Research Of The Method Of Stress Field's Visualization Based On Principal Stress Trajectory

In coal mining,the problems caused by mechanics,such as roadway collapse,and gas outburst,seriously affect the safe production of coal enterprises.So the effective visualization of the stress field by computer application technology has important research significance for analyzing the structure of stress field.The most common visualization method currently used is to plot the contour map of the stress component,but this method does not effectively reflect the basic characteristics of the stress field.The principal stress trajectory is an important means to study the visualization of stress fields.It can show the whole characteristics of the stress field,and reflect the transmission path of the stress field.So it can explain relationship and regular pattern,of which the stress field structure is existed between the roadway instability failure and exposed gas.The paper uses the relevant methods of tensor field visualization in computer graphics to obtain a more effective method for the main stress trajectory through theoretical analysis and algorithm design.The main researches are as follows:Firstly,there is the problem that the two principal stress directions of the stress tensor that cannot be determined by a simple method.According to the continuity of the principle stress field,this paper designs a principal stress family algorithm based on the One-Class SVM,to correct the stress field anomaly data points and classify the two principal stress vectors of all known points,thus transforming the visualization problem of the stress field into the visualization problem of two principal stress vector fields,to lay the foundation for solving the drawing problem of the main stress trajectory;Then,after analysis of the entire topological structure,it is affected by the degradation point of the stress field.The paper proposes a degenerate point extraction algorithm based on real symmetric matrix.The algorithm selects the appropriate feature parameters of the points to draw a contour map,which can reflect the relationship of the location of the degenerate point and the stress's magnitude.According to the correspondence between the degenerate point and the real symmetric matrix,the eigenvalue parameter threshold is controlled by the coefficient of variation,which speeds up the process of extracting the degenerate points.Through the experimental verification,the algorithm,which is compared with the SIFT algorithm,improves the time efficiency;Finally,there are problems,such as trajectory placement or closure,in the traditional trajectory drawing algorithm.The paper proposes a principal stress trajectory placement algorithm based on stress field topology,which uses the methods of interpolation and numerical integration,ghost-cell method,cosine similarity to quickly draw the main stress trajectory by selecting the appropriate seed point.In order to further demonstrate the relationship between the stress field structure and the rock mass structure of the roadway instability failure,the stress value,the main stress trace and the color are combined to construct a three-dimensional mode for displaying the multi-feature information in the stress field.