and yet are maximally different in their decision spaces.
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Yeomans, Julian Scott. "Simultaneous Modelling-to-Generate-Alternatives Procedure Employing the Firefly Algorithm." In Technological Innovations in Knowledge Management and Decision Support, 19–33. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-6164-4.ch002.
Full textAbstract:
“Real-world” decision-making applications generally contain multifaceted performance requirements riddled with incongruent performance specifications. This is because decision making typically involves complex problems that are riddled with incompatible performance objectives and contain competing design requirements which are very difficult—if not impossible—to capture and quantify at the time that the supporting decision models are actually constructed. There are invariably unmodelled elements, not apparent during model construction, which can greatly impact the acceptability of the model's solutions. Consequently, it is preferable to generate several distinct alternatives that provide multiple disparate perspectives to the problem. These alternatives should possess near-optimal objective measures with respect to all known objective(s), but be maximally different from each other in terms of their decision variables. This maximally different solution creation approach is referred to as modelling-to-generate-alternatives (MGA). This chapter provides an efficient optimization algorithm that simultaneously generates multiple, maximally different alternatives by employing the metaheuristic firefly algorithm. The efficacy of this mathematical programming approach is demonstrated on a commonly tested engineering optimization benchmark problem.
Conference papers on the topic "Trusses Design and construction Mathematical models"
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Hahn, Elad, and Offer Shai. "Construction of Baranov Trusses Using a Single Universal Construction Rule." In ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/detc2016-59134.
Full textAbstract:
The kinematic structure of Baranov trusses has been widely studied in the field of mechanism theory. Baranov trusses are seen as the fundamental planar linkages which are a basis for all other planar linkages. As such, they have been used for synthesis of mechanisms as well as their analysis. However, up until now only a limited number Baranov trusses are known and cataloged. In this paper, a method is proposed for generation of Baranov trusses using a new graph representation suitable for linkages of the sort. This method, named the Universal construction rule, is capable of generating a complete set of all feasible Baranov trusses with any number of links. The method has been proven using a mathematical basis from rigidity theory. It is based on the correspondence between Baranov trusses and Assur groups, which are reformulated in terms of graph theory to be known as Assur graphs.
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Takács, Dénes, and Gábor Stépan. "Regenerative Effect of Tire Carcass in Simple Shimmy Models." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-13158.
Full textAbstract:
A simple mechanical model of the towed elastic wheel is constructed and analyzed. The lateral deformation of the tire is described by the time delayed tire model, which considers the memory effect of the contact patch. The deformation outside the contact patch is also modeled with the help of the brush model in order to take into account the effect of the deformation waves that propagate along the circumference of the tire. The mathematical model for small oscillations is composed in the form of a functional differential equation of the neutral type. The linear stability of the towed wheel is analyzed via the construction of stability charts in the plane of the relevant engineering parameters. Simulations are also presented to illustrate the regenerative effect of the tire carcass.
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Stanway, Roger, Neil D. Sims, and Andrew R. Johnson. "Magneto-Rheological Fluids in Squeeze-Flow: Validation of Quasi-Steady Mathematical Models." In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-1176.
Full textAbstract:
Abstract It is now well established that magneto-rheological (MR) fluids can provide the basis for constructing controllable vibration damping devices. Moreover, the characteristics of MR fluids are generally compatible with industrial requirements and there is enormous scope for commercial exploitation. In this paper the authors describe the design and construction of a vibration isolator which incorporates an MR damper. The damper is unusual in that it operates in the squeeze-flow mode. A quasi-steady model of the MR damper is summarised and then extended to include the vibration isolator dynamics. Model predictions are compared with experimental results. It is shown that by employing the MR damper a wide range of control can be exercised over the transmissibility of the vibration isolator. Also the quasi-steady model is able to account for observed behaviour.
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Pe´rez Sa´nchez, Mari´a M., David Balam Tamayo, and Ricardo H. Cruz Estrada. "Design and Construction of a Dual Axis Passive Solar Tracker, for Use on Yucata´n." In ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/es2011-54428.
