High-Rate Test Systems
Extensive capabilities for repeatable results

AROUND THE WORLD, LEADERS IN TRANSPORTATION, CONSUMER PRODUCTS
A N D O TH ER I N D U STRI ES RELY ON M TS HIGH- RATE TEST SYSTEM S TOA C C U R ATELY CH A RA CTERI ZE COMP ONE NT S AND MAT E RIALS T HAT ARES U S C E P TI BLE TO HI GH -RATE D E FORMAT ION.

2

Versatile Systems for a Full Spectrum of High-Rate Testing

Many material properties are strain rate sensitive, meaning they react differently acrossvarious rates of loading. Dynamic mechanical testing helps engineers understandhow susceptible these materials are to damage during high strain rate events, so thatcomponents and structures made from them are not designed with excessive mass orvulnerable to early failure.
High-rate dynamic tests are used to simulate automotive accidents, airplane crashes,
munitions explosions and other high-impact events. In these and other criticalapplications, test engineers need equipment that can perform a variety of tests at thecorrect strain rate. These systems need to capture high-quality data throughout the
test, with streamlined setup and enhanced control of the test.

1.

To meet all of these challenges, MTS delivers a family of high-rate servohydraulic test
systems specifically designed to support a full spectrum of dynamic testing. MTS
High-Rate Test Systems are deployed worldwide to produce accurate, reliable results
for leading companies in industries as diverse as automotive, aerospace, rail, consumer
products, and construction materials.

2.
M I SSIO N -C R ITIC A L A P P L ICATIONS

Dynamic high strain rate testing is required by numerous
standards from ASTM, ISO, EN, DIN, BS and AFNOR.
Typical high strain rate tests include:» High strain rate tensile: ISO 26203-2, ISO 18872, SAE
International J2749» Dart impact penetration: ASTM D1709, ISO 7765-2» Puncture impact behavior: ASTM D3763, ISO 6603-2
3.

» Impact compression

4.

High strain rate test applications include:
1. Crash-worthiness of vehicles
2. Characterization of fasteners, welds, and adhesives
3. Characterization of lightweight materials, 		
including metals, plastics and composites
4. Behavior of building materials during blast impact events
5.

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Choose the Right Range

Test engineers have developed a variety of testing techniques to characterizematerials within specific strain rate ranges that are relevant for crash events.
Relevant for Crash Events
Quasi-Static Testing

Impact Testing

Split Hopkinson Bar
SystemHigh-Rate Servohydraulic System
Impact System
Conventional Servohydraulic System
Electromechanical
SystemConstant Load
System
10E-08

10E-06

10E-04

10E-02

10E+00

10E+02

10E+04

10E+06

Strain Rate(sec-1)

10E+06

10E+04

10E+02

10E+00

10E-02

10E-04

10E-06

10E-08Characteristic
Time (sec)

To configure a suitable servohydraulichigh-rate test system that accurately
simulates dynamic impact events, it isimportant to consider the amount ofenergy that is required for the test, theneeded strain rate and the force atvelocity. Balancing these three elements
sometimes requires tradeoffs for a
cost-effective solution.
Kinetic energy
The energy or work required to breaka specimen depends on the material
properties and the required deformation
for the test; it can be approximated bydetermining the area of the static
material tensile curve up to the desired
total strain level.
The kinetic energy supplied by thehigh-rate system is a function of the total
moving mass, including piston and fixture,and its velocity. In order to maintain aconstant velocity throughout the test,
the kinetic energy must be significantly
greater than the work required to breakthe specimen.

4

Strain rate

Force at velocity

For an initial approximation, it can beassumed that the actuator velocity isequal to the specimen deformation rate.

The force and the velocity of a linear
actuator depends on the piston surface
area, the available differential pressure of
the hydraulic fluid and the available flow
rate. The hydraulic system needs to becarefully configured to enable the system
to deliver the required force at velocity.

Actuator Velocity = (li - lo)/Δt
li = Instantaneous specimen gage lengthlo = Original specimen gage length
Δt = Time interval
ė = Engineering strain rate
The required maximum actuator velocity
can be estimated based on the neededstrain rate and specimen gage length.
Actuator Velocity = lo ė
The assumption for calculating theactuator velocity can be improved byeliminating the system compliance atthe loads of interest and deducting itfrom the displacement data.

In practice, design and configuration ofhigh-rate systems require complex
modeling to fully characterize thedynamic response. MTS has developed
special software programs to configure
an economical system solution for therequired performance.

