Preliminary Study on Optimization of the Tube Hydroforming Process Using the Equivalent Static Loads

In metal forming processes, different parameters (Material constants, geometric dimensions, loads …) exhibits unavoidable scatter that lead the process unreliable and unstable. In this paper, we interest particularly in tube hydroforming process (THP). This process consists to apply an inner pressure combined to an axial displacement to manufacture the part. During the manufacturing phase, inappropriate choice of the loading paths can lead to failure. Deterministic approaches are unable to optimize the process with taking into account to the uncertainty. In this work, we introduce the Reliability-Based Design Optimization (RBDO) to optimize the process under probabilistic considerations to ensure a high reliability level and stability during the manufacturing phase and avoid the occurrence of such plastic instability. Taking account of the uncertainty offer to the process a high stability associated with a low probability of failure. The definition of the objective function and the probabilistic constraints takes advantages from the Forming Limit Diagram (FLD) and the Forming Limit Stress Diagram (FLSD) used as a failure criterion to detect the occurrence of wrinkling, severe thinning, and necking. A THP is then introduced as an example to illustrate the proposed approach. The results show the robustness and efficiency of RBDO to improve thickness distribution and minimize the risk of potential failure modes.

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Nonlinear dynamic response topology optimization using the equivalent static loads method

Computer Methods in Applied Mechanics and Engineering ◽

10.1016/j.cma.2014.10.015 ◽

2015 ◽

Vol 283 ◽

pp. 956-970 ◽

Cited By ~ 35

Author(s):

Hyun-Ah Lee ◽

Gyung-Jin Park

Keyword(s):

Topology Optimization ◽

Dynamic Response ◽

Nonlinear Dynamic ◽

Nonlinear Dynamic Response ◽

Static Loads ◽

Equivalent Static Loads ◽

Equivalent Static Loads Method

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Nonlinear response topology optimization using equivalent static loads—case studies

Engineering Optimization ◽

10.1080/0305215x.2016.1187728 ◽

2016 ◽

Vol 49 (2) ◽

pp. 252-268 ◽

Cited By ~ 8

Author(s):

Zeshan Ahmad ◽

Tipu Sultan ◽

Matteo Zoppi ◽

Muhammad Abid ◽

Gyung Jin Park

Keyword(s):

Topology Optimization ◽

Case Studies ◽

Nonlinear Response ◽

Static Loads ◽

Equivalent Static Loads

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Numerical investigation of plastic flow and residual stresses generated in hydroformed tubes

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/1464420721989746 ◽

2021 ◽

pp. 146442072198974

Author(s):

A Ktari ◽

A Abdelkefi ◽

N Guermazi ◽

P Malecot ◽

N Boudeau

Keyword(s):

Finite Element ◽

Residual Stresses ◽

Finite Element Model ◽

Plastic Flow ◽

Tube Hydroforming ◽

Three Dimensional ◽

Element Model ◽

Tube Cross Section ◽

Straight Wall ◽

Hydroforming Process

During tube hydroforming process, the friction conditions between the tube and the die have a great importance on the material plastic flow and the distribution of residual stresses of the final component. Indeed, a three-dimensional finite element model of a tube hydroforming process in the case of square section die has been performed, using dynamic and static approaches, to study the effect of the friction conditions on both plastic flow and residual stresses induced by the process. First, a comparative study between numerical and experimental results has been carried out to validate the finite element model. After that, various coefficients of friction were considered to study their effect on the thinning phenomenon and the residual stresses distribution. Different points have been retained from this study. The thinning is located in the transition zone cited between the straight wall and the corner zones of hydroformed tube due to the die–tube contact conditions changes during the process. In addition, it is clear that both die–tube friction conditions and the tube bending effects, which occurs respectively in the tube straight wall and corner zones, are the principal causes of the obtained residual stresses distribution along the tube cross-section.

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