MTS Axial Extensometers User Manual

be certain.

Axial Extensometers Product Information

100-006-162 E

Trademark information

Publication information

Manual Part Number Publication Date

100-006-162 A August 1999

100-006-162 B January 2000

100-006-162 C December 2000

MTS, TestStar, and TestWare are registered trademarks of MTS Systems Corporation within the United States. These trademarks may be protected in other countries.

100-006-162 C

100-006-162 D March 2008

100-006-162 E June 2009

* Format change to smaller size to accommodate packaging. No

technical content was changed.

February 2005

Technical Support 5

How to Get Technical Support 5

Before You Contact MTS 6

If You Contact MTS by Phone 7

Problem Submittal Form in MTS Manuals 9

Preface 11

Before You Begin 11

Documentation Conventions 12

Introduction 15

Axial Extensometer Functional Description 17

About DC Conditioning 17

About Wheatstone Bridge 18

Transducer Calibration 19

Axial Extensometer Overtravel Protection 19

Extensometer Zero Reference 20

Axial Extensometer Accessories 20

Contents

Configuration 23

About Quick Attachment Spring Installation 23

How to Install Anchored Springs 24

How to Install an Attachment Adapter 25

How to Install Sliding Springs 26

How to Install Extension Springs or Elastic Bands 30

How to Change Knife Edges 32

About Gage Lengths 35

How to Use Gage Length Extenders 35

How to Use Gage Length De-Extenders 37

How to Connect the Cable 38

Calibration 41

Calibration Overview 41

Certified Calibration 41

Gain 41

Delta K 42

Symmetrical versus Asymmetrical Extensometers 42

How to Use a Vernier Caliper 43

How to Use a Calibration Block 46

How to Use a Calibration Stand 47

Installation 51

Zero Extensometer Output 51

How to Mount an Extensometer 52

About Quick Attachment Springs 53

How to Adjust the Sliding Spring Length 54

How to Select an Anchor Position 56

About Metal Extension Springs 57

Extension Spring Table 58

About Elastic Bands 60

Technical Support

How to Get Technical Support

Start with your manuals

The manuals supplied by MTS provide most of the information you need to use and maintain your equipment. If your equipment includes MTS software, look for online help and README files that contain additional product information.

If you cannot find answers to your technical questions from these sources, you can use the internet, e-mail, telephone, or fax to contact MTS for assistance.

Technical support methods

MTS provides a full range of support services after your system is installed. If you have any questions about a system or product, contact MTS in one of the following ways.

MTS web site www.mts.com

The MTS web site gives you access to our technical support staff by means of a Technical Support link:

www.mts.com > Contact Us > Service & Technical Support

E-mail

techsupport@mts.com

Telephone

MTS Call Center 800-328-2255

Weekdays 7:00 A.M. to 5:00 P.M., Central Time

Fax

952-937-4515

Please include “Technical Support” in the subject line.

Technical Support

Before You Contact MTS

MTS can help you more efficiently if you have the following information available when you contact us for support.

Know your site number and system number

The site number contains your company number and identifies your equipment type (material testing, simulation, and so forth). The number is usually written on a label on your MTS equipment before the system leaves MTS. If you do not have or do not know your MTS site number, contact your MTS sales engineer.

Example site number: 571167

When you have more than one MTS system, the system job number identifies which system you are calling about. You can find your job number in the papers sent to you when you ordered your system.

Example system number: US1.42460

Know information from prior technical assistance

If you have contacted MTS about this problem before, we can recall your file. You will need to tell us the:

• MTS notification number

• Name of the person who helped you

Identify the problem

Describe the problem you are experiencing and know the answers to the following questions:

• How long and how often has the problem been occurring?

• Can you reproduce the problem?

• Were any hardware or software changes made to the system before

the problem started?

• What are the model numbers of the suspect equipment?

• What model controller are you using (if applicable)?

• What test configuration are you using?

Technical Support

Know relevant computer information

If you are experiencing a computer problem, have the following information available:

• Manufacturer’s name and model number

• Operating software type and service patch information

• Amount of system memory

• Amount of free space on the hard drive in which the application

resides

• Current status of hard-drive fragmentation

• Connection status to a corporate network

Know relevant software information

For software application problems, have the following information available:

• The software application’s name, version number, build number,

and if available, software patch number. This information is displayed briefly when you launch the application, and can typically be found in the “About” selection in the “Help” menu.

