Stress/displacement model change: general tests

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

The following topics are discussed:

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):

  1. 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.

  2. Remove the test body.

  3. 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.

  4. 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.

  5. Remove the test body. Since the applied loads are element loads, they will be removed from the test body automatically.

  6. 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.

  7. Apply a thermal load to both bodies.

  8. 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.

  9. 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.

  10. Perform a mode-based steady-state dynamic analysis. The frequency sweep is performed approximately up to the first 10 natural frequencies.

  11. Perform a direct-solution steady-state dynamic analysis. The frequency sweep is performed approximately up to the first 10 natural frequencies.

  12. Perform a subspace-based steady-state dynamic analysis. The frequency sweep is performed approximately up to the first 10 natural frequencies.

  13. 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.