关于Euler方程的一点注记

本文讨论一般二阶线性微分方程２∑ｉ＝ｏψｉ（ｘ）ｙ＾（＾ｉ＾）＝ｆ（ｘ）经变量变换ｘ＝ψ（ｔ）化为常系数线性微分方程的条件及解题步骤，最后，举例说明了上述结果。     

模拟沥青混合料集料的多面体颗粒随机生成算法及程序

为了真实反映沥青混合料中集料的形状、级配及排列,准确模拟其复杂的几何特征与物理性质,提出了模拟沥青混合料的多面体随机生成算法,介绍了算法实现过程中的关键技术问题及程序设计。该算法不仅考虑了矿料级配、颗粒分布的随机性,多面体区域生成及级配的检验与确定,而且考虑到几何与物理参数的转换问题,解决了沥青混合料集料空间结构重构的关键问题。研究结果表明:该算法及程序操作简便,切实可行,为沥青混合料或其他矿物质混合料空间结构重构提供了一种新途径。     

干式气缸套机体气缸加强筋的有限元分析

应用Pro/E三维造型软件和HyperMesh有限元软件,建立了某柴油机组件的实体模型和有限元网格模型,并用Ansys对该柴油机机体进行有限元分析。以气缸套的变形和机体的缸套止口平面的变形作为评价指标,用统计的方法讨论了机体气缸加强筋的效果,发现该机体有气缸加强筋时,气缸套以及机体的缸套止口变形大,影响发动机密封性能,使机械效率下降,不利于排放,从而为该柴油机机体的改进设计提供了依据。     

我国大型邮轮安全监管研究

文中分析了我国大型邮轮旅游市场,邮轮码头基础设施建设,本土邮轮发展情况及邮轮政策出台情况,回顾了世界主要邮轮事故及其对海事安全规则的影响,介绍了我国海事部门进行大型邮轮安全监管的主要举措,指出了我国邮轮海事安全监管存在的问题并提出了一些建议。     

中重型柴油机扩缸前后缸套变形的数值分析

降低缸套壁厚可以在保持发动机紧凑性的同时提高排量,而缸套变形是限制许用厚度的主要瓶颈,针对这一问题,选择缸套壁厚和材料作为变量,缸套变形圆柱度和傅里叶展开系数作为评判指标,研究了薄壁湿式气缸套的可行性。通过对某型柴油机进行有限元分析,发现缸套壁厚从8．25 mm 降低到6．25 mm 后缸套变形明显变大,而改用钢质材料后缸套变形与原机相当,证明了通过降低缸套壁厚同时采用弹性模量更高的材料是一种可行的扩缸方法。     

大型邮轮薄板建造变形控制方法

针对大型邮轮薄板建造易变形的问题,分析薄板材料特性、热输入产生变形、塑性变形、精度不良引起的变形、结构弱引起的变形、预舾装不规范引起的变形和船坞阶段的二次变形等,从原材料应力释放、设计、工艺流程、热输入、吊装运输及堆放、精度控制、预舾装安装、矫平顺序、工艺孔以及修正方案等多方面综合考虑控制以及后期纠正措施.     

Stability of submarine bi-material pipeline-liner system with novel polyhedral composites subjected to thermal and mechanical loading fields

This study is concerned with the thermal and mechanical instability behaviors of composite novel liners encased in deteriorated pipelines. A liner may contain many connected segments, and two adjacent segments may become disconnected after long years of service. In such a case, the single disconnected segment may reduce to a ring. An innovative polyhedral configuration is introduced to improve the bending stiffness of the composite ring that is confined by the pipeline. The radius and bending rigidity of the ring are simplified analytically to facilitate the derivation of the critical buckling load. By employing the classical shell criteria, and defining an admissible displacement function, the expression of the potential energy function is obtained with only two unknown parameters. Taking the first derivative of the energy function to the two unknowns respectively generates two equilibrium equations. By solving the two equations, the analytical buckling load is obtained for a composite polyhedral ring in a thermal variational field. Then, two comparisons are taken between the present analytical predictions and results from elsewhere, and good agreements are obtained. An amplification coefficient is defined as the ratio between the buckling load of the polyhedral and circular rings. Finally, parametric evaluations indicate the amplification coefficient reduces with the increase of thickness-to-radius ratio, the increase of the number of sides, and the increase of the temperature variation, respectively. Therefore, a polyhedral ring with a low thickness-to-radius ratio is recommended in engineering applications.     

基于SVG格式的远洋客船电子地图显示模块构建

对可缩放矢量图形（Scalable Vector Graphics，SVG）技术特点进行分析，结合远洋客船电子地图显示模块功能需求，对电子地图进行功能设计，实现远洋客船电子地图显示模块的构建。以某远洋客船为例，验证基于SVG格式的电子地图显示模块符合远洋客船网络化构建的需求，可为后续远洋客船实现乘员动态导航和构建个性化网络服务平台提供技术基础。