Effects of temperature on strength and failure behavior of CFRP/aluminum alloy multipinned connections

To investigate the influence of environmental temperature on the strength and failure behavior of composite/metal multi-bolt connections, this study examined the tensile strength and failure behavior of CFRP/aluminum alloy multi-bolt connections at different temperature environments ranging from 198.15 K to 423.15 K through experimental and numerical methods. The results show that lowering the temperature increases the strength and initial stiffness of the connection structure, while raising the temperature has the opposite effect. When the environmental temperature exceeds the glass transition temperature of the composite, a noticeable reduction in load-bearing strength occurs. Changes in environmental temperature lead to variations in the load-bearing conditions around different holes in the connection structure, with the first hole on the left side in the tensile direction bearing the highest proportion of the load, resulting in the most severe damage near that hole. The experimental results align well with the finite element numerical simulation outcomes, with a maximum deviation of 5.8% in the tensile strength between experiments and simulations at different temperatures. The failure behavior and regions of the structure show good consistency with the experimental results, validating the effectiveness of the numerical simulation model.