A Method of Ultrasonic Excitement to Control the Size of Surface and Penetrating Cracks in Brittle Materials

Abstract

The invention provides a method for controlling the dimension of surface and penetrating cracks of a brittleness material through ultrasonic excitation. According to the method, firstly, a surface crack or a penetrating crack or a deep buried crack is pre-formed in the brittleness material; at the moment, the crack is difficult to meet the requirement; then, an ultrasonic excitation head is put onto the surface of the brittleness material; an ultrasonic wave generator generates ultrasonic waves; the ultrasonic waves penetrate through the whole material body through passing through the surface of the material; due to the existence of pre-formed cracks, the ultrasonic waves generate mechanical perturbation in the crack position; the mechanical vibration of the ultrasonic waves is converted into mechanical energy in the crack position; the crack generates expansion cracking; the ultrasonic wave input is stopped until the crack dimension meets the requirement. Therefore the surface or penetrating crack meeting the dimension requirement is obtained. The method for controlling the dimension of surface and penetrating cracks of the brittleness material through ultrasonic excitation has the advantages that the method is simple and reasonable; the efficiency is high; the operation is simple and convenient; the control is accurate; the use is economic; the control is accurate; the formed crack is more similar to the real state of the brittleness material crack in rock, concrete, glass, ceramic and the like.

Description

Technical field [0001] The invention belongs to the field of fracture mechanics research and engineering safety prediction and evaluation of brittle solids (such as metals, rocks, concrete, and ceramics), and relates to a method for controlling the surface of brittle materials such as rocks, concrete, ceramics, and glass by ultrasonic excitation and the size of penetrating cracks. Background technique [0002] The fracture of brittle materials such as rocks, concrete, ceramics, and glass with internal cracks is a basic problem in the engineering world. For example, the severe fracture of large-scale rocks can cause earthquakes; the expansion of rock cracks to the overall fracture can cause collapse of water conservancy and traffic tunnels. . Concrete structures widely exist in human daily life, and concrete engineering accidents are also related to the expansion of the original cracks in the concrete to the overall fracture. Therefore, the propagation and failure laws of surface...

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Problems solved by technology

[0010] 1. Traditionally, the groove method, drilling method, etc. are used to make artificial defects on the sample, but the size or shape of the above artificial defects is quite different from the natural defects;

[0011] 2. Use scratches on the surface of the prefabricated part of the sample, and use the three-point bending loading method to generate cracks. This method is not easy to control, and it is easy to cause instability at the crack, direct damage to the sample, and a low production success rate;

[0012] 3. Chinese patent CN101710040A discloses a method for making samples containing surface cracks. Surface crack defects are made by fatigue loading method. Although the operation is simple, fatigue loading will inevitably affect the mechanical properties of other parts of the material except cracks. In addition, the crack size is difficult Precise control, direct sample destruction, low production success rate

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