Structural material with piezoelectric material particles

Abstract

A load-bearing structural member has a continuous structural material with piezoelectric material particles mixed in throughout. The structural material may be any of a variety of suitable materials, such as polymer materials, composite materials, ceramic materials, or concrete. The piezoelectric material particles may be used for evaluating the soundness of the structural member, such as in quality control or structural health monitoring processes. The structural member may include one or more conductive pickups used for receiving signals from the structural member. The signals may be induced by introducing ultrasonic signals or vibrational resonance signals into the structural member. The response from such induced signals may be used for quality control purposes or structural health monitoring. Piezomagnetic, electro-strictive, or magneto-strictive material particles may also be spread throughout the structural material, to amplify and otherwise enhance the signals from the piezoelectric material particles.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The invention relates to structural materials and methods used in the general areas of quality and nondestructive testing, structural health monitoring, and detection of forces.[0003]2. Description of the Related Art[0004]Ultrasonic testing and vibrational resonance techniques are commonly used nondestructive techniques to test the integrity of polymer matrix composite structures and other structures. These techniques may be used to perform quality control tests at the time of manufacture, and / or structural health monitoring tests over the life of the structure. Piezoelectric transducers have been placed on such materials to both generate and receive ultrasonic and vibrational signals.[0005]Ultrasonic testing techniques may employ longitudinal, shear, or surface waves. Defects existing in the structure may cause an irregularity in the ultrasonic signal, if the defect is located in an area probed by the ultrasonic signal...

AI Technical Summary

Problems solved by technology

Defects existing in the structure may cause an irregularity in the ultrasonic signal, if the defect is located in an area probed by the ultrasonic signal.

Defects in the structure may also alter its vibrational resonance response, if the defects are located in an area that is probed by the vibrational signal introduced into the structure.

For nondestructive quality control testing, skilled and expensive technicians have been needed to properly perform ultrasonic scans.

Such ultrasonic testing is often a time consuming operation that slows down production.

Vibrational resonance techniques have not been as commonly used, due to the expense and complexity of developing the necessary experimental apparatus.

The ultrasonic method in particular suffers from the drawback that it is directional.

Full characterization of a structure, especially a complex structure, is a difficult, time-consuming, and expensive operation.

One problem with piezoelectric wafer active sensors is that they must be bonded to the structure, and the bond is prone to break down over time.

Another problem is that such sensors do not easily conform to curved surfaces, and are easily broken.

They may also produce unacceptable irregularities on aerodynamic surfaces, or they may detract from the aesthetic appeal of other structures.

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