Product: ABAQUS/Standard
Substructure's ability to move as a rigid body. The substructures undergo large rotation motions in analyses that generate negligible strain/stress in the substructure. Both *STATIC and *DYNAMIC analyses are verified.
A rectangular substructure is formed. The substructure is subjected to boundary conditions and concentrated loads specified at the retained degrees of freedom that create negligible strain in the substructure but generate large rotations of the model. In the *STATIC analyses the substructure is constrained using springs to prevent numerical singularities.
A second identical mesh is defined without substructures. The displacements, rotations, and reaction forces should be nearly identical between the two equivalent analyses.
All results in the substructure are nearly identical to the results in the regular mesh.
Large rotations, *STATIC, two-dimensional analysis using substructures.
Large rotations, *DYNAMIC, two-dimensional analysis using substructures.
Substructure generation file referenced in the two files above.
Large rotations, *STATIC, two-dimensional analysis without substructures.
Large rotations, *DYNAMIC, two-dimensional analysis without substructures.
Large rotations, *STATIC, three-dimensional analysis using substructures.
Large rotations, *DYNAMIC, three-dimensional analysis using substructures.
Substructure generation file referenced in the two files above.
Large rotations, *STATIC, three-dimensional analysis without substructures.
Large rotations, *DYNAMIC, three-dimensional analysis without substructures.
Large rotations, *STATIC, two-dimensional analysis using substructures.
Large rotations, *DYNAMIC, two-dimensional analysis using substructures.
Substructure generation file referenced in the two files above.
Large rotations, *STATIC, two-dimensional analysis without substructures.
Large rotations, *DYNAMIC, two-dimensional analysis without substructures.
Large rotations, *STATIC, three-dimensional analysis using substructures.
Large rotations, *DYNAMIC, three-dimensional analysis using substructures.
Substructure generation file referenced in the two files above.
Large rotations, *STATIC, three-dimensional analysis without substructures.
Large rotations, *DYNAMIC, three-dimensional analysis without substructures.
Substructures that are subject to elastic small-deformations but undergo large rotations. Both *STATIC and *DYNAMIC analyses are verified.
A rectangular mesh is formed using both the *RETAINED NODAL DOFS and the *RETAINED EIGENMODES options. The loading and boundary contions specified at the retained degrees of freedom are such that elastic small-strain-inducing defomations occur on top of large rotations of the substructure. In the *STATIC analyses additional springs are used to prevent numerical singularities. Results are then compared to results obtained from equivalent analyses that do not use substructures.
All results in the analyses using substructures are nearly identical to the results obtained in the analyses using a regular mesh.
Elastic, small-strain, large rotations, *STATIC, two-dimensional analysis using substructures.
Elastic, small-strain, large rotations, *DYNAMIC, two-dimensional analysis using substructures.
Substructure generation file referenced in the two files above.
Elastic, small-strain, large rotations, *STATIC, two-dimensional analysis without substructures.
Elastic, small-strain, large rotations, *DYNAMIC, two-dimensional analysis without substructures.
Elastic, small-strain, large rotations, *STATIC, three-dimensional analysis using substructures.
Elastic, small-strain, large rotations, *DYNAMIC, three-dimensional analysis using substructures.
Substructure generation file referenced in the two files above.
Elastic, small-strain, large rotations, *STATIC, three-dimensional analysis without substructures.
Elastic small-strain large rotations *DYNAMIC three-dimensional analysis without substructures.
Elastic, small-strain, large rotations, *STATIC, two-dimensional analysis using substructures.
Elastic, small-strain, large rotations, *DYNAMIC, two-dimensional analysis using substructures.
Substructure generation file referenced in the two files above.
Elastic, small-strain, large rotations, *STATIC, two-dimensional analysis without substructures.
Elastic, small-strain, large rotations, *DYNAMIC, two-dimensional analysis without substructures.
Elastic, small-strain, large rotations, *STATIC, three-dimensional analysis using substructures.
Elastic, small-strain, large rotations, *DYNAMIC, three-dimensional analysis using substructures.
Substructure generation file referenced in the two files above.
Elastic, small-strain, large rotations, *STATIC, three-dimensional analysis without substructures.
Elastic, small-strain, large rotations, *DYNAMIC, three-dimensional analysis without substructures.
User-rotated or mirrored substructures that also exhibit elastic small-strain deformation in addition to large rotations.
A rectangular mesh is formed. At the usage level the substructure is either translated and rotated or mirrored.
A second identical mesh is defined without using substructures but accounting for the user-specified rotation/mirroring. The displacements, rotations, and stresses should be nearly identical between the two equivalent analyses.
All results in the substructure are nearly identical to the results in the regular mesh.
User-rotated substructure with large rotation motions, *STATIC, three-dimensional analysis.
Equivalent regular mesh *STATIC three-dimensional analysis.
User-mirrored substructure with large rotation motions, *STATIC, three-dimensional analysis.
Equivalent regular mesh *STATIC three-dimensional analysis.
Substructure generation file referenced in files substr_urot_shell3d_sta.inp and substr_umir_shell3d_sta.inp.
