& Instruments

Test Fixtures & Accessories

Testing of parts and materials often requires that additional support accessory items such as tensile grips, extensometers, bending test fixtures or compression platens be obtained to perform the required task. MTI offers a full range of such testing fixtures and instruments ranging from high capacity tensile wedge grips to low force pneumatic grips or flexural testing assemblies for beams of all sizes. Our selection of grips, test fixtures and instruments would fill many web pages such as this one. Let us save you the time of searching through endless pages by just letting us know your requirements so that we can provide a proven solution to your testing requirements.

The photos below illustrate only of few of our available accessories. Please contact us to fulfill your individual testing requirements.

Probably the most commonly required test fixture is the tensile grip. MTI offers 'Stationary Jaw' wedge grips which means that the grip body moves vertically to open and close the wedge jaw inserts that remain stationary relative to the sample. The wedge inserts open and close laterally and do not impart undesired tensile or compression forces to the specimen while attaching the grip. The wedge angle limits the opening range, and thus the sample thickness, so various interchangeable inserts are offered to accommodate a wide range of specimen thickness.

Pneumatic grips provide a simple and efficient method to clamp test specimens, adjusting to the changing conditions and hold regardless of sample deformation. Multiple interchangeable jaw faces are available in various sizes and surfaces. Grips can be furnished with serrated, smooth, rubber-coated and diamond cut.

Spring-loaded Scissors action grips are intended for soft materials and elastomers such as foam, flexible plastics and elastomers. They provide positive non-slip gripping action and are quick and simple to use. Sample insertion is easy, and the spring pressures of the jaws give a positive non-slip action gripping force.

Rugged clip-on extensometers with gage lengths from 0.5 - 2 inches (and 10 - 50 mm) and measuring ranges from 5% to 100% strain are available. A wide range of materials, including metals, plastics, composites and ceramics can be tested. All models work in both tension and compression. All standard units meet existing ASTM class B-1 and ISO 9513, class 0,5 requirements for accuracy.

Removable compression platens facilitate uniform compression stress distribution during testing. They are available as spherical or fixed platens, fabricated in steel or aluminum or stainless steel. Standards version diameters range from 56 mm (2.2 in) to 346 mm (13.6 in).

Guided-Bend / Weld Bend Test Fixture provides an adjustable span for "U" bend tests of plane plate or welded flat specimens. The fixture consists of a t-slot base with adjustable span supports supported by two tie rods for increased lateral support A center loading nose is included.

Various bending test fixtures are available from MTI. Fixtures sized for the shortest test such as the short-beam-shear test for composites, or for bending long beams such as 40-foot long I-Joists can and have been supplied for our customers. Contact us to discuss your flexural testing requirements.

Straps and webbing require unique grips to overcome the problems of slippage while maintaining sufficient grip force to produce valid test results. The eccentric split cylinder belt design provides just such a capability to support U.S. DOT National Highway Traffic Safety Administration laboratory test procedure FMVSS 209

Probably the most common source of error in materials characterization testing is incorrect measurement of specimen dimensions, or errors in placement of measured dimensions into data processing programs. The simple transposition of two digits in a thickness measurement can have disastrous results. MTI has minimized the chance of such errors by allowing you to attach digital electronic calipers with serial data output directly to the MTI C-DAS control and data acquisition computer. All testing programs are configured to allow you to type in dimension measurements, but far more conveniently you can simply press a button on the micrometer and have width and thickness data transferred directly to the program with no chance of error - and far more rapidly than manual typing. A wide range of micrometers and calipers and gage heads are available and can be adapted to your system. We offer instruments by Starrett, Brown & Sharpe and Mitutoyo as your requirements may dictate.

The MTI BAF-4-2K is a 4-channel general-purpose strain gage bridge conditioning system. It provides amplified and filtered signals for ¼-, ½- and full-bridge strain gage circuits making it ideal for bonded strain gage applications or for multiple extensometer signal conditioning tasks. Each channel is actively filtered after amplification. (The filter characteristics are: 2-pole Butterworth low-pass with a -3 dB cutoff frequency of 2 Hz.) Each independent channels allows for accurate adjustment of bridge excitation voltage, bridge balance and signal gain. Bridge power voltages for each channel can be precisely and independently adjusted from 1.2 to 10 Volts DC. Shunt resistor calibration ports for each channel can easily be switched into the circuit for signal verification and system setup. A convenient digital panel meter can be switched to monitor bridge power or amplified output level signal for each of the four channels. The rear panel provides for either plug connector input of the sensors or convenient 'banana' jack inputs with access to each of the four arms of a strain gage bridge. This also provides a convenient method of quick changing of sensors. Another unique feature of the BAF-4-2K is the convenient 350 Ω bridge completion resistor switch arrangement for each channel on the rear panel of the instrument. Close any combination of three switches to add a completion resistor to the desired leg of the bridge, and at the same time the bright red LED lights to indicate its' presence in the bridge network. Output signals also provided through a multi-pin connector which supplies all amplified signals with common reference. The BAF-4-2K has been called the most user-friendly multi-channel signal conditioner on the market by our customers.