Dissertations / Theses: '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.

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This study is concerned with the design of vehicle structures through the use of Fatigue Equivalent Static Loads (FESL). A large percentage of failures of mechanical structures can be attributed to fatigue. Furthermore, it is also generally accepted that defective structural design is mostly caused by insufficient knowledge of the input loading. The fatigue loads experienced by vehicle structures are especially difficult to quantify. In the current competitive markets, it is essential to use a pro-active, timely and cost effective process to solve fatigue related problems. The heart of the FESL methodology is the ability to condense a large amount of input load data into a single fatigue load. This is achieved by calculating the damage of the measurements and converting it to an equivalent stress, through the use of a calibration matrix obtained from a unit-load finite element analysis. A Fatigue Equivalent Static Load can now be determined, and the vehicle structure can be evaluated for durability.
Dissertation (M Eng (Mechanical Engineering))--University of Pretoria, 2003.
Mechanical and Aeronautical Engineering
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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.

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Trois étapes sont mises en oeuvre ici : la méthode de localisation, la fonction de dommage matériau et le processus de détermination des chargements équivalents en fatigue (CEF). De nombreux essais de fatigue ont été réalisés (415 au total) pour étudier le comportement en fatigue sous chargement multiaxial relaxant et non relaxant sur des éprouvettes de caoutchouc naturel. La durée de vie et les caractéristiques des fissures sont analysées pour finalement introduire un critère de fatigue approprié basé sur le plan critique et permettant de rendre compte de l'effet de déformation moyenne. Ce critère est généralisé à travers une méthode originale de recherche du plan critique. Pour estimer la réponse mécanique locale (méthode de localisation), une méthode de couplage des axes adaptée à la nature non linéaire des structures élastomères est proposée. Elle est basée sur la décomposition multiplicative des tenseurs du gradient de la déformation. Ces deux étapes sont ensuite mises en oeuvre dans le cadre du processus de détermination du CEF. Pour cela, une méthode d'optimisation globale est ajoutée pour déterminer les chargements simplifiés, induisant partout localement le même endommagement en fatigue dans la structure étudiée que le RLD. Le temps de calcul de cette optimisation est réduit en ne considérant qu'un sous-ensemble de points matériels, les plus endommagés, pour la détermination du CEF. Enfin, la méthode a été testée sur une éprouvette afin de souligner ses capacités et de valider l'approche
This 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

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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.

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SANTOS, 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.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO 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.

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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.

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Campbell, 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.

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Athlete load monitoring is standard in high-performance sports environments, and is principally utilised to maximise performance and physiological adaptations, while limiting the deleterious costs of training and competition. Modified wellness questionnaires are a popularly utilised method of load monitoring, and are commonly used to evaluate the athlete training response from a holistic viewpoint. However, there remains a lack of evidence to support their use. This thesis investigated the dosage effects of wellness measures on controlled acute and chronic modulations in training intensity and overall volume; and the associations between wellness and psychological states, load monitoring markers and common performance measures.

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Jonsson, 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.

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In dynamical loaded welded structures fatigue life is often a limiting factor. Common practise is to reduce nominal stress by increased material thickness which leads to oversized, heavy structures. Those practises are replaced by improvement of production and designingtechniques to utilize better properties of high strength steels.When improving for example quality of welds, issues can occur that standards today did not consider and new test methods can be valuable.In this thesis a method for crack detection in non-load carrying T-joints have been tested. Specimens are made from 6mm Strenx 960MC high strength steel. DIC-analyses is made on frames captured be a high-speed camera during fatigue testing. Hypothesis is that crackpropagation starts when relative strain is higher than 10% per 10 000 cycles.Validation of the method is done by beachmarks from variable stress range during the fatigue test. With the same occurrence as framesets for DIC-analyse. Number of beachmarks agree well with the segment when relative strain indicates crackpropagation in a point at the weld toe.
Svetsade 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.

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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.

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The Western Transportation Institute (WTI) was engaged by the California Department of Transportation (Caltrans) to investigate the performance of various bridge deck rehabilitation surface treatments. This study requires that full-scale reinforced bridge deck slabs be tested in a laboratory environment. The deck slabs are to be tested by applying repeated passes of a rolling wheel load to damage the slabs to certain levels of deterioration. The slabs will be mounted in a frame for testing to impose specific support constraints necessary to generate realistic box girder bridge behavior. The intent of the present study was to design the panel support frame and validate that it provides the required restraint conditions needed for testing as well as to determine if it will be possible to generate the damage required in future deck slabs in a realistic time frame. This validation was accomplished by performing an experimental study in which a sample test slab was loaded to failure in one of the bays of the support frame. The slab was loaded with a stationary hydraulic jack over a contact area resembling that of a standard dual tire footprint. In addition, the finite element modeling software, ANSYS, was used to model the laboratory test to aid in interpreting the experimental results. The results from the laboratory test and the related findings from the finite element model were presented in terms of cracking behavior, deflection histories, strain measurements in the steel reinforcement, ultimate capacity, and mode of failure. The results were used in conjunction with the finite element model to validate the performance of the support frame. It was determined that the support frame provides the restraint conditions needed to create the in-service stress conditions of interest in the bridge deck slabs. A fatigue life model that was developed by past researchers was used to assess the expected performance of the deck specimens under the proposed rolling wheel loads.

