Effect of Pultrusion Process Variables on Cyclic Loading Damage of Graphite-Epoxy Composites

Abstract

Recent advances in pultruding composite materials have resulted in a high-performance, cost-effective manufacturing process. However, most research on pultruded products has centered on a specific application; a systematic study of the effects of various process variables on fatigue damage has not been conducted. The present study uses a fractional factorial statistical design to characterize the effects of pultrusion process variables and their interactions on the fatigue damage of pultruded graphite-epoxy. The composite material produced under the varying process conditions was subjected to tensile fatigue. The start and progress of damage mechanisms due to the loading and influenced by the processing conditions of the material are reflected by discernible changes in the loss factor (a measure of damping). The loss factor and modulus of the material were computed in real-time using computer methods. The changes shown by the loss factor are used to characterize the effects of the processing variables on the cyclic damage.