Дисертації з теми "Equivalent fatigue load method"
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Prinsloo, Etienne Pieter Willem. "Fatigue equivalent static load: Methodology for the design of vehicle structures." Diss., University of Pretoria, 2003. http://hdl.handle.net/2263/25966.
Повний текст джерелаDissertation (M Eng (Mechanical Engineering))--University of Pretoria, 2003.
Mechanical and Aeronautical Engineering
unrestricted
Warneboldt, Iona. "Multiaxial fatigue design of elastomeric parts using Equivalent Fatigue Loads." Electronic Thesis or Diss., Brest, École nationale supérieure de techniques avancées Bretagne, 2022. http://www.theses.fr/2022ENTA0002.
Повний текст джерелаThis thesis introduces an Equivalent Fatigue Load (EFL) approach for the multiaxial fatigue design of elastomeric parts. As direct Finite Element Analysis (FEA) calculations of automotive in-service loads (Road Load Data (RLD)) are too expensive, the objective is to derive simplified load blocks as a realistic input for numerical damage calculations. Three streps are applied for this method: the localization method, the material damage function and the EFL determination process. Various fatigue tests have been conducted (415 samples) to study the fatigue behavior of this complex type of relaxing and non-relaxing multiaxial loading on natural rubber specimens. Lifetime and crack features are analyzed to eventually introduce an appropriate critical planebased fatigue measure and to establish a novel mean strain effect model. This criterion is generalized throughout an original critical plane search method. To estimate the local mechanical response (localization method), this thesis identifies an axes-coupling method that is fitted for the nonlinear nature of elastomeric structures. It is based on the multiplicative decomposition of the deformation gradient tensors. These two steps are then implemented in the framework of the EFLdetermination process. For this, a global optimization method is added to determine the simplified load blocks, causing locally the same fatigue behavior in the given structure. The computational costs of this optimization are reduced by only considering a subset of the most damaged material points for EFLdetermination. Finally, the method has been challenged on a specimen to outline its capabilities and to validate the approach
Rinehart, Adam James. "Effects of localized geometric imperfections on the stress behavior of pressurized cylindrical shells." Texas A&M University, 2003. http://hdl.handle.net/1969/37.
Повний текст джерелаSANTOS, RODRIGO BIANCHI. "PARAMETRIC OPTIMIZATION OF TRUSS STRUCTURES UNDER DYNAMIC LOADING USING THE EQUIVALENT STATIC LOAD METHOD." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=35802@1.
Повний текст джерелаCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Otimização estrutural sujeita a carregamentos dinâmicos é um problema desafiador em vários aspectos, a começar pelo grande número de restrições que devem ser atendidas em todos os instantes de tempo. Além disso, o custo computacional para avaliar os gradientes destas restrições é bastante elevado e requer um grande espaço de armazenamento. Na literatura, alguns métodos reduzem o número de restrições avaliando em instantes de tempo selecionados, como o pior caso por exemplo, ou ainda constroem um funcional equivalente, integrando as restrições violadas ao longo do tempo, assim eliminando essa dependência. Nesta dissertação, o método do Carregamento Estático Equivalente (ESL) é utilizado, no qual o problema dinâmico original é transformado em uma sequência de subproblemas de otimização linear estática com múltiplos casos de carga. Um atrativo deste método é a possibilidade da solução de problemas não lineares, evitando o alto custo devido às repetidas análises estruturais e cálculos das restrições. Problemas clássicos de treliças planas submetidas a carregamentos dinâmicos são resolvidos utilizando o método ESL. A função a ser minimizada é a massa da treliça, que está sob restrições de tensão e deslocamento, onde as variáveis de projeto são as áreas da seção transversal dos membros. Além disso, uma interface utilizando ANSYS e MATLAB é desenvolvida para uma abordagem modular, na qual a análise via elementos finitos e a otimização possam ser realizadas separadamente. Este processo viabiliza a otimização de estruturas que apresentam comportamentos não lineares a partir da utilização de diversos softwares comerciais disponíveis no mercado.
