Multiscale Assessments Research Core
Mechanical Loading and Measurement Lab
John Peloquin, PhD
Dr. John Peloquin has 12 years of experience with tissue biomechanics and related methods, including image analysis and computer simulation. He received his PhD from the University of Pennsylvania for the study of crack-like stress concentrators in knee meniscus tissue, under the advisorship of Dr. Dawn Elliott. Subsequent work included measurement of intervertebral disc strain from MRI of living humans and development of FEBio-compatible software for automated finite element analysis. His main research interest is identifying the causal factors responsible for observed soft tissue properties, particularly those pertaining to damage and failure. Dr. Peloquin currently works as a staff researcher in Dr. Elliott’s lab and provides training and support services related to mechanical testing to DCMR clients.
- Analysis Assistance
- Assay/Protocol Development
- Fixture design
- Project development
Versatile and easy to use test frame for uniaxial tension or compression with small–medium loads. Ideal for static and slowly varying tests. More often than not this is the tester you should use.
- Displacement range: ~ 1 m
- Displacement rate: arbitrarily slow to ~ 10 mm/s
- Load cells: 10 N, 100 N, 1 kN.
- Bath for testing in fluid
- Single-column test frame provides ample working space.
- A variety of test fixtures (accessories) are available, including a T-slot table, a wide assortment of tensile grips, and compression platens.
- Often used for uniaxial tension, unconfined compression, confined compression, and 3-point bending.
TA 3510 AT
Dynamic uniaxial tension–compression and torsion at moderate loads. Ideal for cyclic testing and high displacement rates. This test frame should be used when the Instron 5943 does not provide adequate performance.
- Displacement range: ± 25 mm. Starting at ~ 0 mm is recommended.
- Displacement rate: 0.025 μm/s to 1.5 m/s, or 0.00001 Hz to 100 Hz.
- Max axial load: 7500 N dynamic, 5300 N static
- Motorized crosshead height adjustment.
- Rotation range: ± 3600° at up to 50 Hz
- Max torque: 49 N·m dynamic, 42 N·m static
- Load cells: 1250 N axial, 7500 N axial, 70 N·m torque
- Test space: 559 mm wide × 2700 mm tall
- Temperature-controlled bath for testing in fluid
- Accessories include MRI-compatible (available at CBBI) locking compression fixtures
TA 3230 AT Series II
Dynamic uniaxial tension–compression and torsion at small loads. Ideal for cyclic testing and high displacement rates. This test frame should be used when the Instron 5943 does not provide adequate performance.
- Displacement range: ± 12.5 mm. Starting at ~ 0 mm is recommended
- Displacement rate: 0.0065 μm/s to 3.2 m/s, or 0.00001 Hz to 200 Hz
- Max axial load: 450 N dynamic, 320 N static
- Manual crosshead height adjustment with microadjust
- Rotation range: ± 3600° at up to 100 Hz
- Max torque: 5.6 N·m
- Load cells: 10 N axial, 45 N axial, 450 N axial, 0.2 N·m torque, 5.6 N torque
- Test space: 355 mm wide × 417 mm tall (340 mm w/ torsion motor) × 279 mm deep
- Temperature-controlled bath for testing in fluid
- Adapters for Instron test fixtures are available
Uniaxial tension tester design for small forces and simultaneous imaging of the specimen with a confocal or multiphoton microscope. Also useful if it is important that the specimen remain horizontal.
- Compatible with Zeiss 880 microscope at APB
- Displacement: up to 50 mm inter-grip distance
- Displacement rate: arbitrarily slow to ~ 20 mm/s
- Load cells: 10 N, 45 N
- Integrated bath with glass coverslip viewing window for inverted microscopy
Biaxial Tension Tester
Biaxial tension tester for more complete characterization of mechanical properties than is possible through uniaxial testing. It is often impossible to produce an accurate predictive model for an anisotropic material from uniaxial test data alone.
- Displacement range: ~ 10 cm
- Displacement rate: arbitrarily slow to ~ 1 mm/s
- Load cells: 20 N
- Integrated fiducial marker tracking using a camera mounted above the specimen. Fiducial marker strain is calculated in real time and may be used as the test’s controlled variable.
- 4-motor design so the specimen remains centered in the camera’s field of view.
- Integrated rotating polarizers for polarimetry of birefringent materials, for example to measure collagen fiber alignment in tendon or ligament.
- The actuators are connected to the specimen using long sutures.
- Bath for testing in fluid.
NAC HX-7 High-Speed Camera
High-resolution and high-framerate video camera. This camera configuration maximizes resolution at the expense of exhibiting a mid-range framerate. Generally this is the correct trade-off for tests of biological tissue.
- 2560 × 1920 px @ 850 fps
- 1920 × 1080 px @ 2000 fps
- Resolution may be sacrificed further for greater framerate.
- Macro (1× magnification) capable: 30 mm × 20 mm field of view at ~ 40 cm working distance.
- 32 GB memory buffer
Scanning Laser Interferometer
The scanning laser interferometer measures the height profile (i.e., cross-sectional area) of a specimen without contact, which is helpful when the specimen is too soft for accurate micrometer measurements. The specimen is placed flat on an x–y stage and the laser interferometer records a height profile as the x–y stage is traversed.
Zeiss AxioLab A.1 Pol
Transmitted light microscope with linear and circular polarizing filters and a rotating x–y stage. Primarily intended for polarimetry and other transmitted light imaging of slide-mounted sections. Includes a camera for image capture.
Zeiss SV-6 Stereomicroscope
Stereomicroscope for fine dissection and whole-mount imaging of specimens before or after a test. Includes a camera for image capture.
Orthoscan Mini C-Arm Fluoroscope
Continuous low-dose x-ray imaging. Still photos may be triggered using a footswitch. Particularly useful for guided injection or minimally invasive surgery and joint alignment.
Leica SM2400 Sledge Microtome with freezing stage
The freezing stage allows soft tissues to be cut to precise dimensions, with parallel faces and thus uniform thickness. The freezing stage is somewhat larger than typically available in a cryotome rotary microtome.
A deli slicer is available for rapid rough cutting of soft tissue, which is usually cut while semi-frozen and embedded in a cellulose gel. For tough tissues, the resulting slices are somewhat uneven in thickness, but better than using a vibratome or cutting by hand. This is a quicker but lesser-quality alternative to the Leica SM2400 freezing stage microtome.
Vic-2D Digital Image Correlation Software
Measure 2D strain fields from a time lapse image series of a specimen with a speckle-patterned surface. Typically used for analysis of uniaxial or biaxial tension test data.
TA Instruments ElectroForce 400N TestBench
Dynamic uniaxial tension–compression in a horizontal configuration, up to 400 N. Ideal for cyclic testing and high displacement rates. Convenient for small animal work.
- Displacement range: ± 6.5 mm. Starting at ~ 0 mm is recommended
- Cycle frequency up to 100 Hz
- Max axial load 400 N dynamic, ~ 280 N static.
- Load cells: 400 N, 225 N, 22 N (PID only), 5 N (PID only)
- Available test space up to 21.9” (without load cell)
- Adapters allow use of Instron 12 mm socket fixtures
Aurora Scientific 1300A 3-in-1 Whole Animal Muscle Stimulator for Mice
The 3-in1 whole animal muscle stimulator is a high performing, precise test system to test tensile and other mechanical properties of muscle. This system combines in situ, in vivo and in vitro muscle testing using one platform to study muscle physiology in rodent (mouse) subjects. Features include a precision force transducer for in situ tests, force transducer with plate for in vivo tests, and 25mL horizontal bath for in vitro tests. Peak forces range from 0.5 to 10N.