Modeling dynamic developable meshes by the Hamilton principle

In this paper, a new dynamic developable surface model is proposed. The proposed model represents developable surfaces using triangle meshes. A novel algorithm is proposed to introduce the Hamilton principle into these meshes such that the resulting developable model is dynamic, i.e., it can offer a time-dependent continuous path to deform the model. Applications with examples are presented; these show that the proposed technique can model buckled developable surfaces well, and can offer physically-realistic animations of deformed developable surfaces.     

Pulsating Jet Impingement Heat Transfer Enhancement

This article presents results from a numerical study of pulsating jet impingement heat transfer. The motivation is to seek conditions offering a significant enhancement compared to steady flow impingement drying. The CFD software package FLUENT was used for simulating slot-type pulsating jet impingement flows with confinement. The parameter study included velocity amplitude ratio, mean jet velocity, and pulsation frequency. The distance from nozzle exit to surface was three times the hydraulic diameter of the nozzle. The Reynolds number based on the nozzle hydraulic diameter and jet temperature was 2,460 with a mean jet velocity of 30 m/s, which is the base case of the numerical experiments. Results showed that time-averaged surface heat transfer increased with increasing velocity amplitude for the same mean jet velocity. Large velocity amplitudes helped enhance heat transfer by two mechanisms: high jet velocity during the positive cycle and strong recirculating flows during the negative cycle. For the cases with different mean jet velocities but the same maximum velocity, time-averaged surface heat flux decreased with decreasing mean jet velocity. As for the effects of pulsation frequency, with high-velocity amplitude ratio, time-averaged surface heat fluxes were at the same level regardless of frequency. However, at low-velocity amplitude ratio, high frequency caused stronger recirculating flows resulting in greater heat transfer compared to the cases with a lower frequency.     

火灾中受保护钢构件的温度数值计算

利用传热学原理，考虑保护层表面热阻和保护层厚度内温度的非线性变化，建立受保护钢构件在火灾条件下瞬态导热微分方程，并计算其截面温度。     

基于Matlab的教学型机器人空间运动轨迹仿真

根据教学型机器人的实际结构特点，利用Matlab中SimMechanics工具箱建立了运动学仿真模型。并进行机器人关节空间和直角坐标系下的运动仿真。仿真结果表明利用仿真模型可以准确、有效地得到机器人的运动参数和运动轨迹，为机器人分析设计提供了可靠依据。     

三探测器密度测井数据处理方法研究

数据处理方法研究是三探测器岩性密度测井研究的一个重要方面。在Monte Carlo模拟的基础上，提出了2种三探测器岩性密度测井求取地层光电吸收指数Pe和进行泥饼校正求取地层密度ρb的方法；就三探测器岩性密度测井仪DTLD—2的围岩补偿功能进行了研究。结果显示了用计算机模拟方法研究核测井问题可以节省建造实体物理模型的费用和人力，具有广泛的应用前景。     

单孔护壁爆破数值模拟

运用LS-DYNA软件对单孔护壁爆破和切缝药包爆破进行了三维数值模拟,结果显示,由于PVC-U套管的存在,作用于孔壁的爆炸应力波峰值被显著削弱,降低率达到30%～46%,并推迟了其到达保留岩体孔壁时间.与传统的切缝药包爆破相比,保留岩体损伤更小.     

Modern Teaching and Training in Metallurgical Engineering

This contribution deals with advanced educational technologies needed to equip customers from higher education institutions, research and industry with efficient tools supporting their work and operating new skills‐training methods. The challenges are reducing the training costs, improving quality and increasing the number of graduates in engineering departments. The concept of a Virtual Lab based on the combination of various teaching methods and tools is presented. Principles of mathematisation in metallurgical education and training are discussed. An example of online course designed in the form of Virtual Lab is demonstrated.     

有限元仿真分析中的结构周期差异探讨

针对有限元仿真分析中结构自振周期减小的问题，讨论了几种主要的影响因素，并借用商品化设计软件TBSA，ETABS 和有限元分析软件ANSYS，通过对一个简单结构的多次计算，比较了这些因素的影响大小。     

Efficiency of sediment transport by flood and its control in the Lower Yellow River

1IntroductionIntheriversystemwithsediment-ladenflow,WaterUseforSedimentTransport(WUST)isaveryimportantcomponentofecologicalwaterdemands,whichmaintainfundamentalfunctionofallecosystemcomponentsataspecificlevelofcondition[1].EnoughWUSTisthepremisetokeepthestableriver-bedandhealthyriverecosystem;alsoitisthebaseflowofriverfortheexploitationofwaterresources.Comparingwithotherrespectsrelatedwithwaterdemandsofriverecosystemsuchastheminimumflowforfishesorripariantrees,researchesontheWUSTarequite…     

空间柔性机械臂三维动力学数值仿真

本文应用ｄ＇Ａｌｅｍｂｅｒｔ－Ｌａｇｒａｎｇｅ原理，对由基座、（ｎ－１）个柔性连杆及端部负载组成，相互用柱铰连接的柔性链式多体系统进行建模；对在空间技术中，具有一刚杆，两柔杆加上刚性负载所组成的三维机械臂系统，采用Ｇｅａｒ算法进行数值仿真。仿真结果比较符合实际，从而在柔性多体系统的数学模型为刚性常微分方程的情况下，为解决其数值仿真问题，特别是三维问题的数值仿真取得了进展。