层合圆锥壳的声辐射

为了研究流体载荷作用下正交铺设层合圆锥壳的声辐射,详细研究了一个锥壳的声辐射理论模型。通过把层合圆锥壳划分为许多小段圆柱,处理作用在锥壳上的重质流体载荷。然而,锥壳的位移场仍然由单个锥壳的运动方程描述。锥壳的位移利用波传播法和Galerkin法求解。锥壳的远场声辐射利用两端带无限障板的全部圆柱段的声辐射相叠加。声压在波数域表示。研究了层合锥壳的结构声辐射特性。     

几何制造误差对圆柱壳声辐射影响的数值仿真分析

通过ANSYS和SYSNOISE有限元软件对含有制造几何误差的圆柱壳体进行仿真建模和声辐射计算并与理想状态的完善圆柱壳体结果进行对比.查看由不同形式的几何误差所带来的对声辐射的影响,并得出其声辐射有着随几何误差增大而增大的规律.     

加肋圆柱壳制造误差对声学性能的影响研究

利用有限元软件ANSYS和边界元软件Sysnoise对加肋圆柱壳建造中可能产生的椭圆度、轴线倾斜、舱壁倾斜偏移的多种误差进行仿真计算,分析制造过程中产生的不同尺寸误差模型的系统声辐射特性。结果表明,声功率随着几何偏差尺寸增大而增大,但在所确定的加工工艺允许的要求范围内,这些偏差对声辐射影响很小,其中椭圆度对结构声学性能的影响较其他两种结构误差稍大。     

大功率LED汽车前照灯散热设计

基于目前的半导体制造技术,LED输入功率中只有大约15%的能量转化为光能,其它的则转化热能,如果LED散热问题解决不好,输出光功率减小,加速芯片蜕化,寿命缩短,不能突显灯具的优势。文章在某轿车现有前照灯组合结构的基础上,制作了LED汽车前照灯样灯。介绍了热管散热器的导热和散热方式,仿真和测试结果表明散热效果较好,指出热管散热器存在一定的局限性,散热方式应该向智能散热方向发展。     

About the possibilities of using the renewable energy power sources on railway transport

Several electrification systems based on renewable energy power sources (first of all, solar energy) are discussed in respect to their applicability to railway transport and, in particular, to suburban electric trains. Two systems are considered with basic technical details and economic estimation, both including the onboard bank of batteries and the photovoltaic converters (PVC) of solar energy for compensation of energy expenses, which could be positioned either on stations or on wagon's roofs. Sun‐tracking systems and their effect on the solar energy conversion efficiency are discussed in application to stationary and moving PVC platforms. An analysis made shows that introduction of the “green” systems discussed will not only have positive ecological impact, but also can bring a notable economical effect even with today's components, while it could be considerably greater with the usage of new PVCs, which are being developed by the authors. Copyright © 2011 John Wiley & Sons, Ltd.     

声辐射问题的一种新的无限元方法

声波在无限大外域中的传播和衰减问题是研究声与结构相互作用的重要基础。该文提出了一种新的声无限单元耦合有限元方法于外域声辐射问题的计算。应用加权残值法推导了声无限单元的刚度矩阵和质量矩阵,选取的形函数及权函数充分考虑了外域声传播的基本特点及无穷远辐射边界条件。计算实例表明这种方法对于求解无界域声场问题是非常有效的。     

水运对中国经济贡献率测算研究

以经济学中的产业波及理论模型为基础,运用投入产出法对水运行业的感应力系数和影响力系数进行了测算,同时测算并分析了水运业对中国经济、投资、就业的综合贡献率,较为全面地阐述了水运业对中国经济的影响,客观地提出了水运业对中国经济发展的作用和存在的问题。     

提高船舶设备电磁兼容性能方法探讨

针对船舶辅助设备在电磁兼容性测试中存在的问题进行探讨,提出行之有效的解决办法,并对抗强电磁脉冲辐射进行初步探讨,提出解决方案.     

液化蒸气爆炸——火球对人体的伤害评价

为了使操作及管理人员对液化蒸气爆炸所产生的火球对人体所造成的伤害有一个具体的评判标准,本文通过数学公式及计算,结合图表,将液化气体容量与伤害范围以及对人体的伤害程度联系起来。通过此评价方法,人们可以方便地了解到爆炸火球与人体伤害程度的关系,以求更好地避免人体伤亡。实验结果证明了该算法的有效性。     

Simulation and analysis of flexible solar panels’ deployment and locking processes

To predict the attitude of satellite during the whole deployment process and evaluate the lockingimpact, a numerical flexible model of a certain satellite associated with four flexible honeycomb solar panelswas established. The flexible solar panel was modeled by the finite element analysis (FEA), and the motionequations were derived by Lagrangian formulation. The locking process was based on the method of Hertziancontact, which enables one to predict the locking impact on the satellite and the subsequent oscillation of solarpanels. The results reveal that locking operation has great impact on the attitude of the satelhte, and theangular acceleration of satellite reaches 22.03 °/s2 at the locking moment; the flexible solar panels model isfeasible to predict the accurate response of the satelhte during deployment and the oscillation of solar panels;the instantly impulsive force occurred during locking process is about 1.5 kN and the changing time is nearly0.32 s. It provides an effective approach to present the flexible solar panels' deployment process and evaluatethe locking impact.