Development and testing of a modular strain measurement clip.

The research article is about the development and testing of a new low-cost, versatile transducer designed to measure in vitro strains, with testing demonstrating accurate results when compared with traditional measurement techniques.

Development of the Strain Measurement Clip

• The researchers developed a novel transducer, named the modular strain measurement clip, made of stainless steel. This development stemmed from the need for a more affordable, simpler, and more flexible solution compared to current strain measurement methods.
• The clip was designed with adjustable extension arms to provide wider application versatility.
• The clip was equipped with four 350 Omega axial strain gauges formed in a full Wheatstone bridge configuration. This configuration was chosen to make the device compatible with commonly available strain gauge amplifier equipment.

Testing and Calibration of the Clip

• The clip was calibrated and tested, generating a linear response with a minimum of 1.04 mm at high amplifier gain.
• When using reduced amplifier settings, the testing exhibited a linear response over a range of 30.5 mm.
• The stiffness of the clip, defined as 0.6N/mm of extension arm tip displacement, was deliberately kept low to minimize instrumentation artifact.

Validation and Comparative Biomechanical Test

• A validation test was carried out by comparing the strain clips performance with surface-mounted strain gauges and theoretical strain in an aluminum rod under axial tensile loading.
• The measurement techniques were utilized to ascertain the modulus of elasticity of the aluminum rod. The results were found to be within 6% of the known modulus of elasticity for aluminum, showing acceptable accuracy of the clip.
• A comparative biomechanical test was performed on an equine third metacarpal specimen. The results were comparable to that of a traditional bonded strain gauging method, revealing the effectiveness of the new strain clip.
• The clip also proved superior since it was able to measure ultimate strains, unlike traditional strain gauges which failed before the specimen did.

Recommendations and Future Work

• The researchers are continuing to examine the versatility of the strain clip, with further explorations planned for its various applications.
• They also provided recommendations for future versions of the clip, indicating the potential for the device’s continued development and improvement.