CPS4R, CPS3 CAX4R, CAX3, ACAX3, ACAX4 AC3D4, AC3D6, AC3D8, C3D8, C3D8R, C3D4, C3D6, C3D8I M3D4R, M3D3, M3D4 R3D3, R3D4 S4R, S3R, SC6R, SC8R, S4 SFM3D3, SFM3D4R CAX6M, C3D10M C3D8T, C3D4T, C3D6T SC6RT, SC8RT, S4T, S4RT, S3T, S3RT
Using section controls in an import analysis
When transferring results between Abaqus/Standard and Abaqus/Explicit, it is important that the hourglass forces are computed consistently. The enhanced hourglass control formulation (see “Enhanced hourglass control approach in Abaqus/Standard and Abaqus/Explicit” in “Section controls,” Section 24.1.4) is recommended for computing hourglass forces in the original as well as all subsequent import analyses.
Once section controls have been defined in the original analysis, they cannot be modified in any subsequent Abaqus/Standard or Abaqus/Explicit analysis. Therefore, if section controls are to be used in any one analysis in a series of import analyses, they must be specified in the very first analysis. The section controls specified for an element set in the original analysis will be used for the elements belonging to that element set in all subsequent import analyses.
Section controls other than the hourglass control formulation have appropriate defaults depending on the type of analysis and, generally, do not need to be changed. Nondefault values can be chosen subject to certain restrictions.
In an Abaqus/Standard analysis only the average strain kinematic formulation and second-order accurate element formulation are available; other kinematic formulations, element formulations, or section controls that are relevant only in an Abaqus/Explicit analysis can be specified in the Abaqus/Standard analysis. Such controls will be ignored in the Abaqus/Standard analysis but retained for the subsequent Abaqus/Explicit import analysis.
If a kinematic formulation other than average strain is used for solid elements in the Abaqus/Explicit analysis, the differences in the kinematic formulations may lead to errors in Abaqus/Standard if the elements are distorted or undergo large rotations.
Using the first-order accurate element formulation (default) in Abaqus/Explicit and the second-order accurate element formulation (the only available formulation) in Abaqus/Standard is not expected to cause significant errors, since the time increment size in Abaqus/Explicit is inherently small. One exception to this is when the Abaqus/Explicit analysis involves components undergoing several revolutions, in which case it is recommended that the second-order accurate element formulation be used in Abaqus/Explicit.
Input File Usage: Use the following options in the original analysis:
*MEMBRANE SECTION, CONTROLS=name1, ELSET=elset1 *SHELL SECTION, CONTROLS=name2, ELSET=elset2
*SHELL GENERAL SECTION, CONTROLS=name3, ELSET=elset3 *SOLID SECTION, CONTROLS=name4, ELSET=elset4
Use options similar to the following one in the original analysis:
*SECTION CONTROLS, NAME=name1
Abaqus/CAE Usage:
Define section controls when you assign the element type in the original analysis: Mesh module: Mesh
Element Type: Element Controls
Membrane and shell element thickness computation
The computations for membrane and shell element thicknesses are described below.
Shell elements defined using a general shell section
For shells defined using a general shell section, the current thickness is computed based on the effective Poisson's ratio, which is 0.5 by default, in both Abaqus/Explicit and Abaqus/Standard.
Input File Usage: *SHELL GENERAL SECTION , POISSON=
Abaqus/CAE Usage:
Property module: homogeneous or composite shell section editor: Section integration: Before analysis: Advanced: Section Poisson's ratio
Shell elements defined using shell sections integrated during analysis and membrane elements
For shells defined using shell sections integrated during analysis and for membranes in Abaqus/Standard, the current thickness is computed based on the effective Poisson's ratio, which is 0.5 by default. In Abaqus/Explicit, on the other hand, the computation of the thickness could be based either on the effective
Poisson's ratio or the through-thickness strains, with the computation based on the through-thickness strains used by default.
If you do not specify a section Poisson's ratio for shell sections integrated during analysis or for membrane sections in an original Abaqus/Explicit or Abaqus/Standard analysis, the thickness computations in the original and all subsequent import analyses are carried out using the default methods. In other words, the thicknesses in all Abaqus/Standard analyses are computed using the default effective Poisson's ratio of 0.5, while the thicknesses in all Abaqus/Explicit analyses are computed using the through-thickness strains.
When the section Poisson's ratio is assigned a numerical value in an original Abaqus/Standard or Abaqus/Explicit analysis, the thickness computations in the original analysis and all subsequent import analyses are performed using the specified value for the effective Poisson's ratio.
Input File Usage: Use one of the following options:
*SHELL SECTION, POISSON=
*SHELL SECTION, POISSON=MATERIAL
*MEMBRANE SECTION, POISSON=
*MEMBRANE SECTION, POISSON=MATERIAL
Abaqus/CAE Property module: Homogeneous or composite shell section editor: Usage:
Section integration: During analysis: Advanced: Section