Pelamis Bolt Preload Settings

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Pelamis Bolt Preload

User Guide

An ABAQUS/CAE GUI Plug-in to apply preload to all

instances of a bolt in assembly simultaneously

Version 1.0

Dr Richard Craven

March 2014


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Pelamis Materials Database User Guide

Version 1.0 2 March 2014

1 Contents

1 Contents ............................................................................................................................. 2

2 Table of Figures .................................................................................................................. 3

3 Introduction ....................................................................................................................... 4

4 Licensing ............................................................................................................................. 4

5 Prerequisites ...................................................................................................................... 4

5.1 Abaqus Prerequisites .................................................................................................. 4

5.2 User Prerequisites ....................................................................................................... 4

6 Launching Pelamis Bolt Preload ......................................................................................... 5

7 Parts ................................................................................................................................... 7

8 Preload Surface .................................................................................................................. 8

9 Bolt Axis .............................................................................................................................. 9

10 Fix at Current Length Step ............................................................................................... 10

11 Preload ............................................................................................................................. 10

11.1 Size and Grade ....................................................................................................... 11

11.2 User Defined .......................................................................................................... 1112 OK, Apply and Cancel ....................................................................................................... 12

13 Bolts Database ................................................................................................................. 12

13.1 Structure ................................................................................................................ 13

13.2 Adding Bolts or Grades .......................................................................................... 14

Bibliography ............................................................................................................................. 15

Appendix A: Known Issues ....................................................................................................... 16

I. No Known Issues to Date .......................................................................................... 16


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2 Table of Figures

Figure 5-1: Pelamis BP Menu Location ...................................................................................... 5

Figure 5-2: Pelamis BP No Parts Error ........................................................................................ 5

Figure 5-3: Pelamis BP No Part Instances Error ......................................................................... 5

Figure 5-4: Pelamis BP Only Initial Step Created Error .............................................................. 6

Figure 5-5: Pelamis BP Plug-in ................................................................................................... 6

Figure 5-6: Pelamis BP Step Creation Warning .......................................................................... 7

Figure 6-1: Bolted Assembly ...................................................................................................... 7

Figure 6-2: Pelamis BP Part selection ........................................................................................ 7

Figure 7-1: M16 x 120 Bolt Part with Preload Surface Defined ................................................. 8

Figure 7-2: Pelamis BP Choose Preload Surface ........................................................................ 8

Figure 7-3: Part with No internal surface Error Message .......................................................... 9

Figure 8-1: Choose Axis Pelamis BP ........................................................................................... 9

Figure 8-2: Visualising Bolt Preload Axis .................................................................................. 10

Figure 9-1: Fix Current Length Step Pelamis BP ....................................................................... 10

Figure 10-1: Preload definition option .................................................................................... 11Figure 10-2: Bolt Size selection Pelamis BP ............................................................................. 11

Figure 10-3: Bolt Grade selection Pelamis BP .......................................................................... 11

Figure 10-4: User defined Preload Pelamis BP ........................................................................ 12

Figure 11-1: Model with Bolt Preload Applied ........................................................................ 12


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3 Introduction

This document is a user guide for the use of the Pelamis Bolt Preload. (Pelamis BP) tool

within Abaqus. This tool is a plug-in to the Abaqus GUI written using python and the Abaqus

GUI customisation FX toolkit. No knowledge of python is required to use this tool although

knowledge of Abaqus and creating models is assumed. This user guide will step through how

to use the preload tool, to apply preload to all instances of a bolt part in an assembly in one

go rather than applying each bolt preload individually.

4 Licensing

This software is made available under the MIT / X window System License.

Copyright 2014 Pelamis Wave Power Ltd

Permission is hereby granted, free of charge, to any person obtaining

a copy of this software and associated documentation files (the

"Software"), to deal in the Software without restriction, including

without limitation the rights to use, copy, modify, merge, publish,

distribute, sublicense, and/or sell copies of the Software, and to

permit persons to whom the Software is furnished to do so, subject to

the following conditions:

The above copyright notice and this permission notice shall be

included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OFMERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS

BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

SOFTWARE.

5 Prerequisites

This section covers the assumed pre-requisites of the user and Abaqus installation.

5.1 Abaqus Prerequisites

Abaqus 6.13-1 installed, this plug-in may work on other versions of Abaqus but has not been

tested.

5.2 User Prerequisites

A basic understanding of constructing models in Abaqus and an understanding of the

concept of preloading bolts.


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6 Launching Pelamis Bolt Preload

To launch the Pelamis BD the user needs to be in the Loadmodule of Abaqus, then the tool

can be accessed from the Plug-ins > Pelamis > Bolt Preloadmenu,Figure 6-1.

Figure 6-1: Pelamis BP Menu Location

The plug-in will check that the requirements for the plug-in are in place before launching the

gui, and if not will display a dialogue box informing the user of what they need to do before

running the Pelamis BP again. The first check is to check that parts actually exist in the

model, otherwise the following error will be raised,Figure 6-2.

Figure 6-2: Pelamis BP No Parts Error

The second check will check that there are part instances in the assembly and if there are

none will raise this error,Figure 6-3.