• It is also helpful if the names of other non-MTS applications that

are running on your computer, such as anti-virus software, screen savers, keyboard enhancers, print spoolers, and so forth are known and available.

If You Contact MTS by Phone

Your call will be registered by a Call Center agent if you are calling within the United States or Canada. Before connecting you with a technical support specialist, the agent will ask you for your site number, name, company, company address, and the phone number where you can normally be reached.

If you are calling about an issue that has already been assigned a notification number, please provide that number. You will be assigned a unique notification number about any new issue.

Technical Support

Identify system type

To assist the Call Center agent with connecting you to the most qualified technical support specialist available, identify your system as one of the following types:

• Electromechanical materials test system

• Hydromechanical materials test system

• Vehicle test system

• Vehicle component test system

• Aero test system

Be prepared to troubleshoot

Prepare yourself for troubleshooting while on the phone:

• Call from a telephone when you are close to the system so that you

can try implementing suggestions made over the phone.

• Have the original operating and application software media

available.

• If you are not familiar with all aspects of the equipment operation,

have an experienced user nearby to assist you.

Write down relevant information

Prepare yourself in case we need to call you back:

• Remember to ask for the notification number.

• Record the name of the person who helped you.

• Write down any specific instructions to be followed, such as data

recording or performance monitoring.

After you call

MTS logs and tracks all calls to ensure that you receive assistance and that action is taken regarding your problem or request. If you have questions about the status of your problem or have additional information to report, please contact MTS again and provide your original notification number.

Technical Support

Problem Submittal Form in MTS Manuals

Use the Problem Submittal Form to communicate problems you are experiencing with your MTS software, hardware, manuals, or service which have not been resolved to your satisfaction through the technical support process. This form includes check boxes that allow you to indicate the urgency of your problem and your expectation of an acceptable response time. We guarantee a timely response—your feedback is important to us.

The Problem Submittal Form can be accessed:

• In the back of many MTS manuals (postage paid form to be mailed

to MTS)

• www.mts.com > Contact Us > Problem Submittal Form (electronic

form to be e-mailed to MTS)

Technical Support

Preface

Before You Begin

Safety first!

Before you attempt to use your MTS product or system, read and understand the Safety manual and any other safety information provided with your system. Improper installation, operation, or maintenance of MTS equipment in your test facility can result in hazardous conditions that can cause severe personal injury or death and damage to your equipment and specimen. Again, read and understand the safety information provided with your system before you continue. It is very important that you remain aware of hazards that apply to your system.

Other MTS manuals

In addition to this manual, you may receive additional MTS manuals in paper or electronic form.

If you have purchased a test system, it may include an MTS System Documentation CD. This CD contains an electronic copy of the MTS manuals that pertain to your test system, including hydraulic and mechanical component manuals, assembly drawings and parts lists, and operation and preventive maintenance manuals. Controller and application software manuals are typically included on the software CD distribution disc(s).

Preface

Conventions

DANGER

WARNING

CAUTION

Documentation Conventions

The following paragraphs describe some of the conventions that are used in your MTS manuals.

Hazard conventions

As necessary, hazard notices may be embedded in this manual. These notices contain safety information that is specific to the task to be performed. Hazard notices immediately precede the step or procedure that may lead to an associated hazard. Read all hazard notices carefully and follow the directions that are given. Three different levels of hazard notices may appear in your manuals. Following are examples of all three levels.

Note For general safety information, see the safety information

provided with your system.

Danger notices indicate the presence of a hazard with a high level of risk which, if ignored, will result in death, severe personal injury, or substantial property damage.

Notes

Warning notices indicate the presence of a hazard with a medium level of risk which, if ignored, can result in death, severe personal injury, or substantial property damage.

Caution notices indicate the presence of a hazard with a low level of risk which, if ignored, could cause moderate or minor personal injury, equipment damage, or endanger test integrity.

Notes provide additional information about operating your system or highlight easily overlooked items. For example:

Preface

Note Resources that are put back on the hardware lists show up at

the end of the list.

Special terms

The first occurrence of special terms is shown in italics.

Illustrations

Illustrations appear in this manual to clarify text. It is important for you to be aware that these illustrations are examples only and do not necessarily represent your actual system configuration, test application, or software.

Electronic manual conventions

This manual is available as an electronic document in the Portable Document File (PDF) format. It can be viewed on any computer that has Adobe Acrobat Reader installed.

Hypertext links

The electronic document has many hypertext links displayed in a blue font. All blue words in the body text, along with all contents entries and index page numbers, are hypertext links. When you click a hypertext link, the application jumps to the corresponding topic.

