Because in process of mining only generate constrained sub-trees consisting of three small arrays,which is pseudo tree structure based on the originally unidirectional FP-tree,the flaw is avoided in former algorithms which need to generate lots of condi.

The plastic zone size of the crack tip is relative to three dimensional constraint which depends upon not only the plate thickness but also the load and the material property.

Abduction refreshment deduction and constraint maintenance deduction;