Mechanism of stress generation at the epoxy-epoxy interface

Epoxy resins are widely used in power equipment, and due to the material as well as process requirements, multi-layer epoxy structures inevitably exist. The interlayer interface between epoxy layers, formed via secondary curing, causes a potential weak link in the material's properties. This work experimentally measures the temperature and strain at the epoxy-epoxy interface under various conditions, including the presence or absence of epoxy and differing chemical doses of curing agent. Subsequently, an epoxy-epoxy interface strain resin simulation model is established to examine the mechanism of interface stress formation by exploring the curing kinetics of epoxy resins using the Straink method. Experimental measurements and simulation calculations reveal the presence of an interaction between interlayer interfaces during the secondary curing. Changing the dose of curing agent in the post-pouring layer can change the interaction between the layers and regulate the interlayer interface performance.