Figure 6-3: Pelamis BP No Part Instances Error

The final check is that steps have been created, other than the initial step, as the step where

the bolt length is fixed needs to be defined, if only the initial step is defined, the following

error is raised,Figure 6-4.


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Figure 6-4: Pelamis BP Only Initial Step Created Error

The Pelamis BD dialog box will then launch and the plug-in menu will look like this,Figure

6-5.

Figure 6-5: Pelamis BP Plug-in

If no preloadstep was defined prior to running the Pelamis BP, then the plug-in will create a

preload step as the first step after initial and the only step where preload can currently be

applied within Abaqus, and a warning message will inform you that this step has been

created,Figure 6-6.


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Figure 6-6: Pelamis BP Step Creation Warning

The plug in is laid out to guide you step by step through the processes of choosing the part,

picking the internal surface to apply preload too, and the axis along which to apply preload.

The step in the model at which to fix the length of the bolt having applied the preload andthe preload itself, either by specifying bolt size and grade, or by entering preload directly in

Newtons.

7 Parts

The user should have created a part which represents the bolt within the model, and placed

this in the assembly, in every location where this bolt will be used,Figure 7-1.This bolt can

then be selected from the drop down list of parts in the Pelamis BP plugin, .

Figure 7-1: Bolted Assembly

Figure 7-2: Pelamis BP Part selection


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This will then allow the preload defined to be applied to all 20 instances of this part M16 x

120in the assembly.

8

Preload Surface

The preload surface is an internal surface to the bolt, across which the preload force is

applied; this should be created as a surface feature of the bolt part, prior to running the

Pelamis BP plug-in. This surface can be anywhere along the shaft of the bolt, but should be

outside of the region of the shaft that is tied to the bolt hole/nut. When picking the surface

for the preload, the options are Purpleand Brown, Brownshould always be selected,Figure

8-1.

Figure 8-1: M16 x 120 Bolt Part with Preload Surface Defined

While the part M16 x 120clearly has 3 surfaces defined for different purposed,Figure 8-1,

only the Preloadsurface appears in the list of surfaces in the Pelamis BP,Figure 8-2,as theplug-in has an built in check for internal surfaces and only lists the internal surfaces, as

preload has to be applied to an internal surface on the bolt.

Figure 8-2: Pelamis BP Choose Preload Surface


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Choosing a part without an internal surface will result in the following message, Figure 8-3,

asking the user to either pick another part, or create the required internal preload surface

and re run the Pelamis BP.

Figure 8-3: Part with No internal surface Error Message

9 Bolt Axis

The axis is the axis along which the bolt preload is applied; generally this should be

perpendicular to the preload surface and along the axis of the bolt. The datum axes in

Abaqus parts are numbered, where 1 is for the part global X axis, 2 is for the part global Y

axis and 3 is for the part global Z axis, 4 and higher are for user defined axes. If the bolt part

has been created as a revolved solid part, then the axis of revolution will typically be 1 or 2.

If the user has created the bolt as an extrusion and defined a custom axis then this is likely

to be 4 or higher.

The Pelamis BP will list all of the available axes in the selected part in the drop down list for

Axisin the Choose Axisbox,Figure 9-1,allowing the preload axis to be selected.

Figure 9-1: Choose Axis Pelamis BP

Currently there is no way of visualising which axis in the list equates to which axis on the

bolt part, whilst selecting the axis, although this may be implemented in a future version ofthe tool. However, once the preloads have been created for the bolt instances, it is possible

to select an individual bolt preload and visualise both the datum axis and surface preload.

By selecting one of the Bolt Preloads from the loads container in the tree,Figure 9-2.


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Figure 9-2: Visualising Bolt Preload Axis

10Fix at Current Length Step

A bolted analysis requires a multi-step solution, even for a single load case application, this

is because the first step, is equivalent to torqueing/tightening the bolts of the assemblyprior to loading the part. As previously mentioned the bolt preload has to be applied in the

first step after the initial step in the analysis. This equates to the torqueing of the bolts, then

in subsequent steps, the force can continue to be applied, or the bolt length can be fixed.

i.e. assuming it has been tightened to the correct preload and left. The fix at current length

option allows the user to specify which of subsequent steps after preload that the bolt

length should be fixed at. In the drop down step list, only steps in the analysis that are

subsequent to initial and preload are listed,Figure 10-1.

Figure 10-1: Fix Current Length Step Pelamis BP

11

Preload

The bolt preload can be defined in two ways within the Pelamis BP plug-in, either by

specifying the size and grade of bolt, which looks up the required preload, from the bolts

dictionary in bolt_preload.pyor by specifying the preload in Newtons directly,for bolt sizesor grades, not in the bolt preload dictionary or for applying nonstandard preloads.


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These can be selected, by the drop down menu in the preload box,Figure 11-1.

Figure 11-1: Preload definition option

11.1Size and Grade

The bolt preload can be chosen by specifying the size and grade of the bolt, providing these

are in the bolt_preload.py dictionary. This is done by first specifying the size of bolt, from

the drop down menu,Figure 11-2,then selecting the grade, from the list of options for this

bolt size,Figure 11-3.

