A novel finite element investigation of the effects of washer friction in composite plates with bolt-filled holes

Abstract A novel two-dimensional finite element model has been developed in order to satisfactorily represent the effects of washer-plate friction due to bolt torque on the response of bolted CFRP laminated plates loaded in uniaxial tension. A carbon fibre-epoxy laminate of quasi-isotropic lay-up configuration [(±45°/90°/0°) 2 ] s was investigated. The bolt was assumed to be of perfect fit and bolt and washers were assumed to be rigid. A constant in-plane uniaxial tensile stress was applied to the laminate. The degree of lateral clamping pressure, applied normal to the laminate via the washers, was varied from zero to high pressures. In all investigations this lateral clamping pressure was assumed to be uniform over the washer area. Through-thickness effects and interlaminar phenomena were necessarily ignored given the nature of the model. Friction between the plate and the bolt core was also ignored. Results obtained highlight the appreciable effects of washer friction on the laminate's response and likely mode of failure, affecting both the magnitude and location of the plate's in-plane peak global strain components.