Bow Flare波擊力作用下及Plunge現象之艏結構強度分析

Abstract

本文之主要目的在透過有限元素分析，探討貨櫃船船艏bow flare在波擊及plunge現象時之結構強度；在數值解析方面，利用有限元素分析軟體MSC/Patran和Nastran作為分析工具。 在波擊現象中，本文以一實際受損貨櫃船做為樣本船，利用此樣本船結構所建立之有限元素分析模型，作為分析對象，並且參照文獻及法規資料，了解波擊壓力大小及波擊作用時間，設計多組不同之局部動態波擊負荷，對其進行結構應力分析，最後比較分析結果與實際失效結構之關係，可以約略知道實際負荷可能的範圍。 在plunge(艏潛)情況中，以同一貨櫃船做為樣本船，本文引入船體慣性力的方式，來修正勞式驗船協會(LR)對現象所提供的計算方式，消除LR法不合理之拘束條件，以達更真實的情形。藉由本研究方法之分析結果，可作為日後船體結構設計時之考量依據。

The purpose of this article is to study the strength of containership due to bow flare slamming and plunge by using FEA (finite element analysis). In the numerical analysis, finite element software, MSC/Patran and Nastran are used to be the analytic tools. In slamming case, an actual containership with damage in bow structures is used as the sample ship, using the established FE (finite element) model including bow structures as an analytic target .Refer to the rules of classification society and references to know the wave impact pressure and duration time of wave impact, and then design different wave impact situations applied to the bow flare. Comparing the results of the analysis with the actual damaged part of the bow structure, we can know the real wave impacts, approximately. In plunge case, the sample ship is same as slamming case. This article takes the inertial force of the ship structure into consideration to modify the method provided from LR. Eliminating unreasonable constrained conditions of the LR method to achieve a much more realer phenomenon. Referring to the results obtained from this research approach, use it as the basis for the design of ship structures in the future.