Common MTS high-rate test systems solutions include the following servohydraulic load
frames that suit a variety of applications:
Model

Static Force Capacity(kN)
40

Maximum Velocity
at Zero Force (m/s)*
18

Dynamic Stroke
(mm)
250

Operating Pressure
(bar)
210

819.40819.90

90

20

250

280

819.160

160

20

300

280

Complete Test Solutions for Superior Performance

MTS provides specially designed high-rate servohydraulicsystems with all of the technology test engineers need to
conduct accurate, repeatable high strain rate tests. These fully
integrated solutions start with stiff, durable load frames andhigh-response servohydraulics that apply forces from 5 to 500
kN (1 to 110 kip) and achieve velocities from 1 to 21 m/sec (39to 830 in./sec).
MTS FlexTest® digital controls enable high-speed control anddata acquisition, while TestSuite™ TW Elite Software helps
streamline and standardize test programs. In addition, a fullcomplement of accessories, including grips, fixtures and apiezoelectric load washer, address the unique needs of specifichigh-rate tests.
Together, these components deliver an intuitive testing
experience that provides high-quality data as well as flexible
test analysis and reporting.

KE Y SYST E M AT T RIB U T E S» Low-friction actuators with hydrostatic bearings» Extra-long hydraulic cushions prevent actuator damage after specimen
failure» Hydraulic accumulators supply high amounts of energy quickly» Eight data acquisition channels record at rates up to 1.25 million
samples per second simultaneously» Eight optional data acquisition channels available» Test area enclosure and fire control panel protect operators and thesystem» Grips and fixtures accommodate a wide range of specimen types» Three-stage servovalves meet the large hydraulic fluid flow
requirements of high-rate testing» Piezoelectric load washer enables fast, accurate force measurement

MTS high-rate test systems areequipped to deliver strain rates
that are relevant to test standards
for numerous industries.

Electronics
consoleFire control panel
Crosshead lift/
lock control andcontroller handset
Load measurement
charge amplifier

Servohydrauliccontroller

5Servovalves
Three-stage servovalves from MTS
provide superior performance andexceptional durability, and havebeen proven over decades of use in
test labs worldwide.

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Reliable, Durable Components

MTS High-Rate Test Systems are configured with trusted components that are specificallydesigned to work together seamlessly in a variety of dynamic testing applications.

Heavy-duty load frames

Load measurement

Displacement measurement

Rigid load reaction frames minimize
signal distortion caused by unwanted
vibrations, which are common in
high-velocity testing applications.
Load frames are oversized in termsof static load to accomplish this.

MTS high-rate test solutions incorporate
piezoelectric load measurement transducers
and conditioners. The piezoelectrictransducers are stiffer and have less mass
than conventional strain gage based loadcells, which are too elastic for high rate
testing. The time required for the elastic
member to become uniformly deformed
is similar to the elapsed test time.

Actuator displacement is measured witha magnetostrictive device that provides
exceptional accuracy. The absence ofphysical contact between moving partsensures stable performance. The sensing
coils generate high-output signals andprovide common mode rejection fromexternal sources of noise. In addition,
the converter design responds only totorsional strain pulses, so longitudinalpulses caused by shock or vibration
are not detected. At high speeds anaccelerometer mounted to the piston
is used to calculate velocity anddisplacement with greater accuracy.

High-rate actuators
MTS high-rate actuators have speciallydesigned hydraulic cushions to help
decelerate the piston rod without the riskof damage. Steel pistons have sufficient
stiffness for high-rate compression tests
and their large mass results in a moreconstant strain rate during loading.
Accumulators
Most labs use accumulators becauseof the short duration and high flow
requirements of this type of test. A
hydraulic power unit (HPU) reacts too
slowly—by the time the HPU recognizes
the need for hydraulic fluid and tries to
respond, the test is over. And even if the
HPU could respond quickly, a very large
HPU would be required to meet thehigh flow requirements. Accumulators,
charged using a smaller HPU, are capableof supplying high volumes quickly andare therefore much more cost-effective
for high rate testing.

Resolving load oscillation
One potential issue with high-rate tests isload oscillation, or ringing in the stressstrain curve, which occurs as the slack
adapter components slam together andexcite resonances within the load frame.
Ringing is seen in the data as a regularhigh-frequency oscillation. MTS high-rate
test systems mitigate this issue by
minimizing the moving mass.
To further reduce potential ringing at
strain rates greater than approximately
50 s-1 to 100 s-1, it is recommended tomeasure force with a strain gage applied
to the test specimen or the grips.

Data acquisition
MTS-supplied data acquisition boards
feature eight channels of differential
signal acquisition. One channel isdedicated to force transducer data, one
to actuator displacement, one to actuator
accelerometer, and the five remaining toother sources as test needs dictate. Datais collected at a maximum of 1.25 MHz
on all channels simultaneously. High
speed data is read into TestSuite software
for immediate display of results post-test.

