Crack propagation analysis

In the symmetry model the top half of a single-edge notch plate is modeled with a mesh of 2 × 6 CPE4 elements. The lower surface of the bottom row of elements defines the secondary surface of the partially bonded contact pair, and the main surface is defined by an analytical rigid surface. The main surface also lies along the symmetry plane. Nonzero displacement boundary conditions are applied at two nodes remote from the symmetry plane. The time for bond failure and the position of the node at which the bond failure occurs (obtained from pdebnods.inp) are used to give the crack length versus time data in pdebcrgr.inp. The crack opening displacement at a distance behind the crack tip (obtained from pdebnods.inp) is used to specify the data for the COD criterion in pdebcods.inp. The stresses at a distance ahead of the crack tip (obtained from pdebnods.inp) are used to specify the data in pdebnodsd.inp. The time from pdebnods.inp is also used to set the time period for each step in pdebchck.inp.

The complete mesh is analyzed in pdebnods2.inp, pdebcrgr2.inp, and pdebcods2.inp.

Input files pdebnodnlg.inp, pdebcrgnlg.inp, and pdebcodnlg.inp consider finite deformation and finite sliding. The crack length versus time data for pdebcrgnlg.inp and the COD data for pdebcodnlg.inp are obtained from pdebnodnlg.inp.

The top half of a center cracked plate is modeled with a mesh of 2 × 12 CPE4 elements. The lower surface of the bottom row of elements is used to define the secondary surface of the partially bonded contact pair, and the main surface is defined by an analytical rigid surface. The main surface also lies on the symmetry plane. Nonzero displacement boundary conditions are applied on the top row of nodes.

The time for bond failure and the position of the node at which the bond failure occurs (obtained from pdebnodcc1.inp) are used to give the crack length versus time data in pdebcrgcc1.inp. The reference point for the crack length versus time criterion is defined such that the crack propagation occurs simultaneously from both the crack tips.

The crack opening displacement at a distance behind the crack tip (obtained from pdebcodcc1.inp) is used to specify the data for the COD criterion in pdebcodcc1.inp.

The complete mesh is analyzed in pdebnodcc2.inp, pdebcodcc2.inp, and pdebcrgcc2.inp.

The top half of a plate that consists of an edge crack and a center crack is modeled with a mesh consisting of 2 × 12 CPE4 elements. The bottom surface of the lower row of elements is used to define the secondary surface of the initially partially bonded contact pair. The main surface of the contact pair is defined by an analytical rigid surface and also lies along the symmetry plane. Nonzero displacement boundary conditions are applied at two nodes remote from the bonded plane, as shown in the figure.

The complete mesh is analyzed in pdebcrgco2.inp and pdebcodco2.inp.

The problem of a round bar with an external notch (crack) subjected to tensile loading is analyzed as an axisymmetric case. Only the top half is modeled in pdebnodax1.inp, pdebcrgax1.inp, and pdebcodax1.inp. The mesh consists of 2 × 6 CAX4 elements. The lower surface of the bottom row of elements is used to define the secondary surface, while the main surface is defined by an analytical rigid surface. A far-field load $\sigma$ is applied.

Input file pdebnodax1.inp uses the critical stress criterion for crack propagation analysis. The crack length versus time data for pdebcrgax1.inp and the crack opening displacement versus cumulative incremental crack length for pdebcodax1.inp are obtained from pdebnodax1.inp.

The complete mesh is analyzed in pdebnodax2.inp, pdebcrgax2.inp, and pdebcodax2.inp.

This input file tests for the output of the debond variables.