导电叉多工位级进模设计

分析了导电叉成形工艺,设计了成形该零件的具有冲孔、胀形、切边、弯曲等9个工位的排样方案,进行了多工位级进模结构设计。实践证明:模具结构设计合理,工作效率高,零件质量稳定,具有一定的参考价值。     

外壳拉伸件旋转侧切口模设计

外壳零件拉伸成形后,口部边缘不平整,零件常常需要进行口部修边才能达到要求。本文针对零件成形工艺特点,介绍了旋转侧切口模具结构设计,并重点介绍了旋转侧切机构工作过程,对类似模具结构设计具有一定的参考作用。     

高速列车安装板多工位级进模设计

高速列车安装板外形尺寸为275.3 mm×112.5 mm×29.5 mm,其弯曲部分为不规则Z字形,Z字形结构由2个方孔、1个圆孔和1个腰形孔组成,中间设有1条补强筋。根据安装板结构较为复杂的特点,对其成形工艺进行分析,在此基础上制定了3种冲压方案,经过对比分析,最终确定采用9个工位级进模成形制件,并确定了制件压筋预成形整形的排样方案。依次介绍了安装板模具的整体结构设计、模具预成形结构设计和模具成形工序结构设计。冲压成形工艺试验表明,安装板多工位级进模结构设计合理,其中采用预成形工艺能很好地克服制件回弹问题,满足制件大批量生产的需要。     

长管套类紧固件冷镦成形工艺设计

冷镦成形具有生产效率高、产品一致性好、劳动强度低等特点,在紧固件制造方面应用广泛。冷镦成形工艺设计的合理性,将直接影响制件生产的稳定性和生产效率。以一种长管套类紧固件为例,进行了制件成形工艺设计,结合冷镦工艺过程中镦锻力的计算、各工位工艺变形仿真成形与模具结构设计。     

断路器再扣级进模设计

根据断路器再扣零件的外形结构特点,制定了零件的成形工艺,介绍了成形零件的排样与模具结构设计。生产实践表明,模具结构合理、维修方便,完全满足大批量生产的需求,对类似零件的模具设计具有一定的参考作用。     

Type-C外壳成形工艺及级进模设计

级进模冲压成形是一种高效、高品质的金属板料塑性成形工艺方法。研究了TypeC外壳的成形工艺,详细介绍了级进模排样方案,确定了级进模总体结构和关键工位的详细结构设计。该模具结构设计合理、工作稳定、可靠,可完全保证制件质量,能够满足大批量生产需求。     

级进模成形部位的结构设计

介绍了级进模翻边、弯曲又成形部位的结构设计，并指出了在翻边、弯曲、成形工位的结构设计中应注意的问题，为多工位级进模设计提供了依据．     

扩散器壳拉伸成形模设计

分析了扩散器壳拉伸成形工艺特点,确定了拉伸成形模结构,并简述了该扩散器壳成形模结构设计优点。     

温控开关接触片级进模设计

介绍了温控开关接触片的成形工艺,采用了先局部修边、成形、再修边、再成形的方式,由外向内逐步完成的方案,设计了14个工序完成零件关键位置的弯曲成形,并详细介绍了成形工艺和相关的结构设计,使用侧浮动抽芯,保证反弯曲180°的稳定性,解决了零件成形质量不稳定的状况。实际生产表明,冲压级进模成形工艺方案切实可行,模具结构设计合理,制造装配及维修方便,为类似零件的设计和生产提供了依据。     

固定盖板级进模设计

分析了固定盖板的结构,制定了合理的工艺方案和排样方案,设计了成形零件的多工位级进模,经生产实践验证:模具结构设计合理,工作效率高,零件成形质量达到要求,具有较好的经济效益。     

A study on microreplication of real 3D-shape structures using elastomeric mold: from pure epoxy to composite based on epoxy

In this paper, a new replication technique for a real 3D microstructure was introduced, in which a master pattern was made of photo-curable epoxy using a microstereolithography technology, and then it was transferred onto an epoxy-copper particle composite. A helical gear was selected as one of the real 3D microstructure for this study, and it was replicated from a pure epoxy to an epoxy composite. In addition, the transferability of the microreplication process was evaluated, and the properties of the epoxy composite were compared to that of the pure epoxy, including hardness, wear-resistance and thermal conductivity.     

一种改进的非完整轮式移动机器人轨迹跟踪控制方法

针对非完整约束下移动机器人的轨迹跟踪控制中误差收敛速度和平滑性上存在的不足,提出了一种改进的非线性反推跟踪控制算法。在运动学模型的基础上,构造了简单的虚拟变量推导出了反推控制律,且通过Lyapunov函数证明了该控制律的稳定性,并引入了一个反馈控制律,得到了一种新型轨迹跟踪控制器。MATLAB仿真分析表明:改进的非线性反推控制律很好地改善了控制效果,跟踪误差能在较短的时间内收敛,具有良好的抗干扰能力。     

稀释气体对镁熔体在HFC-134a气氛中高温氧化行为的影响

对镁熔体在HFC-134a/空气混合气体中和HFC-134a/CO2混合气体中的氧化行为进行了比较研究.结果发现,镁熔体在这2种混合气体中的氧化行为存在差异,而且这种差异与HFC-134a的浓度有关.当混合气体中HFC-134a浓度较高时,镁熔体在HFC-134a/CO2混合气体中的氧化速度小于HFC-134a/空气混合气体,差别不是很大;然而,当混合气体中HFC-134a浓度较低时,镁熔体在HFC-134a/CO2混合气体中的氧化速度远小于HFC-134a/空气混合气体中的氧化速度.产生差异的原因可能与氧化膜中MgF2和MgO的相对含量有关,也可能与单质的C含量有关.这一结果表明,在HFC-134a浓度保持不变的情况下,把与HFC-134a混合的稀释气体由空气改变为CO2,可提高混合气体的保护效果,尤其是在HFC-134a浓度较低的情况下.     

