Laser ultrasonic system and method for detecting elasticity modulus of material in non-contact mode

Abstract

The invention discloses a laser ultrasonic system and method for detecting the elasticity modulus of a material in a non-contact mode. The system comprises an exciting light-emitting module, a detection light-emitting module, a parallel flat plate, a dichroscope, a phase mask plate, a phase mask plate electric regulator, a dimmer, a first achromatic lens, a phase regulator, a second achromatic lens, a mobile sample table and a signal receiving module. According to the invention, by adjusting the phase mask plate electric regulator, controlling the phase mask plate to be added into and moved out of the system, and combining with the adjustment of the parallel flat plates, the system can be quickly switched between a system for exciting and measuring surface acoustic wave signals and a system for exciting and detecting longitudinal wave and transverse wave signals. By measuring the wave velocities of surface acoustic waves, longitudinal waves and transverse waves measured in the two systems, the elasticity modulus of the material is obtained when the density and Poisson's ratio of the material are unknown.

Description

technical field [0001] The invention belongs to the field of laser ultrasonic non-contact detection, in particular to a laser ultrasonic system and method for non-contact detection of material elastic modulus. Background technique [0002] With the development of material science, various new materials are constantly emerging, and many materials show extraordinary mechanical properties. Therefore, the measurement of mechanical parameters of materials is particularly important. Among them, elastic modulus is one of the very important parameters to characterize the mechanical properties of materials. At present, the conventional method for measuring the elastic modulus of materials is the tensile test method, which is cumbersome, takes a long time to measure, and will cause certain damage to the material. The laser ultrasonic method uses the excitation light to excite the sound wave in the material, and the mechanical parameters of the sample are derived from the measurement ...

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Problems solved by technology

However, due to the measurement error of the distance between the excitation line source and the detection point, it will affect the final result

[0004] In summary, although the "time-of-flight method" in the laser ultrasonic method can avoid damage to the sample compared with the tensile test method, the final result is not very accurate due to the movement distance and measurement distance errors during the measurement process.

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