No abstract

The aim of this study was to investigate the effect of tool tilt angle on friction stir welding (FSW) of polyethylene (PE). The samples were longitudinally butt welded with double passes of rotating cylindrical shouldered tool in a milling machine for different tool tilt angles. The welding parameters had significant effects on tensile properties and fracture locations of the welds. The tensile strength decreased with increasing tool tilt angle. The thickness of the welding zone decreased with increasing tool tilt angle which affects the tensile strength. The interface line between weld passes was formed shorter for the higher welding speeds because of the less effect of the frictional heat.

No abstract

Friction stir spot welding was used to make lap joints on strip specimens of polypropylene. The effects of tool penetration depth and dwell time on joint strength were investigated. The effect of these parameters on tensile failure load of the resulting joints was determined. An optimum combination of parameters that maximizes joint tensile failure load was identified.

The aim of this study is to investigate the effect of hygrothermal aging on both the static and thermo-mechanical behavior of polyetherimide composites. Tensile testing and dynamic mechanical thermal analysis were performed on the hygrothermally aged polyetherimide composites in the climatic cabin. The decrease in the Tg temperature, also following a decrease in the yield energy, indicated the plasticization for hygrothermally aged glass fiber reinforced PEI composite, but both tensile and DMTA analysis pointed out that glass fiber reinforced PEI composite retained its static and dynamic behavior on a large scale. The higher thermal expansion mismatch problem between carbon fiber and PEI matrix caused a remarkable decrease in the static energy values of the composite.