By analyzing the structural characteristics of solid flange, the multi-objective optimization analysis of cold extrusion forming of solid flange was carried out using finite element simulation and the combination of response surface algorithm and NSGA-Ⅱalgorithm. DEFORM-3D finite element simulation software was used to analyze the damage and load of solid flange forming process. Three process parameters of friction factor, the radius of concave die fillet and extrusion speed were selected as the influencing factors, and damage value and load force were selected as the optimization objectives. Simulation was carried out by designing response surface test. Combined with genetic algorithm NSGA-Ⅱ, the multi-objective optimization was carried out, and the optimization solutions were simulated and compared. The error of target value is within a reasonable range. The final results of process parameter optimization are the extrusion speed of 1.46 mm·s -1 , the friction factor of 0.05, and the radius of concave die fillet of 8.00 mm. The simulation test with the optimized parameters was carried out. The results show that the maximum forming load of flange is reduced from 100 kN to 50.9 kN, the damage value is reduced from 1.29 to 0.70, and the forming quality of workpiece is improved.

In the forming process of junction box, in order to understand the influences of different factors on the forming quality of junction box and obtain the optimal forming parameters, the finite element model was established by Dynaform, and combining with Design-Expert software to design the response surface test, and a polynomial regression response model for maximum thinning rate and maximum thickening rate was obtained by experiments. Then, the influence degrees of virtual blank holder force, die clearance and friction coefficient on the maximum thinning rate and the maximum thickening rate of workpiece were further determined, and the maximum thinning rate and the maximum thickening rate were optimized and solved by the non-dominated sorting genetic algorithm with elitist strategy（NSGA-II）to obtain the optimal process parameters as the blank holder force of 21400 N, the die clearance of 1.25 mm and the friction coefficient of 0.08. Simulation experiments were conducted by Dynaform, and the results were validated in the actual production. The study result provides a theoretical basis for the actual production of junction box.

The stamping forming quality of high strength steel is poor at ambient temperature, which easily causes defects such as wrinkle, crack and springback. This article aimed at the defects in automotive rocker arm parts and proposed a multi-objective optimization scheme. The parameters of the drawing process are optimized by finite element simulation of parts. The variable blank holder force model was introduced, and the response surface multi-objective optimization functions between process parameters with maximum springback displacement and maximum thinning ratio were constructed by B-Benhnken test. The objective functions were solved by a non-dominated sorting genetic algorithm with elite hierarchy (NSGA-II), and the Pareto optimal solution set of optimization problem was obtained. The optimal solution results were numerically simulated, and qualified parts with good formation were obtained in trial production, which verified the feasibility of the multi-objective optimization scheme.

将研制的高分子润滑剂在45钢基体表面进行涂覆,通过有限元与实际试验测试润滑剂的实用效果,并利用摩擦磨损试验与扫描电子显微镜表征其摩擦特性,结果表明所制备的高分子润滑剂摩擦系数最小,润滑性能好.利用DeForm-3D软件确定环压试验的理论校准曲线,与实际环压试验结果进行对比,分析高分子润滑剂的摩擦行为,结果表明润滑剂与模具基体发生以物理吸附为主的黏合现象,润滑剂的保护作用有效减少了模具零件之间的摩擦磨损,延长了模具的使用寿命,为更好地指导实践生产提供了借鉴.

In order to improve the lubrication performance of polytetrafluoroethylene (PTFE) coating. Modified graphene (RGO) was prepared by Hummers method and ion modification method. RGO/PTFE composites were prepared by solvent-assisted blending. The surface morphology and microstructure of RGO, PTFE and composites with different concentrations were characterized and analyzed by scanning electron microscopy (SEM), Raman spectroscopy (XRD) and X-ray diffraction (XRD). The tribological properties of RGO, PTFE and composite coatings based on 45# steel were studied by ball-disk friction tests. The wear marks were characterized by scanning electron microscope (SEM), energy dispersive instrument (EDS) and 3D profiler. The results show that 5 wt% RGO/ PTFE composite has lower friction coefficient and the best wear resistance. The friction coefficient of the composite is as low as 0.11, which is 37% and 51% lower than that of single-component RGO and PTFE, respectively. The wear resistance of the composite is 155.8% higher than that of single-component RGO and PTFE. The formulations of lubricating coatings in this paper are independently developed and have excellent antiwear effects. The synergistic mechanism of RGO and PTFE is proposed to explain the improvement of friction properties of composite coatings.

