橡膠材料在土木工程，機械和生醫工程有不少應用，例如i)建築物隔震器，ii)橋樑支承橡皮墊，iii) 取代混凝土中傳統骨材的摻料，iv)隔震樁樁頭的橡皮墊 v)輪胎，vi)生物醫學材料和vii)噴射引擎的固體燃料等。和一般工程材料一樣，橡膠材料強度的折減(strength degradation) 常常因為其內部存在缺陷(孔洞、裂縫)，而又承受了外加的荷重，使得內部的缺陷得以發展和擴大所引致。所以研究材料中孔洞擴張的行為，可提供研究材料強度折減的學理根據，從而推導出含缺陷的材料的組成律(應力與變形的關係)。上一個計畫與大部分現行文?一樣，研究單一種動態荷重作用下孔洞的擴張，而本計畫則更深入的分析各種動態荷重交互作用下孔洞的不穩定擴張。所考慮的荷重交互作用包括i)不同頻率的週期荷重之交互作用，ii) 週期荷重與拉力脈衝荷重的交互作用， iii)週期荷重與突然施加的拉力呆荷重交互作用，iv)先行施加的拉力呆荷重與後加拉力脈衝荷重的交互作用。上述的各種荷重交互作用，在實際的環境常會遇上，而且因為具有一定的難度，之前的文獻中並未有加以研究，故本計畫希望作出一些分析以加深這方面的了解。橡膠屬非線性彈性材料，目前研究非線性彈性孔洞動態問題的文獻中，採用的材料模型皆為新虎克材料模型，此材料模型與實際橡膠材料的行為相差甚遠。本計劃採用由真實實驗數據推導出的Ogden 材料模型，故此可補前人研究之不足。 Rubbers are useful in civil and mechanical engineering. They are the important ingredients of i) vibration isolators, ii) bearings of bridges, iii) rubberized concrete, iv) vibration isolated piles, v) tires, vi) bio-materials, and vii) fuel of jet engines. Strength degradation of rubbers and other engineering materials is often caused by the growth of the defects (voids and cracks) in the materials when they are suffered from some external loading. And thus the study of void growth can enhance the understanding of strength degradation. Such kind of knowledge can help us to derive the constitutive laws of materials with defects. This project studies the dynamic growth of voids in rubbers which are deformed due to the interaction of more than one type of dynamic loadings. The interactions of the dynamic loadings considered in this project include a) the interactions between periodic loadings with different frequencies, b) the interactions between periodic loadings and impulsive loadings, c) the interactions between periodic loadings and suddenly applied dead loads, d) the interactions between suddenly applied dead loads and impulsive loadings. These loading interactions are often found in engineering practice, but were not considered deeply in the past literatures. Therefore, this project tries to make some contributions in this direction. Moreover, the material model used in the existing literatures about the dynamic void growth in nonlinear elastic materials is the neo-Hookean material model, which, however, fails to describe the behavior of real rubbers. And the material models considered in this project is the Ogden material model, which was derived from the experimental data of real rubbers. 研究期間：9908 ~ 10007
