悬臂式堆料机臂架的优化设计

堆料机是散料料场堆积料堆的设备。臂架是堆料机的重要钢结构部件，悬臂式堆料机的堆料臂架铰接在堆料机上部，堆料机工作时，堆料臂架随着堆料机纵向运动（矩形料场），或者绕着中心轴回转运动（圆形料场），同时堆料臂在支承液压缸的作用下，绕着支承铰做变幅运动，将供料带式输送机上的物料，按要求堆积到料场的指定位置，主要结构见图1。     

Tool and process design for progressive forming of an automotive bracket part using finite element analysis

This paper deals with the design procedure of the tool and process for automotive bracket part fabrication. Finite element analysis is introduced to the progressive process to investigate the causes of defects that occur during the forming and bending stages. This paper proposes a new guideline for the progressive process design that modifies the intermediate stages in the progressive process. Finite element analysis and pilot tests are performed again using new strip layout and tool shapes to confirm the validity of the proposed process design. The analysis result shows that the modified process design eliminates defects such as non-uniform thickness distribution and initiation of crack. Then, the automotive bracket part is successfully fabricated through pilot tests using the progressive tools designed in accordance with the proposed guideline.     

Optimal design of a flexure hinge based XYφ wafer stage

Optimal design o1 a XYφ micromotion stage is presented. The stage consists of a monolithic flexure hinge mechanism with three piezoelectric actuators. This paper describes the procedures of selecting parameters for the optimal design. In particular, it presents a mathematical formulation of the optimization problem. Based on the solution of the optimiiation problem, the final design of the stage is also presented. Experimental results indicate that the design procedure is effective, and the designated stage has the total range of 41.5 μm mid 47.8 μm along the X- and Y-axes, respectively, and the maximum yaw motion range of 322.8 aresec (1.565 mrad).     

Modular tool concept and process design for micro impact extrusion

Micro impact extrusion is an appropriate mass production technology for micro structuring of sheet metal. The technology was applied to form sample geometries consisting of ten precision cavities which are intended to be collets for the form- and force-locked integration of piezo rods for later usage of the sheets as “smart sheet metal”. For reasons of flexibility, a modular tool concept was studied and applied. It allows a flexible arrangement of geometry elements but introduces new aspects which need to be considered. This study investigated the influences of tribological- and process parameters onto the microforming process. Therefore forming experiments were performed with different die coatings (titanium nitride, titanium carbon nitride, amorphous carbon), different lubricants (common oil, forming lubricant and without lubrication), as well as two die materials. In contrast to forming processes with established monolithic die configurations, phenomena like tilted structures and the appearance of unwanted burr were investigated. For creating structures with minimal tolerances, these effects need to be considered. The investigation of the influence of process parameters showed, that the lowest surface roughness was achieved without lubrication. Furthermore low-friction coatings and harder die materials improved the forming results.     

Analysis and porthole die design for a multi-hole extrusion process of a hollow,thin-walled aluminum profile

The appropriate die design for multi-hole extrusion is still a challenging task because of the complicated circumstances and large material deformation during extrusion process. In the present study, the material flow during multi-hole extrusion process for producing a hollow and thin-walled profile was revealed by means of numerical simulation based on the Arbitrary Lagrangian Eulerian (ALE) method. The effects of eccentricity ratio, shape of the second-step welding chamber, and uneven bearing length on the exit velocity distribution of extrudate were synthetically investigated, and a two-hole porthole die was designed accordingly. The exit velocity and temperature on the extrudate in this optimized die were analyzed and compared with the initial die, and it was found that both of them exhibit better uniformity, which is beneficial for the enhancement of product quality. Through performing the current work, a logical and effective route for designing multi-hole porthole die was proposed as the guidance for die designers.     

Concurrent design process analysis and optimization for aluminum profile extrusion product development

Owing to intricate interdependency and information feedback among tasks, the concurrent design process probably cannot converge to the correct solution when there are wrong integration and improper interaction between activities. Therefore research on concurrent design process optimization is necessary. In the paper, a novel methodology is proposed to analyze and optimize the concurrent engineering process scientifically. Based on design structure matrix and graph theory, coupled task recognition and design task level plotting are performed for the concurrent design process of aluminum profile extrusion product development. Three factors are used to describe the coupling property of activity, namely sensitivity, complexity and affection factors, which provide the basis to analyze development process quantitatively. And an optimism algorithm is presented to define the initial iteration order of coupled task set. Finally a rational and efficient concurrent design process model is constructed, which can make aluminum profile product development faster, with lower costs and higher quality. The methodology proposed is also applicable to other concurrent engineering fields.     

