Study On Ray Tracing Forward Method In The Blemish Concrete Structure Detection

Reflection seismology based on elastic wave theory in geophysical prospecting technology has proved to be efficient in exploring geological conditions of the earth's crust. Cracks and aggregates in the concrete may be analogous to faults and gravel in the earth's crust and can diffract ultrasonic waves as the seismic waves are diffracted in geophysical investigations. Therefore, it is natural to apply the reflection seismology method to the detection of cracks in concrete structures, to fix on damnification degree of concrete structures for security evaluation . Pre-stack depth migration technique is a migration technology of reflection seismology method, which can restoration of original spatial position of geological structure. This method can obtain more exact imaging of geological structure than else method on complex construct and exquisite speed change. When ultrasonic spreads on blemish concrete structure detection, its wave field is complex and its speed change is great. Therefore, pre-stack depth migration technique is more superiority than else migration method for damning detection. In pre-stack depth migration imaging process, ray tracing is a key to establish the speed model of ray tracing.Because of characteristics of the concrete, this text makes use of ray tracing theories method from the Earth Physics, uses C++ language to program, builds up speed model of the wave in defective concrete structure, carries on ray tracing, imitates the kinematics dissemination of the wave. The ray tracing model is constructed in the blemish concrete medium. What this text study is planar status. The textual ray tracing method is to be applicable to the random speed distributing model. This text studied the shortest path ray tracing method in the concrete structure. Carrying on two stages ray tracing, in the first place, primary ray path is choose, in the second place, it is to carry on correcting primary ray path for confirming the final ray path. This text introduces the detailed procedure process of the arithmetic realization, and according to calculate example , uses the C++ language to program. This text discusses the actual processes that apply ray tracing model positive method to pre-stack depth migration imaging. Integrating experiment , this text researches on ray tracing application in pre-stack depth migration and its advantage for the model that this text builds up. According to research on ray tracing method for the scathing concrete structure, this text discusses the design of the inspiring, receiving system and the best value of correlative parameter by experiment for incarnating system advantage .The speed model this text builds up, draws lessons ray tracing theories method from the Earth physics. Owing to disadvantage of ray tracing theories method, namely ray removes only in a mesh ambulation while carrying on iterative correct. The model that this text builds up is planar, infection factor of ray tracing speed is analyzed firstly under planar model circumstances . The angle attenuation experiment research in this paper was all carried out in lab condition, These methods still need make improvement for engineering practice.