以聚四氟乙烯(PTFE)乳液为主要润滑成分,通过辅助添加剂制备了新型复合高分子水基润滑剂,并进行均匀设计试验获得最优的成分配比.基于Deform有限元模拟镦粗试验探究润滑剂的摩擦行为,通过SEM和EDS表征方法研究润滑机理,发现润滑性能的提高是由于PTFE在基体表面形成了一层转移膜,h-BN吸附在基底表面保护了PTFE膜而有效降低了基体表面阻力,提高了润滑剂的润滑性能,此润滑剂可用于冷挤压成形的润滑.

针对灰斗车拉深成形过程中产生的缺陷问题,基于图像方法对试样进行单向拉伸试验,获得材料真实力学性能参数.借助Dynaform软件对成形过程进行数值模拟,以冲压速度v、 压边力F和摩擦因数C作为影响板料成形质量的因素,以最大减薄率y1和最大增厚率y2作为优化目标,采用Box-Behnken(BBD)设计响应面试验,建立工艺参数与y1、y2之间的二次多项式响应目标函数,得到影响灰斗车拉深成形质量的最优工艺参数组合.最后,通过数值模拟及实际生产进行验证,试验结果表明,该方案有效提高了灰斗车零件的成形质量,消除了灰斗车成形缺陷,为此类拉深件的缺陷优化提供了有效参考.

以压力容器上封头零件为例,通过对零件成形工艺进行分析,以板料最大减薄率为优化目标,基于正交试验,结合灰色关联理论分析和响应面中心复合设计方法,利用Dynaform软件研究了压边力X1、摩擦因数X2、冲压速度X3以及模具间隙X4对封头零件成形质量的影响,得到最优工艺参数为压边力154.8 kN,摩擦因素0.15,模具间隙3.15 mm,冲压速度1000 mm· s-1,此时最大减薄率为7.960％.使用超声波测厚仪测量实体零件不同侧壁位置处的实际减薄率,发现其模拟值与实际值误差分别为0.026％、0.109％和0.236％,结果表明,在工程允许范围内,有限元模拟具有一定可行性,采用该方案生产的实体零件与数值模拟得到的结果相差不大,零件成形质量良好,可进一步指导零件实际生产.

以6016铝合金散热壳体为研究对象,通过分析零件的成形工艺,确定采用Dynaform软件对零件的拉深成形工艺进行有限元模拟,以零件的最大减薄率为评价其成形质量的指标.基于正交试验设计,研究了压边力、摩擦因数、冲压速度以及模具间隙对零件成形质量的影响规律.基于灰色系统(GS)理论分析出与零件最大减薄率关联度较高的工艺参数,并通过响应面法(RAM)进行中心复合设计(CCD),得到最优的工艺参数组合为:压边力为20.1 kN、摩擦因数为0.16、冲压速度为1500 mm·s-1、模具间隙为1.05 mm,零件最大减薄率为23.029％.将采用该方案制得的实体零件与数值模拟结果进行对比和分析,结果表明数值模拟分析结果具有可靠性,可为散热装置零件的成形提供一定指导.

为延长零件使用寿命,降低生产成本,在45钢表面激光熔覆Ni60熔覆层可以达到生产要求,避免资源浪费,实现绿色制造.通过层次分析法确定权重,建立三水平三因素的正交试验,分析熔覆层的宏观和微观形貌、摩擦磨损特性、显微硬度.结果表明:优化后的工艺参数为激光功率3 kW,扫描速度12 mm/s,搭接率45％.合适的工艺参数可以使组织晶粒得到细化,避免裂纹和气孔的产生.优化工艺参数得到的涂层耐磨性更好,摩擦因数比基体低,磨损失重比基体少,磨损机制为磨粒磨损,硬度为基体的3倍.

为解决板料弯曲成形多目标优化问题,提出一种基于响应面法和数学算法结合的多目标优化方法.以汽车C柱零件弯曲成形为例,以冲压速度、压料力和摩擦系数作为影响零件成形质量的因素,以最大减薄率和最大回弹位移量作为优化目标,应用Box-Benhnken设计响应面试验,通过Dynaform模拟获得样本数据,得到关于最大减薄率和最大回弹位移的多项式回归响应模型.然后,结合遗传算法对多目标优化函数进行优化求解.根据带精英策略的改进型非支配排序遗传算法(NSGA-Ⅱ)得到Pareto最优解集.回弹位移量随减薄率的增大而减小,选取最优工艺参数组合,取整得到多目标优化结果,即虚拟冲压速度为546 mm·s-1,压料力为41.67 kN,摩擦系数为0.15.对所取最优工艺参数进行仿真验证和实际试模生产,试模后的零件成形质量良好,为回弹补偿提供了有效的优化方案.

