Improving the mechanical performance of resistance-welded green composite joints using different heating elements

Abstract

This study investigates the tensile and compressive failure behavior of a single-lap joint of green composites obtained by resistance welding. The green composites composed of poly (lactic)acid (PLA) and bamboo fiber were fabricated in a hot compression by the film-stacking method. The different heating elements namely polypyrrole (conductive polymer), carbon fiber (CF) fabric, and stainless steel (SS) mesh were used to perform the resistance welding of nonconductive green composites. The heating time (30, 60, and 90 s) and the percentage of overlapping area covered by the heating element (35, 65, and 100%) were the other two welding parameters considered for experimental investigation. The effect of welding parameters on tensile and compressive failure loads was experimentally investigated through a full-factorial experimental design. The load vs. displacement and failure behavior of the welded specimen under different conditions was extensively investigated. The statistical analysis of the experimental data was performed to find the relative significance of the welding parameters. The type of heating element was found to be the most significant parameter as it has maximum statistical contribution in both tensile and compressive failure loads. The tensile and compressive failure loads were improved by 31% and 63% when CF fabric was used as a heating element as compared to the SS mesh heating element. Similarly, failure loads obtained by using CF fabric were improved by 187% (tensile) and 323% (compressive) when compared one-on-one with polypyrrole heating element.