7

Accessories

Choose from a variety of grips and fixtures tailored for testing plastic dog bones andflat or round specimens made from metal, composites and polymers. Standard grips areavailable for tensile testing of sheet metal specimens, plastics and rubber specimens
and specialized items such as cords or O-rings.
MTS grips for high-rate testing are designed to be light and stiff, which minimizes thenoise/ringing contributed to the load data on impact.

Slack adapter
The slack adapter connects the specimen
to the load train but allows actuator travel
under no load until the desired velocity isachieved. The adapter has two pieces: thered piece (see diagram) is connected to theactuator while the green piece is attachedto the specimen—or to a grip attached tothe specimen.

Special fixtures

Environmental simulation systems

Puncture fixtures are ideal for testing
sheet metal or film materials and canaccommodate a variety of specimen
dimensions. These fixtures provide aclamping restraint that can be mounted on
the load frame or on the actuator. Fracture
test fixtures help determine the energy
absorbed in fracture toughness studies.

MTS complements high-rate systems
with a selection of environmental
simulation systems to test materials
and components under a variety ofreal-world conditions.

A-frame grips

Low-mass grips

Non-contacting strain measurement

These grips are rated for 50 kN (11,000
pounds) and with the appropriate wedge
sets, they can be configured for specimens
up to 1/2” thick.

MTS high rate, low mass grips for flat
specimens have two standard wedge sets:» for specimens up to 1/4” thick» for dynamic forces up to 100 kN

Measuring strain for high rate testing can
be challenging. Contacting extensometers
are lower cost but can’t be used at higher
strain rates. Strain gages are often expensive
to prepare, install and monitor and the
maximum strain that can be measured islimited.Video extensometer solutions withhigh-speed camera systems can often meetthe needs for both precision and costeffectiveness. An MTS Applications
Engineer can help you configure theappropriate solution for your testing needs.

Slack adapter allows
free, unloaded, actuator
displacement to achievevelocity before loading

Piezoelectric devicefor dynamic load
measurement

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After the specimen is loaded into the test
system, the actuator is raised so that thetwo conical surfaces (one on each piece)
are separated by a distance slightly greaterthan what is required for the actuator toreach the desired test velocity. As long as
these two cones are separated, the actuatormoves freely. The slack adapter travels
under no load until the two conicalsurfaces connect and instantaneously
load the specimen.

Designed for Operator Safety

Fire control panel

Test area enclosure
The test area enclosure helps maintain
operator safety and protect others in thelab. Each enclosure is fabricated fromextruded aluminum and acrylic sheet.
Front and rear access doors provide fullaccess to the machine for maintenanceand test setup. These doors are safety
interlocked to the system controller toprevent system operation—except at very
slow rates—during specimen installationand calibration.

Electronic hardware includes a high-rate
fire control panel located in the electronics
console. This panel is used to selectdifferent performance modes, charge theaccumulators, and initiate a test.

SilentFlo™ Hydraulic Power Units (HPUs).
MTS servovalves are available with flowsof 112, 340, or 680 lpm rated at 70 bar
pressure drop. Servovalve pilot pressure
ensures tight control of the system actuator
at startup.

MTS SilentFlo HPUs offer the latest
advancements in servohydraulic power
generation. Available in a variety ofcapacities to accommodate required test
loads and speed, they deliver clean andquiet hydraulic power. They can be
deployed directly in the lab, eliminating
the cost of special pump housing facilities
and reducing supply line cost and spacerequirements.

Dependable Hydraulic Performance
Industry-leading hydraulic products
enhance the performance of MTS high-rate
test systems. Key components of thesolution include MTS servovalves and

The SilentFlo 515 family features innovative
energy efficiency, health monitoring andsystem integration options to reduce total
cost of ownership.

9

State-of-the-art Digital Controls

Stable, precise system control, which is critical for conducting high-rate testing, isprovided by a state-of-the-art FlexTest controller. FlexTest digital controllers equip
users with all the tools needed to define and automate virtually any material, component
or structural test. Versatile FlexTest controllers provide high speeds and channel
densities to keep pace with evolving test demands, and share common hardware
boards and user interface tools to simplify test standardization and optimization
across test laboratories. FlexTest controllers support the full offering of MTS test
application software, including MTS TestSuite MP software.

Versatile test software
MTS TestSuite Multipurpose Testing
Software lets you graphically build andrun monotonic and cyclic tests withefficiency, from an easy-to-use interface
that is readily adaptable to your evolving
needs. You can easily test to specificindustry standards—or pursue yourown interpretation of a standard—with
customizable, “plug-and-play” test
methods. The software also captures all
setup data and test results, allowing you
to quickly repeat tests, analyze data withstand-alone Analysis Software, and designand create reports with a convenient
Excel Add-In.

