PSI - Issue 38

Amaury Chabod et al. / Procedia Structural Integrity 38 (2022) 382–392 Amaury CHABOD / Structural Integrity Procedia 00 (2021) 000 – 000

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to any hot spot, whatever radius or notch belong to structure, and we are able to apply more precise and exhaustive fatigue analyses on the whole component.

6. Conclusion This paper shows how to turn strain gage discrete information into a fatigue damage analysis on the whole structure. Firstly, strain gage optimization uses the modal basis to optimize the strain gages positions and orientations, so that we maximize the strain gage responses and the representativity for all modes. The next step is to validate the FE model representativity as compared to the test with known load time history and a so-called virtual strain gage process. Then, strain gage measurement is performed in service with unknow loads, to obtain acceleration effect on the component. Using modal stresses and a load reconstruction process, the modal coordinates are deduced. Thereafter, stress histories are reconstructed on all nodes of FE model, combining modal histories with modal stresses thanks to the principle of modal superposition and assuming model linearity. Finally, we are then able to perform fatigue damage analyses on the whole FE model. References Wickham, M. J., 1992, “Optimal Experimental Design for the Instrumentation of a Multi- Axis Load Transducer.”, Ph.D. thesis, University of Minnesota Wickham, M. J., Galliart, D. R., Nachtsheim, C. J. and Riley, D. R., 1994, "The Design and Application of a Multi-Axis Load Transducer.", SAE paper 940250. Wickham, M. J., Riley, E. R. and Nachtsheim, C. J., 1992, "The Optimal Design of a Multi-Axis Load Transducer", Proceedings of the 1992 ASME International Computers in Engineering Conference and Exposition, G. A. Gabriele, ed., ASME, New York, Vol. 1, pp. 175-179. Wheeler, B., 2011, "AlgDesign, Algorithmic Experimental Design", h. www.rdocumentation.org/packages/AlgDesign/versions/1.1 7.3/topics/optFederov Hoffman, K., 1989, "An Introduction to Measurements using Strain Gages.", Hottinger Baldwin Messtechnik, GmbH, Darmstadt. Munson, K., Mentley, J., 2015, Benefits of Load Reconstruction nCode Webinar. He J., Fu Z. F., 2001, Modal Analysis, Butterworth-Heinemann, pp. 25-28, p. 33 Dhatt G., Thouzot G., 1984, Une présentation de la méthode des éléments finis, Editeur Paris et Les Presses de l’Université Laval Québec, p157, p370, p380-410 Craig R. Jr., Kurdila A., 2006, Fundamentals of Structural Dynamics, Second Edition, pp 325-327 Lieurade H. P., Concentration de C ontraintes, Techniques de l’Ingénieur BM 5 040 nCode DesignLife Theory Guide, Analysis run, Standard SN analysis engine, Combination method, Critical plane Heyes P., 2015, “Multiaxial Life Prediction” .

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