Structural optimization subject to dynamic loading is a challenging problem in many aspects, starting with the large number of constraints that must be respected at all instants of time. Furthermore, the computational cost to evaluate the gradients of these constraints is significantly high and requires a large storage space. In the literature, some methods reduce the number of constraints evaluating at selected instants of time, such as the worst case. Alternatively, a single equivalent functional is constructed to eliminate the time dependence by integrating the violated constraints over time. In this work, the Equivalent Static Load (ESL) method is used, in which the original dynamic problem is reduced into a number of static linear optimization problems with multiple load cases. An attractive feature of this method is the possibility of solving non-linear problems, avoiding the high cost due to repeated structural analyzes and constraint calculations. Classical problems of plane trusses subjected to dynamic loads are solved using the ESL method. The function to be minimized is the truss mass, which is subjected to stress and displacement constraints, where the design variables are the cross-sectional areas of the members. In addition, an interface using ANSYS and MATLAB was developed for a modular approach, in which finite element analysis and optimization can be performed separately. This process makes possible the optimization of structures that present non-linear behavior from the use of most structural analysis software packages available on the market.
Bahai, Hamid R. S. "A hybrid method for load, stress and fatigue analysis of drill string screw connectors." Thesis, Queen Mary, University of London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284406.
Повний текст джерелаCampbell, Patrick George. "Critically examining the capacity of wellness measures as a method of monitoring training load and the athlete training response." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/134391/1/Patrick_Campbell_Thesis.pdf.
Повний текст джерелаJonsson, Björn. "A digital image correlation method for detection of fatigue cracks in non-load carrying T-joints." Thesis, KTH, Lättkonstruktioner, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-234905.
Повний текст джерелаSvetsade konstruktioner under dynamisk belastning blir utmattningshållfastheten ofta en begränsande faktor. Praxis har varit att öka materialtjockleken för att minska nominella spänningen, vilket fungerar bra. Användning av höghållfasthetsstål som tillåter slankarekonstruktioner och viktminskningspotential är det tillvägagångssättet inte aktuellt.Ökad kontroll av svetskvalitet i kombination med kunskap om vilka defekter som påverkar utmattningslivslängden ger möjligheter till viktoptimering. I detta examensarbete har en metod för sprickdetektering under utmattningstest av ickelastöverförande T-förband testats. Provstavar tillverkade av 6mm Strenx 960MC stål. DIC analys genomfördes på bildrutor inspelade av en höghastighetskamera med hypotesen att sprickpropagering detekteras vid 10% relativ töjningsökning per 10 000 cykler.Validering utförs med hjälp av ”beachmarks” från varierande spänningsnivåer under utmattningstestet. Bildsekvensenerna som fångas med höghastighetskameran sammanfaller med slutet på ena spänningsnivån. Antalet ”Beachmarks” visar en sprickfront på ca 200 300μm vid 10% relativ töjning.
Gilbert, Andy Michael. "Validation of a laboratory method for accelerated fatigue testing of bridge deck panels with a rolling wheel load." Thesis, Montana State University, 2012. http://etd.lib.montana.edu/etd/2012/gilbert/GilbertA0512.pdf.
Повний текст джерелаLindholm, Martin, Metin Uçar, and Nermin Dzanic. "The load carrying unit of articulated haulers : Analysis of the welded connections." Thesis, Växjö University, School of Technology and Design, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-5818.
Повний текст джерелаDetta examensarbete handlar om finita element analys av svetsade förband i korgen på Volvo dumpern A40E. Det genomfördes i samarbete med Volvo CE i Braås. Uppgiften var att ge företaget en lämplig lösning för att minska mängden svetsskarvar på den främre delen av lastenheten. För att uppnå detta har en rad analyser genomförts med hjälp av CATIA och ANSYS på både de befintliga och de justerade (potentiella ersättare) svetsade förbanden. Analyserna visar att utmatningshållfastheten av svetsade förband huvudsakligen beror på inbränningsdjupet. Med andra ord, förstärka svetsförband genom större inbränning är mer fördelaktigt än att använda mer svets på utsidan. Slutsatsen blev att både produktionstid och kostnad kan minskas genom justering av de svetsade förbanden. Eftersom svetsförband på lastenheten är sammankopplade bör mer omfattande studier som inkluderar alla svetsar genomföras för att uppskatta effekterna av liknande justeringar.
