基于面-体布尔运算的断层切割矿体三维模型

针对矿体被断层面切割的地质现象,目前三维地质体建模往往是通过相邻地质剖面上的地质体轮廓线按三角网直线方式连接实现,断层面切割矿体的空间形态关系难以正确反映在三维可视化模型中。基于三角网格模型,提出了一种断层面切割矿体三维模型的面-体布尔运算算法。首先对矿体和切割矿体的断层面三角网格进行检测,构建拓扑关系;然后基于相交测试求得交线环;最后提取结果域多边形并进行三角剖分。针对断层面切割矿体形态进行了定量研究,分别定义了"获取断层面上的矿体"和"获取断层面下的矿体"两种切割算子,通过切割组合得到最终的切割结果,该算法避免了传统布尔运算中交线跟踪连接成环和点与多边形的包含测试等运算量较大的操作。以贵州省水银洞金矿床为例,结合地质解译和三维地质建模方法,采用该算法对矿床中与断层相交的矿体进行了切割运算。研究表明:基于布尔运算的断层切割矿体三维模型能够正确反映矿体与断层面之间的吻合关系,为研究断裂与矿化分布之间的定量关系提供了可靠依据。

FOUR-AXIS WIRE-EDM SIMULATION OF COMPLICATED MODELS

In the verification of wire electrical discharge machining （EDM）, the motion and the performance of the wire-EDM system are analyzed. The maximum inclining angle of the wire is calculated. The relevant judgment methods are used for the collision between the wire, the fixture, and the machining table. In the wire-EDM simulation, the generated solid model can he used to investigate programming results and to check the machining accuracy. The generation algorithm for the solid model in the simulation is solved based on Boolean operations. The wire swept volume for each cutting step is united to form the entire wire swept volume. Through Boolean subtraction between the stock model and the entire wire swept volume, the solid model in the wire-EDM simulation is generated. The method is also suitable for the wire path intersection occurred in cutting cone-shaped models. Finally, experiments are given to prove the method.

一种任意多面体网格的三维VOF界面重构算法

针对任意多面体网格的三维流体体积方法(VOF)提出了一种界面重构算法。算法引入了一种新的多面体数据结构,在此基础上提出了一种针对任意凸多面体的切割算法。本文利用牛顿迭代法同时结合多面体几何特性,实现了任意三维网格中的VOF界面重构。数值计算实验表明,算法能适用于不同类型的多面体,并具有较高的收敛效率。最终算法在非结构化网格中成功实现了球形界面的VOF界面重构。