"冲压模具的结构分析与拆装"网上虚拟实验

按传统方式进行实验在不同程度上影响实验教学的质量和效率;在远程教育中,由于教学机构与学生在空间上分离,学生无法到学校实验室做具体的实验,已经成为制约远程教育教学质量的一个重要因素。本项目开发的“冲压模具的结构分析与拆装”网上虚拟实验,不仅可以为接受网络教育的人群提供网上虚拟实验的软件环境,而且可以显著改善在校教学的实验教学条件,对于贫困地区的教学和培训尤具优势。     

丰花月季的两步法快速繁殖技术研究

文章研究了4个丰花月季品种的先嫁接后扦插的两步快速繁殖技术,并提出了提高繁殖成活率的措施。     

差强度高精度尼龙工件的数控铣削加工

在装夹及加工差强度易变形尼龙类零件过程中,应该充分考虑零件材料特性。根据工件特点及其受力分析,采用合理的工装夹具、刀具及选用合理的刀具路径、切削用量,才能保证零件的加工精度,提高生产效率。     

Performance evaluation of minimum quantity lubrication by vege- table oil in terms of cutting force, cutting zone temperature, tool wear, job dimension and surface finish in turning AISI-1060 steel

In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication （MQL） has been suggested since a decade ago as a means of addressing the issues of environmental intrusiveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of MQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimen- sional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by MQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.     

Analysis of tensioned membrane structures considering cable sliding

In routine design of tensioned membrane st ructures, the membrane is gen erally modeled using space membrane elements and the cables by space cable eleme nts, with no sliding allowed between the membrane and the cables. On the other h and, large deflections are expected and sliding between the membrane and the cab les is inevitable. In the present paper, the general finite element code ABAQUS was employed to investigate the influence of cable sliding on membrane surface o n the structural behavior. Three analysis models were devised to fulfill this pu rpose: (1) The membrane element shares nodes with the cable element; (2) The cab le can slide on the membrane surface freely (without friction) and (3) The cable can slide on the membrane surface, but with friction between the cable and the membrane. The sliding problem is modeled using a surface-based contact algorithm . The results from three analysis models are compared, showing that cable slidin g has only little influence on the structure shape and on the stress distributio ns in the membrane. The main influence of cable sliding may be its effect on the dynamic behavior of tensioned membrane structures.     

Parameter estimation of cutting tool temperature nonlinear model using PSO algorithm

INTRODUCTION In modern metal cutting theory,research on cutting tool is one of the major concerns.To under-stand the characteristics of a new cutting tool,many experiments(such as cutting force experiment,cut-ting temperature experiment,anti-striking experiment,etc.)should be conducted to obtain an enormous amount of experiment data.The development of a proper cutting tool temperature model is a very dif-ficult task due to the large number of interrelated parameters(cutting speed,feed,dept…     

乳化型切削液在铝合金加工中的应用

切削液在机械零部件加工过程中是不可或缺的元素,相比钢铁材质的加工,铝合金加工对切削液的冷却、润滑性能要求更高。切削液的浓度、压力、流量等工艺指标对工件的加工质量有巨大的影响。在选用切削液时应从公司的实际情况出发,在保障零件加工质量的同时,兼顾通用性、兼容性、经济性。     

基于高速切削的模具加工技术

采用高速切削技术加工模具,已经成为现代模具制造业的发展趋势,对模具加工工艺产生了巨大影响;为了达到理想的加工效果,基于高速切削的模具加工技术必须配置合理的高速切削机床、选用合理的切削刀具、采用优化的加工工艺及策略。     

Steam as coolant and lubricant in turning of metal matrix composites

Green cutting has become focus of attention in ecological and environmental protection. Steam is cheap, poilution-free and eco-friendly, and then is a good and economical coolant and lubricant. Steam generator and steam feeding system were developed to generate and feed steam. Comparative experiments were carried out in cutting AA6061-15 vol.% SiC （25 p.m particle size）, with cubic boron nitride （CBN） insert KB-90 grade under the conditions of compressed air, oil water emulsion, steam as coolant and lubricant, and dry cutting, respectively. The experimental results show that, with steam as coolant and lubricant, gradual reduction in the cutting force, friction coefficient, surface roughness and cutting temperature values were observed. Further, there was reduction in built up edge formation. It is proved that use of water steam as coolant and lubricant is environmentally friendly.     

国际教练员－运动员关系研究现状、热点和前沿的可视化分析

以 Web of ScienceTM数据库中的文献为来源,以1991－2013年国际教练员－运动员关系领域的442篇文献为分析对象,借助 HistCite 软件进行文献的可视化分析,从年代分布,研究重要地区、机构和学者,研究的历程,研究的热点和前沿文献进行分析,结果表明：国际教练员动员关系的研究呈逐年上升的趋势,形成了以英国和美国为代表国家,Jowett S 、Amorose AJ、Vallerand R 、Duda JL等11名高影响力学者;国际教练员－运动员关系历程主要有三个阶段;研究的热点主要集中在执教、动机、知觉、模型、领导、内在动机、问卷、团队、凝聚力、成对、移情、准确性、成绩、精英和职业倦怠方面研究的前沿主要集中在教练员－运动员关系的跨文化研究、教练员－运动员关系的多样化研究等6方面的研究。