EXPERIMENTAL AND NUMERICAL STUDIES ON MULTI-BOLT DOUBLE COVER BUTT JOINTED GLASS FIBRE REINFORCED COMPOSITE LAMINATES WITH ALUMINIUM BUTT STRAPS

Numerical and experimental studies on multi-bolt double cover butt jointed glass fibre reinforced composite laminates with Aluminium butt straps (size 270 x 72 x 3/4/5 mm) subjected to a tensile load are presented. Experiments were conducted using the assembled specimens in Instron testing machine under uniaxial load. The test specimens exhibited bearing failure of the laminate at all bolt points followed by net tension failure along the line of bolts close to the grips. Investigation are conducted to study the effects of material composition, consistency of fabrication, bearing-bypass interaction / damage onset, specimen thickness on the stress-strain behaviour of the specimen, load distribution in bolts, types of fit and friction, material anisotropy and contact condition under bolt preload. Influence of these parameters on the contact stresses around the bolt and stresses in the butt straps are discussed. Finite element analysis was carried out using ANSYS for various parameters and results were compared with test data.