R-PVC透明片材挤出机头的结构及应用技术

介绍了R—PVC片材采用衣架式挤出成型的机头结构特征，阐述了材料选择、流道分析、加工要点和装卸、维护方面的技术问题，并提出了解决方法。     

内衬层生产线挤出机机头流道有限元分析

建立挤出机头的三维有限元模型,采用ANSYS有限元分析软件对内衬层挤出压延生产线挤出机头流道进行模拟和分析,得到在一定工艺条件下机头内部流道的流场分布情况并分析其原因。为今后挤出机流通的优化设计提供一定的理论依据。     

基于ANSYS的进料加速器的流场分析

在钻井液离心分离过程中,螺旋推料器是推料分离的关键部件,其内部喂料腔对物料的加速及扩散性能直接关系到离心机的生产能力及分离效果。本文对卧式螺旋卸料的钻井液离心机进行了优化设计,对喂料腔进行改进设计,并初步设计了喂料加速叶片,通过对比分析,确定了圆柱叶片对物料的加速及扩散效果更佳。     

分段多点成形过程有限元数值模拟关键技术研究

分段多点成形是一种新的大型板材成形方法，对该成形过程进行数值模拟是预测成形缺陷、分析成形质量的有效手段。提出利用动力显式算法分析板料成形过程，利用静力隐式算法分析回弹过程，从而为分段多点成形过程的多工步数值模拟提供了一个可行的解决方案。对其中的一些关键技术的实现进行了研究，提出了相应的解决方法并通过实例证实了其有效性。     

基于流场仿真的多路阀流道结构优化

采用流体仿真软件对多路换向阀的桥路进行流场仿真,并通过速度场和压力场的对比,指出了多路阀桥路流道结构的优化方向和优化结果.仿真结果表明,在桥路结构转折处采用圆弧过渡,能够大大减少压力损失、平缓流场,为液压元件流道结构设计提供了一种工程设计的新途径,具有广阔的应用前景.     

基于流场仿真的多路阀流道结构优化设计

采用流体仿真软件对多路换向阀的桥路进行流场仿真,并通过速度场和压力场的对比指出了桥路流道优化方向和优化结果,为液压元件流道结构设计提供了一种工程设计的新途径.     

组合机床多轴箱中间箱体的有限元模态分析

以组合机床多轴箱中间箱体为研究对象,运用Pro/E三维建模软件建立了多轴箱中间箱体的实体模型并导入ANSYS软件,在网格划分时采用智能网格划分方法,得到理想的有限元分析模型。最后利用Block Lanczos方法进行多轴箱中间箱体结构模态分析。模态分析结果对多轴箱中间箱体的设计和改进具有一定的意义。     

多点成形基本体群曲面造型的有限元方法

基本体群成形曲面的生成是多点成形技术中十分重要的问题之一。给出基于１８自由度三角形单元描述的连续的目标形状曲面,通过接触点计算确定基本体行程从而构造出成形曲面的方法。对规则曲面的数值计算表明,该方法的计算结果具有很高的精度。     

循环链码多点模拟载荷检验装置

皮带秤检验是为了维护皮带秤在日常使用中的准确度,众多循环链码的生产厂家生产的循环链码只能检验皮带秤的一个使用点,循环链码多点模拟载荷检验装置是根据用户的需求可设计检验两个检验点或三个检验点(即40%、80%或30%、60%、90%;)两点检验装置在广东省台山电厂使用了4台套,现场测试结果的稳定性、重复性和线性度均在允许误差范围内。     

基于无线通信的点对多点温度传感器网络

介绍了一种基于"一线总线"数字化温度传感器DS18820和工作于2.4 GHz ISM频段射频收发芯片nRF2401AG点对多点温度传感器网络的设计方案.分析了点对多点无线通信模型的结构原理及其特点,设计了基于突发传输模式的点对多点双向无线通信协议.并以AT89LV51和AT89C2051为核心,给出了该系统软件控制过程和硬件电路设计.实践表明:该系统测温精度高、使用方便、抗电磁干扰能力强、数据通信稳定性高、成本低,可以广泛用于各种电力系统设备多点测温.     

ANSYS/LS-DYNA在热镀锌板拉深成形中的应用

根据连续介质力学及有限元理论,运用动力显式算法建立有限元模型,利用ANSYS/LS-DYNA软件模拟镀锌薄板的拉深过程,分别采用不同的界面结合力进行拉深过程模拟,确定板料和镀锌层的界面结合力,并对钢板和镀锌层的应力结果进行比较分析,所得结果可为生产实际提供指导.     

