铝合金三角形波纹夹芯板对平头弹抗冲击特性数值模拟研究

为研究铝合金三角形波纹夹芯板对平头弹体的抗冲击性能及损伤特性，利用有限元软件ABAQUS/Explicit建立弹体冲击靶板的数值模拟模型，并结合实验验证了模型及其参数的有效性。基于数值计算结果，分析了三角形波纹夹芯板几何结构对其防护性能、失效模式和能量吸收的影响规律及机理，并与等面密度单层板进行对比分析，研究结果表明，靶体几何结构对其抗冲击性能存在影响，三角形波纹夹芯板抗冲击性能低于单层板抗冲击性能。此外，增加芯体拓扑结构夹角能显著提高三角形波纹夹芯板的抗冲击性能，并且靶板几何形状会对其失效模式及耗能特性存在影响。     

任意角带式输送机转弯装置应用研究

煤炭运输线路出现变向转弯时，通过多台传统带式输送机搭接实现输送，存在设备投资大、运输系统复杂、人员需求多等问题。介绍了任意角带式输送机转弯装置的工作原理、结构组成和特点，任意角带式输送机转弯装置由转向模块、改向模块、受料模块及其他辅助装置组成，当巷道转弯角度变化后，仅需要调节转向和改向滚筒即可实现带式输送机转向。该设备结构新颖、承载力大、运转安全可靠，可实现对带式输送机防逆转、制动，克服了转向运行时胶带的滑移和受力不均等问题，实现了减人提效，同时，安装时不需要开掘机电设备硐室，减少了巷道工程量，具有广阔的推广前景。     

Anchor plate bearing capacity in flexible mesh facings

This work addresses the problem of the loading capacity of an anchor plate coupled with a steel wire mesh in soil retaining applications. The interaction mechanism between the flexible mesh facing, the underlying soil layer and the plate is studied starting from the results of several laboratory punch tests involving both the plate and the mesh only, and the whole soil-mesh-plate system. The experimental tests have been reproduced by adopting a 3D discrete element model where also the wire mesh is discretized as an assembly of interconnected nodal particles. The interaction between these particles is ruled by elasto-plastic tensile force–displacement laws in which a distortion is introduced in a stochastic manner to account for the wires’ geometrical irregularities. The mesh model is then validated with reference to a set of punch tests in which the shape and size of the punching element as well as the nominal wire diameter were varied. Subsequently, the model is extended to a punch against soil test configuration permitting an insight into the nontrivial local mechanism between the mesh facing and the underlying granular layer. The good agreement between the numerical predictions and the experimental observations at the laboratory scale allowed us to extend the model towards more realistic field conditions for which the role of the mesh panel boundary conditions, the mesh mechanical properties, the soil mechanical properties and the anchor plate geometry is investigated.     

三角形微通道饱和沸腾传热系数的预测

基于以丙酮为工质的三角形截面微通道饱和沸腾传热的实验数据,通过最小二乘法对实验数据进行参数拟合,得到一组新的经验参数,结合Thome提出的预测圆形截面微通道饱和沸腾传热系数的三区模型,对微通道饱和沸腾的传热系数进行了预测。结果表明:该三区模型可以较好地预测出传热系数随着干度的变化趋势,并得到90.04%的实验值和预测值误差在30%之内,吻合度较好。     

三高测量技术探测岩溶

阐述了三高测量技术的内涵和特点，以珠江水泥厂岩溶探测为例，阐述了三高技术对溶岩探测的应用及效果，经处理直观，形象地反映了岩溶的发育分布情况及形态。     

一种新型格构式刚架平面外稳定的实用算法

截面为三角形的轻型空间格构式刚架的平面外整体稳定性是设计中必须考虑的问题。从结构的全过程分析着手 ,考虑几何非线性 ,经过大量的计算机分析 ,对这种结构体系的整体稳定性能进行了研究 ,并通过对所得数据的归纳和与等效实腹式刚架的比较 ,提出了一个简便可行的稳定验算方法。     

浅谈市政工程施工测量放线程序化

将道路工程平面上直线段 ,圆曲线段 ,缓和曲线段内任意一点的坐标和高程 ,同附近控制点 (测站点 )的坐标和高程编制成计算机操作程序 ,实现施工区域内任意一点测量放线程序化     

一类全系数模糊规划问题及其求解方法

模糊规划是不确定规划的重要一类,对许多带有模糊信息的实际问题都能进行有效地处理,对模糊规划的求解方法进行讨论不仅具有理论意义,还具有实际意义.为寻求一类全系数模糊规划问题的求解方法,利用三角(或梯形)模糊数的排序准则并结合禁忌搜索算法设计了一种求解系数均为三角(或梯形)模糊数的规划模型的人工智能算法.数值算例表明笔者所提方法行之有效.     

Fast accessing Web3D contents using lightweight progressive meshes

Accessing Web3D contents is relatively slow through Internet under limited bandwidth. Preprocessing of 3D models can certainly alleviate the problem, such as 3D compression and progressive meshes (PM). But none of them considers the similarity between components of a 3D model, so that we could take advantage of this to further improve the efficiency. This paper proposes a similarity‐aware data reduction method together with PM, called lightweight progressive meshes (LPM). LPM aims to excavate similar components in a 3D model, generates PM representation of each component left after removing redundant components, and organizes all the processed data using a structure called lightweight scene graph. The proposed LPM possesses four significant advantages. First, it can minimize the file size of 3D model dramatically without almost any precision loss. Because of this, minimal data is delivered. Second, PM enables the delivery to be progressive, so called streaming. Third, when rendering at client side, due to lightweight scene graph, decompression is not necessary and instanced rendering is fully exerted. Fourth, it is extremely efficient and effective under very limited bandwidth, especially when delivering large 3D scenes. Performance on real data justifies the effectiveness of our LPM, which improves the state‐of‐the‐art in accessing Web3D contents. Copyright © 2015 John Wiley & Sons, Ltd.