The 3-D contact stress in bolted joint parts and its contact coverage are investigated ex-perimentally with the photoelastic method and the newly developed caustics method.

• 所得实验结果为汽缸盖接触联结系统的设计、机械螺栓联结零件的有限元计算及其可靠性分析，提供了实验依据，并开拓了焦散线法实验的应用范围。