- 學位論文
足跟墊軟組織之機械特性量測與分析
Measurement and Analysis on Mechanical Property of Heel Pad
摘要
本研究主要建立一組可以有效模擬出後足部軟組織之機械特性的數學模型，並且藉由體外量測後足部的應力鬆弛實驗，經由最佳化的方式求出與應力鬆弛實驗結果相符的組成律係數值。藉由此數學模型可計算出後足部的能量消散率，並與超音波儀器進行後足部非侵入式量測的實驗結果進行比較。 本研究中實驗對象為年輕、非糖尿病患之不同體重的男子兩名，分別將其進行應力鬆弛實驗以及EDR實驗，藉由應力鬆弛實驗結果代入所建立的數學模型而模擬出遲滯曲線及能量消散率並與EDR實驗的結果比較，得到受試者A的能量消散率(實驗值31.05%、模擬值29.37%)，受試者B的能量消散率(實驗值46.27%、模擬值38.36%)。 最後本研究建立一組非線性彈簧與一組非線性vogit模型串聯的數學模型可有效模擬出軟組織的黏彈特性。而不再需要使用超音波儀器進行後足部非侵入式量測，以符合經濟效益，降低成本。並且發現當阻尼項組成律之係數值越小，則應力鬆弛衰竭速度越快，能量消散率則越大，反之亦然。當彈簧項組成律之係數值越小，則應力鬆弛衰竭程度越大且遲滯曲線的斜率越小，反之亦然。
並列摘要
This research is to develop a set of mechanical model which can simulate heel pad effectively, and perform the stress relaxation experiment to get the coefficients of constitutive law using the optimization method. Then we get the EDR (energy dissipation ratio) of heel pad by mechanical model, and compare to the experiment result of the non-invasive measurement by the ultrasound . The experiment subjects are two young and non-diabetes men .First we perform the stress relaxation and EDR measurements on them, then compare the hysteresis curves and energy dissipation ratio which are simulated by the mechanical property models to EDR experiment results. The comparison results are 31.05% of experiment value and 29.37% of simulation value for subject A , and 46.27% of experiment value and 38.36%of simulation value for subject B. Finally we build a set of mechanical model which is a series of a nonlinear spring and a nonlinear vogit model to simulate the viscoelastic property of heel pad effectively. As a result, we do not need to perform the non-invasive measurement by the ultrasound to decrease cost and conform to economic benefits. The result shows that when the damping coefficients are smaller, the stress rate decreases faster and EDR becomes higher, and vice verse. When the spring coefficients are smaller, the stress rate decreases faster and the slope of hysteresis curve becomes smaller, and vice verse.