利用機械應力集中行為對骨質疏鬆之模擬

USING MECHANICAL BEHAVIOR OF STRESS CONCENTRATION FACTOR TO SIMULATE OSTEOPOROSIS

李益鳴(Yi-ming Lee)

指導教授 ： 簡昭珩

大同大學/工程學院/機械工程學系所/碩士(2008年)

摘要

骨質疏鬆症已成為人類步入中年後常見的症狀，本文將以二種不同的方式研究骨質流失時對力學行為的影響。
首先，以靜力學的觀點分析人體腿骨於爬階運動之行為，再輔以有限元素軟體分析腿骨於運動狀態下受力情形；研究結果發現，在無外力作用或特殊衝擊造成腿骨負擔的情況下，即使人體患有骨質疏鬆症，在正常的爬階運動中腿骨仍不易因骨質流失而產生斷裂。
此外，籍由材料幾何形狀的改變，以材料產生缺口(Notch)的方式來探討應力集中與骨質疏鬆的關係；研究發現，骨質密度與應力集中因數成反比，且與應力集中缺口之深度成反比例關係；但與應力集中缺口之半徑則成正比。而骨質密度的減少更直接影響骨骼能承受之應力，故當骨質開始產生變化時，患者仍應留意並防止骨質繼續流失。

關鍵字

機械力學 ； 骨質疏鬆症 ； 應力集中

並列摘要

The osteoporosis is a common symptom which comes after human middle-age . The article that using two different way to research on ossein outflow, and it makes the influences of mechanics behavior.
Using statics viewpoint analyzes human body thighbone behavior of the movement in climbing stairs, and it analyzes the situation of motional stress by Pro/ Mechanica. Under the situation of thighbone is without external force or special impact, we will find that the movement of climbing stairs is not easily to make the fracture of thighbone caused by the ossein outflow.
By using the notch theory, We studied the relationship between the stress concentration factor and the osteoporpsis. The researches discovered that the BMD are in an inverse ratio to the stress concentration factor and the depth of notch, but it is proportioned to radius of notch .The decrease of BMD directly affect the ultimate stress of bones when BMD starts to decrease. We suggest that the patients should pay more attentions to prevent them from outflow of ossein.

並列關鍵字

osteoporosis ； stress concentration factor ； BMD

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