新的嵌套排样算法

以多边形定点算法原理为基础，得出了新的嵌套求解算法成功解决了优化排样问题。并以C语言程序设计为基础，使算法在计算机上得以实现。     

一种基于四叉树结构的排料算法

提出了一种利用四叉树结构来描述矩形物体排料过程的算法。为了确保排料布局的合理性，满足工业上的一刀切要求，需采用组合规则和邻接规则来合成矩形块，这样做还可减少废料碎片、降低算法复杂度、提高板材利用率。     

一种实用钣金CAD排样算法

将人工智能领域中的遗传算法和模拟退火算法相结合,成功地应用到LFB算法中,利用遗传模拟退火混合算法的全局优化搜索能力,得到了较LFB算法更优的排样结果。同时对混合算法中的几个影响参数进行了简单的讨论,为钣金件排样系统的开发提供一种实用的算法。     

Joint modelling of obstacle induced and mesoscale changes—Current limits and challenges

Obstacles considerably influence boundary layer processes. Their influences have been included in mesoscale models (MeM) for a long time. Methods used to parameterise obstacle effects in a MeM are summarised in this paper using results of the mesoscale model METRAS as examples. Besides the parameterisation of obstacle influences it is also possible to use a joint modelling approach to describe obstacle induced and mesoscale changes. Three different methods may be used for joint modelling approaches: The first method is a time-slice approach, where steady basic state profiles are used in an obstacle resolving microscale model (MiM, example model MITRAS) and diurnal cycles are derived by joining steady-state MITRAS results. The second joint modelling approach is one-way nesting, where the MeM results are used to initialise the MiM and to drive the boundary values of the MiM dependent on time. The third joint modelling approach is to apply multi-scale models or two-way nesting approaches, which include feedbacks from the MiM to the MeM. The advantages and disadvantages of the different approaches and remaining problems with joint Reynolds-averaged Navier-Stokes modelling approaches are summarised in the paper.     

Optimal packing using the multiple mating method

A new method for the solution of the packing problem is presented. The method introduces a mating concept to the problem. The mating allows one or more objects to be positioned relative to the other by applying mating conditions that are derived from the geometric features among them. Once mated, objects within a mating pair or a mating group are treated as one object and do not need to be positioned separately. In addition, overlap calculation among objects within the mating group is not necessary. The algorithm thus brings a significant reduction in search space and the overall time taken to converge.     

集聚区牵伸倍数对紧密纱质量的影响

为了探讨紧密纺集聚区牵伸倍数对成纱质量的影响,在自行改造的EJM128K-SM型细纱机上进行了纺纱试验.集聚区牵伸倍数采用1.03倍～1.10倍,测试了CJ 14.6 tex紧密纱的毛羽、强伸性能及条干均匀度指标.结果表明:集聚区牵伸倍数对成纱质量有影响,随着集聚区牵伸倍数增大,紧密纱毛羽增多;集聚区牵伸倍数过大或过小,紧密纱断裂强力、强力CV、断裂伸长率等强伸性能指标较差,成纱条干均匀度也会有轻微的恶化.综合分析,纺CJ 14.6 tex紧密纱,集聚区牵伸倍数以1.05倍为宜.     

基于嵌套问题的半圆轴瓦单元化装箱设计与容器选择

针对工厂不规则形状工件单元化装箱与搬运的实际需要,以汽车与发动机行业常见的内凹形状的半圆轴瓦为代表,研究它的单元化装箱和最终标准容器的选择,提出半圆轴瓦等同件装箱过程中的特殊嵌套问题.这一嵌套问题不同于常见的平面下料嵌套问题,是将三维物体简化为二维问题来考虑,既有嵌套,也有装箱.分析嵌套柱形成的几何关系,将嵌套柱看作长...     

Multiple Translational Containment Part I: An Approximate Algorithm

We present an algorithm for finding a solution to the two-dimensional translational approximate multiple containment problem: find translations for k polygons which place them inside a polygonal container so that no point of any polygon is more than 2ε inside of the boundary of any other polygon. The polygons and container may be nonconvex. The value of ε is an input to the algorithm. In industrial applications the containment solution acts as a guide to a machine cutting out polygonal shapes from a sheet of material. If ε is chosen to be a fraction of the cutter's accuracy, then the solution to the approximate containment problem is sufficient for industrial purposes. Given a containment problem, we characterize its solution and create a collection of containment subproblems from this characterization. We solve each subproblem by first restricting certain two-dimensional configuration spaces until a steady state is reached, and then testing for a solution inside the configuration spaces. If necessary, we subdivide the configuration spaces to generate new subproblems. The running time of our algorithm is , where s is the largest number of vertices of any polygon generated by a restriction operation. In the worst case s can be exponential in the size of the input, but, in practice, it is usually not more than quadratic. Received June 24, 1994; revised August 22, 1995.     

基于光固化法的嵌套器件的工艺研究

简述了合理添加支撑结构的方法,并分析了成型表面粗糙的原因,提出了提高面型精度和避免飘移的多种措施,为嵌套类复杂器件的光固化加工提供了参考。     

集聚区牵伸倍数对紧密纱综合性能的影响

探讨紧密纺集聚区牵伸倍数对不同线密度紧密纱综合性能的影响.通过改变牵伸胶辊、输出胶辊直径的大小,来改变集聚区的牵伸倍数,然后纺制不同线密度的精梳紧密纱,测试其成纱性能.结果表明:当集聚区牵伸倍数为1.07倍时,CJ 27.8 tex和CJ 18.2 tex纱的综合性能较好;当集聚区牵伸倍数为1.05倍时,CJ 9.7 tex和CJ 7.3 tex纱的综合性能较好.