Impact damage and modelling of flaws in glass reinforced plastic adhesively bonded lap-shear joints

TWI Industrial Member Report Summary 779/2003

R S Court and P Bastid 

Background

The full potential of composite materials has yet to be exploited by industry, partly due to lack of data for the design and reliability of adhesively bonded composite joints. Design engineers need a better understanding of how their performance is affected by the presence of flaws in either the substrate or joint area. There is only limited quantification of the damage tolerance characteristics of composite materials and joints and this, combined with a lack of readily available design data, means that high safety factors are applied to designs.

Objectives

• To determine the effect of flaws caused by impact damage on the residual quasi-static strength of adhesively bonded composite joints.
• To compare the effect of impact damage and engineered interlaminar flaws on the residual quasi-static strength of typical composite adhesive joint geometries.
• To assess the effect of a tapered adherend design on joint performance.
• To develop models to predict the performance and assess the structural integrity of flawed composite joints.