一种可调整支架的优化设计

可调整支架可以快速装拆并可灵活调整支撑外形,在军事目标的伪装防护方面有很好的应用前景.针对轻便可靠的设计要求,采用优化设计的方法,利用ANSYS的优化设计模块,选择可调整支架的支撑杆外径和壁厚、角钢的截面宽度和厚度等10个参数为优化变量,针对纵向雪压和横向风栽两种最恶劣的工况,以满足力学条件为约束,以支架的质量最轻为优化目标,对可调整支架进行了优化分析,最终通过对优化结果的分析确定了合理的结构设计参数.应用表明.优化后的可调整支架在满足强度的前提下实现了减重的设计目标.     

电器支架冲压工艺及模具设计研究

针对电器支架批量大、尺寸小、尺寸和形位公差要求高的情况,设计合理的排样图及模具结构,分析冲压生产该支架可能产生的带料扭曲变形、2-φ1.6 ±0.05mm孔位置尺寸精度难以保证,以及冲裁不完全或断面重复冲裁等缺陷的产生原因,并找到了相应的解决措施.     

不对称万向节叉冷挤压成形有限元模拟和模具设计

基于DEFORM-3D软件对不对称万向节叉冷挤压成形过程进行有限元仿真,分析成形过程中行程载荷曲线、金属流动、温度场和等效应力分布,预测了模具设计中可能出现的问题。根据有限元分析结果指导设计了一套不对称万向节叉的模具,有效缩短了模具设计周期,降低了模具设计成本。     

Analysis and die design of flat-die hot extrusion process 2. Numerical design of bearing lengths

This paper deals with the assignment of bearing lengths for the control of material flow in the flat die hot extrusion. The design process makes the use of the three-dimensional non-steady analysis using the thermo-rigid–viscoplastic finite element method that includes an automatic remeshing module. The exit velocity distribution of the workpiece obtained from the analysis results was used to find appropriate values for the factors used in the proposed bearing length design equation. This equation for designing bearing lengths is a function of the cross-sectional thickness and distance from the die center of die exit section. A geometric factor was included in formulation of the design equation to consider the end region of the die exit. The appropriate values of factors were determined from three-dimensional analyses of flat-die hot extrusion processes with single and double channel-sections. The analysis of a flat-die hot extrusion process with a L-section was used to verify the proposed design equation. It was found that the design equation determined bearing lengths that resulted in a fairly uniform exit velocity distribution throughout the extruded section. From the results of this study, it was found that the proposed design equation can be effectively used to estimate appropriate bearing lengths.     

Optimal ram extrusion of wood-plastic composites

Analysis focuses on how the crystallinity of the thermoplastic matrix and the packing of the wood filler affect the physicomechanical and tribological properties of long components produced by ram extrusion from molding compounds based on reinforced wood-plastic composite.     

一种康普顿光源柔性激光反射镜架的结构设计

设计了一种应用于康普顿光源激光光路精密调节系统的柔性激光反射镜架。该柔性激光反射镜架采用压电陶瓷电机驱动,通过机构中单自由度柔性铰链的弹性变形实现反射镜沿经度和纬度方向的两个转动自由度,实现对激光束入射角的精确调节。首先基于机构伪刚体模型,分别构建了机构运动学模型和输出刚度模型;然后利用有限元分析工具对机构理论位移和应力分布进行了仿真分析;最后利用视觉检测对镜架的可调节范围进行了实验验证。实验结果表明其经纬方向调节范围均在1.2°以上,柔性镜架各项参数设计合理,满足康普顿光源调节系统要求。     

软管支架冲压工艺及模具设计

通过分析软管支架多向弯曲件的冲压工艺性,对工艺方案的选择进行分析比较和确定,对不同工序的模具进行合理化的设计。     

微小卫星星敏感器支架的优化设计与试验

针对卫星结构中星敏感器支架在随机激励下加速度响应均方根(RMS)值过大的问题,提出了星敏感器支架优化设计方法。简述了星敏感器安装点随机响应的基本理论,对卫星结构进行了模态和加速度响应灵敏度分析。以星敏感器安装点RMS值最小为目标,以基频和体积分数为约束,建立了星敏感器支架随机响应优化模型,并对支架进行了拓扑优化设计。最后,利用MSC.PATRANNASTRAN对优化处理后的支架模型进行了工程分析。结果显示:星敏感器安装点随机响应RMS值降低了20%以上,支架结构轻量化率达到了50%。另外,利用振动试验台对支架进行了振动试验。实验显示:有限元分析结果与试验数据相对误差低于15%,表明设计的支架的性能参数满足设计指标,验证了所采用优化方法的可行性。     

