Influence of end-conditions during tube hydroforming of aluminum extrusions

Experimental and numerical investigation of free-bulge formation during hydroforming of aluminum extrusions

“…As expected, higher forming limits were obtained in the tests with axial feed. Further studies have been carried out by the authors [11] to compare the forming limits of aluminum extrusion tubes obtained from "free-end", "pinched-end" and "forced-end" experiments. It was found that "free-end" experiments give the lowest forming limits followed by "pinched-end" and "forced-end" hydroforming.…”

Quality of the Hydroformed Tubular Parts

“…Explicit finite element codes were proved to have much better capabilities to handle such kind of nonlinear behavior exhibited by the metal forming process and provide a better understanding of the plastic deformation mechanism over implicit finite element analysis [7][8]. Similar to other forming processes, development of forming limit diagrams (FLD) [9] enabled designers and manufacturers to determine process limitations and to estimate the forming characteristics of the tube as an essential task in tube hydroforming. The obtained FLDs can be used to optimize the hydroforming tool geometries and also to develop criterion for material failure.…”

Loading path optimization of tube hydroforming process

“…1(b)). Earlier studies by the authors [9,10] revealed that using material parameters (in power-law model) obtained from simple tensile tests of curved specimen [ASTM-B557M] would yield a better estimation of the bulge height vs. internal pressure during free-end and pinched-end hydroforming of aluminum extrusions compared to flat tensile specimen [ASTM-B557] data. Tensile test data on the curved specimen (cut from tube cross section) were curve fit to the power law model ð sZ K 3 n Þ and yielded a K-value of 265.2 MPa and n-value of 0.166 [9].…”