130转向节成型问题的探讨

通过改进预锻模膛的设计，利用镦粗成型、反挤成型的原理，有效解决了130转向节板部模锻成型时充不满的问题。     

多目标质量的粉末包套等通道挤扭成形致密工艺参数优化

剧烈塑性变形法—挤扭以剪切塑变为主变形方式,成形工艺复杂,影响因素很多,难以精确地建立工艺参数与成形质量之间的关系;选取优化合理的工艺参数匹配是材料尤其是粉末材料成形无破裂、塑性好、致密化程度高等成形质量的关键。以等通道横截面扭转角、螺旋角、摩擦因子、挤压速度、初始相对密度为自变量,正交试验为设计方案,对纯铝粉末烧结材料进行一道次包套等通道扭挤数值模拟,获得以等效塑性应变、静水压力、最大损伤值、相对密度数据,通过层次分析法计算多质量目标的权重,运用追踪点法和灰色系统理论的灰色关联度优化工艺参数,使设计目标值达到等效应变最大、静水压力最大、最大损伤值最小、相对密度最大。模拟和试验结果表明,运用多目标优化组合参数进行等通道挤扭成形能使纯铝粉末体材料迅速地形变累积,静水压力提高,损伤值显著地减小,致密效率高,晶粒明显细化,提高了材料综合质量。     

重载汽车转向节臂的强度分析及结构优化

重载汽车转向节臂结构复杂,承受弯扭组合变形的作用,强度分析至关重要。通过ANSYS软件对汽车转向节臂在承受非线性载荷时进行模拟分析,采用参数化命令得到了转向节臂的等效应力分布规律。通过修改应力值较大区域处的圆弧半径,对转向节臂进行结构优化设计,模拟显示,改进后的结构应力分布较为合理,最大应力值明显减小,为转向节臂的结构设计提供了理论参考。     

转向节减震孔复合刀具的设计

转向节为汽车大批量生产中的通用部件,其中的45减震孔在转向节生产中需要多道工序加工,严重影响了加工效率。针对以上问题,在对45减震孔加工刀具组合设计的可行性分析的基础上,对工艺进行了优化改进,设计了专用组合刀具,从而对转向节的批量生产效率的提高起到了重要作用。     

锥齿轮冷挤压成形加工数值模拟研究

为了解决人工设计锥齿轮冷挤压模具过度依赖经验的问题,将数值模拟应用到锥齿轮模具设计中。设计了一套用于冷挤压加工锥齿轮的三层组合凹模,制定了相应的工艺措施,利用Deform-3D软件对锥齿轮的冷挤压加工过程进行了数值模拟,分析了加工过程中的载荷曲线、速度场、应力场和温度场,获得了有关锥齿轮变形规律的基本情况。研究结果表明,通过改善润滑条件、优化模具几何参数可以提高冷挤压加工锥齿轮的成形质量,并对锥齿轮冷挤压加工工艺流程定制、模具设计具有一定的指导意义。     

摩托车倒档锥度环温挤压成形有限元模拟及模具设计

通过对摩托车倒档锥度环温挤压成形过程进行有限元模拟与分析,解决成形过程中出现的问题,并设计出摩托车倒档锥度环的温挤压成形模具。模拟结果显示,优化工艺参数后的成形件质量良好,只有少量纵向毛刺和飞边,材料利用率高,表明温挤压是一项有效的毛坯精化技术。     

轻型汽车转向节的工艺分析及夹具的三维设计

以某型汽车转向节为例,分析其加工工艺,制订其加工工艺路线。由于加工转向节过程中需要在机床上进行装夹,所以对铣准45端面的夹具进行了设计,从而改善了转向节的加工工艺,提高了生产效率及产品质量,降低了生产成本。     

液-固挤压Al2O3sf /LY12复合材料管材成形过程的数值模拟

针对液-固挤压复合材料管材的成形过程,采用热刚塑性准耦合有限元法进行了数值模拟,以揭示其塑性变形行为.通过自行开发的有限元模拟系统软件,利用网格重新划分技术,得到了复合材料液-固挤压变形过程中的应力场、应变场及变形力,并对有关问题进行了分析.与试验结果相比较,验证了该系统的可靠性,为保证制件成形质量和合理选择工艺参数提供了理论依据.     

