Location

Snowmass Village, CO

Start Date

1-1-1995 12:00 AM

Description

It is well-known [1], [2] that when materials are fractured, substantial local electric fields are generated. These fields are capable of accelerating charged particles from the nascent interfaces, giving rise to a class of phenomena known as “exo-emission” or “fracto-emission”. The released “exo-particles”, consisting of electrons, ions, and charged clusters or fragments, can be collected and analyzed directly. Usually, such experiments are performed under conditions of high or ultra-high vacuum. This type of particle emission has been extensively studied previously, most notably by Dickinson and his co-workers [2] — [7]. Except for previous studies of fracturing rock, performed in connection with early-warning detection of earthquakes [8], [9], and the work of Dickinson, little has been done to characterize the radio wave emission that attends material fractures. Furthermore, no previous studies of radio wave emission from the elastically or plastically strained materials have been reported. Early qualitative studies of the visible light and radio wave emission from delaminating layers of adhesively bonded polymers and metals were reported by Derjagun and his co-workers. Emission during deformation suggests itself as a possible method for diagnosing the state of dynamic material strain in situations where contact methods are not feasible or are undesirable. Examples of such potential applications are too numerous to delineate here; they include the detection of high speed particle impacts on spacecraft structures, dynamic test of radioactive, extremely hot or cold structures, and others. We also note that for the elucidation of the detailed mechanism of fracture, radio-wave emission may have advantages over other methods since, unlike acoustic or ultrasonic methods, the speed of propagation of the detected signal is much greater than the speed of the propagating crack-front in the material, so little or no deconvolution is required.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

14A

Chapter

Chapter 4: Transducers, Sensors, and Process Control

Section

Sensors and Process Control

Pages

1175-1182

DOI

10.1007/978-1-4615-1987-4_149

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

NDE Applications of Radio Wave Emission from Stress and Fracture

Snowmass Village, CO

It is well-known [1], [2] that when materials are fractured, substantial local electric fields are generated. These fields are capable of accelerating charged particles from the nascent interfaces, giving rise to a class of phenomena known as “exo-emission” or “fracto-emission”. The released “exo-particles”, consisting of electrons, ions, and charged clusters or fragments, can be collected and analyzed directly. Usually, such experiments are performed under conditions of high or ultra-high vacuum. This type of particle emission has been extensively studied previously, most notably by Dickinson and his co-workers [2] — [7]. Except for previous studies of fracturing rock, performed in connection with early-warning detection of earthquakes [8], [9], and the work of Dickinson, little has been done to characterize the radio wave emission that attends material fractures. Furthermore, no previous studies of radio wave emission from the elastically or plastically strained materials have been reported. Early qualitative studies of the visible light and radio wave emission from delaminating layers of adhesively bonded polymers and metals were reported by Derjagun and his co-workers. Emission during deformation suggests itself as a possible method for diagnosing the state of dynamic material strain in situations where contact methods are not feasible or are undesirable. Examples of such potential applications are too numerous to delineate here; they include the detection of high speed particle impacts on spacecraft structures, dynamic test of radioactive, extremely hot or cold structures, and others. We also note that for the elucidation of the detailed mechanism of fracture, radio-wave emission may have advantages over other methods since, unlike acoustic or ultrasonic methods, the speed of propagation of the detected signal is much greater than the speed of the propagating crack-front in the material, so little or no deconvolution is required.