10

High-rate closed-loop control vs.
open-loop control
Servohydraulic materials testing systems
are normally run in closed-loop control.
However, for high-rate tests, the piston ismoving at such a velocity that real-time
control is not as effective because servovalve
response, the inertia of the moving massand the compliance of the hydraulic fluid
become limiting attributes. In addition, thecontrol loop’s ability to correct disturbancesdiminishes as the event time approaches
the response time of the valve.
For servohydraulic high-rate testing, acommand waveform is created and sent
to the servovalve, at which point the test
is essentially open-loop. There is no time
for real-time corrections based on theerror signal. This situation is overcomeby iterating the command waveform
before the test using dummy specimens toachieve the desired response. Once thecommand waveform is created, testing
can begin.

Unparalleled Service and Support

MTS high-rate test systems are backed by the global MTS Service and Support
organization. This highly experienced team offers lifecycle management services for
all MTS test systems and is committed to maximizing the uptime and operational
efficiency of each system. With the expertise to support test equipment frompre-installation to decommission and at every point in between, MTS has theservice solutions to meet your needs for test schedule predictability, data integrity,
system performance optimization and budget management.

Onsite services

Calibration and alignment

MTS field service engineers have aworldwide reputation for applications
expertise and will respond to requests forsupport or repair quickly and efficiently.

All test labs must calibrate their testing
equipment to help ensure data accuracy.
MTS provides top-quality, accredited
calibration services and load framealignment services to minimize data
variance.

Engineering services
MTS offers a complete set of professional
engineering services, including systems
engineering, test consulting and facilities
design services.
Training
MTS training programs are designed
to improve operator efficiency andoptimize system performance. Expertly
led and completely customizable, thesecourses provide engaging hands-on
learning experiences.

Maintenance and monitoring
Based on decades of service experience,
MTS has developed a set of well-definedroutine maintenance offerings tailoredfor specific systems and components, tohelp extend equipment life.
Upgrade solutions
As technology improves, an upgrade
is often the most economical way of
expanding lab capabilities and extending
the life of existing test equipment. MTS
offers upgrades and replacements formechanical components, controllers
and software.

11Regional Business Centers

T HE AM E R IC AS

EU R O PE

A S I A / PA C I FI CMTS Systems Corporation
14000 Technology Drive
Eden Prairie, MN 55344-2290
USA
Telephone: 952-937-4000
Toll Free: 800-328-2255
E-mail: info@mts.com
Internet: www.mts.com

MTS Systems France
BAT EXA 16
16/18 rue Eugène Dupuis
94046 Créteil Cedex
FranceTelephone: +33-(0)1-58 43 90 00
E-mail: contact.france@mts.com

MTS Japan Ltd.
Raiden Bldg. 3F 3-22-6,
Ryogoku, Sumida-ku,
Tokyo 130- 0026
Japan
Telephone: +81 3 5638 0850
E-mail: mtsj-info@mts.com

MTS Systems (Germany) GmbH
Hohentwielsteig 314163 Berlin
Germany
Telephone: +49-(0)30 81002-0
E-mail: euroinfo@mts.com

MTS Korea, Inc.
2nd F, Bundang Yemiji Building, 31,
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Telephone: +39-(0)11 45175 11 sel. pass.
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Datavägen 37b
SE-436 32 Askim
SwedenTelephone: +46-(0)31-68 69 99
E-mail: norden@mts.com
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98 Church Street,
Hunslet,
Leeds
LS102AZ
United Kingdom
Telephone: +44 (0) 113 270 8011
E-mail: mtsuksales@mts.com

MTS Systems Corporation
14000 Technology Drive
Eden Prairie, MN 55344-2290 USA
ISO 9001 Certified QMS
http://www.mts.com

MTS Systems (China) Co., Ltd.
Floor 34, Building B,
New Caohejing International
Business Center,
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Xuhui District
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Telephone: +021-24151000
Market: +021-24151111
Sales: +021-24151188
Service: +021-24151198
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Kormangala, Bangalore – 560 029
India
Telephone: + 91 80 46254100
Email: mts.india@mts.com

MTS and FlexTest are registered trademarks and SilentFlo, MTS TestSuite, andAdvantage are trademarks of MTS Systems Corporation in the United States.
These trademarks may be protected in other countries. RTM No. 211177.
© 2023 MTS Systems Corporation
100-351-634c HighRate • Printed in U.S.A. • 12/23