It is important to model the flow behavior of an aged aluminum alloy AA6082 as an extrusion material before design and optimize of the forming process. In this study, the isothermal compression tests were carried out on Gleeble-3800 thermal simulator in the temperature range of 423-773 K and the deformation condition of 0.01-1.0 s(-1) to study the cold temperature and hot deformation behavior of aluminum alloy AA6082. Considering the experimental error, the discussion based on friction and temperature correction is carried out. According to the modified data, based on the traditional Arrhenius constitutive model, a method combining the strain compensation Arrhenius model and PSO-BP neural network was proposed to describe the flow behavior of aluminum alloy AA6082. The prediction ability and stability of the model are evaluated by using the linear correlation coefficient(r), the average relative errors (AARE), the Root mean square errors(RMSE) and the relative errors (RE) in statistical analysis. The results show that the 3-10-8-1 double hidden layer neural network model based on PSO-BP has higher effect in predicting the flow characteristics of aging aluminum alloy AA6082 than that of Arrhenius model based on strain compensation. The linear correlation coefficient, mean relative error and root mean square error are 0.9996 %, 2.001 % and 1.665 MPa respectively.

在汽车油箱托盘拉深成形过程中,以压边力x1、冲压速度x2、摩擦系数x3和模具间隙x4作为汽车油箱托盘拉深成形质量的影响因素,以板料的最大减薄率y1和最大增厚率y2作为仿真优化目标,通过设计响应面试验,基于DYNAFORM软件进行仿真模拟,获得样本数据,得到最大减薄率y1和最大增厚率y2的多项式回归响应模型,结合带精英策略的非支配排序遗传算法NSGA-Ⅱ对多目标优化函数进行优化求解.工艺参数优化结果为:压边力73 kN,冲压速度1 m·s-1,摩擦系数0.15,模具间隙1.575 mm,采用优化的工艺参数进行仿真试验,结果表明,成形件质量得到改善.

针对某车型的后备箱盖板拉延成形时出现的破裂和起皱现象,首先,基于DYNAFORM建立后备箱盖板的有限元模型;其次,探究压边力x1、拉延筋1的阻力x2和拉延筋2的阻力x3对后备箱盖板拉延成形的综合影响,建立中心复合试验设计(CCD)方案,通过中心复合试验设计方案构建了影响成形的工艺参数的二阶响应面法(RSM)模型,以板料的最大减薄率y1和最大成形力y2为优化目标,建立多目标优化函数;运用改良型的遗传算法(GA)进行模型寻优,获得影响后备箱盖板成形的最佳工艺参数组合,即x1=520.05 kN,x2 =80.03 N·mm,x3 =82.18 N.mm;最后,对最佳工艺参数组合进行试验验证,试验结果表明,提出的方法可有效地提高汽车后备箱盖板的成形质量,同时对类似覆盖件的成形质量控制具有一定的指导意义.

利用有限元分析软件DYNAFORM对一种浅拉深、大尺寸电机盖板零件进行冲压成形数值模拟试验,研究各主要工艺参数及拉延筋对拉延成形质量的影响,并分析缺陷产生的原因.采用正交试验和综合分析法进一步优化工艺参数,以减少板料成形过程中出现的破裂、起皱和拉深不充分缺陷.研究表明,通过合理布置拉延筋及优化工艺参数,可以有效提升拉延成形质量.最终得到的最优工艺参数组合为:拉延筋阻力系数50％、压边力600 kN、摩擦因数0.16、冲压速度5000 mm/s、凸凹模间隙1.1t,通过模拟试验验证该工艺参数组合的准确性和有效性.

