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船舶在航行时发生砰击是一种高度非线性的物理现象。本文基于势流理论Rankine源法,研究用时域非线性方法计算船舶运动响应,获得船波垂向相对运动速度;并选取合适的砰击压力系数,计算船舶砰击载荷。最后用该方法评估了一艘集装箱船艏部砰击强度,验证了该方法的合理性。 相似文献
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Box-shaped damage affected volumes are applied, with parametric variation of their positions and extensions, to an otherwise intact shuttle tanker in full load condition. The vessel's deadweight is numerically calculated and the lightweight is estimated using semi-empirical formulations to a great extent. For each damage configuration, the final position attained by the ship is investigated and the corresponding global loads are assessed, in terms of still water vertical bending moment and shear force. The ship is considered to be floating in the absence of waves and a quasi-static version of a generalized adaptive mesh pressure integration technique code, for progressive flooding of floating objects, is used to model the progression of the floodwater and the vessel's attitude. The probabilistic model suggested by the Marine Environment Protection Committee of the International Maritime Organization (MEPC-IMO) is considered for the collision induced probabilistic distribution of the damage boxes. A total of 90 damage cases are considered and comparisons of the maximum loads and the location where these take place is carried out relative to the intact case. The minimum design values for still water bending moment and shear force, included in the Common Structural Rules for Bulk Carriers and Tankers of the International Association of Classification Societies (IACS), are introduced in the analysis and their envelopes are compared with the numerically obtained values in light of a probabilistic assessment. Several conclusions are taken regarding the effects of the damage parameters variation, and important findings are presented specifically when accounting for the MEPC-IMO probabilistic distribution, in opposition to a uniform distribution of the damage cases. 相似文献
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高墩大跨度曲线桥悬臂施工阶段非线性分析 总被引:7,自引:1,他引:7
以高墩大跨径曲线桥为研究对象,以非线性稳定理论为基础,利用有限元法对其在悬臂施工阶段荷载状态进行计算分析;通过对不同曲率半径、墩高、系梁个数的非线性计算,对荷载比例系数和悬臂端计算结果进行比较分析,总结出高墩大跨径曲线刚构桥曲率半径、墩高、系梁个数与荷载系数、悬臂端位移的关系,为设计及施工提供科学依据。 相似文献
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彭朝军 《西南交通大学学报》1993,(4):66-71
用局部应力—应变法预测疲劳寿命的关键是危险点局部应力—应变响应的确定和循环计数。工程上常用Neuber法或修正Neuber法近似计算局部应力—应变响应。本文对Neuber法进行了改进,改进后的方法避免了对每一名义应力变程都需要建立新的坐标原点和解非线性方程组的繁琐计算,能够保证足够精度,程序简单,计算速度快,尤其适合大样本复杂载荷历程下的疲劳寿命预测。 相似文献
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文章从设计标准、交通荷载、材料参数及设计方法四方面阐述我国现行规范中沥青路面结构设计的原理及存在的问题,并提出了需进一步完善的建议。 相似文献
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在平台设计过程中,海洋平台受到的风载荷是稳性分析与结构设计需要考虑的重要因素。本文采用CFD技术,对某型半潜式钻井平台在作业工况下受到的风载荷进行了预报,分析了湍流模型、风速剖面形式、湍流强度分布等因素对半潜式钻井平台风载荷的影响。结果表明:不同湍流模型对海洋平台风载荷的预报偏差在2%以内,可以忽略湍流模型的影响;风速剖面对风载荷有较大影响,随着风速梯度的增加而增大;湍流强度分布对海洋平台风载荷的影响在6%以内。研究结论可为建立高精度的海洋平台风载荷数值预报方法提供技术支持。 相似文献