基于多目标优化策略的框架车转向杆系优化设计

为改善和提高框架车转向性能,基于多目标优化理论对框架车转向杆系结构进行了优化设计研究。建立面向转向杆受力和转角多目标优化的参数模型,并应用多目标决策方法中的分层序列法,在ADAMS中建立框架车转向杆系的仿真分析模型。分析结果表明,应用多目标优化方法可以减小各轴线轮胎实际转角与理论转角的误差,同时使杆系受力情况得到较大改善。     

面向小型企业的转向节工装设计

汽车转向节外形不规则,空间位置复杂,加工部位多,精度要求高,在大型企业中常见的加工方式为流水线专机加工。而对于生产设备和人员都很有限的小型企业来说,需要根据实际情况来合理安排工艺路线。转向节工装夹具的设计使用Creo 2.0建模与虚拟装配,有效缩短了设计周期,使该企业可以在有限资源下生产符合图纸要求的转向节产品。     

重型车辆转向节臂强化路耐久性断裂试验

为研究某重型车辆在试验场强化耐久路可靠性试验中发生的转向节臂锥体根部断裂问题,从材料组织结构特性和工艺装配精度角度考虑,对转向节臂断裂故障模式进行了详细分析。在断裂口附近粘贴全桥弯曲应变片并布置与转向系统关联的测试传感器,采集断裂部位的弯曲应变、侧向加速度及转向横拉杆位移等试验数据。依据缺口根部循环应力-应变滞回环曲线方程及诺伊贝尔(Neuber)原理,将测试的名义应力载荷转换成断裂部位的局部应力-应变响应,利用曼森-科芬(Manson-Coffin)平均应力修正方程计算断裂位置的疲劳寿命和损伤。分析和计算结果表明,转向节臂材料特性满足设计技术条件,而工艺装配锥度及表面粗糙度不满足图纸设计精度,转向节臂与转向节的装配接触面积只达到30%,导致转向节臂锥体根部产生局部高集中应力,最终发生弯曲低周疲劳断裂。     

An optimization strategy for die design in the low-density polyethylene annular extrusion process based on FES/BPNN/NSGA-II

An optimization strategy for die design in the polymer extrusion process is proposed in the study based on the finite element simulation, the back-propagation neural network, and the non-dominated sorting genetic algorithm II (NSGA-II). The three-dimensional simulation of polymer melts flow in the extrusion process is conducted using the penalty finite element method. The model for predicting the flow patterns in the extrusion process is established with the artificial neural network based on the simulated results. The non-dominated sorting genetic algorithm II is performed for the search of globally optimal design variables with its objective functions evaluated by the established neural network model. The proposed optimization strategy is successfully applied to the die design in low-density polyethylene (LDPE) annular extrusion process. A constrained multi-objective optimization model is established according to the characteristics of annular extrusion process. The minimum of velocity relative difference, δu, and the minimum of swell ratio, S _w, that, respectively, ensure the extrinsic feature, mechanical property, and dimensional precision of the final products are taken as optimization objectives with a constrained condition on the maximum shear stress. Three important die structure parameters, including the die contraction angle α, the ratio of parallel length to inner radius L/R _i, and the ratio of outer to inner radius R _o /R _i, are taken as design variables. The Phan-Thien–Tanner constitutive model is adopted to describe the viscoelastic rheological characteristics of LDPE whose parameters are fitted by the distributions of material functions detected on the strain-controlled rheometer. The penalty finite element model of polymer melts flowing through out of the extrusion die is derived. A decoupled method is employed to solve the viscoelastic flow problem with the discrete elastic-viscous split-stress algorithm. The simulated results are selected and extracted to constitute the learning samples according to the orthogonal experimental design method. The back propagation algorithm is adopted for the training and the establishment of the predicting model for the optimization objective. A Pareto-optimal set for the constrained multi-objective optimization is obtained using the constrained NSGA-II, and the optimal solution is extracted based on the fuzzy set theory. The optimization for die parameters in the annular extrusion process of low-density polyethylene is performed and the optimization objective is successfully achieved.     

KEY TECHNIQUES IN R＆D OF OUT-SIZE EXTRUSION PRESS WITH OIL-DRIVEN DOUBLE ACTION

A modern design method,in which traditional design formulas are conjoined with numerical simulation and optimization,is successfully used to design the out-size extrusion frame precisely so that the press cost can be saved. A new technology used for decompressing by a multi-steps dynamical mode is put forward,which makes it possible to decompress the large flow-volume high-pressure oil in the main cylinders. In addition,a method for realizing the fixed mandrel process by hydraulic support is proposed and its control equation is established. Pre-tightening frame tests are carried out by over-operating pressure on 100 MN aluminium extrusion press with oil-driven double action,which is developed based on the above key techniques and is the largest press so far in the world,and the results show that the frame structure designed is reasonable and reliable,and the modern design method used is an useful tool for designing large and out-size heavy plastic forming machinery. The results of decompressing curve in main cylinder and noise inspection indicate that multi-steps dynamical mode for decompressing the large flow-volume high pressure oil is valid and reliable. Meanwhile,the fixed mandrel process is well realized based on the control equation. These key techniques have been used in the development of 125 MN aluminium extrusion press with oil-driven double action.     

