Lightweight Design and Verification of Gantry Machining Center Crossbeam Based on Structural Bionics

The lightweight and high efficiency of natural structures are the inexhaustible sources for engineering improvements. The goal of the study is to find innovative solutions for mechanical lightweight design through the application of structural bionic approaches. Giant waterlily leaf ribs and cactus stem are investigated for their optimal framework and superior performance. Their structural characteristics are extracted and used in the bio-inspired design of Lin MC6000 gantry machining center crossbeam. By mimicking analogous network structure, the bionic model is established, which has better load-carrying capacity than conventional distribution. Finite Element Method （FEM） is used for numerical simulation. Results show better specific stiffness of the bionic model, which is increased by 17.36%. Finally the scaled models are fabricated by precision casting for static and dynamic tests. The physical experiments are compared to numerical simulation. The results show that the maximum static deformation of the bionic model is reduced by about 16.22%, with 3.31% weight reduction. In addition, the first four natural frequencies are improved obviously. The structural bionic design is a valuable reference for updating conventional mechanical structures with better performance and less material consumption.

Comparative analysis by simulating and testing pole impact for hot stamping front crossbeam of automobile

Hot stamping 22MnB5 steel plate with ultra-high strength has been widely used for body structural members in consideration of automobile safety and lightweight.This paper presents a verification program of simulating and testing pole impact in order to verify if the front crossbeam reinforcement assembly can meet the design requirements,reduce the overall vehicle simulation and test cost and shorten the operation period.In the same condition,the simulation proved conforming to the design requirements;however,the bumper cracked at the impacting point in the course of pole impact test.The analysis of the crack by optical microscope,Vickers and scanning electron microscope indicates that mixture of ferrite,bainite and martensite was produced in the weld heat-affected zone of the 340/590DP tow hook holder and the 22MnB5 front crossbeam;therefore,their hardness and mechanical property were reduced obviously,so that they fractured when impacted.No welding process with continuous weld but spot welding or other bonding method may be employed for the reason that the capacity of the 22MnB5 steel plate in the weld heat-affected zone was reduced obviously.

Lightweight design of automotive front crossbeam assembly

This paper reviews the development course of the front crossbeam assembly for a self-owned brand vehicle model based on lightweight and passive safety performance. Combining with an A00 model variant, the paper details the design of extruded aluminum-alloy front crossbeam assembly from the perspectives of optimal design, performance verifi- cation, lightweight effect and cost control. The following results in the technical and engineering applications have been achieved. The weight of the developed aluminum-alloy crossbeam can be reduced by 51%. The simulated analysis of the collision rigid wall, the 40 % offset hammering as well as the static crush test of energy-absorbing box show that af- ter reasonable materials matching and size optimization of the crossbeam and the energy-absorbing boxes, the level of crash safety can be improved. The price of aluminum-alloy front crossbeam can be lowered by using the extruding die in- stead of the stamping die to reduce the die cost-sharing.

基于FASTAMP的汽车横梁支架拉延工艺设计及制件检测

针对某型号汽车横梁支架拉延成形过程,借助于FASTAMP软件对其成形过程、成形极限图和减薄率进行预测。设计了合理的拉延工艺,防止起皱和拉延不足等现象的产生。同时,利用UG软件进行了拉延模具整体结构方案设计,并对设计出的拉延模进行装配及产品试制;借助于三维自扫描仪,扫描获取试模后的制件云数据。利用Geomagic_Control X检测软件进行检测,得出了符合要求的贴合度数值,验证了拉延模设计的合理性。

某型机上大梁高效加工工艺研究

针对某机型梁类零件典型结构的工艺性分析及加工方案,根据TC4材料的加工特点,合理选择刀具几何参数及切削参数,阐述了在数字化加工中的具体实施过程,从而总结并提炼出了指导性的工艺资料。

Reinforcement and numerical analysis on the corbel of a halfthrough arch bridge

Corbels support the crossbeams of half-through arch bridges. They are prone to cracking easily due to their characteristics and complicated loading conditions. Based on a practical diagnosis of a bridge crossbeam, we bonded steel plates onto bridge corbels to strengthen them. We carried out a numerical analysis on the effectiveness of the reinforcement by using the commercial sof^are ANSYS. The numerical analysis shows that the stresses near the section break increased slightly, but the variation amplitude was small and all the stresses were within an allowable range. The loading test indicates that it is feasible to strengthen the corbel with vertical bonded steel plates. Therefore, the reinforcement is effective and economical. This reinforcement method is suitable for this type of corbel and can be applied in similar cases.

Weldability of 780 MPa Super-High Strength Heavy-Duty Truck Crossbeam Steel

CO2-shielded welding experiments of newly developed, 780 MPa super-high strength heavy-duty truck crossbeam steel were conducted, and the microstructure, microhardness, mechanical properties, and impact tough- hess of the welded joint were studied. The evolution of the microstructure of the welded joint occurred as follows.. welding seam （acicular ferrite＋proeutectoid ferrite）→fusion zone （granular bainite-long strip M/A island）→coarse grain zone （granular bainite-long strip or short bar M/A island）→fine grain zone （ferrite＋ pearlite＋ blocky M/A is- land）→mixed grained zone （ferrite＋granular bainite＋blocky M/A island）→base metal （proeutectoid ferrite＋gran- ular bainite-hlocky or granular M/A island）. Increasing the density of the grain boundaries can effectively improve the impact toughness, and the blocky M/A island hindered crack propagation more effectively than the long strip M/A island. The new hot-rolled 780 MPa super-high strength steel had excellent weldability. The welding technology was applied under the following conditions： welding voltage was 20 to 21 V, welding current was 200 to 210 A, and the gas flow rate was 25 L/rain.

基于Ansys软件的汇矩式液压机械零件设计

利用传统方法设计的汇矩式液压机械零件,在机械运行时,存在生产效率低的问题。针对上述问题,利用Ansys软件来设计汇矩式液压机械零件。本次研究以汇矩式液压机的上横梁零件为研究对象。首先分析汇矩式液压机的机械结构,然后通过有限元Ansys软件根据其结构建立上横梁的原始有限元分析模型,并求解得到了应力应变分布云图,最后通过云图分析出上横梁的受力情况,以此来优化汇矩式液压机械上横梁原有设计零件。结果表明:在液压机上安装优化设计后的上横梁零件,完成一次业务所需时间为5 s,要远远少于安装优化设计前的8 s,说明优化后的上横梁设计的更为合理,能够提高汇矩式液压机运行效率。