Stress Relaxation and Stiffness of 17-7PH Belleville Springs in a Stacked Configuration
Abstract
An investigation was performed to determine the effects of parallel stacking on the stiffness and stress relaxation of 17- 7PH Belleville springs. Parallel stacking refers to Belleville washers stacked with the concave side of all washers in the stack facing the same direction. Load versus displacement curves and stress relaxation data were generated for two single-disc experiments and for two double-disc, parallel stack experiments. In theory, the stiffness of a parallel stack of disc springs should be equal to the sum of the stiffness values for the individual springs. However, the measured stiffness values for the two double-disc stacks were only 73% and 85% of the respective sums for the individual discs. Spring force losses due to stress relaxation were always less than 2% for periods up to 1318 h. It was concluded that for displacement- controlled applications having stringent force requirements, spring stiffness must be measured for each disc, and load losses associated with a parallel, stacked configuration must be accounted for in the system design.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 20, 2003
- Accession Number
- ADA417741
Entities
People
- D. J. Chang
- G. L. Steckel
Organizations
- The Aerospace Corporation