We have developed a Java-based boundary element program front end, the Electronic Handbook of Fracture (e-Handbook), for fracture analysis of multiple curvilinear cracks in the two-dimensional general anisotropic solids. The e-Handbook provides a graphic user interface for the preparation of the input files, runs a Fortran program for the mixed-mode fracture analysis and displays the stress intensity factors at each crack tip. The e-Handbook can be used as the electronic handbook of the stress intensity factors for custom two-dimensional crack configurations not available in the existing handbooks.
Although the existing stress intensity factor handbooks have extensive coverage of two- and three-dimensional cracks, they are limited to isotropic solids. Despite the increasing application of anisotropic materials in composite and biomimetic materials, there is no systematic and well catalogues source for the stress intensity factors of cracks in the anisotropic solids. The e-Handbook is an attempt to alleviate this situation by providing a boundary element based computer program to calculate stress intensity factors for arbitrary two-dimensional cracks in the general anisotropic solids.
The original boundary element program written in Fortran requires an input file to specify the material constants, boundary and crack geometry and the boundary condition. The preparation of the input file in text form is time consuming, prone to errors and the debugging is difficult. The e-Handbook alleviates this situation and provides a graphic user interface for the preparation of the input files. As we specify the boundary, crack geometry and the boundary condition, they are displayed graphically for quick verification. The modification and refinement of the boundary element mesh for the boundary and the cracks can be performed interactively with instant graphical display of the new mesh. In addition, the material constants for the anisotropic solids are selected from the database without typing individual constant. After creating the input file graphically in the pre-processing, the e-Handbook runs the Fortran program for the mixed-mode fracture analysis. In the post-processing, the e-Handbook displays the stress intensity factors at each crack tip upon clicking the tip by mouse.
The e-Handbook can specify a basic set of two-dimensional multiply connected geometry automatically. The shape and size of outer boundary and those for the inner boundaries (or holes) can be selected from a set of regular polygons initially, which, subsequently, can be modified interactively to create an arbitrary boundary geometry. Both center and edge cracks can be introduced with no restriction of the number and the shape. The general anisotropic solid with up to 21 elastic constants can be modeled with the assumption of the generalized plane strain for which the in-plane and the out-of-plane deformations are coupled. The mixed-mode fracture analysis will provide the mode I, II and III stress intensity factors at each crack tip. The simple case when the in-plane and the out-of-plane deformations are decoupled can also be handled.
The e-Handbook is available for free download at this site. The instructions for installation to your computer and other pertinent information can also be found. The accuracy of the stress intensity factors is typically of 0.1 % error if the recommended guideline for crack meshing is followed. This is because the special crack-tip singular element is used to model the crack singularity mathematically to provide the accuracy and the speed of calculation. Thus the e-Handbook can be used as the electronic handbook of the stress intensity factors for custom two-dimensional cracks. By using the e-Handbook of fracture, the stress intensity factors of any two-dimensional crack configurations in the general anisotropic solids can be obtained quickly with extreme accuracy.
contributors
- Ji Han Hsieh (Rutgers University)
- Mitch Denda (Rutgers University)
- Jorge Redondo (University of the Andes, Merida , Venezuela)
- Maria E. Marante (Lisandro Alvarado University, Barquisimeto, Venezuela)
- Julio Flolez-Lopez (University of the Andes, Merida , Venezuela)