Three levels of substructures are created for this particular analysis. The lowest level is a 2 × 2 mesh of CPE4 elements. The next level comprises two of the first-level substructures, and the third level is the actual structure. The use of unsorted retained degrees of freedom is tested during the creation levels. The loading and boundary conditions specified at the retained degrees of freedom are such that elastic small-strain-inducing defomations occur in addition to the large rotations of the substructure. A second identical mesh is defined without substructures and the results are compared.
All results in the substructure are nearly identical to the results in the regular mesh.
Lowest level substructure generation file.
Second level substructure generation file.
Third level substructure generation file.
Large rotations, *STATIC, two-dimensional analysis.
Large rotations, *STATIC, two-dimensional analysis without substructures.
A rectangular substructure is formed. A gravity load is then applied by using the *SUBSTRUCTURE GENERATE, GRAVITY LOAD=YES option during generation and *DLOAD type GRAV at the usage level. The loading is such that the substructure undergoes large rotations. An equivalent regular mesh is also created, and the results are compared.
All results in the substructure are nearly identical to the results in the regular mesh.
Large rotations, gravity-loaded, *STATIC, two-dimensional analysis using substructures.
Large rotations, gravity-loaded, *DYNAMIC, two-dimensional analysis using substructures.
Substructure generation file referenced in the two files above.
Large rotations, gravity-loaded, *STATIC, two-dimensional analysis without substructures.
Large rotations, gravity-loaded, *DYNAMIC, two-dimensional analysis without substructures.
Large rotations, gravity-loaded, *STATIC, three-dimensional analysis using substructures.
Large rotations, gravity-loaded, *DYNAMIC, three-dimensional analysis using substructures.
Substructure generation file referenced in the two files above.
Large rotations, gravity-loaded, *STATIC, three-dimensional analysis without substructures.
Large rotations, gravity-loaded, *DYNAMIC, three-dimensional analysis without substructures.
Multiple substructures connected with connector elements and *COUPLING options in large motions. Substructures included in a *RIGID BODY option in large rotations. How to switch quickly from a *RIGID BODY model of a part to a small-strain large-motion representation of the same part.
The common 4-bar mechanism is analyzed (see “Overconstraint checks,” Section 20.6.1 of the ABAQUS Analysis User's Manual). The two-dimensional rigid bodies are meshed using CPE4 elements. The *COUPLING option is used to attach connection nodes to the ends of each bar, and connector elements are used to enforce the appropriate kinematic constraints between the bars. The bars are gravity loaded, and *CONNECTOR MOTION is used to drive the mechanism. Since the four bars are identical in shape, only one substructure is generated. The substructure is then translated, mirrored, and rotated at the usage level to create four copies of the substructure in the appropriate locations. Results from both *STATIC and *DYNAMIC analyses are verified against equivalent analyses that do not use substructures.
In addition, at the usage level one of the substructures is turned into a rigid part using the *RIGID BODY option. The attached input files illustrate how one can very efficiently switch from a rigid (faster to run) model (substr_4barrb_solid2d_sta.inp and nosubstr_4barrb_solid2d_sta.inp) to a small-deformation large-rotations efficient subtructure representation of the same model (substr_4bar_solid2d_sta.inp). The substructure analysis is typically significantly faster to run than the regular mesh models (nosubstr_4bar_solid2d_sta.inp).
All results in the substructure are nearly identical to the results in the regular mesh.
Substructure generation file for one bar in the mechanism.
*STATIC analysis of the gravity-loaded 4-bar mechanism using substructures.
*DYNAMIC analysis of the 4-bar multibody with one substructure included in a *RIGID BODY definition.
*STATIC analysis of the gravity-loaded 4-bar mechanism without substructures.
*DYNAMIC analysis of the 4-bar multibody using four separate *RIGID BODYs and no substructures.
*DYNAMIC analysis of the gravity-loaded 4-bar multibody using substructures.
*DYNAMIC analysis of the gravity-loaded 4-bar multibody without substructures.
A rectangular substructure is formed. The applied loads and boundary conditions are such that the substructure exhibits large rotations. After a 45° rotation, impact with a rigid surface occurs. Results are compared with results from an equivalent model without substructures.
All results in the substructure are nearly identical to the results in the regular mesh.
Large rotations, *DYNAMIC, three-dimensional analysis using substructures and contact.
Substructure generation reference in the file above.
Large rotations, *DYNAMIC, three-dimensional analysis without substructures and contact.
Use of *MPCs, *MODEL CHANGE, *INITIAL CONDITIONS, and *RESTART with substructures with large rotations.
Several input files are created to test various features with large rotation substructures. Results are compared with equivalent models that do not use substructures.
All results in the substructure are nearly identical to the results in the regular mesh.
Substructure generation referenced in the files below.
*DYNAMIC, two-dimensional analysis using substructures, *MPCs, and *INITIAL CONDITIONS.
*DYNAMIC, two-dimensional analysis without substructures and *MPCs and *INITIAL CONDITIONS.
*RESTART analysis from substr_misc_solid2d_dyn.inp using substructure.
*RESTART analysis from nosubstr_misc_solid2d_dyn.inp without substructures.
*MODEL CHANGE analysis using substructures.
*MODEL CHANGE analysis without substructures.
Substructure generation referenced in the file below.
One retained node analysis using substructures.
Equivalent analysis without substructures.
Substructure generation referenced in the files below.
Perturbation step after a geometrically nonlinear static rotation.
Perturbation step after a user-specified rotation.