立式加工中心滑座结构改进及性能分析

以DVG850高速立式加工中心滑座为研究对象,以轻质多孔结构为基础对原模型进行改进,运用Pro/E造型软件建立滑座的模型,用ANSYS Workbench有限元分析软件对滑座进行静力学分析、模态分析,得出:改进后的轻质多孔结构滑座的静刚度和抗振性能优于原模型,而且还减轻了质量。再通过对轻质多孔结构的滑座进行拓补优化,在满足静刚度和抗振性能的前提下质量进一步减少,与原模型相比质量减少19.08kg。滑座性能提高,同时为滑座及其他类似结构的进一步设计与研究提供了参考依据。     

双掺矿物掺合料轻骨料混凝土性能试验研究

试验研究了粉煤灰、矿渣粉复合掺合料对LC30页岩陶粒轻骨料混凝土坍落度、抗压强度、抗冻融性能、抗碳化性能和自由收缩性能的影响规律。结果表明:总掺量不变时随着粉煤灰相对掺量的增加,坍落度逐渐增加;矿物掺合料提高了混凝土后期抗压强度,总掺量为30%、粉煤灰矿渣粉掺入比例2∶3时28 d抗压强度高于基准试验组14.3%;总掺量一定时掺入比例为2∶3的试验组,混凝土抗冻性能、抗碳化性能和抗自由收缩性能最佳;掺入比例一定时,掺量为30%的试验组的力学性能和耐久性能更优。     

极限挖掘载荷下挖掘机铲斗轻量化设计

为研究如何在满足强度要求的前提下降低铲斗的质量,提出一种基于连续挖掘轨迹和极限挖掘力的铲斗轻量化设计方法。基于连续轨迹理论选定当挖掘机器人动臂处于主挖区内,由铲斗、斗杆液压缸交替挖掘的4段轨迹作为研究前提,计算并分析了连续轨迹上极限挖掘力的数值变化规律;使用APDL语言建立铲斗参数化模型,以极限挖掘力为外载荷研究铲斗结构强度的变化规律;以铲斗质量和应力为优化目标建立铲斗结构优化模型,使用遗传算法对铲斗进行优化。结果表明：铲斗液压缸挖掘时铲斗的应力、变形明显大于斗杆挖掘;优化后铲斗的质量减少了5.27%、最大应力减少了6.23%,验证了优化方法的可行性。     

A new lightweight metal-composite-metal panel for applications in the automotive and other industries

A new lightweight metal-composite-metal (MCM) panel is developed. This panel consists of two layers of 0.2-mm thick stainless steel sheet with a layer of woven fabric (semi-flexible composite) in between. The stiffness and the dent resistance of this MCM-panel are compared to those of corresponding panels pressed in 1-mm thick aluminium, 0.8-mm thick carbon steel and 0.8-mm thick stainless steel sheets. Compared to the aluminium panel, the MCM-panel exhibits a slightly smaller stiffness. However, the MCM-panel displays a larger dent resistance than the aluminium and the carbon steel panels. The new panel is 46% heavier than the aluminium panel. However, it is 60% lighter than the carbon and stainless steel panels. This new panel is expected to have many applications in manufacturing of parts for car, train and bus bodies, appliances and household machines. Machine chassis and air cargo containers are other examples of products, in which the new panel can be used. Production of the new panel requires that the tools be heated. The cycle time is short, since a newly developed and patented method for ultra-rapid heating of tools has been used in this study. The production is economical, since the cycle times is short and recycled fibres can be used. The production process is not completely optimized yet. However, the conducted experiments show that the panel stiffness and dent resistance are benefited, if the tool pressure applied during the heating is low.     

轻烧白云石轻质墙体材料的研究

将白云石在合理的温度和时间下煅烧 ,以煅烧后的白云粉为主要原材料 ,配以调和剂以及各种外加剂、活性改性材料 ,在常温常压条件下自然养护 ,制成轻质内墙砌块、陶粒空心砌块及玉米秸轻质隔墙板。具有生产工艺简单、投资小、成本低廉、轻质高强等优点     

硬脂酸对轻质碳酸镁改性的研究

利用硬脂酸对轻质碳酸镁进行改性,研究了硬脂酸的用量、反应温度、反应时间对改性效果的影响,最终确定了最佳的改性条件。测定了改性轻质碳酸镁的沉降体积、吸油值和活化度并用红外光谱和热失重进行表征。实验结果表明轻质碳酸镁经改性后,亲水表面变为亲油表面;硬脂酸与轻质碳酸镁之间并不是简单的物理吸附,而是发生了化学反应,形成了新的化学键。     

Lightweight design of automotive front side rails with TWB concept

Due to the continuous tightening of various regulations for conserving energy and protecting the environment, the weight reduction of and automobile body becomes an increasingly important issue. In order to reduce the weight of an automobile, we have brought forward a method of replacing the simple structure with the tailor-welded blank (TWB), in which a design process is appropriately defined for a front side rail. Focusing on the thickness determination of TWB, we have deduced the constraint inequalities of strength, bending stiffness, and torsion stiffness to prevent the thickness from decreasing unboundedly due to the lightweight requirement, thus reducing the weight of the front side rail satisfying the design demands of these three factors. The full-width frontal impact simulation of the whole car after redesign in the front side rails has been performed to verify vital performances such as deformation mode, energy absorption, and acceleration.     

基于LDAP的统一用户管理系统的设计和实现

统一的用户管理是电子政务信息基础架构的重要部分.文章讨论了基于LDAP目录服务的统一用户管理系统的设计和实现.通过利用LDAP的树状信息结构、快速响应大容量访问和广泛复制的能力，可以充分提高统一用户管理系统的可扩展性、可靠性和可伸缩性。     

轻质莫来石浇注料及其在轧钢加热炉上的应用

介绍了轻质莫来石骨料及用该骨料配制的轻质莫来石浇注料的性能，并介绍了该浇注料在轧钢加热炉上的应用情况。     

采用机械钻铣轻量化技术的轻型镜研制

以φ400mm轻型平面镜为例，介绍了采用机械减重法制造轻型镜的工艺技术。镜坯的轻量化采用了刚度虽不是最优，但工艺性最好的圆孔结构，并采用专门设计的钻头钻孔，再用氢氟酸消除微裂纹。加工结果表明，该镜的减重比达44．5％，但仍具有足够的刚度，且没有影响加工精度的变形。