不同鞋內墊材料之硬度與勁度組合對於足底壓力分佈的影響

Effects of different insole material hardness and stiffness combinations on the plantar ressure distribution

李建軒(Chien-Hsuan Lee)

指導教授 ： 陳文斌 ； 鄧復旦

國立臺北科技大學/機電學院/機電整合研究所/碩士(2011年)

摘要

過大的足底壓力集中一般被認為是造成糖尿病患者因神經性病變造成足部潰瘍的主要因素。臨床上常使用全觸式鞋內墊進行保守性治療，以達到壓力重新分佈及減壓的效果，並常以鞋墊材料之硬度作為選擇材料之標準。本研究目的為結合足底壓力實驗及三維動態有限元素分析，探討不同硬度及勁度之鞋內墊材料特性對於足底壓力峰值的影響。
本研究量測十三種市售材料之硬度及勁度，並以此作為選擇材料之依據製作九雙不同材料組合之雙層全觸式鞋內墊，進行足底壓力量測。此外，建構包含足部、全觸式鞋內墊及鞋具之三維有限元素模型進行動態有限元素分析。而有限元素分析中之鞋內墊及足底軟組織之非線性材料特性則是由材料試驗機及本研究室所開發之足底軟組織力量位移探測系統所取得。
研究結果顯示材料硬度與勁度間相關係數為0.814，呈現顯著高度正相關。利用足壓實驗及有限元素分析皆得到上層材料硬度或勁度上升，前足及後足之壓力峰值或von Mises stress則增加。足底壓力峰值(21%)和盟麥斯應力( 8%)會隨著上層材料之硬度(61%)及勁度增加(71%)而上升。第一、第二及第三蹠骨頭介面間足底軟組織最大盟麥斯應力，於硬度或勁度較低之下層材料，會隨著上層材料的硬度或勁度增加而上升。不論使用何種鞋內墊材料組合，軟組織之最大盟麥斯應力發生於第三蹠骨頭下方介面間，大小為350-400kPa。
本研究所提供之不同鞋墊材料特性資料庫及一套完整實驗和有限元素分析流程，可作為未來鞋內墊製作前之有效評估工具。

關鍵字

鞋內墊 ； 硬度 ； 勁度 ； 足底壓力 ； 足部有限元素模型 ； 動態分析

並列摘要

High plantar pressure is often believed to be associated with plantar ulceration in diabetic patients with neuropathy. Custom-made foot orthoses are frequently prescribed in routine clinical practice to prevent or treat plantar ulcers by reducing and redistributing the exceeded plantar pressure. However, the insole hardness is often used as a criterion in selecting insole material. The objective of this study was to combine the plantar pressure measurement and three-dimensional dynamic finite element (FE) analysis to evaluate the effects of insole material combinations with different hardness and stiffness value on the peak plantar pressure (PPP) distribution.
Thirteen commercial orthotic materials were collected for measuring the stiffness and hardness values. Based on the results of material testing, nine pairs of two-layer total contact insoles were manufactured. The plantar pressure measurement and a three-dimensional finite element model of the human ankle-foot complex, total contact insole and outsole layer were developed to evaluate the effects of material combination on the plantar pressure distribution by the same subject. The non-linear material properties of FE model of insole and soft tissue were measured by using material testing machine and self-established instrument.
For the correlation analysis, highly significant positive correlation was found between the insole material stiffness and hardness(r=0.814). From the plantar pressure measurement and finite element analysis, both in the forefoot and rearfoot region, the PPP or von Mises stress was raised with the hardness or stiffness increased of upper layer material under the same bottom layer material. In our finding, PPP and von Mises stress increased (21% and 8%) in association with the increased hardness and stiffness of upper-layer material (61% and 71%), respectively. From finite element analysis, the max. von Mises stress in the 1st, 2nd and 3rd metatarsal was raised with the hardness increased of upper layer material under the lower hardness or stiffness bottom layer material. Moreover, the results showed the max. von Mises stress of 350-400kPa, located below the third metatarsal head surface in all of the insole material combination. The established database of different insole materials and an integrated process of experiment and finite element analysis of this study will serve an effective evaluation tool for insole design.

並列關鍵字

Insole ； Hardness ； Stiffness ； Plantar pressure ； Finite element foot model ； dynamic simulation

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