Low-speed finite element frontal impact analysis on aluminum alloy bumper made of 6063-T6

Abstract

In this research, a low-speed impact numerical simulation has been performed on a 6063-T6 Aluminum alloy bumper welded by MIEA technique using ANSYS® LS-DYNA® Workbench™ 19.2, according to the requirements of the Federal Motor Vehicle Safety Standards and Regulations. For the numerical simulation, mechanical properties were obtained from quasi-static tensile tests in 6063-T6 aluminum alloy joints, these joints were manufactured using the MIEA (modified indirect electric arc) technique and a MIG welding process and post-weld heat treatment (PWHT). For the numerical impact simulation, the following parameters have been used: mass of the impactor of 1000 kg, speed of the impactor 4 km/hr and material of the impactor AISI 4130 steel. The simulation study showed that aluminum alloy joints used in bumper beam has excellent mechanical strength under low-speed impact conditions. Among the mechanical properties that have been recovered due to PWHT are the following: it was possible to harden the fusion zone, that is, there was an increase in hardness values from 80 HV0.1 to 98 HV0.1, the heat affected zone was eliminated, obtaining hardness values of approximately 110 HV0.1, a recovery in yield strength (59%) was observed, that is, in welding condition (170 MPa) and welding condition plus PWHT (270 MPa). In terms of tensile strength, a recovery (42%) was observed, going from welding condition (214 MPa) and welding condition plus PWHT (304 MPa). Tensile strength also had an increase ranging from 214 MPa to 304 MPa. This represents an increase of 42 pct. Finally, the simulation showed that the welding zone on the bumper has very good resistance to low speed impact since no permanent deformations were observed, that is, after the impact the bumper returns to its initial position.