Numerical Simulation Of The Propagation Of Elastic Waves In Stones Of ESWL

ESWL(Extracorporeal shock wave lithotripsy),which is highly praised as one of the three most important medical treatment technologies as MRI ,CT。Developed over twenty years ago,ESWL is a innovation revolution for kidney stone removal.It's non-invasive treatment method can greatly lighten the pain of the patients.The paper review the development and status of ESWL at first,also it simply explains many problems which are not definite in this field.The focus are all on the fracture mechanism of kidney stones with shock wave's direct impact.In order to definite the propagation of shock waves in the kidney stones,the paper introduce the fundmental theory of Characteristic Curve Method and Finite Difference Method. The author then constructs the Explicit Difference Scheme based on Characteristic Curve Method.Programming with Fortran95,the author solve the algebraic equations and obtains the numerical solutions of propagation of elastic waves.In this work the author simulates the propagation of 1-dimension elastic waves in three materials with different boundary conditions.The numerical results are dealt with Origin pro7.5.The numerical values appear that that Characteristic Curve Method is able to perfectly simulate the propagation of elastic waves with step load on the boundary of the solid materials.All the analysis demonstrate that the tensile stress due to the reflection of the pulse with a step compressive front with pressure of the order of 30MPa decaying to a negative pressure of 10MPa at the end of the stone is go up to a higher value,with continuous impact which is enough to destroy the stones in human body.