SEDL / STP / STP893-EB / STP35353S

Improvement of Edge Delamination Strength of Composite Laminates Using Adhesive Layers

Chan, WS
Senior engineering specialist, Research Group; chief of LHX Airframe and Stress; and former staff member, Research Group, Bell Helicopter Textron Inc., Fort Worth, TX

Rogers, C
Senior engineering specialist, Research Group; chief of LHX Airframe and Stress; and former staff member, Research Group, Bell Helicopter Textron Inc., Fort Worth, TX

Aker, S
Senior engineering specialist, Research Group; chief of LHX Airframe and Stress; and former staff member, Research Group, Bell Helicopter Textron Inc., Fort Worth, TX

Pages: 20    Published: Jan 1986

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Abstract

A thin but tough adhesive inner layer placed in laminates at the proper interface has been found to give improved delamination strength. Static tension tests of laminates with (±30²/˙90³/∓30²)^T and (±35/0/90)^s layups of graphite/epoxy show that the added adhesive inner layer effectively suppresses delamination until final failure. The effects of adhesive layers on interlaminar stresses and strain-energy release rate have been studied analytically using a finite-element method. It was found that the introduction of adhesive layers reduced the interlaminar stresses. Although there was no significant change in total strain-energy release rate, there was a significant decrease in the G¹ (tension mode) percentage of the total strain-energy release rate.