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Lindholm, 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.

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Detta 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.

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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.

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Le polycarbonate est de plus en plus utilisé en ingénierie à cause de ses bonnes propriétés mécaniques. Il n'existe pas de procédure de dimensionnement bien établie pour tenir compte de la présence d'une concentration locale de déformation ou de contrainte dans une structure soumise à un chargement cyclique. Nous proposons un modèle de prévision de la durée de vie d'éprouvettes entaillées d'un polycarbonate en fatigue thermique. Le banc d'essai de fatigue thermique conçu est constitué d'un bâti assurant le maintien de l'éprouvette, d'un système de chauffage et de refroidissement, d'une unité de mesure et de régulation de la température, d'un système extensometrique ainsi que d'une unité informatique permettant la réalisation des cycles thermiques et l'asservissement précis des équipements. Des essais en traction isotherme sont réalisés pour déterminer les lois de comportement de notre polycarbonate dans l'intervalle de température des cycles thermiques. Les essais de cyclage thermique sur des éprouvettes lisses permettent de déterminer les lois de fatigue du matériau en terme d'énergie de déformation dissipée. L’analyse par la méthode des éléments finis permet de déterminer les coefficients de concentration de contrainte et la densité d'énergie de déformation dissipée en fond d'entaille. Notre modèle est obtenu en combinant la loi de fatigue du matériau et la loi d'évolution de la densité d'énergie de déformation dissipée en fond d'entaille en fonction du coefficient de concentration de contrainte. Ce modèle simple peut être utilisé pour déterminer la résistance à la fatigue d'autres matériaux et sous différents modes de sollicitation

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Peprník, Pavel. "Mostový jeřáb 125t." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230007.

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This diploma thesis deals with the assessment of drafted steel construction of overhead travelling crane by using finite element method. The crane’s lifting capacity is 125t/32t. It is going to be placed in hall of Slovácké strojírny, a. s. in Uherský Brod. Span of the crane is 25.8 meters, wheelbase is 6.7 meters and lifting height is 17 meters. My work contains analysis and assessment of crane construction with a load of fatigue according to ČSN 27 0103.

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Günther, 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.

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Neto, 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/.

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Este estudo tem como objetivo principal comparar estruturas de pavimentos flexíveis projetadas através dos métodos empírico do DNER e mecanístico, considerando-se alguns materiais de pavimentação utilizados na região de Campo Grande, estado do Mato Grosso do Sul. Como objetivos decorrentes, pode-se destacar a obtenção das características resilientes e de fadiga destes materiais e a proposta de um catálogo simplificado de estruturas de pavimentos para a referida região. Para a efetivação da pesquisa, foram coletados materiais típicos do subleito da região e daqueles mais utilizados na composição de bases e capas dos pavimentos locais. Após as suas caracterizações, realizaram-se ensaios de compactação, CBR, triaxiais cíclicos e compressão diametral estática e dinâmica. As análises mecanísticas foram realizadas utilizando-se o programa computacional FEPAVE, que leva em conta o comportamento elástico não-linear dos materiais, considerando-se o critério de confiabilidade. A partir da análise comparativa dos métodos de dimensionamento, observou-se que, ora as estruturas estabelecidas pelo método mecanístico são idênticas às determinadas pelo método do DNER, ora são mais esbeltas, ora são menos esbeltas, dependendo do tipo de material que constitui as camadas e do nível de confiabilidade adotado. Verificou-se ainda que a caracterização dos materiais através dos ensaios de módulo de resiliência, vida de fadiga e deformação permanente é imprescindível quando se deseja projetar um pavimento empregando-se o método mecanístico. Por fim, elaborou-se um catálogo simplificado de pavimentos flexíveis para a região de Campo Grande MS, com as intenções de contemplar o uso de materiais locais e auxiliar os engenheiros na concepção de seus projetos
This 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

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Susetyo, Budi. "Modélisation de l'impédance harmonique de charges agrégées." Grenoble INPG, 1995. http://www.theses.fr/1995INPG0027.

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Les applications de l’électronique de puissance contribuent à la pollution harmonique des réseaux électriques. Pour estimer le niveau de distorsion de tension, les différents composants du réseau doivent être modélisés en régime harmonique, en particulier les charges consommatrices, industrielles, commerciales et domestiques. L’étude concerne la modélisation de l’impédance harmonique des charges qui peuvent être séparées en deux grandes catégories: les charges passives et les charges dites actives qui réalisent une conversion d’énergie électromécanique. Les modèles disponibles pour les charges élémentaires sont récapitules en termes de complexité et de précision. Puis une méthode d’agrégation est développée, permettant d'obtenir un circuit équivalent d'ordre minimal et de structure compatible avec celle du réseau. La méthode d'identification des paramètres de ce circuit est basée sur une représentation fréquentielle de l’impédance harmonique, afin d'obtenir une réponse qui coïncide avec celle du réseau réel. Ce modèle agrège est utilise pour étudier la sensibilité de l’impédance harmonique aux variations aléatoires des paramètres caractéristiques du réseau et des charges.

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Jain-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.

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碩士
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.

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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.

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Wang, 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.

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碩士
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.

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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.

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碩士
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.

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Dissertations / Theses on the topic 'Equivalent fatigue load method'

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