Finite-element simulation of hole-flanging process of circular sheets of anisotropic materials

A hole-flanging operation on a flat circular sheet with a hole in the center is simulated by an incremental elasto-plastic finite-element method, which incorporates strain-hardening and anisotropy in the direction normal to the sheet, with care taken to describe the boundary conditions of penetration, separation and the alternation of the sliding—sticking state of friction. The simulation clearly demonstrates the processes of generation of deformation shape until unloading. The calculated sheet geometries and the relationship of punch load to punch stroke are in good agreement with the experimental data.The stress at the hole periphery in the flange is assumed to a state of circumferential uniaxial tension, in order to simplify the fracture mode as a simple tension test. By making use of the instability of uniaxial tension, an approximate relationship to determine the onset of necking of the hole periphery in the hole-flanging process is derived and it is found to be influenced by the process geometry and the plastic properties of the material, such as the stress-concentration factor K, strain-hardening n and normal anisotropy R, and the estimated value, being obtained by the derived equation, agrees well with the experimental data.It is noted that the derived relationship for estimating the instability of the hole-flanging process can be combined into the developed finite-element model to simulate the critical condition of the limiting deformation of the hole-flanging process. This combined method could possibly be applied towards improving both the manufacturing process and the design of tools for the hole-flanging operation.     

Measurement of properties of graphene sheets subjected to drilling operation using computer simulation

Drilling being one of the primary machining processes find wide spread applications in manufacturing of functional components. Optimization of drilling process performance requires critical understanding of process parameters which govern the mechanism of drilling process. Machining process at nanoscale level has been studied extensively using numerical modeling approaches owing to complexity in conducting experiments at nanoscale level. In this paper, we propose a new evolutionary approach based on multi-gene genetic programming (MGGP) to numerically model the drilling process of graphene sheet, a two dimensional nanoscale material. The performance of our proposed MGGP model is compared with that of the artificial neural network (ANN) and we observe that our predictions are well in agreement with the data obtained using conventional numerical approach for modeling machining process of nanoscale materials. We anticipate that our proposed MGGP model can find applications in optimizing the machining processes of nanoscale materials.     

挤压设备的液体定量

在一些不同的作业过程中,除松散物料之外,液体也经常定量.为了精确地保持配方,重要的是精确定量的液体量.所说的液体量是对配料过程时预先确定的(kg),或是对连续过程时预先确定的(kg/h).     

基于PLC的挤出机控制系统设计

通过对双螺杆挤出机工作过程的分析,设计出利用Siemens S7-200系列PLC结合变频器构成的双螺枰挤出机控制系统,实现了挤出机电机的无级调速控制以及料筒恒温控制.     

挤出机螺杆的参数化设计

在AutoCAD2004平台上,用Visual LISP语言开发了挤出机螺杆的CAD程序,用对话框控制语言(DCL)编制了螺杆参数输入对话框。使用该方法可以方便、快捷地设计挤出机螺杆。     

宽谐振区光学纳米天线的谐振

提出了一种有双谐振频率和较宽谐振区域的纳米天线结构.利用有限积分法,计算了由金构成的表面等离子体光学纳米天线的谐振特性,研究了在谐振区域内谐振频率和谐振电场随位置变化的情况.结果表明,在不同谐振频率下存在两个谐振电场,在中间区域,谐振频率为270 THz,在侧边间隙区,谐振频率为390 THz;激励源为1 V/m时,其谐振电场均达700 V/m以上,是普通偶极子天线的18倍;第一谐振区域的谐振场集中在10～25 nm,在此范围内,谐振电场较大、谐振频率几乎不变;加上折射率为1.5的玻璃衬底后,天线的谐振电场达到800 V/m,与没有衬底时相比,谐振频率变化很小.研究的天线结构在高性能的光学纳米天线、太阳能电池和生物传感器方面有潜在的应用价值.     

Constitutive law for AZ31B Mg alloy sheets and finite element simulation for three-point bending

The constitutive law to describe the anisotropic and asymmetric mechanical behavior of AZ31B magnesium (Mg) alloy sheets at room temperature has been developed here for the plane stress condition, based on the orthotropic yield criterion proposed by Cazacu O, Plunkett B, Barlat F. [Orthotropic yield criterion for hexagonal closed packed metals. International Journal of Plasticity 2006;22:1171–94] and different isotropic hardening laws for tension and compression. Experimental procedures to obtain the material parameters of the yield surface and the hardening laws have been discussed for the AZ31B Mg alloy sheet. For verification purposes, finite element simulation results based on the developed constitutive laws have been compared with experimental results for a three-point bending test.