基于CAE分析的汽车制动液罐注射模设计

分析了汽车制动液罐注射件的结构特点,使用Moldflow软件对制品的注射成型过程进行CAE分析,确定了模具的浇注系统和成型工艺条件。模具为三板式点浇口结构,采用嵌件抽芯、斜导柱抽芯和液压抽芯相结合的方式实现模具的抽芯要求,并在此基础上完成了模具设计。     

Friction and the development of hard alloy surface microstructures during wear

Investigations of wear in sliding friction of WC-Hadfield steel hard alloy against cast tool steel have been carried out in a broad range of velocities and pressure values. Structural and phase composition variations have been revealed. Friction-affected zone was found to be 450 μm in depth. Structural γ → α, γ → transformation regions are located within 100 μm of the surface. These transformations contributed to the total solid solution deformation hardening.     

摩擦提升机的虚拟样机研究

钢丝绳传动特性是摩擦式提升机设计一个重要的考虑因素.为了研究摩擦提升机提升过程中钢丝绳的动力学特性,为安全运行提供保证,通过虚拟样机技术及其支撑软件ANSYS和RecurDyn,利用相对节点法建立了钢丝绳的多体动力学仿真模型,构建了简化后的摩擦式提升机虚拟样机仿真模型.通过对摩擦提升机虚拟样机的仿真分析,获得了仿真模型的运动学、动力学特性数据,得到了与理论分析相吻合的结果.为设计经济、可靠的多绳摩擦提升机系统提供了有力的工具和实现方法,还可以推广应用到其他挠性传动的分析.     

A new adaptive backstepping Coulomb friction compensator for servo control systems

A new Coulomb friction compensator is proposed for servo control systems in this paper. The novelty of the new approach lies in its capability of assigning the eigenvalues of the resulting closed loop system while attacking the problem. First, based on the standard backstepping methodology, an implicit Lyapunov function, with part of the components being only symbolically constructed at the very beginning, is utilized. To increase the robustness of the system against disturbance and model inaccuracy, an integral term is employed in the design. Using part of the variable gradient method, we are able to turn the implicit Lyapunov function into an explicit one, which is positive definite, and whose time‐derivative is negative definite. Second, it will be shown that the resulting closed loop error system is a switched linear system with two possible active modes that share the same set of eigenvalues, which is at our disposal. Unlike the common adaptive control design methods, such as the Control Lyapunov Function approach, in which the gains are typically positive but otherwise arbitrary, and are hence difficult to choose and have a lack of connection with the system's performance, our new scheme imposes two further constraints on the gains. It turns out that we can then match these gains with the coefficients of the desired characteristic equation of the closed loop system. In this respect, the gains are linked to the system's overall performance, which is a new and very appealing feature for such a scheme. Finally, a procedure of constructing a common Lyapunov function is provided to prove exponential stability of the aforementioned switched linear system. In addition, using the invariance principle, we will show the convergence of the estimated Coulomb friction coefficient to its real value. Numerical simulations are given to validate the effectiveness of the design and its robustness against friction time‐variations. Compared to existing results, the proposed scheme is much simpler, hence, much more advantageous computationally. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

上下风向条流动方案分析

本文以上下风向条流动分析为例简要介绍TMPI的作用，通过应用MP16．1软件对两种CAE流动方案进行填充对比分析，得到了一种切实可行的方案，充分展现了CAE技术在浇注系统设计和注射模具开发过程中所起到的突出作用。     

Effects of road surface appearance and low friction warning systems on driver behaviour and confidence in the warning system

Warning systems for slippery road conditions are a potential newcomer among driver support systems. A total of 75 participants drove in a high-fidelity driving simulator on roads with both visible and invisible ice, to investigate to which extent drivers rely on a low friction warning system. Three experimental groups with different versions of a low friction warning system and a control group without warning system were compared. All drivers ranked the systems according to trust. A system displaying recommended speed received the best ratings. Driving speed was analysed for three particular segments of the route. Generally, lowest speeds were achieved with the recommended speed system. The participants drove more slowly on a slippery segment that looked icy than on the segments that looked dry when they did not receive a low friction warning. When they received a warning for low friction they also lowered their speed for the segment looking like asphalt. The results provide guidelines for how to present low friction warnings to drivers. The design has substantial effects on the resulting behaviour and therefore it can have a high impact on traffic safety. So far, not much research on low friction warning systems has been reported.     

Interface Characteristics and Laboratory Constructability Tests of Novel Fiber-Reinforced Polymer/Concrete Piles

Conventional pile materials such as steel, concrete, and timber are prone to deterioration for many reasons. Fiber-reinforced polymer (FRP) concrete composites represent an alternative construction material for deep foundations that can eliminate many of the performance disadvantages of traditional piling materials. However, FRP composites present several difficulties related to constructability, and the lack of design tools for their implementation as a foundation element. This paper describes the results of an experimental study on frictional FRP/dense sand interface characteristics and the constructability of FRP–concrete composite piles. An innovative toe driving technique is developed to install the empty FRP shells in the soil and self-consolidating concrete is subsequently cast in them. The experimental program involves interface shear tests on small FRP samples and uplift load tests on large-scale model piles. Two different FRP pile materials with different roughness and a reference steel pile are examined. Static uplift load tests are conducted on different piles installed in soil samples subjected to different confining pressures in the pressure chamber. The results showed that the interface friction for FRP materials compared favorably with conventional steel material. It was shown that toe driving is suitable for installation of FRP piles in dense soils.     

CSP连铸结晶器液位控制系统

介绍珠钢连铸采用Co60为放射源的结晶器液位控制系统配置、控制方式和控制算法．     

边界点集规划与注塑模具浇口位置的优化

根据平衡流动路径特点，提出了以理想流动模式为目标、基于制件边界几何信息的浇口位置优化选取的原则；并以平板制件单浇口注射成型工艺为例，研究了最佳浇口位置的描述方法并建立了相应的数学模型，给出了优化算法及制件边界特征点集的规划提取方法；根据所建数学模型和所选用优化计算方法，开发了相应的计算软件，经实例验证，算法和模型可靠。     

伺服系统摩擦的改善

通过分析摩擦对伺服系统运动过程的影响 ,总结出其产生的原因 ,并提出应用加速度负反馈可有效地克制低速的跳动问题 ,实践证明行之有效