Full textAbstract:
In this investigation, we propose to use the thermal expansion properties of metals in a bimetallic strip as a base of operation of a passive solar tracker. The design process involved the determination of all aspects necessary to make a first prototype based on requirements and operating conditions previously identified. Predictive mathematical models were used to decide critical aspects. Certainly, some aspects of the design were determined experimentally to ensure the proper functioning of the solar tracker. The product of this research was the construction of a prototype with the ability to be placed with an average angular difference of 25 degrees to the position of the sun, under controlled conditions. The device created is a passive solar tracker with two degrees of freedom, one used to track the sun daily, operates automatically actuated by the bimetallic strip, the other one is manually adjusted in seasonal changes to compensate the variation in the decline of the sun along the year. Although the accuracy of the system is low, the cost of production is well below the purchase price of any commercial solar tracker, and its construction is simple, making it an economical alternative to increase the production of photovoltaic energy on a PV panel currently fixed.
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Solov'eva, Anastasiya, Sergey Solov'ev, Leonid Shevcov, and Valeriya Piven'. "ANALYSIS OF RELIABILITY OF FLAT TROUSERS BASED ON P-BLOCKS." In PROBLEMS OF APPLIED MECHANICS. Bryansk State Technical University, 2020. http://dx.doi.org/10.30987/conferencearticle_5fd1ed0352ef87.51750998.
Full textAbstract:
The paper considers an approach to the probabilistic analysis of the reliability of flat trusses based on
p-boxes (probability boxes, p-boxes). Modeling of stochastic parameters in the form of p-blocks is justified for building pavement structures due to significant variability of climatic loads, variations in the physical and mechanical properties of coating materials, installation tolerances and other uncertainties. The advantage of this method is the possibility of using it with incomplete (limited) statistical information - when it is difficult to determine the probability distribution law or the parameters of a random variable. Variants of constructing p-blocks are illustrated for various types of incompleteness of statistical information: for an unknown distribution law using Chebyshev's inequality, for interval estimates of the parameters of random variables, etc. Information is given on the possibility of performing algebraic operations on p-blocks. The probability of no-failure operation with such approaches will be presented as an interval of values. If the interval is too wide (uninformative), the quality of statistical information should be improved by conducting additional tests. The paper presents mathematical models of limiting states taking into account the variability of the basic random variables. The possibility of using the proposed approach in the framework of most practical problems in the construction industry for assessing the safety of statically definable farms is shown. As a result, a formula is given for assessing the reliability of a truss as a conditional mechanical sequential system (in terms of the theory of reliability), taking into account the lack of information about the dependence of its elements. The algorithm for analyzing reliability is considered on a numerical example. The developed approach can be used for other types of statically definable hinge-rod systems.
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Schneider, Peter, Andreas Köhler, Sven Reitz, and Roland Jancke. "Behavioral and Network Modeling for Efficient Design of Adaptive Systems." In ASME 2014 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/smasis2014-7733.
Full textAbstract:
Adaptive systems usually implement the entire cycle of measurement and data acquisition, signal conditioning and processing as well as process control. Especially, for the design of adaptive signal processing and control algorithms detailed insight into the interaction between the system components is of crucial importance. System level simulations are a suitable way to gain insight and to support algorithm design and test. However, an adequate mathematical representation of the system behavior is needed to take advantage of this method. In the paper a generic methodology for behavioral modelling is introduced. Important steps of the modelling process are described and illustrated by two examples. For a gyro sensor system the combination of different modeling methods is demonstrated. Network modeling and in particular an approach for the construction of network models for magnetic systems is discussed for an electromagnetic switching device.
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Mu¨ller, Andreas. "Geometric Characterization of the Configuration Space of Rigid Body Mechanisms in Regular and Singular Points." In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84712.
Full textAbstract:
The kinematics of rigid body mechanisms is considered from a differential-geometric perspective. Geometric properties of a mechanism are intrinsically determined by the topology of its configuration space — the solution set of closure functions. The mechanism kinematics is usually characterized by the tangent space and tangent cone to the configuration space, i.e. by locally considering its topology. There are, however, mechanisms for which this is not sufficient. Generally, beside the topology, a complete picture of the kinematics needs both, the configuration space and the ideal generated by the closure functions. Tangent spaces/cones are differential-geometric objects associated to a variety. Two additional objects are introduced in this paper: the kinematic tangent space and the kinematic tangent cone. Three locally equivalent models for the mechanism kinematics are introduced. Due to their different mathematical nature the different models admit to apply specific mathematical tools. The analysis of model I is based on Lie group and screw algebraic methods, while model II and III are analyzed using methods from algebraic geometry. A computationally efficient algorithm for the construction of the kinematic tangent cone is presented. Its application is shown for several examples. A novel mechanism is presented of which the differential and local degree of freedom are different in regular points, so-called ‘paradox-in-the-small’.
