Fretting Damage

Advanced Simulation Software Services

Fretting wear occurs when components in contact rub against each other and, eventually, wear away parts of the contacting surfaces. Design issues associated with fretting are:

• How long will the joint last before fretting wear degrades its performance?  
• What happens to the material that is worn away?  
• How can the joint design be improved to minimize and control fretting?

SIMULIA’s team of engineers can assist you with design problems resulting from fretting wear. Our engineers are experienced in the fundamentals of proper joint design and can help identify design modifications to remedy fretting problems. For example, fretting wear is a complicated function of contact pressure, friction in the joint, and relative motion between the components. Fretting can be controlled by limiting the relative motion between the parts or by increasing or decreasing contact pressure.

One of our customers observed fretting wear in an electro-mechanical fuel injector valve. The valve was composed of three components: a stainless steel valve body, an electromagnetic top plate, and a screw joining the two. Due to magnetic actuation of the valve, relative motion between the plate and the valve body caused fretting wear in the joint during injector operation. This eventually loosened the joint and caused the injector to malfunction. The Abaqus FEA model generated by SIMULIA Services allowed the customer to improve the joint and choose the best of several redesign alternatives.