https://popups.uliege.be/esaform21/index.php?id=3585 Publications of Auteurs Pedro André Prates fr 0 https://popups.uliege.be/esaform21/index.php?id=2364 Tube hydroforming (THF) is a plastic forming process that uses tubes with an initial circular cross section, in which pressurized fluid and axial feeds are applied for producing parts with various cross-sectional shapes. Despite of the complexity of THF process, a great progress in the automotive and aerospace industry has been made due to its advantages, such as, consolidation and weight reduction over conventional stamped and welded parts. The analysis of THF process is typically based on deterministic approaches, excluding scattering effects that influence the process reliability. Thus, robust design of tube hydroforming aims to vanish noise factors effects on process responses by considering the influence of process parameters variability. If this fluctuation is not monitored, then the fluctuation of the hydroformed parts quality may contribute to high scrap rates. In this work, the influence of variability in the THF material and process parameters (e.g. yield stress, strength coefficient, strain hardening exponent, plastic anisotropy, initial tube thickness and bulged length) on the bursting pressure is analyzed resorting to a response surface model. The statistically significant variables, which mostly influence the free bulge hydroforming process, are identified through an analysis of variance. Assuming that the input parameters variability follows the normal distribution, the probability distribution of the bursting pressure is evaluated by involving random process variables into the built response surface model. It was shown that the initial tube thickness is the most statistically significant variable, whereas the strain hardening exponent is the least statistically significant variable. Tue, 23 Mar 2021 17:52:10 +0100 Fri, 02 Apr 2021 09:47:14 +0200 https://popups.uliege.be/esaform21/index.php?id=2364 https://popups.uliege.be/esaform21/index.php?id=2158 The industrial demand for products with better quality and lower production costs have encouraged the widespread application of the finite element analysis (FEA) in the development and optimization of sheet metal forming processes. To ensure that the FEA solutions are reliable and robust it is important to take into account the uncertainties that inevitably arise in a real industrial environment. In this context, a numerical study on the influence of the material and process uncertainty in the stamping results of a square cup is presented. In this analysis, it is assumed uncertainty in the elasticity properties, hardening law parameters, anisotropy coefficients, blank thickness, friction coefficient and in the blank holder force. The effect of the uncertainty in these input parameters is evaluated in the punch force, equivalent plastic strain, thickness and cup geometry. Firstly, quasi-Monte Carlo method was used to evaluate the variability in the simulation outputs, considering the uncertainty of the input parameters. This analysis shows that the geometry is the output most sensitive to the uncertainty of the input parameters. Afterwards, a variance-based sensitivity analysis was carried out to identify the input parameters that most influence the output variability. It was concluded that the hardening law parameters and the anisotropy coefficients have the most influence in the stamping results variability of a square cup. Tue, 23 Mar 2021 13:53:05 +0100 Fri, 02 Apr 2021 09:46:28 +0200 https://popups.uliege.be/esaform21/index.php?id=2158