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Natke, H. Günther, N. Cottin, and M. Oeijeklaus. "Some Recent Advances in Model Updating." In ASME 1997 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/detc97/vib-4142.
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Abstract Model updating has now become a well-known field of application in engineering. The following is restricted to spatially discretized mathematical models. First, the classical sensitivity (including sensitivities of the measuring errors) and the selective sensitivity within updating are mentioned. The latter leads to a computational construction of selective excitation force vectors. Reliable estimates can then be obtained. The solutions of updating methods which result in nonlinear equations with respect to the parameters to be estimated are the global minima of these equations. This problem will be solved by applying interval arithmetic. Additionally, hints are given with regard to an efficient arithmetical procedure by massive parallel computing. Large-sized problems need the reduction of the model orders. Substructuring and incomplete modal transformations are the methods that are well-known and applied. Some necessary and sufficient conditions are discussed in this context. Examples will demonstrate the subjects discussed. The outlook mentions more advanced signal processing and identification methods which take non-stationary processes and non-linearly behaving systems into account.
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Hu, Zhen, Chao Hu, Zissimos P. Mourelatos, and Sankaran Mahadevan. "Dynamic Model Discrepancy Quantification in Simulation-Based Design of Dynamical Systems." 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/detc2018-85374.
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Discrete-time state-space models have been extensively used in simulation-based design of dynamical systems. These prediction models may not accurately represent the true physics of a dynamical system due to potentially flawed understanding of the system, missing physics, and/or numerical approximations. To improve the validity of these models at new design locations, this paper proposes a novel dynamic model discrepancy quantification (DMDQ) framework. Time-instantaneous prediction models are constructed for the model discrepancies of “hidden” state variables and are used to correct the discrete-time prediction models at each time step. For discrete-time models, the “hidden” state variables and their discrepancies are coupled over two adjacent time steps. Also, the state variables cannot be directly measured. These factors complicate the construction of the model discrepancy prediction models. The proposed DMDQ framework overcomes these challenges by proposing two discrepancy modeling approaches: an estimation-modeling approach and a modeling-estimation approach. The former first estimates the model discrepancy and then builds a non-parametric prediction model of the model discrepancy; the latter builds a parametric prediction model of the model discrepancy first and then estimates the parameters of the prediction model. A subsampling method is developed to reduce the computational effort in building the two types of prediction models. A mathematical example and an electrical circuit dynamical system demonstrate the effectiveness of the proposed DMDQ framework and highlight the advantages and disadvantages of the proposed approaches.
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Xiao, Mi, Liang Gao, Xinyu Shao, Haobo Qiu, and Li Nie. "Comparison of Gene Expression Programming and Common Metamodeling Techniques in Engineering Design." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-47130.
Full textAbstract:
To reduce the tremendous computational expense of implementing complex simulation and analysis in engineering design, more and more researchers pay attention to the construction of approximation models. The approximation models, also called surrogate models and metamodels, can be utilized to replace simulation and analysis codes for design and optimization. Commonly used metamodeling techniques include response surface methodology (RSM), kriging and radial basis functions (RBF). In this paper, gene expression programming (GEP) algorithm in evolutionary computing is investigated as an alternative technique for approximation. The performance of GEP is examined by its innovative applications to the approximation of mathematical functions and engineering analyses. Compared to RSM, kriging and RBF, GEP is demonstrated to be more accurate for the small sample size. For large sample sets, GEP also shows good approximation accuracy. Additionally, GEP has the best transparency since it can provide explicit and compact function relationships and clear factor contributions. Overall, as a novel metamodeling technique, GEP exhibits great capabilities to provide the accurate approximation of a design space and will have wide applications in engineering design, especially when only a few sample points are selected for approximation.