分布式PDM系统中的产品数据对象分布模型

产品数据对象分布问题一直是分布式产品数据管理（DPDM）研究的热点。基于当前硬件条件的限制和信息的海量性,把合适的产品数据对象分布于合适的位置成为决定一个分布式产品数据管理系统性能的很重要因素。因此,该文以国内某通信公司的实际应用为背景进行了产品数据对象分布分析,提出了一个综合目标驱动的产品数据对象分布模型,所提出的产品数据模型通用性强,便于推广应用。     

Experimental research of drop‐on‐demand droplet jetting 3D printing with molten polymer

Three‐dimensional (3D) printing technology has become an effective method for parts manufacturing and got a certain application in many fields. Now, drop‐on‐demand droplet jetting 3D printing appears as a new method of manufacturing technology which has a proven research progress for metal, colloid, and liquid resin materials. However, there are hardly any researches of droplet jetting 3D printing with molten polymer. So, considering molten polymer as the jetting material with droplet jetting method is an explorative direction. In order to attain the molten polymer droplets and achieve droplet jetting 3D printing with molten polymer, the 3D printing technology of differential melt (3DPDM) is developed independently. According to 3DPDM, a complete set of drop‐on‐demand droplet jetting 3D printer have been developed. In this work, PP (6820) was chosen as the experimental material. Under the different print parameters such as the rotation speed of screw, nozzle diameter, mechanical impact frequency, heating temperature, the space between nozzle and platform, the form, and deposition of droplets were studied. Furthermore, the optimal print parameters were summarized. By printing models with the optimal print parameters, it turned out that the 3DPDM is able to achieve drop‐on‐demand droplet jetting 3D printing with molten polymer. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45933.     

基于数字照相量测技术的风荷载作用下玻璃幕墙变形量测研究

利用数字照相量测技术,测定了风荷载作用下玻璃幕墙玻璃面板的平面位移分布.玻璃面板为3090 mm×1450 mm,厚度为6 mm的中空玻璃,实验选取右下角800 mm×1200 mm的玻璃面板为实验对象.本文对测量结果进行了分析和讨论,同时分析了该方法相对于传统测量方法的可行性及优越性,实验结果表明:从玻璃幕墙的玻璃面板对角线方向的位移-荷载曲线可以看出,位移从面板左上角向面板边缘呈增大的趋势;相同位置的位移随风荷载的增大逐渐增大;另外,数字照相量测技术使实验过程简单化,计算结果全场化、直观化.