1.3.2 Generalized plane strain elements with relative motion of bounding planes

Product: ABAQUS/Standard  

Elements tested

CPEG3    CPEG3H    CPEG3HT    CPEG3T    CPEG4    CPEG4H    CPEG4HT    CPEG4I    CPEG4IH    CPEG4R    CPEG4RH    CPEG4RHT    CPEG4RT    CPEG4T    CPEG6    CPEG6H    CPEG6M    CPEG6MH    CPEG6MHT    CPEG6MT    CPEG8    CPEG8H    CPEG8HT    CPEG8R    CPEG8RH    CPEG8RHT    CPEG8T   

Problem description

Material:

Linear elastic, Young's modulus = 30 × 106, Poisson's ratio = 0.3.

Boundary conditions:

.

Step 1 (Perturbation)

An out-of-plane displacement of 0.01 units (motion of one bounding plane relative to the other) is applied to degree of freedom 3 of the reference node, which is the change in fiber length degree of freedom.

Analytical solution:

Stresses

At every node 3.0 × 105.

Strains

At every node –3.0 × 10–3, 1.0 × 10–2.

Step 2 (Perturbation)

A relative rotation of 0.01 radians about the y-axis is applied to degree of freedom 5 of the reference node (the rotation degree of freedom of one bounding plane relative to the other).

Analytical solution:

Stresses

Maximum tensile stress 1.5 × 105.

Strains

Maximum tensile strain 5 × 10–3.

Results and discussion

For Step 1, all element types yield the exact solution. The results for Step 2 are given in the following table:

Element type
CPEG31.264 × 1054.167 × 10–3
CPEG3H1.264 × 1054.167 × 10–3
CPEG3HT1.264 × 1054.167 × 10–3
CPEG3T1.264 × 1054.167 × 10–3
CPEG41.131 × 1053.750 × 10–3
CPEG4H1.131 × 1053.750 × 10–3
CPEG4HT1.131 × 1053.750 × 10–3
CPEG4I1.500 × 1055.000× 10–3
CPEG4IH1.500 × 1055.000 × 10–3
CPEG4R1.125 × 1053.750 × 10–3
CPEG4RH1.125 × 1053.750 × 10–2
CPEG4RHT1.125 × 1053.750 × 10–2
CPEG4RT1.125 × 1053.750 × 10–3
CPEG4T1.131 × 1053.750 × 10–3
CPEG61.500× 1055.000× 10–3
CPEG6H1.500× 1055.000 × 10–3
CPEG6M1.504× 1055.000 × 10–3
CPEG6MH1.504 × 1055.000× 10–3
CPEG6MHT1.504 × 1055.000× 10–3
CPEG6MT1.504 × 1055.000× 10–3
CPEG81.500 × 1055.000 × 10–3
CPEG8H1.500 × 1055.000 × 10–3
CPEG8HT1.500 × 1055.000 × 10–3
CPEG8R1.500 × 1055.000 × 10–3
CPEG8RH1.500 × 1055.000 × 10–3
CPEG8RHT1.500 × 1055.000 × 10–3
CPEG8T1.500 × 1055.000 × 10–3

Second-order quadrilateral elements, first-order incompatible mode elements, and quadratic triangles yield the exact solutions. Modified triangles yield nearly exact solutions. Other element types exhibit stiff response.

Input files

ecg3sas2.inp

CPEG3 and CPEG3H elements.

ecg4sas2.inp

CPEG4, CPEG4I, CPEG4R, CPEG4IH, CPEG4H, and CPEG4RH elements.

ecg6sas2.inp

CPEG6, CPEG6H, CPEG6M, and CPEG6MH elements.

ecg8sas2.inp

CPEG8, CPEG8R, CPEG8H, and CPEG8RH elements.

ecg3tas2.inp

CPEG3HT and CPEG3T elements.

ecg4tas2.inp

CPEG4HT, CPEG4RHT, CPEG4RT, and CPEG4T elements.

ecg6tas2.inp

CPEG6, CPEG6H, CPEG6MT, and CPEG6MHT elements.

ecg8tas2.inp

CPEG8HT, CPEG8RHT, and CPEG8T elements.