Experimental and numerical study on bearing failure of countersunk composite–composite and composite–steel joints

Tensile experiments were conducted on composite–composite joints and composite–steel joints with countersunk bolts while three-dimensional finite element models using progressive damage method on composite were developed to simulate bearing failure of joints. Experimental results showed good repeatability and bearing damage showed obvious difference between the two kinds of joints. Solid elements were chosen to model all the parts and laminates were partitioned into actual number of plies in order to gain accurate stress distribution and damage profile in each ply. A 3D Hashin-type criteria and degradation rules were implemented using a user subroutine in ABAQUS. Numerical results had good agreement with experimental results considering clearance effects. Composite–steel joints showed better carrying capacity than composite–composite joints according to load–displacement curves and damage evolution processes. Delamination were more severe in composite–composite joints indicating that it is necessary to pay attention to designing composite laminates and structures under certain load condition.