Formability prediction of tailor-welded blanks in hydraulic bulging using flow curves from biaxial tensile tests

Abstract

In this work, the formability of laser-welded tailored blanks of low carbon steel of two different thickness combinations in hydraulic bulging has been studied by numerical simulation. For material modeling, flow curves of the parent sheets were obtained in biaxial stress condition by conducting hydraulic bulge tests. These curves were used to extrapolate the uniaxial tensile curves up to large strains using the work equivalence principle. The limiting dome height in conventional forming and hydraulic bulging of tailor-welded blanks has been predicted in finite element simulations using the flow curves obtained directly from the hydraulic bulge tests and the extrapolated uniaxial tensile curves. Hydraulic bulging and conventional forming experiments on tailor-welded blanks have also been conducted to validate the predicted results. It has been found out that the predicted limiting dome height of the tailor-welded blanks in conventional forming and hydraulic bulging using extrapolated uniaxial tensile curves is closer to the experimental values when compared to the results obtained by using stress–strain curves obtained from hydraulic bulge tests. It has also been found that using an extrapolated uniaxial tensile curve it is also possible to predict strain distribution and percentage thinning more accurately. It has been observed that with an increase in thickness ratio, the peak pressure increased but the predicted values of peak pressure using flow curves obtained directly from hydraulic bulge tests are closer to the experimental values.

Effect of strain rate on tensile behavior of tailor welded blanks

“…4,5 Despite the mentioned advantages, TWB forming has difficulties such as premature failure, wrinkling, and weld line displacement due to the difference in mechanical properties and nonuniform strain distribution of its constituent sheets. 6,7 Much research has been done to investigate the mechanical properties of TWB. Some studies have shown that by rising the thickness ratio of TWB made of cold-rolled low-carbon steel, 8 the formability decreased.…”

“…4,5 Despite the mentioned advantages, TWB forming has difficulties such as premature failure, wrinkling, and weld line displacement due to the difference in mechanical properties and nonuniform strain distribution of its constituent sheets. 6,7…”

Neural Network-Based Multi-Objective Optimization of Adjustable Drawbead Movement for Deep Drawing of Tailor-Welded Blanks

“…Heo et al [17] investigated how the drawbead dimensions affect the movements of the weld line during the forming of TWBs. Kumar and Digavalli [18] numerically evaluated the formability of low-carbon steel TWBs with two different thicknesses in hydraulic bulging. It was found that with an increase in the thickness ratio, the peak pressure increases, and simulation results will be closer to experimental ones.…”