以铝合金蓄能器壳体冷挤压为例,针对实际生产中筒壁存在缺陷现象,基于有限元软件DEFORM-3D和响应面法与多目标优化的NSGA-Ⅱ相结合的方法对此进行多目标优化分析.首先将AA6061铝合金棒料进行室温拉伸实验获得应力应变数据,导入DEFORM-3D构建FEM模型.其次以凸模工作部分过渡圆角(X1)、挤压速度(X2)、摩擦系数(X3)为优化变量建立关于挤压载荷(Y1)和壳体零件表面损伤度(Y2)的数学模型,方差结果表明:模型精度较高能很好的描述2个优化目标对设计变量的响应,同时由3D响应面图可以直观分析挤压载荷与零件表面损伤度关于响应变量之间存在一定冲突性.为解决冲突,采用NAGA-Ⅱ进行多目标优化,得到一组Pareto最优解;进而得到挤压成形合理的工艺参数范围:X1为0.64～0.68 mm,X2为5.8～6.2 mm/s,X3=0.1.最后选用一组较优参数组合进行试验验证,结果表明工件成形性能与质量良好,仿真结果与试验结果具有较好的可靠性.

为提高燃气灶外壳零件的成型质量和安全性能,课题组基于DYNAFORM建立燃气灶外壳的有限元模型并完成优化模拟.以圆角半径A、压边力B和模具间隙C作为影响零件成形质量因素,以最大减薄率y1和最大增厚率y2作为优化目标,应用Box-Benhnken(BBD)设计响应面(RSM)试验;采用DYNAFORM6.0有限元软件模拟试验并获得样本数据,得到y1与y2的多项式回归响应模型;结合遗传算法对多目标优化函数进行优化求解,根据带精英策略的改进型非支配排序遗传算法(NSGA-Ⅱ)获得优化后Pareto最优解集.最后选取了最优工艺参数组合:取整得到A为13 mm,B为335 kN,C为0.84 mm.根据NSGA-Ⅱ预测结果y1为23.32％,y2为2.80％,经数值模拟验证,最大减薄率和最大增厚率分别为23.39％和2.96％,因此试验结果和预测结果误差低至0.3％.文中采用的零件成形质量多目标优化方法准确度高,为提高同类外壳零件的成形质量提供一种有效的优化方案.

U形件弯曲成形过程中比较突出的问题是回弹,通过将响应面法(RSM)与有限元仿真软件Dynaform相互结合,基于NUMISHEET'93的U形弯曲标准考题,将凹模圆角半径选定为Rd=8 mm,以模具间隙、摩擦系数、冲压速度3个参数作为影响因素,竖直方向的回弹位移作为优化目标,建立17组试验方案,对U形件弯曲成形过程进行仿真模拟.借助Design-Expert 8.1对17组数据进行拟合处理,得到关于优化目标的二次非线性回归方程与优化的参数组合,即模具间隙为1 mm、摩擦系数为0.15、冲压速度为800 mm·s-1.优化的参数组合代入有限元软件再次仿真得到回弹位移为0.731 mm,其与方程拟合值0.738 mm相差约1％,并在前人研究基础上将回弹位移进一步减少了26.2％,最后进行了实物弯曲验证.RSM与Dynaform的结合减少了有限元模拟的次数,有效地提高了板料弯曲的成形精度与质量.

针对某企业冷挤压生产20MnCr5花键轴齿部挤出长度难确定以及镦粗部位尺寸不合格问题,提出坯料结构尺寸优化方法.首先,利用Gleeble 3800对退火软化处理后的材料进行冷压缩试验,获取材料的力学性能曲线,再结合数值模拟软件DEFORM-3D,根据花键轴齿部以及镦粗部位的成形缺陷对预制坯结构尺寸进行优化设计,选取预制坯小径部位长度、预制坯小径部位直径和预制坯过渡区锥角为主要影响因子,以零件的齿部成形长度为约束条件,齿部实际成形长度与目标长度差的绝对值为优化目标,建立9组正交试验方案.将优化的预制坯用于生产试制,即预制坯小径部位长度为158.5 mm、直径为Φ18 mm、过渡区锥角为12°,得到了满足生产要求的花键轴零件.

对带凸缘圆筒件拉深成形工艺进行有限元模拟,以压边力、摩擦因数、冲压速度和模具间隙为影响因素,零件减薄率为质量参考指标,设计正交试验方案.根据灰色系统(GS)理论计算结果,通过响应面法(RSM)进一步优化工艺参数,得到最优工艺参数组合为:压边力5.2 kN,冲压速度4 000 mm/s,摩擦因数0).1,模具间隙2.16 mm.模拟结果显示圆筒件减薄率为22.94％,增厚率为6.83％,该优化方案可为拉深件实际生产提供参考.