Comparison of Continuum Shell and Solid Element-Based Modeling Strategies for Mesoscale Progressive Damage Analysis of Fiber Composites

Failure behavior prediction of carbon fiber reinforced plastics (CFRP) is a challenging task. Several damage mechanisms, which have to be considered for an adequate determination of a structures load-carrying capacity, occur. These failure types interact and several individual failure types can occur sequentially before the limit of the load-carrying capacity is reached. In the relevant literature, different mesoscale modeling strategies for the Progressive Damage Analysis (PDA) are available. For example, the individual plies can be modeled with Continuum Damage Mechanics (CDM) using solid or continuum shell elements. In addition, Fracture Mechanics (FM) can be used to model failure in the through-thickness direction. However, no modeling recommendations or guideline are available to decide for a modeling strategy as a trade-off between accuracy and numerical effort. In this work, several modeling strategies are compared by their prediction accuracy and calculation effort with the help of an Open Hole Tension (OHT) test campaign performed by the authors. Using these OHT specimens with different layups made from M21-T700GC thermoset CFRP material, Abaqus/Explicit was used in combination with a user-defined material model which uses Cuntze's Failure Mode Concept in 2D for continuum shell and in 3D for solid elements to predict damage initiation and progression in the plies. Each of the two variants is optionally combined with cohesive contacts to model delamination. Two modeling strategies can be recommended. An efficient variant based solely on CDM and a more complex one combining CDM with FM to model interlaminar failure.

Automated summary

Failure behavior prediction of carbon fiber reinforced plastics (CFRP) is challenging due to the multiple damage mechanisms involved. This study compared different modeling strategies for Progressive Damage Analysis (PDA) using an Open Hole Tension (OHT) test campaign. Two recommended modeling strategies were identified: an efficient variant based solely on Continuum Damage Mechanics (CDM) and a more complex variant combining CDM with Fracture Mechanics (FM) to simulate interlaminar failure.