1. Workshop 13 Bolt Pretension
Compressed Gasket
REFERENCE:
Training Manual
Bolt Pretension (9-19)

2. 13. Bolt Pretension Compressed Gasket
Purpose
Demonstrate the basic bolt pretension analysis procedure
Goal
Create pretension elements, apply the bolt preloads using multiple loadsteps, and review the results
Model Description
Bolted gasket
Stiff Plate
Stiff plate
Soft gasket
bolt1
bolt2
bolt3
October 15, 2001
Inventory #
W13-2

3. 13. Bolt Pretension … Compressed Gasket
STEPS TO FOLLOW:
1. Start an ANSYS Interactive session in the working directory specified by the instructor using “pretension” as the jobname
2. Resume the PRETENSION database
Utility Menu > File > Resume from
Select “pretension.db1”
[OK]
OR enter the following command:
RESUME, pretension, db1
3. Plot the elements
Utility Menu > Plot > Elements
EPLOT
NOTE: The pretension.db1 database contains the completed geometry, material, and boundary condition definitions for this finite element model.
October 15, 2001
Inventory #
W13-3

4. 13. Bolt Pretension … Compressed Gasket
4. Create the pretension section for bolt #1
Main Menu > Preprocessor > Sections > Pretensn Mesh >Picked Elements
Select two elements (440,441) at center of vertical beam (bolt #1)
[OK]
Select center node (528) between two elements
Section number = 1
Section name = bolt1
Separation surface normal to = Y-axis
[APPLY]
OR enter the following commands:
/PREP7
ESEL,S,,,440,441
PSMESH, 1, bolt1, , all , , , Y, ,528
Pick two elements
Pick center node between elements
ANSYS will assign a node number for the pretension node.
October 15, 2001
Inventory #
W13-4

5. 13. Bolt Pretension … Compressed Gasket
4. Create the pretension section for bolt #2
Main Menu > Preprocessor > Create >Sections > Pretensn Mesh >Picked Elements
Select two elements (452,453) at center of vertical beam (bolt #2)
[OK]
Select center node (551) between two elements
Section number = 2
Section name = bolt2
Separation surface normal to = Y-axis
[APPLY]
OR enter the following commands:
/PREP7
ESEL,S,,,452,453
PSMESH, 2, bolt2, , all , , , Y, ,551
Pick two elements
Pick center node between elements
October 15, 2001
Inventory #
W13-5

6. 13. Bolt Pretension … Compressed Gasket
4. Create the pretension section for bolt #3
Main Menu > Preprocessor > Create >Sections > Pretensn Mesh >Picked Elements
Select two elements (464,465) at center of vertical beam (bolt #3)
[OK]
Select center node (574) between two elements
Section number = 3
Section name = bolt3
Separation surface normal to = Y-axis
OR enter the following commands:
/PREP7
ESEL,S,,,464,465
PSMESH, 3, bolt3, , all , , , Y, ,574
Pick two elements
Pick center node between elements
October 15, 2001
Inventory #
W13-6

7. 13. Bolt Pretension … Compressed Gasket
The pretension section information and the pretension
node number are reported in the output window:
October 15, 2001
Inventory #
W13-7

8. 13. Bolt Pretension … Compressed Gasket
5. Apply 10,000 pound pretension load to the three bolts
Main Menu > Preprocessor > Loads > Apply > Pretension Section …
bolt1
Apply at LS 2
Force = 10000
Lock at LS 3
0.1% of force
[APPLY]
bolt2
Apply at LS 3
Lock at LS 4
bolt3
Apply at LS 4
Lock at LS 5
[OK]
OR enter the following commands:
SLOAD,1,9,TINY,FORC,10000,2,3
SLOAD,2,9,TINY,FORC,10000,3,4
SLOAD,3,9,TINY,FORC,10000,4,5
October 15, 2001
Inventory #
W13-8

9. 13. Bolt Pretension … Compressed Gasket
5. Run solution and post process results
Util Menu > File > Read input from…
PT_Util.dat
[OK]
OR enter the following commands:
/INPUT,PT_util.dat
NOTE: PT_util.dat input file is set up to solve five load steps. The first load is run prior to pretensioning any bolts, to capture the initial configuration for display animation purposes. The input file then animates the results.
October 15, 2001
Inventory #
W13-9