複合材料端蓋之強度分析

Abstract

本論文在研發一高可靠度的脹破式飛彈發射箱前端蓋，此端蓋滿足基本功能需求，其可承受之靜態外壓高出靜態內壓數倍，該端蓋在受到發射箱內一衝壓撞擊時，會按預設之破裂路徑破裂成四片板殼片，並隨內壓飛離發射箱口以讓箱內之飛彈順利射出。端蓋之外型為一微拱之版殼結構，由四片複合材料板經黏著劑膠合而成，調整端蓋厚度及黏著劑強度可改變端蓋之受壓強度及脹破壓力。 理論方面，利用有限單元法來分析及設計端蓋之幾何模型，探討發射筒端蓋之應力分佈，並以適合的破壞準則為基礎驗證端蓋的破壞情況。另製作七比一之縮小尺寸端蓋，進行靜態內壓、靜態外壓及內衝壓的試驗，研究理論分析與實驗之破壞模式與強度，比較理論值與實驗值相當接近，故證明本文所設計的發射筒端蓋可以達成設計目標。

The concepts of designing a frangible laminated composite canister cover are elaborated. The frangible canister cover is designed in such a way that its static external failure pressure is much higher than its static internal failure pressure and it will fail in a predetermined pattern when subjected to an impulsive internal pressure. The frangible canister cover is a convex shell structure and it is fabricated using four plate-like laminated composite parts with bound adhesively. The stress distribution in the canister cover is determined using the finite element method and the failure of the cover identified on the basis of an appropriate failure criterion. A number of laminated composite canister covers were fabricated and subject to static internal pressure, static external pressure and dynamic internal pressure testings. The failure modes of the frangible covers are studied and the experimental results used to verify the theoretical predictions. Close agreements between the experimental and theoretical results have been observed. The present study shows that the design of highly reliable frangible covers can be achieved.