Stress/displacement model change: general tests

This problem contains basic test cases for one or more Abaqus elements and features.

This page discusses:

Elements tested
Features tested
Problem description
Results and discussion
Input files

ProductsAbaqus/Standard

Elements tested

Structural elements

B21
B22
B23
B21H
B22H
B23H
B31
B32
B33
B31H
B31OS
B31OSH
B32H
B32OS
B32OSH
PIPE21
PIPE21H
PIPE22
PIPE22H
PIPE31
PIPE31H
PIPE32
PIPE32H
ELBOW31
ELBOW31B
ELBOW31C
ELBOW32
MAX1
MAX2
MGAX1
MGAX2
M3D3
M3D4
M3D4R
M3D8
M3D8R
M3D9R
SAX1
SAX2
SAXA11
SAXA21
STRI3
S3
S3R
S4R
STRI65
S4
S4R5
S8R
S8R5
S9R5

Two-dimensional continuum elements

CAX4
CAX4H
CAX4I
CAX4R
CAX8
CAX8H
CAX8R
CGAX3HT
CGAX3T
CGAX4
CGAX4H
CGAX4HT
CGAX4R
CGAX4RHT
CGAX4RT
CGAX4T
CGAX8
CGAX8H
CGAX8HT
CGAX8R
CGAX8RHT
CGAX8RT
CGAX8T
CPEG4T
CPEG8
CPEG8H
CPEG8R
CINAX4
CINPS4
CPE4
CPE4H
CPE4I
CPE4R
CPE4RP
CPE4RT
CPE4T
CPE8
CPE8H
CPE8P
CPE8PH
CPE8R
CPE8RP
CPS3
CPS4
CPS4I
CPS4R
CPS4RT
CPS4T
CPS6
CPS6M
CPS8
CPS8R

Three-dimensional continuum elements

C3D4
C3D4H
C3D6
C3D6H
C3D8
C3D8H
C3D8I
C3D8IH
C3D8R
C3D8RH
C3D8RT
C3D10
C3D10H
C3D10MH
C3D10MT
C3D15
C3D15V
C3D15VH
C3D20
C3D20H
C3D20R
C3D20H
C3D20RH
C3D27
C3D27H
C3D27R
C3D27H
C3D27RH
CIN3D8

Miscellaneous elements

DASHPOT1
DASHPOT2
JOINTC
LS3S
LS6
MASS
SPRING1
SPRING2

Features tested

This section includes a very general set of tests for the reactivation with strain of stress/displacement elements.

Each test contains a pair of bodies, each modeled with either one or two elements, so the tests are one-element or two-element tests. In many cases more than one pair of bodies is in a single input file.

One of these bodies, the reference body, is loaded in various ways without ever being removed from the analysis. The other body, the test body, has the same material and thickness properties; however, the test body has a significantly different initial configuration than the reference body, in such a way that it has different stiffness, volume, and mass. During the first step of the analysis, the test body is deformed into the same shape as the reference body. It is then removed and reactivated strain free while in this configuration so that the initial configurations of the two bodies are now identical.

The bodies are then given identical loadings, and the behavior of the two bodies should be identical. To test reactivation with strain, a further removal and a reactivation, this time with strain, occurs for the test body. This kind of reactivation does not reset the initial configuration of the test body, so the behavior of the two bodies should still be identical.

Problem description

Outline of steps (Steps 8–13 are applied for all but the few element types for which dynamic steps are not supported):

Deform the test body into the identical shape as the undeformed reference body. For structural elements this requires applying rotations as well as displacements at the nodes of the test elements so that the normals, as well as the nodal coordinates, coincide.
Remove the test body.
Reactivate the test body without strain. The reactivation should reactivate the test body in the identical configuration as the reference body. Element properties such as cross-sectional area or thickness will be reset to their values at the beginning of the analysis.
Apply element loading to both bodies. Both bodies will deform in the same manner. The load applied during this step will remain active throughout the remainder of the analysis.
Remove the test body. Since the applied loads are element loads, they will be removed from the test body automatically.
Reactivate the test body with strain. Previously applied loads will be reactivated automatically as well. No additional loads are applied during this step. The final configuration of the test body will be identical to that at the end of Step 4 for both bodies. From this step through the remainder of the analysis, the test and reference bodies will provide identical results.
Apply a thermal load to both bodies.
Perform a frequency extraction. Eigenvalues occur in pairs because of the pairs of identical bodies in the input file. Sufficient eigenvectors must be extracted to represent each body of each pair of bodies equally.
Perform a transient modal dynamic analysis using the extracted eigenmodes. A concentrated load is applied at one node. The duration of the analysis is approximately one-tenth of the first fundamental time period.
Perform a mode-based steady-state dynamic analysis. The frequency sweep is performed approximately up to the first 10 natural frequencies.
Perform a direct-solution steady-state dynamic analysis. The frequency sweep is performed approximately up to the first 10 natural frequencies.
Perform a subspace-based steady-state dynamic analysis. The frequency sweep is performed approximately up to the first 10 natural frequencies.
Perform a nonlinear transient dynamic analysis using the direct-integration dynamic implict procedure. The loads and time step size used are those used in Step 9.

