Influence of dissimilar composite adherends on the mechanical adhesion of bonded joints for small blade wind turbine applications

Abstract

Both small and medium wind blade manufacturing require the use of adhesives to assemble the shells and spar web of the wind blade. During this process, several parts made with different composite manufacturing process such as vacuum infusion and hand lay-up need to be joined. It is necessary to consider that the assembly process of the wind blade is not perfect due to variations of the adhesive thickness along the blade. This paper reports the experimental and numerical analysis of dissimilar composite adherends on the mechanical adhesion of bonded joints for small wind turbine blades.For this study, three fiber glass-reinforced adherend types: hand lay-up, vacuum infusion (at 0.4 and 0.8 bar), and two adhesive thickness (0.7 and 1.3 mm) were selected. The testing results showed that the adherend type is not important when thin adhesive thicknesses are used (0.7 mm) in single lap joints (SLJ). Nevertheless, the influence of the adherend type on SLJs with 1.3 mm adhesive thickness has a great effect. Also, the use of adherends made with a vacuum infusion process with 0.4 and 0.8 bar improves the joint strength in relation to a hand lay-up adherend. Good agreement was found between the numerical and experimental results.