Analysis and design of flat-die hot extrusion process 1. Three-dimensional finite element analysis

Non-steady-state-coupled three-dimensional analysis is required for investigating complex material flow in practical flat-die hot extrusion processes of aluminum alloys in various channel sections. It is important since the material flow behavior actually determines the amount of distortion of the extruded product. Thus, a non-steady thermo-rigid-viscoplastic finite element program was developed for numerical simulations of the process. Since severely deforming elements of the workpiece can easily interfere with the sharp edges of the flat-die, an automatic remeshing module based on a simple section-sweeping scheme and new contact algorithm were incorporated to allow continuous simulation without manual intervention with less volume loss and computation time. With developed finite element program, non-steady finite element analyses of extrusion processes were carried out for two types of channel-section with constant bearing length of 5 mm. From simulation results, it was found that the exit velocity of the workpiece varied depending on the cross-sectional thickness of the exit and the amount of deflection of the workpiece was not greatly affected by variations of either the workpiece temperature or punch velocity under the present simulation conditions.     

Optimal design of a squeeze film damper using an enhanced genetic algorithm

This paper represents that an enhanced genetic algorithm (EGA) is applied to optimal design of a squeeze film damper (SFD) to minimize the maximum transmitted load between the bearing and foundation in the operational speed range. A general genetic algorithm (GA) is well known as a useful global optimization technique for complex and nonlinear optimization problems. The EGA consists of the GA to optimize multi-modal functions and the simplex method to search intensively the candidate solutions by the GA for optimal solutions. The performance of the EGA with a benchmark function is compared to them by the IGA (Immune-Genetic Algorithm) and SQP (Sequential Quadratic Programming). The radius, length and radial clearance of the SFD are defined as the design parameters. The objective function is the minimization of a maximum transmitted load of a flexible rotor system with the nonlinear SFDs in the operating speed range. The effectiveness of the EGA for the optimal design of the SFD is discussed from a numerical example.     

Effects of extrusion variables on temperature distribution in axisymmetric extrusion process

A numerical method was developed to simulate the non-steady-state temperature distributions during forward extrusion process. The velocity, strain rates, and strain fields within the deformation zones during extrusion were obtained, using upper bound method of analysis to obtain internal heat generations coupled to the necessary heat transfer conduction equations. The computer program written in C++ language essentially simulates the extrusion process and takes into account extrusion variables such as material properties, friction conditions, extrusion velocity, extrusion ratio, die preheat temperature, billet height, percentage reduction in area, and die land length. The effects of billet height and percentage reduction in area on the temperature distributions within the dead metal zone give good agreements with experimental results. It is found that the higher the billet's heights and higher the percentages reduction in areas, the higher the temperature rises during the extrusion process. The die land zone shows increasing temperature rise with increasing friction coefficient, while increasing friction coefficient has no effect on the dead zone temperature. Also, increasing speed of deformation shows an increasing dead zone temperature rise than a more gradual die land temperature rise. It can be stated that the extrusion temperature increases proportionally to the increase of the container temperature.     

某矿用自卸车电池包支架强度试验研究与结构改进设计

EV矿用自卸车电池包支架由于需要搭载大型电池包而对强度有较高要求,但是在对其整体结构及各项性能进行加强的同时又需要限制其质量指标的增加量,因此,对于结构设计而言,需要在严格的质量指标限制下,在达到强度要求的同时,提升其性能。为此,结合有限元分析与随机振动试验原理,提出一种新的试验方法对其强度进行试验验证,基于CAE仿真结果及相关优化方法,可在其质量增加量不超过1%的前提下优化支架结构,从而使电池包支架的结构强度得到有效提升。     

推杆杆头冷挤压新工艺

气门推杆杆头是柴油机配气系统的关键零件，推杆杆头球窝表面粗糙度设计要求为Ra3．2um，原工艺采用单轴自动车床车出来，表面粗糙度一直达不到设计要求。为了解决这一问题，我们借鉴进口的日本QD32柴油机气门推杆结合部整体是挤压加工的做法(其表面加工质量相当好)对推杆杆头球窝采用了挤压光整加工工艺，以提高表面加工质量。     

基于拓扑优化的发动机支架的结构设计

在Hyper Mesh中建立了汽车发动机的安装支架有限元模型,利用Radioss求解器进行强度分析计算。运用Opti Struct优化分析软件对发动机支架在满足最危险工况的要求下进行了拓扑优化,根据拓扑优化的结果确定支架的材料合理布局方式,最终在满足设计要求的情况下成功确定了合理的设计方案。