水下爆炸之結構爆震反應

Abstract

本文探討有限元素分析水下爆炸對結構爆震反應的特性及其應用，分成三個部分，先對水下爆炸的水域網格大小及排列對爆震波傳遞分析結果之影響進行比較研究，以確認計算精確度可接受之網格尺寸。其次針對Ramajeyathilagam & Vendhan[2004]以空氣為背壓之嵌板之近距離爆炸試驗模型作為比較基礎進行有限元素分析，探討完整的水域與板殼模型及簡化四邊固定的板殼模型之分析結果與文獻試驗相同爆炸條件的試驗結果比較，探討流固耦合的影響及本文分析方式的正確性。最後分析一艦艇在水下爆炸下，船舯之結構的衝擊反應。炸藥位置在不同角度及距離下，考慮相同炸藥量與相同的龍骨爆震因子但不同入射角度，進行船體遭受到水下爆炸之爆震波衝擊的動態分析，比較其動態反應之差異。結果顯示，相同爆震因子，不同的爆炸位置，不同的爆炸方向，對結構的衝擊反應均有明顯差異。

The study aims to explore the characteristics of the dynamic response of structures subjected to UNDEX and its application by finite element analysis.The study contains three parts.First, the study conducted basic research on the FE models for analysis of underwater explosion and the effects of mesh at water domain on the results of shock pressure distribution. Second, a plate model adopted from the experiment model of Ramajeyathilagam & Vendhan [2004] with water domain were established. The analysis results were compared with experiment results.The results from FE-models and experiment are compared to verify the accuracy of the FE-model and the influence caused by fluid-structure interference. Finally, the dynamic responses of mid-ship structure subjected to underwater explosion was investigated.The cases with the same mass of TNT but under different keel shock factor and detonation positions are compared. Results show that the impact responses of ship structure subjected to UNDEX with the same shock factor but different detonation position and detonation direction has significant difference in acceleration and stress of structural members in different cases.