Engineering an efficient two‐phase local search algorithm for the co‐rotating twin‐screw extruder configuration problem

The twin‐screw configuration problem arises during polymer extrusion and compounding. It consists in defining the location of a set of pre‐defined screw elements along the screw axis in order to optimize different, typically conflicting objectives. In this paper, we present a simple yet effective stochastic local search (SLS) algorithm for this problem. Our algorithm is based on efficient single‐objective iterative improvement algorithms, which have been developed by studying different neighborhood structures, neighborhood search strategies, and neighborhood restrictions. These algorithms are embedded into a variation of the two‐phase local search framework to tackle various bi‐objective versions of this problem. An experimental comparison with a previously proposed multi‐objective evolutionary algorithm shows that a main advantage of our SLS algorithm is that it converges faster to a high‐quality approximation to the Pareto front.     

滚珠丝杠副加载试验台测控系统设计

一体化工业计算机系统目前在测控领域应用广泛.通过对滚珠丝杠副轴向力加载试验功能分析,拟定了滚珠丝杠副轴向力试验方案,构建了基于一体化工业计算机控制的测控系统,基于虚拟仪器技术平台和LabVIEW编程语言,设计了测控软件.实践验证与测试表明,一体化工业计算机结合虚拟仪器技术平台开发测控系统可以大大降低其软、硬件研发周期.     

Comparison of multiple linear regression and artificial neural network in developing the objective functions of the orthopaedic screws

Optimizing the orthopaedic screws can greatly improve their biomechanical performances. However, a methodical design optimization approach requires a long time to search the best design. Thus, the surrogate objective functions of the orthopaedic screws should be accurately developed. To our knowledge, there is no study to evaluate the strengths and limitations of the surrogate methods in developing the objective functions of the orthopaedic screws. Three-dimensional finite element models for both the tibial locking screws and the spinal pedicle screws were constructed and analyzed. Then, the learning data were prepared according to the arrangement of the Taguchi orthogonal array, and the verification data were selected with use of a randomized selection. Finally, the surrogate objective functions were developed by using either the multiple linear regression or the artificial neural network. The applicability and accuracy of those surrogate methods were evaluated and discussed. The multiple linear regression method could successfully construct the objective function of the tibial locking screws, but it failed to develop the objective function of the spinal pedicle screws. The artificial neural network method showed a greater capacity of prediction in developing the objective functions for the tibial locking screws and the spinal pedicle screws than the multiple linear regression method. The artificial neural network method may be a useful option for developing the objective functions of the orthopaedic screws with a greater structural complexity. The surrogate objective functions of the orthopaedic screws could effectively decrease the time and effort required for the design optimization process.     

4U平行四边形机构的一类新用途——整体设计为两足步行机构

提出了将4U平行四边形机构整体设计为两足步行机构的一类新用途.此类两足步行4U平行四边形机构均由4个构件和4个万向铰组成,能够实现平面运动.根据万向铰布置方式的不同,分为3种构型.在针对构型Ⅰ的前期研究基础之上,应用螺旋理论分析了构型Ⅱ和Ⅲ的自由度,并分别对其进行了运动学分析、步态分析和稳定性分析.此外,还将3种构型的性能与应用作了进一步的分析与比较.运用ADAMS软件建立3种构型的动力学模型,仿真其运动的全过程,验证该类构型及其运动的可行性.制作出2台样机,实现了预期的运动.     

农作物秸秆膨化机加工性能试验研究

利用小型自热式单螺杆挤压膨化机对农作物秸秆进行膨化加工试验。将螺杆螺距,喷嘴出口间隙,秸秆物料含水率,秸物料粒度作为试验因素,经单因素试验和二次通用旋转组合设计试验找出其对秸秆膨化加工性能（膨化压力,生产率,度电量等）的影响规律,并得出最佳参数组合。     

转矩流变仪RC90系统的技术与应用

介绍了转矩流变仪的发展、基本原理和应用。各种混合器、单螺杆挤出机、双螺杆挤出机、模具和后挤出机系统都能与RC90装配。RC90可用于对材料的熔融性能和热稳定性、颜料分散性、交联、固化和硫化性能以及挤出可加工性能等的研究。     

单螺杆挤出机熔体输送区螺棱间隙对熔体停留时间分布的影响

计算了螺棱间隙与熔体在熔体输送区停留时间分布的关系。分析表明：螺棱间隙不仅影响停留时间的量值而且影响其分布，并且这些影响可反映到一个由螺棱间隙几何参数和螺杆几何参数构成的无量纲数的影响中。     

同向双螺杆挤出机的共混技术

本文论述了聚合物共混须用同向双螺杆挤出机的原理、特征及不同物料的共混技术。     

一步法注射螺杆钻具橡胶定子胶料的研制

本文叙述了油田用一步法注射螺杆钻具定子胶料的配方设计.通过对硫化体系及炭黑用量的对比性实验,优选出了既能满足工艺需求又达到了产品性能要求的配方,使产品合格率达到100%.     

系列变螺距螺杆的设计计算

为了使罐头包装机具有柔性加工的功能并提高设备利用率,根据圆柱形罐的螺杆供送机构的原理,设计开发了可调变螺距螺杆供送机构和对应不同罐径的系列变螺距螺杆。根据对罐的运动规律要求,给出了变螺距螺杆结构参数的设计计算方法以及罐的运动规律的计算分析方法。阐明了罐运动规律与螺杆长度、罐直径、螺距、螺距数之间的关系。研究的变螺距螺杆的设计计算及运动规律分析方法适合常用的罐径系列。