Temperature effect on mechanical performances and failure mechanisms of single-lap countersunk-screwed CFRPI-metal joint

摘要

This paper seeks to experimentally and numerically probe temperature effects on mechanical performances and failure mechanisms of single-lap countersunk-screwed CFRPI-metal joints. Quasi-static tension tests were performed on single-lap countersunk-screwed CCF300/AC721-30CrMnSiA joints at -40 degrees C, -25 degrees C, RT (room temperature), +250 degrees C and +350 degrees C, and temperature impact was analyzed and discussed from experimental results. By considering thermal-mechanical interaction, non-linear shear constitutive relationship and complicated failure modes, an improved PDM (progressive damage model) was devised to simulate mechanical performances and failure mechanisms of single-lap countersunk-screwed CCF300/AC721-30CrMnSiA joints, and the predictions agree well with the experimental results. Based on numerical results, it is demonstrated that temperature effect on joint performances arises from the changes in clamping and friction forces and in interlaminar properties of material with temperature, and delamination around screw hole is likely the primary reason for final failure of joint.