A tissue tester was designed to enable rate controlled indentation of the soft tissues of the residual limbs of below-knee (BK) amputees. Thus viscoelastic phenomena such as pre-conditioning, hysteresis and stress relaxation could be assessed. The tissue tester accommodates indentor excursions of 0-30 mm, performs indentations at rates from 0-5 mm/s, measures reaction forces up to 44 N, and accommodates multiple loading/unloading cycles. The tissue tester is controlled via a notebook personal computer which makes the entire test system portable and amenable for use in a clinical or research environment The system output consists of force-displacement curves obtained during cyclic loading of the tissue at varying indentation rates at sites of clinical significance to BK prosthetic design. Indentation followed by force monitoring over a fixed time duration allows stress relaxation of the tissue to be assessed. The indentor positioning error (mean error less than 4.4%) is independent of indentor position and load, but dependent on indentation rate. Indentation rates are accurate to within 3% of the desired value and are independent of indentor position and load.
|Original language||English (US)|
|Number of pages||2|
|Journal||American Society of Mechanical Engineers, Bioengineering Division (Publication) BED|
|State||Published - Dec 1 1996|
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