Dynamic tensile failure of CFRP/aluminum bolted joints: Experimental and numerical investigation

The dynamic tensile failure of composite/metal bolted joints is governed by the coupled effects of stress concentration, local contact deformation, and rate-dependent damage evolution. In this study, single-bolt CFRP (Carbon Fiber Reinforced Polymer)/7075 aluminum joints are found to exhibit a pronounced strain-rate strengthening effect, with the peak stress increasing from 438.18 MPa at 1000 s −1 to 579.29 MPa at 3000 s −1 . Using split Hopkinson tension bar tests with high-speed imaging, damage was consistently observed to initiate around the composite bolt hole and became increasingly localized as the strain rate increased. More importantly, the combined high-speed observations and numerical results suggest that the local failure morphology under high-strain-rate loading is closely associated with transient secondary bending and bolt tilting, which intensify compressive damage in the region perpendicular to the loading direction and thus influence the evolution of hole-edge damage. An Abaqus/Explicit model based on the three-dimensional Hashin failure criterion was developed. The model predicted the peak stress with an error of 4.08% and successfully reproduced the main damage evolution features. These results provide new insight into the rate-dependent local failure mechanism of composite/metal bolted joints and offer a useful basis for the design and assessment of impact-resistant hybrid joint structures.