The work presented in this master thesis is about the finite element analysis of the welded connections in load carrying unit of the articulated hauler, Volvo A40E. It was performed in cooperation with Volvo CE in Braås. The task was to provide the company with an appropriate solution to reduce the amount of weld used on the front part of the load carrying unit. To accomplish this, a series of analyses utilising CATIA and ANSYS was performed on both existing and adjusted (potential replacement) welded connections. The analyses brought to light the fact that the fatigue resistance of welded connections significantly depends on the penetration depth. In other words, reinforcing the welded connections by deeper penetration is more beneficial than providing support from outside through thicker weld. It was concluded that applying adjusted welds lessens both the production time and cost. Nevertheless, since the welds on the load carrying unit are correlated; more extensive studies covering all welds should be carried out to estimate the impacts of similar replacements.
Dossou, Dossouvi. "Fatigue thermique d'un polycarbonate : modèle de prédiction de durée de vie d'éprouvettes entaillées." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL135N.
Повний текст джерелаPeprník, Pavel. "Mostový jeřáb 125t." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230007.
Повний текст джерелаGünther, Thomas [Verfasser], and A. [Akademischer Betreuer] Albers. "Methode zur Optimierung von Motor-Dauerlauf-programmen als Teil des Validierungsprozesses auf der Basis thermomechanisch schädigungsgleicher Ersatzkollektive am Beispiel eines Al-Si-Zylinderkopfes = A method for optimization of engine durability-test-programs as a part of the validation process based on a load-collective with thermomechanical equivalent damage by the example of an Al-Si cylinder head / Thomas Günther ; Betreuer: A. Albers." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/123507255X/34.
Повний текст джерелаNeto, Rogerio Silveira Bezerra. "Análise comparativa de pavimentos dimensionados através dos métodos empírico do DNER e mecanístico e proposta de um catálogo simplificado de pavimentos para a região de Campo Grande (MS)." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/18/18137/tde-03052004-153504/.
Повний текст джерелаThis study has as main objective to compare structures of flexible pavements designed by two different methods, the DNER empirical method and the mechanistic method, being considered some paving materials used in the area of Campo Grande, state of Mato Grosso do Sul. As secondary objectives, it can stand out the obtaining of the mechanical properties of these materials and the proposal of a simplified catalog of flexible pavements for the referred area. For the accomplishment of the research, typical materials of subgrade, base course and surface layer were collected. After their characterizations, tests of compaction, CBR and repeated load were executed. The mechanistic analyses were accomplished being used the software FEPAVE, that takes into account the non-linear resilient modulus of the materials, being considered the reliability criterion. Starting from the comparative analysis of the design methods, it was observed that the structures established by the mechanistic method can be identical, more slender or less slender to the ones obtained by the empirical method, depending on the type of the material that constitutes the layers and the reliability level adopted. It was also verified that the characterization of the materials by repeated load tests (resilient modulus, fatigues life and permanent deformation) is indispensable when one want to project a pavement being used the mechanistic method. Finally, a simplified catalog of flexible pavements was elaborated for the area of Campo Grande MS, with the intentions of to contemplate the use of local materials and to aid the engineers in the conception of their projects
Susetyo, Budi. "Modélisation de l'impédance harmonique de charges agrégées." Grenoble INPG, 1995. http://www.theses.fr/1995INPG0027.
Повний текст джерелаJain-Zhi, Yeh, and 葉建志. "Fatigue Analysis of Go-kart Frame by Equilibrium-Equivalent Structure Stress Method." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/82105801661379591489.