Figure 11-2: Bolt Size selection Pelamis BP

Figure 11-3: Bolt Grade selection Pelamis BP

The bolt preloads are calculated to be 60% of the yield load of the bolt. If another preload is

required, or a bolt size or grade is required that is not available in the drop down list, then

there is a user defined option.

11.2User Defined

The user defined option allows for the user to specify any preload in Newtons,Figure 11-4.


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Figure 11-4: User defined Preload Pelamis BP

12OK, Apply and Cancel

To create the preloads and leave the plug-in dialogue box open to apply preload to another

set of bolts, click the Apply, clicking Ok will create the preloads and close the dialogue box,

and cancel button closes the Pelamis BP dialogue box without generating any preloads

When pressing OK or Apply, the Pelamis BP plugin will create all of the bolt preloads for the

instances of the bolt part selected, . It will also print an update specifying the instance the

preload applied to and the magnitude of the preload applied as in the example below.

Applying 60.2kN preload to M16 x 120-1 instance

When all of the preloads have been applied the following message will be given

Finished applying preload to all instances of M16 x 120 in assembly

Figure 12-1: Model with Bolt Preload Applied

13

Bolts Database

The bolt preload database is a python file which contains all of the information on the bolt

sizes, grades and preload in a Python dictionary. In the two sections below, how to read and

understand the file and how to add bolts sizes and grades to the file will be discussed.


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The file is called materials_database.py and can be found in the Pelamis Materials Database

folder within the abaqus_plugins folder at the following location

..\abaqus_plugins\pelamisBoltPreload\boltPreload\bolt_preload.py

The file can be opened and modified with any text editor such as Notepad++.

13.1Structure

The file is split into three sections, a header, a definition of the dictionary, and the bolt

preload database itself.

The header section looks like this, which shows information on the version of the file, and

when it was last updated along with a comment on the units and naming conventions for

adding bolt preloads to the file.

# ######################################################

# PELAMIS BOLT PRELOAD DICTIONARY

# ######################################################

# Version: 1.0

# Author: Dr R Craven

# Last Modified: 05/03/2014

# File to store bolt preloads for Pelamis Bolt Preload Plug-in

# ######################################################

# NOTES FOR ADDING MATERIALS

# ######################################################

# All Properties MUST be entered in SI Units

# ALL BOLT SIZES MUST BE LOWER CASE! i.e. m08, or m10

# ALL GRADES MUST BE LOWER CASE! i.e. 8.9 zinc plated

# Preload must be given in Newtons

The dictionary section sets up the structure of the dictionary and allows the Pelamis MD

Plug-in within Abaqus to read the bolt preloads this looks like:

# set up dictionary

bolts = {}

The final section is the bolt preloads, these are defined for each bolt size and each has a

specified preload defined in newtons

# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

bolts['m16']={

'8.8 zinc plated':60200,


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'12.9 black passivated':101500,

'a4-70 stainless steel':42300,

}

13.2Adding Bolts or Grades

To add a grade to an existing bolt, simply add an extra line to the dictionary for the chosen

bolt size, ensuring the line is between the {}for the dictionary and ends with a comma as

below where the following line has been added '10.9 black passivated:86200,to the

M16 bolt.

# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

bolts['m16']={

'8.8 zinc plated':60200,

'10.9 black passivated:86200,

'12.9 black passivated':101500,

'a4-70 stainless steel':42300,

}

To add an entirely new bolt size, simply copy and paste and existing bolt dictionary and

change the size of the bolt from m16to m64for instance and include any of the grades that

are appropriate and update the preload values to suit the new bolt size.

After making any changes to this file, abaqus will need to restart before any of the changes

made will appear in the drop down list for the size and grade of bolts.


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Bibliography

D-ST-200018 Pelamis Technical Pocket Book (Mechanical)

Pelamis Bolt Preload Code Manualhttp://spitfire/svn/abaqus_scripts/abaqus_plugins/pelamisBoltPreload/Documentation/Pel

amis Bolt Preload.chm
http://spitfire/svn/abaqus_scripts/abaqus_plugins/pelamisBoltPreload/Documentation/Pelamis%20Bolt%20Preload.chmhttp://spitfire/svn/abaqus_scripts/abaqus_plugins/pelamisBoltPreload/Documentation/Pelamis%20Bolt%20Preload.chmhttp://spitfire/svn/abaqus_scripts/abaqus_plugins/pelamisBoltPreload/Documentation/Pelamis%20Bolt%20Preload.chmhttp://spitfire/svn/abaqus_scripts/abaqus_plugins/pelamisBoltPreload/Documentation/Pelamis%20Bolt%20Preload.chmhttp://spitfire/svn/abaqus_scripts/abaqus_plugins/pelamisBoltPreload/Documentation/Pelamis%20Bolt%20Preload.chm


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Version 1 0 16 March 2014

Appendix A: Known Issues

I. No Known Issues to Date

Pelamis Bolt Preload Settings

Documents

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