Method of measuring angle of conical tip inside cylinder based on laser ultrasonic technology

The invention discloses a method of measuring an angle of a conical tip inside a cylinder based on laser ultrasonic and optical fiber technology. The method comprises steps: (1) a conical side surface inside the cylinder under effects of laser is built, and a thermo-elastic coupling equation for a conical angle wave is built; (2) the equation is solved; (3) a thermo-elastic coupling finite element equation is built, transient temperature field distribution inside the model is calculated, and the temperature field serves as a body load for structural analysis to calculate a strain displacement field in the model; (4) a frequency dispersion curve for conical angle waves generated and excited by laser on wedge-shaped bodies with different wedge-shaped tip angles; (5) a conical angle wave signal on a measured object is excited and received; (6) an actually-measured signal is extracted, and two-dimensional Fourier transform is adopted for signal treatment to obtain the frequency dispersion curve for the conical angle waves; and (7) angles of wedge-shaped tips are simulated through an adjustment theory, different frequency dispersion curves are obtained until to coincide with an experimental result, and an actual angle value is obtained through inversion. The wedge-shaped tip angle can be well measured, and quality monitoring and maintenance on the wedge-shaped tip material can be carried out more efficiently.