The research on failure analysis of fluid cylinder and fatigue life prediction

• The fluid cylinders failure caused by fatigue and corrosion.
• The structure of the fluid cylinder can meet the requirement of static strength.
• The response to cyclic loading is controlled by strain at the fatigue weak area for fluid cylinders’ materials.

To analyze the reasons of fluid cylinders’ rupture, macro-analysis, SEM, composition inspection, metallographic analysis, hardness test and mechanics performance test of fluid cylinders materials were implemented. Two different kinds of fatigue life prediction methods have been proposed which are based on total life analysis and strain–life methodology. The results indicate that: the failure cylinders’ material quality is satisfactory. Fatigue damage caused by high working, stress and corrosion is the main reason of cracking. The fatigue life prediction illustrates that strain–life methodology is well adapted to fluid cylinders.