4.7.1 Test 1.1: Center cracked plate in tension

Product: ABAQUS/Standard

Elements tested

CPE8 CPE8R

Problem description

Mesh:

Collapsed elements with 1/4 point midside nodes are used at the crack tip. One-quarter of the test geometry is modeled. A coarse and a fine mesh are tested.

Material:

Young's modulus = 207 GPa, Poisson's ratio = 0.3.

Boundary conditions:

along edge AB, along edge DE.

Loading:

Uniform stress, 100 N/mm².

Reference solution

This is a test recommended by the National Agency for Finite Element Methods and Standards (U.K.): Test 1.1 from NAFEMS publication “2D Test Cases in Linear Elastic Fracture Mechanics,” R0020.

Target solution: K/K = 1.325, K =

Results and discussion

The results are shown in the following table. The values enclosed in parentheses are percentage differences with respect to the reference solution.

Element Type	K/K (Coarse)	K/K (Fine)
CPE8	1.325 (0.0%)	1.333 (+0.63%)
CPE8R	1.329 (+0.3%)	1.334 (+0.63%)

Remarks

K = . An average of the J values calculated by ABAQUS, excluding the first contour, is used in reporting the results. Experience has shown that the crack-tip elements do not give sufficiently accurate results to give good estimates of the J-integral for the first contour.

Input files

nlf11f8c.inp

CPE8 elements, coarse mesh.

nlf11f8f.inp

CPE8 elements, fine mesh.

nlf11r8c.inp

CPE8R elements, coarse mesh.

nlf11r8f.inp

CPE8R elements, fine mesh.