This example models a simple flexible link component using three-dimensional continuum elements.
To perform the analysis for the link modeled with solid elements:
Enter the following commands to extract the input files from the compressed archive files provided with the Abaqus release:
abaqus fetch job=adams_ex1 abaqus fetch job=adams_ex1_nodes abaqus fetch job=adams_ex1_elements
Enter the following command to execute the Abaqus analysis:
abaqus job=adams_ex1
Enter the following command to execute the Abaqus Interface for MSC.ADAMS and translate the results file generated in the Abaqus analysis to a modal neutral file for use with ADAMS/Flex:
abaqus adams job=adams_ex1
The solid element link model used in the MSC.ADAMS four-bar linkage model is shown in Figure 4–1.
The link is modeled with 642 C3D10 tetrahedral solid elements (1368 nodes).Because the solid elements have only displacement degrees of freedom at their nodes, multi-point constraints are used to provide a connection to the other components in the MSC.ADAMS model. Two nodes are added along the centerline of the beam at the centers of the hinge holes. The C3D10 nodes that lie on the faces of the hinge holes are connected to the extra nodes with BEAM-type multi-point constraints, allowing the nodes to transmit both forces and moments between the link and other MSC.ADAMS components.
The options used to define the single substructure are those described in “The Abaqus substructure model,” Section 2.1. Twenty fixed-interface vibration modes are computed to represent the dynamic behavior of the link.
MSC.ADAMS uses the fixed-interface vibration modes and the constraint modes to characterize the flexibility of the link. The eight lowest fixed-interface vibration frequencies computed by Abaqus are shown in Table 4–1. These frequencies are reported in the adams_ex1.dat file.
Table 4–1 Fixed-interface vibration frequencies for the solid link model.
| Frequency, Hz |
|---|
| 206 |
| 391 |
| 570 |
| 1124 |
| 1228 |
| 1817 |
| 1879 |
| 2541 |
Table 4–2 Nonzero frequencies for the solid link model that are used by ADAMS/Flex.
| Frequency, Hz |
|---|
| 194 |
| 535 |
| 574 |
| 1055 |
| 1551 |
| 1762 |
| 1801 |
| 2653 |
The Abaqus input file for the solid model, adams_ex1.inp, is shown below.
*HEADING Link modeled with C3D10 solid elements ** ---------------------------------------------- ** ** NODE DEFINITION ** *NODE,input=adams_ex1_nodes.inp ** ** *NSET, NSET=LEFTCYL 8,9,17,18,70,71,72,73,125,126,127,128,134,135,207, 229,230,278,309,310,311,312,313,314,373,374,375,376, 377,378,389,390,391,392,498,533,534,535,546,565,566, 677,688,734,1058,1059,1073,1085,1114,1115,1311,1312, 1325,1335,1356,1357 ** *NSET, NSET=RIGHTCYL 6,7,15,16,66,67,68,69,121,122,123,124,136,137,231, 232,303,304,305,306,307,308,367,368,369,370,371,372, 393,394,395,396,479,480,481,487,488,506,635,654,957, 958,976,977,1004,1026,1219,1220,1234,1235,1257,1287 ** *MPC BEAM,LEFTCYL,10000 BEAM,RIGHTCYL,20000 ** ---------------------------------------------- ** ** ELEMENT DEFINITION ** *ELEMENT,TYPE=C3D10,ELSET=PROP1,INPUT=adams_ex1_elements.inp ** ** ** ---------------------------------------------- ** ** ELEMENT PROPERTY DEFINITION ** *SOLID SECTION,ELSET=PROP1,MATERIAL=STEEL ** ** ---------------------------------------------- ** ** MATERIAL DEFINITION ** *MATERIAL,NAME=STEEL *ELASTIC 2.069999944E+11, 3.000000119E-01, *DENSITY 7.800000000E+03, ** *NSET,NSET=RETNODES 10000,20000 ** ** ---------------------------------------------- ** *STEP *FREQUENCY,EIGENSOLVER=LANCZOS 20, *BOUNDARY RETNODES, 1,6 *ELEMENT MATRIX OUTPUT, MASS=YES, ELSET=PROP1 *NODE FILE U *END STEP ** ** ---------------------------------------------- ** ** SUBSTRUCTURE GENERATION ** *STEP *SUBSTRUCTURE GENERATE, TYPE=Z1, RECOVERY MATRIX=YES, MASS MATRIX=YES, OVERWRITE *RETAINED NODAL DOFS, SORTED=NO RETNODES, 1,6 *SELECT EIGENMODES,generate 1,20 *SUBSTRUCTURE MATRIX OUTPUT, STIFFNESS=YES, MASS=YES, RECOVERY=YES *END STEP