KEY TECHNIQUES IN R&D OF OUT-SIZE EXTRUSION PRESS WITH OIL-DRIVEN DOUBLE ACTION

A modern design method, in which traditional design formulas are conjoined with numerical simulation and optimization, is successfully used to design the out-size extrusion frame precisely so that the press cost can be saved. A new technology used for decompressing by a multi-steps dynamical mode is put forward, which makes it possible to decompress the large flow-volume high-pressure oil in the main cylinders. In addition, a method for realizing the fixed mandrel process by hydraulic support is proposed and its control equation is established. Pre-tightening frame tests are carried out by over-operating pressure on 100 MN aluminium extrusion press with oil-driven double action, which is developed based on the above key techniques and is the largest press so far in the world, and the results show that the frame structure designed is reasonable and reliable, and the modem design method used is an useful tool for designing large and out-size heavy plastic forming machinery. The results of decompressing curve in main cylinder and noise inspection indicate that multi-steps dynamical mode for decompressing the large flow-volume high pressure oil is valid and reliable. Meanwhile, the fixed mandrel process is well realized based on the control equation. These key techniques have been used in the development of 125 MN aluminium extrusion press with oil-driven double action.     

转向节疲劳性能与减振器阻尼关系研究

为探明减振器阻尼系数对转向节疲劳寿命的影响规律,以某紧凑型SUV为研究对象,通过对转向节模态分析与测试,建立其柔性体模型与疲劳仿真分析模型;以实车参数建立了整车刚柔耦合多体动力学模型,并以试验场强化路实车采集的轮心六分力和转向节监测点应变信号为基础,应用虚拟迭代法仿真获取了转向节载荷-时间历程(模态位移);应用模态应力恢复法运算分析了减振器在不同阻尼系数条件下转向节的疲劳寿命,探讨了二者的相互关系。研究表明,在兼顾整车舒适性与安全性的阻尼系数范围内,随减振器阻尼系数增大,转向节疲劳寿命先增后减,即影响其疲劳寿命的主要区域损伤面积先减后增,而影响转向节疲劳寿命的次要区域损伤面积始终随着减振器阻尼系数的增大而增大。     

现代冷挤压成形技术研究与应用

现代冷挤压技术已经从传统的冷挤压成形基本方法发展成复合挤压、复动挤压、闭塞挤压、分流挤压、控制流动挤压等多种形式,分别阐述了各种冷挤压新技术的成形原理、成形特点和基本方法,并对现代冷挤压模具也作了必要的论述。并根据冷挤压成形特点,对传统的冷成形与新技术成形特点与原理以及传统模具结构与现代模具结构等做了较详细的分析。     

基于多向挤压的超长异形轴径向挤压工艺研究

传统锻压方法成形阶梯轴,多采用轴向正挤压方法,所加工轴的长度受水压机开口高度的限制。为此,本文基于多向挤压技术提出了阶梯轴径向挤压成形方法,来加工“超长”阶梯轴,并通过数值模拟的方法对新工艺与传统工艺进行了比较,其优势为可以实现采用小吨位水压机加工“超长”异形阶梯轴;可以有效减小毛坯轴的轴肩过度体积,减少材料浪费。     

弹体温成形工艺改进的研究

针对弹体温成形实际生产过程中模具寿命低及壁厚差大的问题,通过对温成形工艺参数的分析,提出弹体温成形过程的改进方案,即在温挤压工步之前增加预成形工步,在温挤压工步之后增加变薄拉深工步.经对改进工艺的计算机模拟及实验验证表明,此改进的工艺能够减小壁厚差,降低凸模温升,延长凸模寿命.     

花键管挤压成形研究

分析了冷挤压成形花键管的可行性，包括挤压成形的力学计算、摩擦力分析和模具的初步设计。应用模拟分析软件，根据初步的设计结果，模拟花键管冷挤压成形的挤压变形过程，受力状况及应力分布。并根据模拟结果适当改进模具结构。最终进行模具的设计加工和表面磷化皂化处理，有效减小挤压加工过程中的摩擦，在压力机上完成花键管的挤压成形。     

基于离合器转向的AGV及路径跟踪控制器设计

介绍了一种基于离合器转向的新型AGV的总体结构、转向控制方式、路径跟踪控制系统硬件组成和控制软件流程;分析了转向力矩的形成原理;研究了用于路径跟踪的增量式PID控制器设计方法,确定了输入量和控制器算法,试验选择了控制器参数。