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Optimisation avec prise en compte des incertitudes dans la mise en forme par hydroformage

Abstract : Hydroforming process is widely used in automotive and aerospace industries. Deterministic design optimization have been used to control and optimize this process in the last decade. However, under realistic conditions, different parameters such as material properties, geometric dimensions, and load exhibits unavoidable scatter that can affect the stability and the reliability of the process.It is interesting to introduce the uncertainties in parameter and to consider their variability. The main objective of this contribution is to evaluate the reliability and optimization of the hydroforming process in the presence of uncertainties.The first part of this thesis proposes a general approach to evaluate the spatial probability of failure in hydroforming process mainly in the critical region. With the proposed approach it is possible to avoid failure during hydroforming process.This method is based on Monte Carlo simulation coupled with metamodels, the forming limit curve is used as failure criteria for potential plastic instabilities.The second part of this thesis is the optimisation of the hydroforming process under uncertainties. Using illustrative examples, it is shown that probabilistic approach is an efficient method to optimize the process, to decrease the probability of failure and make the process insensitive or less sensitive to sources of variability. The difficulty lies in the considerations of the reliability constraints, which require a large computational effort and involve classical numerical problems, such as convergence,accuracy and stability. To overcome this problem, response surface method with Monte Carlo simulations were used to evaluate the probabilistic constraints.Probabilistic approach can ensure a stable and reliable process and decrease the percentage of defects parts significantly. Through this part, two methods were used : Reliability-Based Design Optimization and robust optimization.The last part consists of optimizing the process with Multi-Objective (MO) strategy taking account of the uncertainty. Metal forming process is MO problem that consists of optimizing more than one performance simultaneously. The main goal isto study the evolution of the Pareto front when some uncertainties can affect the objective functions or the parameters. In this part, a new methodology is proposed which presents the solutions in a new space and classify the whole solution with their probability of failure. This classification allows to identify the best solutionand can provide an idea about the reliability of each solution.
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https://tel.archives-ouvertes.fr/tel-00625437
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Submitted on : Monday, December 19, 2011 - 2:42:38 PM
Last modification on : Saturday, May 11, 2019 - 3:31:20 AM
Long-term archiving on: : Tuesday, March 20, 2012 - 2:20:28 AM

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2011ISAM0003.pdf
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  • HAL Id : tel-00625437, version 1

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Mohamed Anis Ben Abdessalem. Optimisation avec prise en compte des incertitudes dans la mise en forme par hydroformage. Autre [cond-mat.other]. INSA de Rouen, 2011. Français. ⟨NNT : 2011ISAM0003⟩. ⟨tel-00625437⟩

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