A second set of verification problems is added to test the element loads. These are the input file names with _dl added to the end of the file name. The first four steps are identical to the test described above. The remainder of the steps test most of the available distributed load options for each element type.

A final category of tests includes material and initial conditions tests. This group of verification also consists of two-body test cases. These analyses apply initial conditions to various material properties such as void ratio, kinematic shift tensor, and others.

The test body is removed during the first step of the analyses. Because removal occurs in the first step, the initial conditions will remain in place when the test body is reintroduced strain free in the second step. Displacement boundary conditions are then applied to both bodies, which must show identical behavior.

Results and discussion

It is not necessary to check the results to an analytical solution for these tests. However, it is necessary to determine if the test body is being reintroduced back into the analysis properly. Proper reintroduction requires that the test and reference bodies behave identically after the second step. All test elements produce results that match the reference elements.

Input files

Structural element tests

pmcp_beam2d.inp: Two-dimensional beam elements.
pmcp_beam2d_dl.inp: Two-dimensional beam elements, element loading test.
pmcp_beam3d.inp: Three-dimensional beam elements.
pmcp_beam3d_dl.inp: Three-dimensional beam elements, element loading test.
pmcp_pipe2d.inp: Two-dimensional pipe elements.
pmcp_pipe2d_dl.inp: Two-dimensional pipe elements, element loading tests.
pmcp_pipe3d.inp: Three-dimensional pipe elements.
pmcp_pipe3d_dl.inp: Three-dimensional pipe elements, element loading tests.
pmcp_elbow3d.inp: Elbow elements.
pmcp_shell.inp: General shell elements; includes rebar, cylindrical orientations, and NODAL THICKNESS.
pmcp_shell_dl.inp: General shell elements, element loading tests.
pmcp_shell5.inp: 5-degree-of-freedom general shell elements; includes rebar, cylindrical orientations, and NODAL THICKNESS; no reactivation WITH STRAIN.
pmcp_shell5_dl.inp: 5-degree-of-freedom general shell elements, element loading tests.
pmcp_memb.inp: General membrane elements; includes rebar, orientations, and NODAL THICKNESS.
pmcp_memb_dl.inp: General membrane elements, element loading tests.
pmcp_aximemb.inp: Axisymmetric membrane elements, element loading tests; includes rebar.
pmcp_axishell.inp: Axisymmetric shell elements, element loading tests; includes rebar.
pmcp_saxa.inp: Axisymmetric shell elements with nonaxisymmetric loading, excluding element loading tests; includes rebar.

Two-dimensional continuum element tests

pmcp_cax.inp: Axisymmetric continuum elements.
pmcp_cax_dl.inp: Axisymmetric continuum elements, load test.
pmcp_cgax.inp: Axisymmetric elements with twist; includes load test, excludes dynamic steps.
pmcp_cgax3t.inp: Coupled temperature-displacement axisymmetric triangular elements with twist; includes load test, excludes dynamic steps.
pmcp_cgaxt.inp: Coupled temperature-displacement axisymmetric quadrilateral elements with twist; includes load test, excludes dynamic steps.
pmcp_cpe.inp: Plane strain elements.
pmcp_cpe_res.inp: Restart from pmcp_cpe.inp; Step 4 onward duplicated.
pmcp_cpe4_ori.inp: CPE4 element with ORIENTATION.
pmcp_cpe4h_ori.inp: CPE4H element with ORIENTATION.
pmcp_cpe8_ori.inp: CPE8 element with ORIENTATION.
pmcp_cpeg.inp: Generalized plane strain elements.
pmcp_cps.inp: Plane stress elements.
pmcp_cpstri.inp: Triangular plane stress elements.
pmcp_cps4_ori.inp: CPS4 element with ORIENTATION.
pmcp_cps8_ori.inp: CPS8 element with ORIENTATION.
pmcp_infinite2d.inp: Infinite elements.
pmcp_2dpore.inp: Pore pressure plane strain elements.
pmcp_2drebar.inp: Plane strain, plane stress, and axisymmetric elements with rebar.
pmcp_2drebar_res.inp: Restart from pmcp_2drebar.inp; Step 4 onward duplicated.
pmcp_2dtemp.inp: Coupled temperature-displacement elements.
pmcp_2dtemp_cgaxt.inp: Coupled temperature-displacement axisymmetric quadrilateral elements with twist.
pmcp_2dtemp_cgax3t.inp: Coupled temperature-displacement axisymmetric triangular elements with twist.
pmcp_2dtemp_cpeg4t.inp: Coupled temperature-displacement generalized plane strain quadrilateral elements.
pmcp_2dtemp_nodyn.inp: Coupled temperature-displacement generalized plane strain quadrilateral elements, excludes dynamic steps.

