A simple and efficient implementation of localizing gradient damage method in COMSOL for fracture simulation

• A simple and efficient COMSOL implementation is presented for the LGDM. • COMSOL is used due to its highly intuitive and versatile user interface. • The implementation is found computationally efficient for 1D, 2D and 3D problems. • The obtained results are validated with published references or experimental results. In the present work, a computer implementation of the localizing gradient damage method (LGDM) is presented in a commercial finite element (FE) package, COMSOL. The LGDM is adopted because it can accurately model damage/fracture initiation and propagation. The accuracy of LGDM is due to its thermodynamically consistent formulation using the micromorphic framework. Among available FE implementation software, the COMSOL is preferred for current implementation due to its several advantages. Firstly, the COMSOL user interface (UI) is highly intuitive and informative because, unlike other software, it displays the mathematical basis for every option in the UI. Using this, someone with a knowledge of the mathematical theory of FEM can master COMSOL quickly without any prior experience. Secondly, many customization options available in COMSOL are helpful for advanced users who intend to implement new models. Thirdly, COMSOL’s equation-based modelling feature is handy while implementing a new nonlinear coupled field model, like LGDM. It is shown in this work that COMSOL only needs the strong form of PDE to solve and performs weak formulation/linearization of the PDE in the background. This drastically reduces the implementation time for highly nonlinear models because users only need to provide the PDE’s strong form to COMSOL. Apart from these advantages, the COMSOL implementation is computationally efficient and is capable of solving complex/large scale problems with minimal computational resources. A detailed discussion on the COMSOL implementation for a nonlinear model is presented and sample simulation files are provided as supplementary material that would be helpful to users/researchers working on similar coupled field models.