Crack growth

During a crack growth analysis Zencrack carries out a number of steps to re-generate the mesh with an advanced crack position. This advancement of the crack simulates the crack growth in the structure:

• Process the results of a finite element analysis to determine fracture mechanics parameters
• Integrate these data with the crack growth law and load history to calculate growth at each crack front node
• Re-distribute nodes along the crack front if necessary to maintain outer surfaces
• Check whether the crack-blocks need to be transferred to the next line of elements
• Apply boundary shifts to the outer regions of the replaced elements (if necessary)
• Apply relaxation to the elements surrounding the replaced elements (if necessary)
• Re-map the internal nodes of the crack-blocks taking account of the current crack front(s) and any non-planar crack history.

For some classes of problem the boundary shifting algorithm is extended to allow crack-block transfer from one element location to another. This enables large scale crack growth through the structure.

The crack growth examples section provides a number of examples that demonstrate the effectiveness of the re-meshing capabilities within Zencrack during a crack growth analysis. Two examples are highlighted here, the second of which gives a demonstration of the crack-block transfer capability in Zencrack:

Interaction of multiple surface cracks. More...

Effect of bending on crack development in thick plates. More...