Analysis of failure mechanism and stress influence on cylinder

Cylinder, which converts pressure of compressed gas into mechanical energy, is one of main pneumatic actuators in electromechanical products. With application of cylinder becoming broader and broader, the demand on high reliability of cylinder gets more and more urgent. In order to improve the reliability of cylinder, it must be made clear the failure mechanism of it beforehand. This paper first shows detailed structure of the tested A series of cylinder, then gives deep insight into the failure mechanism of this kind of cylinder with experimental phenomena gained from a large number of accelerated lifetime tests, such as wear of piston edge, accumulated debris in the lid of piston rod, noticeable ground traces on the piston rod and damage of the piston sealing ring. This paper also presents a microscopic explanation to the wear process of cylinder´s moving parts with theory of cumulative damage, which demonstrates cylinder´s micro failure process. At last it analyzes failure data obtained in the accelerated lifetime tests using lifetime data analysis software, mainly including the influence each stress (temperature, actuating frequency, pressure and speed) has on the lifetime of cylinder and why this happens, which further validates the failure mechanism of this kind of cylinder is wear of moving parts.