K&C’s innovative Meshfree Computation Solid Dynamics (CSD) solver.

FEMFRE is developed towards a vision for a truly predictive, large-deformation, solid mechanics solver for simulating materials and structures in extreme environments. Originally designed as a hybrid Finite Element and Meshfree solver, K&C has since focused FEMFRE development towards an advanced, Meshfree, thermo-mechanical solid dynamics solver.

Features & Benefits

  • Flexible input format that currently supports at least one commercial code input format. This facilitates a user familiar with another commercial code to quickly use and explore FEMFRE.
  • Backend that automatically creates integration cells and subdomains by Hexahedral-splitting or Voronoi tessellation. Our goal is working towards a completely Meshfree solver workflow, where only CAD geometry is required for use with FEMFRE, without the need for a mesh.
  • Implements the latest techniques in stabilized nodal/particle integration schemes and enhanced nodal/particle method shock treatments. Our goal is to remove, or at least minimize, the need for tuning ad-hoc numerical controls that challenge predictive capability in solid mechanics codes (e.g., erosion, hourglass, etc.).
  • OpenMP and MPI solver parallelization. FEMFRE executables are consequently suitable for both local workstations and high-performance computing platforms.
  • FEMFRE is powered by K&C’s material library, ExML (Extreme Material Library), which includes Release IV of the K&C Concrete Model and K&C’s adaptation of the Johnson-Cook model for metals, among others current in the library. Each material in ExML has material parameters already fit to material characterization data and ready for use, or new ones can be generated through our Dynamic Material Characterization laboratory (DMC).
  • Automatic contact detection and mechanics.
  • Binary VTU output files for visualization using Paraview. There is no need to learn any new post-processing software.
  • No cost user-license for collaborators, partners, and interested researchers and practitioners. We are committed to making FEMFRE available to the modeling and simulation community interested in advancing this technology towards our vision to increase safety, security, and affordability.
  • Access to FEMFRE’s source code repository for selected collaborators, partners, and co-developers.

By implementing and maturing Meshfree methods [1-3], including particle and cell-based nodal integration methods, we intend for FEMFRE to solve problems that most finite element mesh-based solvers remain challenged by. These include problems involving:

  • Materials and structures undergoing extremely large deformations
  • Materials exhibiting complex nonlinear behaviors up to and beyond failure
  • Responses governed by evolving surfaces and contact conditions
  • Structures that are difficult or time-consuming to discretize with hexahedral finite elements

 

FEMFRE can now be used as a tool and research platform for those in the modeling and simulation community interested in supporting the vision for this powerful solver. FEMFRE is powered by K&C’s Extreme Materials Library (ExML), which includes a host of common solid materials characterized in our Dynamic Material Characterization laboratory. FEMFRE is therefore applicable to  many blast, shock, impact, and intense fluid-structure interaction problems [4].

 

K&C’s current efforts for FEMFRE development are in refining, extending, and validating to solver towards the vision for the prediction capability.

FEMFRE
Taylor Bar Impact Benchmark

REFERENCES

[1] Y. Wu, J. Magallanes, H. Choi and J. Crawford, “Evolutionary Coupled Finite Element Meshfree Formulation for Modeling Concrete Behaviors under Blast and Impact Loadings,” J. Eng. Mech., vol. 139, pp. 525-536, 2013.

[2] Y. Wu, J. Magallanes and J. E. Crawford, “Fragmentation and debris evolution modeled by a point-wise coupled reproducing kernel/finite element formulation,” Int. J. of Dam. Mech., pp. 1005-1034, 2014.

[3] J. Chen, M. Hillman and S. Chi, “Meshfree Methods: Progress Made after 20 Years,” J. Eng. Mech., vol. 143, no. 4, 2017.

[4] J. Magallanes, D. Wilmes, C. Meakin, Y. Wu and J. Crawford, “KC-FEMFRE: K&C’s Finite Element and Meshfree Code for Computational Solid Dynamics,” Karagozian & Case, Inc., TR-19-01.1, Glendale, CA, 2019 (Proprietary)

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