Search Results

This paper presents cost-benefit analysis of glass and carbon fiber reinforced thermoplastic matrix composites for structural automotive applications based on press forming operation. Press forming is very similar to stamping operation for steel. The structural automotive applications involve beam type components. The part selected for a case study analysis is a crossbeam support for instrument panels.

The purpose of this study is to examine the effect of spot weld spacing on the stiffness and natural frequency of a two-piece welded body structure. The variation in spot weld spacing may occur either by design or due to assembly mistakes. In this study, rectangular beam cross sections with six different weld flange orientations are first considered. Finite element analysis is performed to compare the fundamental frequencies of these sections in bending and torsion. Weld pitch and sheet thickness are varied on two of the sections considered, namely the L-shaped and the clamshell sections. The effects of spot weld spacing on the bending stiffness, torsional stiffness, frequency response and mode shapes of these two sections are determined. Comparisons are made with seam welded sections. It is shown that the torsional stiffness and first torsional frequency can be severely affected by weld pitch, but the effect on the bending performance is not as severe.

This paper presents the results of fatigue tests conducted on tailor-welded aluminum blanks consisting of 1.66 mm thick and 1.06 mm thick AA 5754-O sheets. The method of joining the sheets was friction-stir welding. The primary purpose of this study was to determine the effect of tensile pre-strains on the fatigue performance of the welded joint. The welded specimens as well as unwelded 1.06-mm thick specimens were subjected to tensile pre-strains of 60 and 80% of their respective uniform strains before the fatigue tests. Fatigue S-N data of all these specimens were compared with similar data for unstrained specimens. Microscopic examinations were conducted to understand the failure modes.

Spot friction welding shows advantages over resistance spot welding for joining light alloys for automotive applications. In this research, fatigue behaviors of spot friction welded joints in lap shear specimens of AM-60 magnesium alloy and AA 5754 aluminum alloy were investigated. Static and fatigue tests were conducted with Mg-Mg, Al-Al and Al-Mg specimens. Fatigue S-N curves were obtained for all these specimens using load-controlled fatigue tests. Finite element analysis was conducted to investigate the stress distribution and the location of maximum stresses in spot friction welded joints in Mg-Mg specimens.

Current plastic intake manifolds are manufactured using the injection molding process. In this paper, thermoforming is explored as an alternative to injection molding for making intake manifold shells, which can then be joined by one of the welding techniques used for thermoplastic materials. The investigation reported here includes press-forming experiments of a simple bowl shaped shell and subsequent welding experiments to join these shells.

Spot friction welding is considered a cost-effective method for joining lightweight automotive alloys, such as magnesium and aluminum alloys. An experimental study was conducted to investigate the strength of spot friction welded joints of magnesium to magnesium, aluminum to aluminum, magnesium to aluminum and aluminum to magnesium. The joint structures and failure modes were also studied.

This paper presents the static and fatigue strength evaluation of clinched joints in 6111-T4 aluminum alloy sheets. Clinched joints are mechanical joints produced a cold forming technique using a small die-punch combination. A design of experiments approach is used to determine the optimum die-punch combination that produces the least variation in the static pull-out load in single lap shear tests. Fatigue S-N curves are determined for several different clinched joints in load-controlled fatigue tests with the load ratio equal to 0.1. The effect of heat exposure, typically experienced in paint ovens, on the static strength as well as fatigue S-N behavior are also examined.