纏繞式複合材料壓力容器之可靠度分析

Abstract

本文針對纏繞式複合材料壓力容器受內壓情形下，研究以隨機強度為變數的可靠度分析。藉由使用破壞準則及有限單元法來完成壓力容器的首層破壞分析，而所用之破壞準則為最大應力準則及Tsai-Hill準則，並以上述準則來推導極限方程式。再利用直接數值積分及串聯系統的假設即可計算出複合材料壓力容器的可靠度。 實驗方面可分為材料強度試驗與首層破壞試驗。根據結果，證實用韋氏分佈來表示數據的變化性乃是最佳的機率分佈，可用此機率分佈來分析可靠度。本文所舉之範例可驗證可靠度分析方法的可行性與精確性。

A method formulated on the basis of the concept of first-ply failure and the structural reliability theory is presented for the reliability analysis of filament-wound composite pressure vessels with random strength parameters. The first-ply failure analysis of the filament wound composite pressure vessels is achieved via the use of different phenomenological failure criteria and the finite element method. The maximum stress and Tsai-Hill criteria are used to establish the limit state equation. The direct numerical integration method together with the series system hypothesis are adopted to compute the reliability of the pressure vessels. Experimental investigations of lamina strength distributions and first-ply failure of filament-wound composite pressure vessels were performed. It has been found that the lamina strengths and the first-ply failure load of the vessels can be well fitted by Weibull distributions. Baseline probability distributions of lamina strength parameters constructed from the tests are used in the reliability analyses of the filament-wound composite pressure vessels. The accuracy of the proposed methods in reliability analyses of the filament wound composite pressure vessels are verified by the experimental results.