Preparation method of ultrasonic transducer for concrete structure detection/monitoring

Abstract

The invention discloses a preparation method of an ultrasonic transducer for concrete structure detection / monitoring, which comprises the following step: respectively attaching a packaging layer to the internal and external surfaces and the top and bottom ends of a piezoelectric element to obtain an ultrasonic transducer, wherein the packaging layer on the external surface of the piezoelectric element is a mixture of cement, heat-resistant unsaturated polyester resin, curing agent methylethyl ketone peroxide and accelerator cobalt naphthenate; and the packaging layer on the internal surface and the top and bottom ends of the piezoelectric element is a mixture of cement, epoxy resin, curing agent T-31 and epoxy reactive diluent. The piezoelectric element is in a circular tube shape; and the packaged piezoelectric element has a hollow structure inside. The transducer is simple to prepare and convenient for distribution, has the characteristics of simple structure, high power capacity, large acoustic radiation area, high radiation efficiency, low frequency, uniform radial radiation, high sensitivity and the like, is very suitable for detecting / monitoring some large-size concrete structures, some foundation piles and the like, and has wide application prospects in concrete detection / monitoring.

Description

Technical field [0001] The present invention involves the preparation method of an ultrasonic converter and the ultrasonic converter obtained. It specifically involves a preparation method for a round tube ultrasonic converter for concrete structural inspection / monitoring.field. Background technique [0002] In recent years, the buried cement -based sensor has attracted much attention because of the concrete material and has attracted much attention because of the concrete structure.However, the current cement -based sensors are mostly based on shelter piezoelectric ceramics or piezoelectric composite materials. Most of them use their thickness vibration molds to directly point out or receive sound waves in the direction of 360 ° in one direction.The radiation area is small, especially for some large concrete structures and some base pile inspections / monitoring, and the formation is complicated, and multiple sensors need to be buried, which is time -consuming and laborious.Cases ...

AI Technical Summary

Problems solved by technology

However, the current cement-based sensors mostly use sheet-like piezoelectric ceramics or piezoelectric composite materials as components, and mostly use their thickness vibration mode, which only has good directivity in one direction, and cannot radiate or receive sound waves in the horizontal 360° direction. The radiation area is small, especially when inspecting / monitoring some large concrete structures and some foundation piles, the layout is complicated, and it is necessary to bury multiple sensors, which is time-consuming and laborious

The piezoelectric ceramic circular tube or piezoelectric composite material that produces radial stretching vibration has the characteristics of simple structure, stable performance, uniform directivity along the radial direction, high receiving sensitivity, easy array formation, and easy portability, etc., and can overcome sheet piezoelectricity. The radiation area of ​​the material or piezoelectric composite material is small, and the directivity is good only in one direction, and it is unable to radiate or receive sound waves in the horizontal 360° direction.

In 2011, the applicant applied for a patent (CN201110394992.7) named a 1-3 type arc or ring piezoelectric composite material and its preparation method, which only disclosed a ring (or round tube) The shape of the piezoelectric composite material, but how to match it, package it into a transducer is not involved

In addition, there are still some circular tube-shaped transducers or sensors disclosed, but most of these transducers are composed of radially polarized piezoelectric ceramic circular tubes and thin-walled metal prestressed tubes. The metal prestressed tube provides sufficient radial prestress for the piezoelectric ceramic tube. This type of piezoelectric transducer is basically assembled by the method of thermal expansion and contraction. This method not only requires high processing technology, but also the size of the prestress Difficult to control and adjust, more importantly, there are essential differences between the external metal and concrete in terms of structure, composition, and performance, and the compatibility between the two is poor, so it cannot be used for concrete structure inspection / monitoring

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