4.7.7 Test 6: Compact tension specimen

Product: ABAQUS/Standard

Elements tested

CPE8 CPE8R

Problem description

Mesh:

Collapsed elements with 1/4 point midside nodes are used at the crack tip. Half of the test geometry is modeled.

Material:

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

Boundary conditions:

at point A, along edge BA.

Loading:

Concentrated force, P = 1000 N.

Reference solution

This is a test recommended by the National Agency for Finite Element Methods and Standards (U.K.): Test 6 from NAFEMS publication “2D Test Cases in Linear Elastic Fracture Mechanics,” R0020.

Target solution: K/K = 9.659, K₀ =

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
CPE8	9.572 (–0.9%)
CPE8R	9.639 (–0.2%)

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

nlf6xf8x.inp

CPE8 elements.

nlf6xr8x.inp

CPE8R elements.