Simultaneously Measure Axial Deflection On Opposite Sides Of The Specimen With A Single Extensometer
The Series 632.17 Averaging Axial extensometer is designed to simultaneously measure the axial deflection on opposite sides of the specimen. The extensometer is typically used to perform testing on solid or tubular composite or metal specimens.
The extensometer consists of two sensor units, one on either side of the specimen. The sensor units measure the axial deflection over the gage length of the specimen. Two contact points, connected to each sensor unit assembly, contact the specimen. The contact points are made of hardened steel or (as an option) carbide. Both materials are available with conical point contact ends or vee-chisel contact ends.
Mounting
- A patented support system consisting of flexures strategically located on the extensometer securely attaches the extensometer to the specimen.
- A curved forcing flexure connected to the two sensor unit assemblies holds the extensometer in place even under acceleration loads, such as those that occur during dynamic testing.
- Flexures attached to the specimen contact assemblies allow the contact points freedom of movement without providing erroneous strain input to the extensometer.
- This freedom of movement allows the extensometer to conform to the specimen shape during testing (such as bending or twisting) without slippage, or distortion of the output.
- The extensometer is positioned on the specimen by pressing on the finger grip pads to separate the contact points and placing them against the specimen.
- The two sensor unit assemblies can be repositioned along the forcing flexure to accommodate specimens of different dimensions.
Signal Output
- The output cable from each sensor unit may be joined at the connector and then connected to a single specified dc controller or dc conditioner located in the system console to provide an averaged output (option 001) of the two sensor units.
- The output cable from each sensor unit may have an individual connector which is then connected to separate specified dc controllers or dc conditioners for individual outputs (option 002) from each sensor unit.
Accuracy
The 632.17 Averaging Axial extensometer is designed for extremely accurate strain measurements. Exceptional accuracy and linearity are provided by the cross flexure design, which ensures true center-point bending throughout the entire travel range of the extensometer.
- Non-linearity is 0.15% of the travel range or less (typically 0.10% of this range). Maximum hysteresis is within 0.10% of the maximum travel range.
- The cross-flexure design provides very good lateral stability, requires low activation force and helps maintain extensometer calibration over long periods of use.
Conditioning Electronics
The extensometer is used with MTS conditioning electronics or other conditioning electronics capable of providing an excitation voltage of 8 volts (not to exceed 12 volts). The extensometer
output is approximately 3.4 millivolts per volt of excitation. Bridge resistance is 500 ohms for option 001 (averaged output) and 1000 ohms for option 002 (individual output).