Mechanism of improvement of formability in pulsating hydroforming of tubes

The mechanism of improvement of formability by the oscillation of internal pressure in a pulsating hydroforming process of tubes was examined. Free bulging hydroforming experiments of mild steel tubes under oscillating and constant inner pressures were performed. For a high constant pressure, a round bulge with local thinning was observed, whereas wrinkling occurred for a low constant pressure. The occurrence of these defects was prevented by oscillating the internal pressure in the pulsating hydroforming. In the pulsating hydroforming, a uniform expansion in the bulging region was obtained, and thus the formability was improved by preventing the local thinning. It was found from an observation of deformation behaviour, using a video camera, that the tube is uniformly expanded by repeating the appearance and disappearance of small wrinkling. The cause of the uniform expansion for the pulsating hydroforming was also interpreted from the variation of stress components. In addition, a similar deference in deformation behaviour between the oscillating and constant inner pressures was also obtained in finite element simulation.     

板料对向液压成形模拟算法开发及应用

基于BT壳单元和有限元增量理论开发了板料对向液压成形模拟算法,对液体压强所施加的区域进行判定,并对该区域液压力进行计算.将算法集成到自主开发的冲压成形模拟软件FASTAMP中,适用于复杂汽车覆盖件的对向液压成形.以实际生产的汽车覆盖件卡车顶盖为例,采用实际液压加载曲线进行成形分析.针对成形中的折叠和破裂缺陷,对该加载曲线进行优化,工件的成形质量得到提高.模拟结果与实验结果基本相符验证了对向液压成形模拟算法的准确性和实用性.     

影响自适应油源输出量参数的建模与仿真研究

针对某系统的自适应油源液压系统,在分析其结构的基础上,对自适应油源液压系统控制原理进行了数学推导,建立了自适应油源液压系统控制数学模型,绘制了自适应油源控制流程图。利用AMESim仿真软件建立了自适应油源液压系统的仿真模型,仿真了定量元件参数对自适应油源液压系统输出的影响,并对仿真结果进行了分析。仿真结果对自适应油源液压系统故障诊断和系统优化具有很好的参考价值。     

变厚度板带材产品及其深加工

从产品深加工角度,介绍了3类纵向变厚度板的生产方法、用途及其节材效果。差厚板（TRB）通常由单机架四辊冷轧机生产,目前主要用于汽车轻量化;纵向变厚度板（LP）由现代化热轧中厚板轧机生产,主要用于造船、桥梁和建筑;介于二者之间的统称为优化承载变厚度板材（LOP）,可热轧、冷轧或者温轧,其宽度小于LP板,厚度一般大于TRB板,目前及有前景的典型应用有卡车用变断面板簧、局部变壁厚管、锥形管原料等等。     

一种组合添加剂在碱性无氰镀锌中的作用

通过在碱性无氰镀锌溶液中添加一种组合添加剂获得了晶粒尺寸在60nm以内的纳米晶镀锌层,并通过对比有无添加剂时Zn的析出电位、镀锌层微观形貌及晶粒度的差异,分析了组合添加剂中两种组分的作用。结果表明,两种添加剂分别起到细化晶粒和整平作用,二者一起使用有很强的协调作用。     

Numerical simulation of friction stir butt-welding of 6061 aluminum alloy

A two-dimensional computational fluid dynamics model was established to simulate the friction stir butt-welding of 6061 aluminum alloy. The dynamic mesh method was applied in this model to make the tool move forward and rotate in a manner similar to a real tool, and the calculated volumetric source of energy was loaded to establish a similar thermal environment to that used in the experiment. Besides, a small piece of zinc stock was embedded into the workpiece as a trace element. Temperature fields and vector plots were determined using a finite volume method, which was indirectly verified by traditional metallography. The simulation result indicated that the temperature distribution was asymmetric but had a similar tendency on the two sides of the welding line. The maximum temperature on the advancing side was approximately 10 K higher than that on the retreating side. Furthermore, the precise process of material flow behavior in combination with streamtraces was demonstrated by contour maps of the phases. Under the shearing force and forward extrusion pressure, material located in front of the tool tended to move along the tangent direction of the rotating tool. Notably, three whirlpools formed under a special pressure environment around the tool, resulting in a uniform composition distribution.     

狭小空间移动焊接机器人角焊缝跟踪的动力学控制

文中对移动焊接机器人在大型结构件中狭小空间的角焊缝跟踪控制问题进行了研究,首先,建立了焊接机器人在直角角焊缝处的运动学模型;然后,基于牛顿-欧拉方法分析了焊接机器人驱动轮、机器人移动本体及十字滑块的动力学行为,并建立了焊接机器人的整体动力学模型;最后,在对整体动力学模型合理简化的基础上,设计了焊接机器人焊缝跟踪控制的鲁棒PI控制器.应用MATLAB软件进行了仿真分析,并进行了试验研究,通过结果可以看出,该方法可实现移动焊接机器人在狭小空间内直角角焊缝的跟踪,且具有较高的跟踪精度.