A COMPARATIVE ANALYSIS OF POTENTIAL-BASED AND NON-POTENTIAL-BASED COHESIVE MODELS FOR SIMULATING LOADING AND UNLOADING IN SLIDING ELASTIC LAMINATES

Abstract

When materials break, the process is incredibly complex. To predict and analyze these failures, engineers and scientists use computational tools called Cohesive Zone Models (CZMs)1. These models fall into two main camps: potential-based models, which use a single energy function to describe the fracture process, and non-potential-based models, which offer more freedom to describe complex behaviors, especially when a material is repeatedly loaded and unloaded2. This study takes a close look at both approaches, comparing them in the context of laminated materials sliding against each other3. We've developed a unified mathematical framework that allows us to build both types of models from the ground up, showing how to incorporate the effects of loading and unloading in a natural way, even when the fracture properties change with direction4. Our analysis, backed by clear numerical examples, reveals major differences in how these models predict stiffness, energy loss, and permanent damage5. We show that potential-based models, while elegant, have serious limitations and can produce unrealistic results under the complex conditions of mixed-mode unloading6. In contrast, the non-potential-based approach proves to be a robust and reliable tool that works well in all situations7. These findings help clarify which model to choose for a given problem and offer critical insights for accurately predicting failure in advanced composite materials.