Representation of Fracture Micro Surface of Metals using Virtural Reality

在断口分析中，使用断口表面形貌分析(FRASTA)技术可以很好地了解材料内部发生的详细断裂过程。本研究将虚拟现实技术引入FRASTA，并对其适用性进行了检验。系统的开发：将扫描电子显微镜下的地形数据传输到图形工作站，并利用虚拟现实技术进行分析。此外，虚拟现实软件为我们提供了一种在显微空间内的准体验。算法：首先在显示器上同时显示两个共轭曲面。然后，它们中的一个相对于另一个固定表面移动。曲面可以平行移动，也可以旋转。计算两个曲面之间的相对距离，并绘制该距离的等高线图。通过观察这张等高线图，我们可以很容易地确认匹配的程度。如果我们对结果不满意，我们将返回匹配步骤。反复迭代直到得到满意的结果。例如：将所提出的方法应用于随机载荷下的疲劳断口，证实了以下性能。1.通过两个共轭曲面的匹配来观察断裂过程。2.断裂面-投影图系列的观察。3.骨折过程的动画绘制。结论：利用虚拟现实技术开发的图形系统使我们能够进入微观空间，并在任意要求下操纵虚拟表面。因此，更容易理解微断裂过程。

Outline : in the fractographical analysis, the detailed fracture process that occurred inside the material can be understood well by using the technology called fracture-surface topography analysis (FRASTA). In this research, virtual reality technology is introduced into FRASTA,and its applicability is examined.Development of System : The SEM topographical data are transfered to the graphic workstation and are analyzed using the technique of virtual reality. Furthermore, the virtual reality software aid to provide us with a quasi-experience within the micrograhpic space.Algorithm : Two conjugate surfaces, are shown on the display simultaneously first. Then one of them is moved relatively to the other fixed surface. The surface is either moved in parallel or rotated. Relative distance between two surfaces is calculated and the contour map of the distance is drawn. By observing this contour map, we can acknowledg the degree of matching easily. If we are not satisfied with the result, we will return to the matching step. This iteration is repeated until the satisfactory result is obtained.Examples : Apllying the developed method to the fracture surfaces of the fatigue under random loads, the following performaces are confirmed. 1.Observation of the fracture process by matching two conjugate surfaces. 2.Observation of the series of fractured area-projection plots. 3.Animation drawing of the fracture process.Conclusion : It is shown that the developed graphic system using virtual reality enables us to get into the micro space and to manipulate virtual surfaces under arbitrary requirements. And thus it becomes easier to understand the microfracture process.