In-plane compression of bi-laterally confined layered structure: Plastic model and parametric study

Discrete layered structures are commonly used in various functional configurations, such as power batteries. However, the mechanical behavior of the discrete layered structure in the in-plane direction is not well understood due to the complexity of inter-layer interactions. In this study, we investigated the behavior of layered structure under in-plane compression with fixed boundary conditions using theoretical analysis, FE simulations and material tests. In FE simulations, a layered structure could exhibit a specific stable compression deformation pattern until local collapse occurs. To understand the underlying mechanisms, we identified two secondary behaviors, referred to as squeeze elements, during the in-plane compression process. By properly recognizing crucial parameters, we modeled and analyzed the mechanical behaviors of the squeeze elements using plastic theory. The primary behaviors of the layered structure are then explained by examining the mechanical relationship between the squeeze elements and the entirety of the structure. Additionally, the impact of the lateral constraints and the layer numbers on the layered structure is analyzed and verified. Significantly, we discovered a non-monotonic influence of lateral constraints on the maximum energy absorption of the layered structure before local collapse. This finding is further supported by in-plane compression tests conducted on pouch cell batteries. From a structural integrity standpoint, we emphasize the importance of integrated design in the lateral direction to enhance the safety tolerance of functional layered structures subjected to in-plane compression.