Three-dimensional continuum element tests

pmcp_c3d8.inp: C3D8 element with ORIENTATION and REBAR.
pmcp_c3d8_dl.inp: C3D8 element loading test.
pmcp_c3d8h.inp: General test of C3D8H element.
pmcp_c3d8h_dl.inp: C3D8H element loading test.
pmcp_c3d8i.inp: General test of C3D8I element.
pmcp_c3d8i_dl.inp: C3D8I element loading test.
pmcp_c3d8ih.inp: General test of C3D8IH element.
pmcp_c3d8ih_dl.inp: C3D8IH element loading test.
pmcp_c3d8r.inp: General test of C3D8R element.
pmcp_c3d8r_dl.inp: C3D8R element loading test.
pmcp_c3d8rh.inp: General test of C3D8RH element.
pmcp_c3d8rh_dl.inp: C3D8RH element loading test.
pmcp_c3d8rt.inp: General test of C3D8RT element.
pmcp_c3d8rt_dl.inp: C3D8RT element loading test.
pmcp_c3d10mt.inp: General test of C3D10MT element.
pmcp_c3d10mt_dl.inp: C3D10MT element loading test.
pmcp_c3d15v.inp: General test of C3D15V element.
pmcp_c3d15v_dl.inp: C3D15V element loading test.
pmcp_c3d15vh.inp: General test of C3D15VH element.
pmcp_c3d15vh_dl.inp: C3D15VH element loading test.
pmcp_c3d20.inp: General test of C3D20 element.
pmcp_c3d20_dl.inp: C3D20 element loading test.
pmcp_c3d20h.inp: General test of C3D20H element.
pmcp_c3d20h_dl.inp: C3D20H element loading test.
pmcp_c3d20r.inp: General test of C3D20R element.
pmcp_c3d20r_dl.inp: C3D20R element loading test.
pmcp_c3d20rh.inp: General test of C3D20RH element.
pmcp_c3d20rh_dl.inp: C3D20RH element loading test.
pmcp_c3d27.inp: General test of C3D27 element.
pmcp_c3d27_dl.inp: C3D27 element loading test.
pmcp_c3d27h.inp: General test of C3D27H element.
pmcp_c3d27h_dl.inp: C3D27H element loading test.
pmcp_c3d27r.inp: General test of C3D27R element.
pmcp_c3d27r_dl.inp: C3D27R element loading test.
pmcp_c3d27rh.inp: General test of C3D27RH element.
pmcp_c3d27rh_dl.inp: C3D27RH element loading test.
pmcp_infinite3d.inp: CIN3D8, infinite element test.
pmcp_prisms.inp: General test of C3D6, C3D6H, C3D15, and C3D15H elements.
pmcp_prisms_dl.inp: Element loading test of C3D6, C3D6H, C3D15, and C3D15H elements.
pmcp_tets.inp: General test of tetrahedral elements.
pmcp_tets_dl.inp: Element loading test of tetrahedral elements.

Miscellaneous element tests

pmcp_jointc.inp: JOINTC element.
pmcp_linespring.inp: Line spring element.
pmcp_spring.inp: Spring, dashpot, and mass elements.
pmcp_substr.inp: Substructures constructed of beam elements.

Material/initial condition tests

pmcp_cap.inp: Cap plasticity with initial stresses.
pmcp_clay.inp: Cam-clay model with initial stresses.
pmcp_foam.inp: Crushable foam material.
pmcp_hyperelastic.inp: Hyperelastic material.
pmcp_hyperfoam.inp: Hyperfoam material.
pmcp_initstress.inp: Initial stresses in elements and NODAL THICKNESS are included.
pmcp_mises.inp: Mises plasticity with initial shift in kinematic hardening tensor.
pmcp_porous.inp: Porous metal plasticity.

These tests include elements CAX4, CAXA41, CPE4, CPS4, CGAX4, S4R, and M3D4R. Rebars are included with the CAX4, M3D4R, and S4R elements.