Creating Virtual Spring Bolt Tightening Connection Properties
A virtual spring bolt tightening connection property is nearly identical to a virtual rigid bolt tightening connection property. The main difference is that a virtual spring bolt tightening connection property accounts for elastic deformation of the bolt and the assembly, whereas a rigid bolt tightening connection property accounts for deformation of the assembly but not of the bolt. Both properties take into account pretension in a bolt-tightened assembly in which the bolt is virtual—not modeled explicitly with a part.
The computation is carried out according to a two-step approach. In the first General Static Step of the analysis the model is submitted to tension forces due to bolt tightening by applying opposite forces on the two surfaces representing the assembly constraint. In general, the first step in your simulation history will not contain other loads, so the bolt tightening connection property can be evaluated and used as a precondition for the rest of the analysis. Then in the second General Static Step of the computation the relative displacement of the two bolt surfaces (obtained in the first step) is fixed while further loading is applied to the model. During these two steps the relative motions of both surfaces and the translations perpendicular to the coincidence constraint axis are linked. If no General Static Steps are included in the analysis, the bolt is loaded in the first Static Linear Perturbation Step. Since bodies can be meshed independently, virtual spring bolt tightening connection properties are designed to handle incompatible meshes.
A virtual spring bolt tightening connection property is defined in terms of the two surfaces that may interact. These surfaces are indicated through the definition of an assembly constraint or an analysis connection. You can use an assembly constraint defined in the Assembly Design workbench to define the contact surface pairing between the bolt thread and the bolt support tapping. Alternatively, you can use a general analysis connection defined in Abaqus for CATIA V5 to define the contact surface pairing. For a description of the analysis connections that support virtual spring bolt tightening connection properties, see the Generative Structural Analysis User's Guide. Table 6–9 summarizes the constraints that can be used to define a virtual rigid bolt tightening connection property in Abaqus for CATIA V5.
Table 6–9 Virtual spring bolt tightening connection properties.
| Assembly Design Workbench | Abaqus for CATIA V5 | |
|---|---|---|
| Coincidence Constraint | Contact Constraint | General Analysis Connection |
 | | |
This task shows you how to create a virtual spring bolt tightening connection property between two parts.
Click the Virtual Spring Bolt Tightening Connection Property icon
.The Virtual Spring Bolt Tightening Connection Property dialog box appears. A symbol representing the virtual spring bolt tightening connection property appears on the corresponding faces, and a Virtual Spring Bolt Tightening Connection Property object appears in the specification tree under the Properties objects set.
You can change the identifier of the virtual spring bolt tightening connection property by editing the Name field.
In the specification tree, select an assembly constraint created previously in the Assembly Design workbench or a general analysis connection created previously in Abaqus for CATIA V5.
The Supports field is updated to reflect your selection.
If necessary, modify the default values of the force parameter. Tightening is represented by a positive force. A virtual spring bolt tightening connection property can exert only a positive force; a negative force is interpreted as zero.
Enter the translational and rotational stiffness values for the virtual spring.
The virtual spring is modeled as a general spring; the spring stiffness may be different for each linear and torsional direction in which the spring acts.
Click OK in the Virtual Spring Bolt Tightening Connection Property dialog box.