Повний текст джерела大葉大學
機械工程研究所碩士班
94
Competition Go-kart is not equipped with differential gear and suspension system, so it is very important to raise tire fraction by the ability of load transfer of kart frame. In this study, Finite Element Analysis (FEA) was used to perform static, dynamic, and modal analyses of the kart frame. With some designed clamps used in static and dynamic tests, experiments on the characteristics of the frame were conducted. Every test about the mechanical property was done to validate the accuracy of the analytical theory and design method. Most components of machines have the characteristic of accumulating of damage during cyclic loading, and this is the reason of fatigue of material. Generally, S-N curve is used to describe the life of material in fatigue test, but actually, it must be combined with suitable fatigue mode to obtain the value of accumulation of damage of the material. In the analysis of fatigue life of kart frame, by observing the results of static test, it was found that the welding point near the front wheel of frame may be the critical location, and stress concentration occurred. Also, the stress could not be precisely calculated at the weld toe due to the singularity of stress. Therefore, by the method of equilibrium-equivalent structural stress and FEA, the structure stress at the welding point was precisely calculated. By incorporating the Manson-Coffin equation of strain and fatigue life, the fatigue life of whole frame was obtained. In the simulation racing track, the path was too short and could not solve the working life of chassis by strain amplitude. When the strain amplitude was 10 times amplified, the 165 cycle loading history of the chassis could be obtained.
Su, Wen-Shyong, and 蘇文雄. "Computational Method of EndoFEM on Fatigue Crack Opened/Closure Load." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/00392131442595071251.
Повний текст джерелаWang, Yi-Ji, and 王亦如. "Application of LRC Method on the Equivalent Static Wind Load of Large Span Structures." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/42367103163505125396.
Повний текст джерела淡江大學
土木工程學系碩士班
99
Since large span roof structures generally comprise lots of members to resist loads, the time history analysis for these members due to wind loads is time costly. For this reason, this main objective of this thesis is to investigate the effects of wind loads on these types of structures using LRC method. The main advantages of this method are that the peak response of each member can be obtained and then the equivalent static wind loads can be generated and used for structural design. The wind pressure data used in the thesis were adopted from the wind tunnel tests for semi-circular roof structures. The data were transformed into the nodal loads in the structure and then used for the analysis. The roof structures with height-span ratios ranging from 0.2 to 0.5 are analyzed. The comparison of the peak responses of structural members obtained from LRC and time history method indicates that the difference is approximately 20%. This discrepancy is mainly due to the correlations among the large number of nodes. However, LRC is still a good method for use in the structural design.
Chen, Chia-Lin, and 陳佳林. "The Effects of Protocol (Combinations of Pace and Load) and Gender on the Muscular Fatigue of Elbow after Performing Repetitive Tasks with Equivalent Loadings." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/96517184053036066768.
Повний текст джерела國防管理學院
後勤管理研究所
93
Present study intends to evaluate the effects of gender and fatigue protocol on the fatigue of elbow. Ten subjects, 5 males and 5 females, were recruited. A nested-factorial design is employed, in which the independent variables include gender, subject (nested within gender), and fatigue protocol. The fatigue protocol, combinations of cycle time (CT=6 or 12 sec) and load (25%, 37.5%, and 50% MVC (Maximum Volitional Contraction)), is a 20-min repetitive task of elbow extension/flexion. Each cycle time consists of both exertion and relax and the cumulative dose (load*exertion time) over the 20-min duration is the same. The dependent variables are the shift in MVC (denoted by ΔMVC) after completing the fatigue protocol, the heart rate (HR) and electromyography during the protocol, the subjective fatigue perceived assessed by Borg’s 10-point scale after completing the fatigue protocol, and the recovery in MVC after the protocol evaluated every minute for successive ten times. For the ΔMVC, male had a greater reduction in MVC (male ΔMVC=-4.3 kg, female ΔMVC=-2.2 kg), and the protocol of CT=6 combining load=50%MVC had the greatest reduction in MVC (ΔMVC=-4.9 kg) among all 6 protocols. As to HR, female average HR (83.3 beats/min) is higher than that of male (78.1 beats/min), and the HR for CT=6 is higher than that of CT=12. Next for the subjective fatigue perceived, it is general that heavier the load, higher the fatigue perceived. This fact is also true for the EMG observed during the protocol. Detailed about the MVC recovery is also discussed.