Effect of cork powder concentration and service temperature on strength characteristics and failure modes of adhesively bonded lap joints

Abstract

In this study, the combined effects of cork powder particles addition and service temperature on the strength characteristics of lap joints was experimentally investigated. Two types of lap joints i.e. single lap joint (SLJ) and double strap joint (DSJ) with two different adherend material configurations were manufactured using a two-component epoxy system Araldite©️ LY 556. CFRP and Aluminum alloy 5083 was used as adherends in the fabrication of the lap joints. Cork powder was added in the amounts of 0.25, 0.5, 0.75, and 1 wt% in the host resin and was mechanically mixed at an elevated temperature of 50 °C, below the Tg of epoxy adhesive. The prepared adhesive was then used to make adhesive lap joints. The joints were then tested at four different temperatures of 25, 50, 75, and 100 °C by utilizing a universal testing machine equipped with thermal chamber. The results of the study showed that the joint strength can be increased up to a certain extent with the increase in cork powder addition, however, in general, will be negatively affected by the increase in service temperature. Also, the reinforcing effect of cork powder remained significant even at temperatures close to the glass transition temperature of epoxy adhesive.