/PRELOAD
Block Format Keyword Defines a preloading stress applied to the section of a 3D bolt.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/PRELOAD/preload_ID/unit_ID | |||||||||
preload_title | |||||||||
sect_ID | sens_ID | Itype | Preload | Tstart | Tstop |
Definition
Field | Contents | SI Unit Example |
---|---|---|
preload_ID | Bolt preloading block
identifier. (Integer, maximum 10 digits) |
|
unit_ID | Optional unit
identifier. (Integer, maximum 10 digits) |
|
preload_title | Bolt preloading block
title. (Character, maximum 100 characters) |
|
sect_ID | Section identifier to
which the preloading is applied. The preloading force is applied
along local Z direction of the section. 2 (Integer) |
|
sens_ID | Sensor identifier.
(Integer) |
|
Itype | Preloading type.
(Integer) |
|
Preload | Preloading
value. Default = 0.0 (Real) |
or |
Tstart | Start time for bolt
preloading. 6 Default = 0.0 (Real) |
|
Tstop | Stop time for bolt
preloading. 6 Default = 1030 (Real) |
Comments
- The preloading tension stress is applied to the solid elements defined by the sect_ID. This can be used to preload a bolt modeled with solid elements.
- The sect_ID input is mandatory. Its normal vector (which is the local z direction of the section coordinate system) defines the preload direction in the bolt. The elements intersected by the cross-section are used to apply the preload.
- If Itype = 1, the uniform preloading stress is calculated using the preload defined force divided by cross-section initial area defined by the sect_ID.
- If Itype = 2, the preloading stress value applied to the elements of the section is user-defined.
- /TH/SECTION should be defined to output the preload force in the model.
- The preloading occurs at Tstart. The material stiffness of the elements defined by cross-section is reduced and a tensile stress is applied to the elements. The stress creates the preload force in the bolt. Next, the material stiffness of the preload elements is increased until it reaches its original values at Tstop time. Refer to Preload in the User Guide for more information.
- The resulting preloading force in the bolt can be less than the user-defined value. This is due to the initial deformation of the section elements or initial gaps between the parts being bolted.