Design of conformal cooling channels for an automotive part

The cooling system plays a crucial role in determining the productivity and quality of an injection molding process. With the current growth of Solid Freeform Fabrication (SFF) techniques, mold designers have been striving for not only improvement in cooling system performance but also for a method to do so automatically. In this paper, a method is proposed for developing a conformal cooling system that facilitates uniform cooling over the entire mold surface with minimum cycle time. Based on the temperature distribution after the filling stage, the mold surface is split into zones which will be cooled by optimized subconformal channels obtained from the optimization process. The optimization process in which the objective function is stated as minimization of the cooling time with boundaries ensuring a realistic design will optimize the cooling system layout in terms of cooling channel size and location. Finally, all subcooling channels are combined to generate the entire conformal cooling system for the injection mold.     

同步推进电动机模态分析

本文运用有限单元法和模态分析理论,结合大型商业化工程分析软件PRO／E和ANSYS对某同步推进电动机进行了振动模态分析。这项工作为今后各型推进电机的整机及其它零部件的有限元分析与优化设计以及动态响应计算奠定了一定的基础。     

圆形竖井钢波纹板-模袋混凝土支护结构现场试验研究

为解决喷射混凝土工作环境差、能耗高以及施工中跑浆、漏浆等问题，提出钢波纹板结合模袋混凝土的新型支护方案。依托圆形竖井，采用倒挂井壁逆作施工法展开现场试验，分析灌注压力的变化规律及其影响。结果表明: 1）模袋混凝土可充填开挖面与钢波纹板之间的构造间隙及预留空间，与钢波纹板形成具有一定强度和刚度的组合结构，能够维持开挖面稳定、抵抗开挖面变形，施工工艺具有可行性； 2）根据现场监测结果可知，在混凝土灌注过程中，模袋内混凝土流动性良好，能充分填充模袋，注满后，灌注压力逐渐消散，且钢波纹板产生的环向应变很小，支护结构在工作状态下均匀受力； 3）试验选用的土工布均具有透气、透水、不透浆的特性，能有效解决喷射混凝土施工存在的跑浆、漏浆等问题，但材料特性和加工性能略有差异； 4）钢波纹板与模袋混凝土结合形成的新型支护结构，为隧道等地下工程支护技术提供了新思路，具有重要意义。     

Analysis and Research on the Tunnelling Technology of Compound EPB Shield Machine in High-strength Hard Rocks北大核心CSCD

It's really challenging for shield driving when hard rock partially intrudes into the excavation section of metro tunnels. Abnormal cutter wear is excessive during shield excavation in hard rock and comprehensive perfor⁃ mance of excavation system decreases greatly, resulting in abnormal advancing parameter, small penetration rate and low advance rate. Taking Shenzhen Metro line 9 project as the background, the main difficulties encountered for the compound EPB shield during driving in high-strength granite and the reasons were analyzed, the corresponding countermeasures were presented. EPB shield drove through the hard rock section safely and smoothly attributed to reasonable cutter configuration, in-time cutter replacement and proper advancing parameters. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Mold EX-Press软件在“塑料模具设计”课程教学中的作用

随着计算机的高速发展,网络技术已成为教学的重要手段。通过介绍Mold EX-Press软件的功能,结合"塑料模具设计"课程的各教学模块,分析该软件在提高学生设计能力、对模具的各组成部分教学的作用,提高了教学效果。     

基于Web的面向产品开发过程的客车PDM系统的研究

分析了现有PDM系统应用状况，针对客车产品的开发过程和技术管理的特点，构造了基于Web的面向产品开发过程的客车产品数据管理系统的总体结构，并研究了系统实现的关键技术与方法。     

浙江民营船厂转模势在必行

详细介绍了浙江民营船厂的造船模式,并对浙江民营船厂转模提出意见。     

低熔点合金模具在起重机油箱上体成形中的应用

论述了低熔点合金材料的性能及特点,介绍了低熔点合金模具的特点及其在板料冲压工艺中的应用,指出了在工艺及模具设计时应注意的问题.以分析起重机油箱上体工艺特性和设计其低熔点合金拉深模具结构为例,论述了低熔点合金冲压模具的结构特点及优势.     

基于LOM原型快速制造发泡模具的研究

以制造泵体发泡模具为例,详细介绍了在LOM原型的基础上,通过LOM原型的预处理、电铸和电弧喷涂等工艺手段快速制造发泡模具的过程。实验证明:基于LOM原型,通过电铸铜和电弧喷涂紫铜相结合制造发泡模具与传统加工方法相比是一种周期短、成本低的制模方法,所制得的模具更能满足生产要求。     

滑架翻模工艺在桥梁高墩施工中的应用

阐述了滑架翻模施工工艺的特点和优越性,结合工程实例,从高墩施工准备、过渡段施工、滑架安装等方面详细介绍了滑架翻模施工的工艺流程,可为滑架翻模施工技术在高墩施工中的应用提供参考.