Preface

Introduction

MODEL

632.27

MODEL

634.31

MODEL

634.12

MODEL

632.26

632.29F-30 Opt. 001

MODEL

632.13

MODEL

632.11

This manual describes the MTS axial extensometer family. Axial extensometers measure changes along the length of a specimen. Axial extensometers are suitable for a variety of static and dynamic testing applications including tension/compression testing, low and high cycle fatigue, creep/stress relaxation testing, and strain rate testing. Several accessories are available such as gage length extenders, gage length deextenders, knife edges, and attachment methods. Not all accessories are available for all models.

Contents

Axial Extensometer Functional Description 17

Axial Extensometer Accessories 20

Introduction

Assorted Extensometers

What you need to know

This manual assumes that you know how to use your system controller. See the appropriate manual for information about performing any controller-related step in this manual’s procedures. You are expected to know how to:

• Select a control mode.

• Manually adjust the actuator position.

• Zero a sensor output.

• Install a specimen.

Axial Extensometer Functional Description

An axial extensometer is a sensor attached to a specimen that measures a dimensional change (gage length or strain) that occurs in the specimen while being tested. Extensometers use a Wheatstone bridge circuit to detect the dimensional changes. Because they are DC devices, they require a DC conditioner for signal processing. The following paragraphs describe the functions of the axial extensometers.

About DC Conditioning

The transducer requires a DC conditioner to process the transducer signal. A DC conditioner provides a DC excitation voltage to the transducer. Any changes to the gage length of the transducer change the excitation signal. The changed signal is output to the DC conditioner as feedback. The DC conditioner processes the signal and makes it available to the controller where the signal may be used.

Introduction

Typical Conditioning Circuit

About Wheatstone Bridge

Feedback

Excitation

Sensor Bridge

The axial transducer uses precision, resistance-type, foil strain gages bonded to a metallic element to form a Wheatstone bridge. Two knife edges on the transducer arms contact the specimen. Elongation or compression of the specimen causes movement of the transducer arms. This movement bends the metallic element, changing the resistance of the strain gages. The change in the balance of the Wheatstone bridge produces an electrical output that is proportional to the displacement of the transducer arms.

Introduction

Transducer Calibration

Overtravel Blocks

Zero Stop

Upper Arm

Lower Arm

The DC conditioner and the transducer signal must be calibrated. Calibration ensures that the transducer signal accurately represents the gage length measure by the transducer. Calibration involves adjusting the excitation voltage and gain of the DC conditioner to achieve the desired transducer signal. The purpose of calibration is to equate a specific transducer displacement to a specific voltage. When the transducer is calibrated, it is matched to a DC conditioner. If either component of the matched pair is changed, recalibration is required.

Axial Extensometer Overtravel Protection

Introduction

When a specimen fails, the extensometer arms can be subjected to movement beyond the rated travel. Overtravel protection is accomplished with a pair of overtravel blocks. One block limits the tension travel and the other limits the compressive travel to the rated range of the extensometer.

Extensometer Zero Reference

There are three zero reference methods used by MTS’s extensometers: zero pin, zero stop, and fixture. The zero reference position is important when calibrating the extensometer output signal or when mounting an extensometer to a specimen.

Zero pin

Some extensometers includes a zero pin that can be inserted into a zero reference hole. This locks the extensometer arms in the zero reference position. This is useful for specimen installation.

Zero stop

Some extensometers include a zero stop block built into the arms of the extensometer. A zero stop block works like overtravel blocks. When installing a specimen, pinch the two arms of the extensometer together. This stops the extensometer’s arms in the zero position.

Fixture

Some extensometers require special fixtures that set the arms of the extensometer into the proper zero reference positon.

Axial Extensometer Accessories

Note Not all accessories are available for all extensometers. Check

with MTS Systems Corporation for a list of possible accessories for your extensometer.

Accessories available for the axial extensometers include the following:

• Gage length extenders increase the gage length of the extensometer

without changing its travel. An extension bracket is mounted to one arm of an extensometer to increase the gage length.

• Gage length de-extenders decrease the gage length of the

extensometer without changing its travel. De-extender hardware is mounted to both arms of an extensometer to decrease the gage length.

• Cable connectors from the extensometer can be an Amphenol or a

PT connector.

• A Model 650.03 Extensometer Calibrator can help with the local

calibration of any extensometer.

Introduction

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