Prestressed bonding failure suppression mechanism and process development for inner fillets of sealing strips

Abstract

Owing to physical property disparities between sealing strips and bonded substrates, the inner fillet bonded areas are susceptible to asynchronous dimensional changes under long-term service and environmental alternating loads, which further leads to debonding defects. Traditional bonding processes lack effective stress regulation mechanisms, and existing elastic mechanics studies suffer from critical limitations like inadequate solution adaptability and a disconnect between mechanical analysis and process optimization. This study proposes a prestress bonding mechanism and builds a polar coordinate elastic mechanics model, accurately solving the nonlinear stress field via function fitting and Time-Stepping algorithms to uncover the quantitative correlation between rolling parameters and compression amount, and develops a human-robot collaborative bonding equipment. Tests under 70 N pressure show the inner fillet compression ≥2.5 mm, straight segment midpoint compression ≥6 mm, total compression reaching 22.3 mm and bonding trajectory error controlled within 0.3 mm, all meeting industrial standards. This process is designed to ensure that the sealing strip achieves debonding-free performance for at least 10 years under the combined effects of extreme environmental conditions (such as high temperature, low temperature, and humidity fluctuations) and human factors. Fundamentally resolving inner fillet debonding from a mechanical perspective, this study constructs a complete “mechanism modeling — process development — equipment design — experimental verification” technical chain, offering theoretical and engineering support for optimizing the inner fillet bonding process of flexible components.