A Coupled Peridynamic-Finite-Element-Simulation for the Damage Analysis of Fibre Reinforced Composits

• Applicants: Professor Dr.-Ing. Ulrich Gabbert; Dr.-Ing. Christian Willberg
• Subject Area: Mechanics
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 456427423

For the design, evaluation and approval of safety-relevant lightweight structures, the prediction of damage behavior and residual strength within the scope of a damage tolerance assessment is decisive. Sufficiently precise and robust methods for the evaluation of a progressive damage are still missing for fiber reinforced plastics (FRP). Therefore, the damage initiation is usually utilized to determine the load-bearing capacity, which results in a conservative design. The key challenge of the analysis of FRPs in comparison to metallic materials consists in the heteroge-neity of the material which results in complex failure mechanisms. A simulation method for the strength assessment has to take into account the damage initiation as well as the damage pro-gression including all involved mechanisms and their interactions. The aim of the project proposal is the development of an improved damage assessment method for FRPs. The proposed solution is a new adaptive approach consisting of an interlink of the peridynamic methodology for potentially damaged parts of a structure with a FEM approach for undamaged regions. The objective of the approach is a significant improvement of the prediction accuracy of the load-bearing capacity of a structure which helps to develop more robust, safer and resource-conserving structures. The peridynamic theory is a promising method for analyzing the damage of homogeneous and heterogeneous materials. But, the application of the peridynamic approach for undamaged regions requires an unnecessary high effort for receiving sufficient accurate results. In contrast, the FEM as a classical continuum mechanics based approach is very efficient, if continuous stress distributions can be assumed and finite elements with higher shape functions (p-elements) are applied. In view of the applicants a coupling of a peridynamic based simulation method with the FEM will result in a robust and efficient methodology to predict the damage initiation and the damage progress in specified (critical) regions. This approach also allows the modeling of the feedback of a damage region to the un-damaged area of a structure.In the proposed project the peridynamic will be extended to model damages in anisotropic FPR materials on an energy based damage approach, and to an appropriate coupling method with finite elements of higher order shape functions, respectively. The software tools, developed in the proposed project will be freely-available as open-source software for other researchers in accordance with the DFG objectives of sustainability of research software in the context of the DFG program “e-Research Technologies”.

• DFG Programme: Research Grants