Bolt Modeling

Innovation Intelligence®

Section 19

Bolt Modeling

Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.

Bolt Modeling workbench

• Application | Special | Bolt Modeling


Bolt - Head

• A bolt is modeled as 2 parts, the head and the tail. The head portion can be modeled in

one of several ways. Most common type is top and bottom RBE connected by a bar

element.

T o p R B E

B o t t o m R B E

B a r

T o p R B E

B a r

B o t t o m R B E

B a r

T o p R B E

B o t t o m R B E

B a r

Mid RBE B a r


Edge Based Bolt-Head (Ex:Cover.gda)

• To create the head part of the bolt hole, the bolt holes are identified by manually by

selecting the single edge on top and bottom of the holes. Multiple bolts can also be

created by selecting top and bottom edges for each bolt hole.


Edge Based Bolt-Head (Contd.)


Face Based Bolt-Head (Ex:Cover.gda)

• It is possible that a model can have a lot of bolts and it makes it difficult to manually

pick all the edges. So the another option is provided to model bolt heads on all the hoes

on a face. User need to select the face(s) where bolt head sits and specify the bolt hole

diameter range.


Face Based Bolt-Head (Contd.)


Bolt - Thread

• The thread portion of the bolt can be modeled in one of several ways.

B o t t o m R B E

T o p R B E

B o t t o m R B E

B a r

B o t t o m R B E

B a r

T o p R B E


Configuration of bottom RBE

• Down

• Up

• Both

• Sections

D o w n S e c t I o n s


Edge Based Bolt-Thread (Ex:Carrier.gda)

• To create the thread part of the bolt hole, the bolt holes are identified by manually

selecting the single edge on top of the holes. Multiple bolts can also be created by

selecting top edges for each bolt hole.


Edge Based Bolt-Thread (Contd.)


Edge Based Bolt-Thread (Contd.)


Face Based Bolt-Thread (Ex:Carrier.gda)

• User need to select the face(s) and specify the bolt hole diameter range.


File based bolt modeling (Ex: Diff_Case.gda)

• Bolt Modeling | Import Bolt

• Bolts can also be modeled by directly importing the bolt definition file. Importing bolt will

create both head and thread portion of bolts. There are three different blocks in the file

called BOLT, HEAD_DEF and THREAD_DEF define bolt, head and thread

respectively. The complete definition for each key work of the bolt definition file is

available in F1 help.

• Sample bolt definition file (BoltDefinition.dat).

BoltDefinition.dat

BoltDefinition.dat

BoltDefinition.dat

BoltDefinition.dat

BoltDefinition.dat

BoltDefinition.dat

BoltDefinition.dat

BoltDefinition.dat

BoltDefinition.dat

BoltDefinition.dat

BoltDefinition.dat


Bar Pretension

• Bolt Modeling | Bar Pretension

• User can model the pre tension in the tightened bolt in several ways. The tension in the

tightened bolt is modeled by creating RBEs, Bars and force by selecting the edges on

bolt hole. This option is referred as “Edge Based”.

• Different types of Bar Pretension are

• Through

• Threaded


Through / Threaded (Edge Based)

T o p R B E

B o t t o m R B E

B a r

F o r c e

T o p R B E

B o t t o m R B E

B a r

F o r c e

T o p R B E

B o t t o m R B E

B a r

F o r c e

T o p R B E

B o t t o m R B E

B a r

F o r c e

B a r

T o p R B E

B o t t o m R B E

F o r c e


Through (Ex: BarPretension.gda)

• This type can be modeled by selecting the top edge of bolt shank hole and bottom edge

of threaded hole.


Through (Contd.)


Threaded (Ex: BarPretension.gda)


RBE Based (Ex:RBEBased_BarPretension.gda)

• Bar pretension can also be modeled by directly selecting the RBEs/Nodes referred as

“RBE Based” and “Node Based” respectively.


Node Based (Ex:RBEBased_BarPretension.gda)


Solid Pretension

• Bolt Modeling | Solid Pretension

• User can model the pre tension in the tightened bolt by applying solid pretension for the

following solver,

• Abaqus

• Ansys

• Nastran

• Permas

• There are three ways of creating Abaqus bolt,

• Creating pretension face

• Using existing pretension face

• Find pretension face


Abaqus – Creating pretension cut

• Ex: Bolt.gda

• Define the plane where to create the pretension cut.


Abaqus – Using existing pretension cut

• Ex: Bolt_With_Cut.gda

• Select the pretension cut face in the bolt


Ansys, Nastran, Permas solid pretension

1. There are three ways of creating Ansys, Nastran and Permas bolt

1. Creating pretension cut

2. Using existing pretension cut

3. Using the faces apart in the bolt

2. Creating pretension cut (Ex: Bolt.gda)

• User need to define the plane to create pretension cut and solid pretension

based on solver.

3. Using existing pretension cut (Ex: Bolt_With_Cut.gda)

• User need to select the existing pretension cut to create solid pretension based

on solver.

4. Using the faces apart in the bolt (Ex: Bolt_With_Face_Apart.gda)

• User need to select the two face apart in the bolt to create solid pretension

based on solver.


Bolt.gda, Bolt_With_Cut.gda, Bolt_With_Face_Apart.gda


Solid Bolt

• Bolt Modeling | Solid Bolt

• User need to define the axis and

pivot point followed by the parameters.

• Templates can be exported/imported.


Solid bolt patterns

Pattern 1 Pattern 2 Pattern 3 Pattern 4


Connection

• Bolt Modeling | Connection

• Creates connection between bodies automatically.

• Rigid Bar

• Equivalence

• RBE


Rigid Bar (Ex: Connection.gda)

• Bolt Modeling | Connection | RBAR

• User can select either the option between two bodies (Rigid body/Bar body) or all

bodies to connect the free nodes by RBAR by identifying the matching nodes based on

the tolerance value specified.


Rigid Bar (Contd.)

RBAR


Equivalence (Ex: Connection.gda)

• Bolt Modeling | Connection | Equivalence

• RBE center nodes and bar body free nodes, which lie within the given tolerance will get

equivalence.


Equivalence (Contd.)

Node equivalence


RBE (Ex: Connection.gda)

• Bolt Modeling | Connection | RBE

• User need to select dependent and independent body, based on the tolerance specified

the matching nodes will be connected by a RBE.


RBE (Contd.)

Dependent body

Independent body

Connecting RBE

Documents

Bolt Modeling