Time Reversal Guided Wave Inspection Method for Non-through-thickness Defects in Pipes

A time reversal guided wave inspection method is numerically simulated by using finite element method(FEM),where the non-through-thickness small defect in a pipeline model is analyzed with solid elements models.The reflection coefficients of L(0,2) mode are calculated when the time reversal method is used.Results show that the temporal-spatial focusing effect of the time reversal method can realize energy focusing on the defect.So,the time reversal guided wave method is more favorable to the small defect inspection in pipes.In addition,the angular-profiles of the time reversal waves are employed to give the defect's location in the circumferential and radial direction.