Thermo‐Mechanical Coupled Modeling and Experimental Investigation of Damage Evolution in Composite Structures During Friction Stir Blind Riveting

Abstract

ABSTRACT Friction stir blind riveting (FSBR) is a promising joining technology for composite–metal hybrid structures; however, damage formation and evolution in composite laminates during the riveting process remain insufficiently understood. In this study, an integrated experimental and numerical approach was developed to investigate damage mechanisms in CF/PEEK–AA6061 FSBR joints. A thermo‐mechanically coupled finite element model was established using ABAQUS/Explicit to simulate the entire riveting process, including rivet penetration, material deformation, temperature evolution, and delamination propagation. The model predictions of penetration morphology, force–displacement response, temperature distribution, and damage evolution showed good agreement with experimental observations, demonstrating its capability for process and damage prediction. Combining ultrasonic C‐scan characterization, cross‐sectional analysis, and multi‐physical field evolution from simulations, the influence mechanism of rivet structures on composite damage was systematically revealed. The results indicate that rivet‐induced damage is primarily governed by the interaction between material removal behavior and thermo‐mechanical loading. Rivets dominated by frictional extrusion generate concentrated stresses and localized high‐temperature regions, leading to matrix softening and accelerated interlaminar damage propagation. In contrast, the cutting–chip evacuation mechanism effectively releases radial extrusion forces, homogenizes stress distribution, and suppresses delamination. This study provides a thermo‐mechanical modeling approach for predicting damage evolution during FSBR and establishes the relationship between riveting process characteristics and composite damage formation, offering theoretical guidance for low‐damage joining of composite–metal hybrid structures.