Use FEACrack™ to automatically generate 3D crack meshes for finite element analysis to compute the crack front stress intensity, K, and J-integral. An intuitive Windows® interface guides you step-by-step through building the model, running the analysis, and viewing the results. Creating a 3D crack mesh is significantly more complicated than a mesh for an uncracked component; FEACrack™ makes crack mesh generation easy.
The crack mesh generator creates ready-to-run FEA input files for several programs: Warp3D, ABAQUS, ANSYS, and creates neutral mesh files for FEMAP and PATRAN. Warp3D is available in the public domain and is distributed with FEACrack™ at no additional cost. ABAQUS and ANSYS must be purchased separately.
More details are given below:
To build the 3D crack mesh select from the pre-defined library of structural geometries or the advanced user-defined geometry. Select the crack shape from surface, through-wall, buried, and fillet toe cracks. Cracks can also be located within a seam weld for several geometry choices. Enter the crack and geometry dimensions, and choose the boundary conditions such as pressure, forces, and displacement constraints. Default material data is available. The 3D crack mesh is automatically generated and the FEA input file is created. For a parametric case study, a list of crack dimensions can be given to automatically generate numerous crack meshes.
For more complex geometries, the user-defined geometry option allows a 3D crack mesh to be created within an arbitrary six-sided volume. The user-defined geometry can be used to create a complete crack mesh model for analysis, or can be inserted into a larger model and connected by tied contact. The user imports the definition mesh (created outside of FEACrack™) of brick or tetrahedron elements into FEACrack™ to describe the geometric shape of the 3D crack mesh. Several input file formats are available for importing the definition mesh, or it can be pasted into spreadsheet forms. The user selects the crack location and orientation from pull down menus that reference the corner node ID numbers of the given definition mesh.
The finite element analysis can be run directly from the FEACrack™ file control wizard, which provides an easy way to run a list of input files. The FEACrack post-processing module reads the results to display the stress or strain as a color map on the mesh, the mesh deformed shape, and the crack results. The crack front J and K results are shown in x-y plots and listed in data spreadsheets. Elastic-plastic J results can be used to compute reference stress and a failure assessment diagram (FAD) for fracture evaluation. Multiple result files can be loaded for easy comparison of J and K results due to changing model parameters
An elastic fatigue crack growth analysis capability is available for the pre-defined geometry choices: the model is continually remeshed with the increasing crack size based on computed growth rates at various points along the crack. The crack front stress intensity K is used to compute the crack growth rate and update the crack dimensions for the next mesh and analysis step. The fatigue loading can be constant or variable amplitude; several fatigue crack growth models are available. The standard focused crack mesh is used for this type of crack growth analysis.
Using the cell-type crack mesh, crack growth analysis can be computed using node release, porous Gurson material, or cohesive material methods. This type of crack growth analysis does not require remeshing and can use elastic-plastic material. A remote domain definition is used to compute the J-integral around the crack growth zone, which allows a J-R crack growth resistance curve to be computed from the results.
The specific file types for each FEA program supported by FEACrack™ are listed below. Please contact Quest Reliability for any additional details for using a particular FEA program.
Warp3D (http://cern49.cee.uiuc.edu/cfm/warp3d.html) is a 3-D finite element analysis program developed in the Civil Engineering Department at the University of Illinois, Urbana. It is available in the public domain and is distributed with FEACrack™ at no additional cost. Warp3D fully supports the 3-D brick element crack meshes generated by FEACrack™ for linear or non-linear analysis, and supports tied contact. FEACrack™ creates the *.inp text input file, and reads both the *_wrp.out text output file and the *_wrp.bpf binary packets file.
ABAQUS is a full-featured finite element analysis program available from ABAQUS, Inc. (http://www.abaqus.com/) and must be purchased separately from FEACrack™. FEACrack™ creates the *.inp text input file, and reads the *_abq.fil output results file. Quest Reliability is an ABAQUS software partner.
ANSYS is a full-featured finite element analysis program available from ANSYS, Inc. (http://www.ansys.com/) and must be purchased separately from FEACrack™. FEACrack™ creates the *.ans text input file, and reads the *.rst binary results file. Th™e stress, strain, and displacement results are used in the J-integral module to compute the J-integral results along the crack front. Quest Reliability, LLC is an ANSYS Enhanced Solutions Partner.
For further information about FEACrack™ and other programs, please contact us.