複合材料三明治板之衝擊分析及實驗

Abstract

本文利用由多層位移場理論所推導而得之有限單元法，來探討複合 材料三明治板的力學行為，內容著重於動態衝擊分析。 在有限單元法方面，建立一三角板元素以及方形元素，考慮複合材 料三明治板承受板中央衝擊的情形，以不同元素來分析預測衝擊接觸 力與板中央的應變情形，並比較不同元素之特性。 衝擊分析方面，對複合材料三明治板進行靜態壓凹實驗，建立接 觸力與板凹陷量之關係式，用以預測衝擊過程中的接觸力與板的應變 情形；另外亦採用文獻中之複合材料三階段接觸定律來進行衝擊問題 模擬。考慮不同厚度與角度疊層方式的複合材料三明治板，受到衝擊 物以不同速度撞擊下的力學行為，並將兩種接觸定律之理論分析結果 與實際衝擊實驗值作一比較。

A finite element method, which is formulated on the basis of the layerwise linear displacement theory, is used to study the mechanical behavior of laminated composite sandwich plates subjected to impact. Two types of finite elements, namely, three-node isoparametric triangular finite element and nine-node plate element, in conjunciton with an empirical contact law derived from the statical indentation test of laminated composite sandwich plates are used for the theoretical investigation. The impace problem is solved via the use of Newmark's integration scheme and Newton-Raphson method. The proposed method is then used to evaluate the contact force and strains of the plates during impact. A number of examples of laminated composite sandwich plates with different length-to-thickness ratios, fiber angles and number of layer groups striked by an impactor with different velocities are studied. Results obtained via various theories are compared with experimental results. The suitability and accuracy of the proposed method are illustrated by means of the examples.