Damage Initiation and Fatigue Behavior of Carbon-Fiber Composite Disk Springs 2015-01-9084

The disk spring offers the potential of significant weight savings when designed with continuous fiber reinforced composite materials. The internal stresses in a disk spring are ideally suited for composite material application due to their superior resistance to in-plane and bending stresses. In this study, a composite laminate disk spring is designed, analyzed and fabricated to take advantage of the low specific strength and weight and high damage tolerance of composite laminates. The design of the disk composite spring considers effects of the laminate stacking sequence and the geometric variables on the disk spring's mechanical performance. A continuum damage finite element analysis approach is used to understand the damage initiation and evolution as a function of applied load. Experimental analysis and a progressive damage analysis based on virtual crack closure technique are performed to evaluate the damage tolerance of the disk spring under fatigue loadings. Results show how a methodology can be used to study the crack propagation in carbon fiber disk springs.