US Government As Represented by the Secretary of the Army

The United States of America As Represented by the Secretary of

Julius Frankel

Agostino Abbate

Mark A Doxbeck

Moayyed A Hussain

Pankaj K Das

William J Korman

Jeffrey Braunstein

Stephan C Schroeder

Wilfried Scholz

Bryon Knight

Vito J Colangelo

The present invention is a nondestructive and quantitative laser ultrasonic laser apparatus and associated method for determining adhesion quality of a coating on a substrate. The apparatus of the invention is preferably a pulsed laser for generation and Michelson-type interferometer based system and includes a rotary probe head assembly for making evaluations within a cylindrical test specimen. The method of the invention includes data analysis that uses acquired data from the ultrasonic laser apparatus and computes the dispersion relation or curves (frequency versus velocity) using a ridge-following technique in wavelet analysis and from this, outputs the adhesive quality of the coating by comparing it with a theoretically based determination of a particular coating/substrate bond system. The invention is used for evaluating adhesion quality of coatings used in a gun bore.

Nondestruction coating adhesion evaluation using surface ultrasonic waves and wavelet analysis

An apparatus and/or system is described which uses the photocharge voltage concept in lieu of optical scattering techniques to measure surface topology and properties of materials. The system is based on the measurement of a small electrical potential difference which appears on any solid body when subjected to illumination by a modulated laser light. This voltage is proportional to the induced change in the surface electrical charge and is capacitively measured on various materials. The characterization of coatings to be used inside the base of guns is just one possible application for use by the U. S. Army.

Photocharge microscope

A system which enables the user to measure continuously or intermittently or by remote command the thickness changes, above or below the water, under variable temperature changes of underground culverts with reliability. A liquid delay is used to couple the sound to the culvert comprising a focused transducer (10) screwed into a hollow cone-like structure called a 'squirter' or 'bubbler' (11) providing the operator of the system a means for searching for good echoes from which calculations of thickness with a computer can be made using the known velocity and echo return times.

Thickness measurement of in-ground culverts

A system can take transverse measurements of an elongated workpiece. The tem has a base for holding the workpiece oriented in an axial direction. A carriage mounted on the base can move axially. This carriage has a linear measurement device for providing a linear signal signifying the axial position of the carriage. An ultrasonic assembly is mounted on the carriage, and includes a nozzle for projecting a stream of liquid against the workpiece. This ultrasonic assembly also has an ultrasonic transducer for transmitting an ultrasonic wave into the stream and for detecting an ultrasonic wave returning in the stream. This ultrasonic transducer has a transducer terminal for exchanging signals signifying the occurrence of ultrasonic waves transmitted into and returning from the stream. A control device is coupled to the transducer terminal for (a) exchanging signals with the ultrasonic transducer, (b) initiating transmission of an ultrasonic wave into the stream, and (c) receiving a signal signifying the return of ultrasonic waves in the stream. This control device can provide a sense signal signifying the operation of the ultrasonic assembly. The system also has a signal processor coupled to the carriage and the control device for providing in response to the linear signal and the sense signal, an evaluation signal signifying the straightness of the workpiece.

System for taking transverse measurements

A method for and system of measuring the thickness of a component dimension f a sample material. Sound waves are coupled for transmission along a component direction of a sample material and also through first and second reference standards to provide first and second reference thicknesses. As the sound wave signal is transmitted, the time for the sound wave signal to traverse the sample thickness and the first and second reference thicknesses is measured. The thickness of the sample is calculated by calculating the velocity of the signal from the traverse times for the first and second reference thicknesses. Preferable, the calculations are made by a computer, and may be repeated over a period of time to calculate a change of thickness as a function of time. The computer may be used to compare the instantaneous thickness of the sample with at least one parameter such as information used to control a process, a predetermined minimum or maximum thickness a predetermined rate of change with respect to a minimum or maximum time, or a predetermined uneven change in thickness between a plurality of sample thicknesses. The sample may in fact comprise a plurality of locations on a tube, and the process may control a tube being subjected to plating process or a tube that is subject to at least potential erosion of its thickness.

Automated thickness measurement system

A device is presented for measuring residual stresses in a solid component. he device includes a hardness measuring component which has an indenter for determining hardness at various locations. Stress (.sigma.) data is obtained by converting the hardness measurements according to the formula

Stress tester

A method for measuring the plating on the inside of a gun barrel, including he steps of providing ultrasonic pulses against a gun barrel to be plated, and plating the inside while monitoring the echoes from said waves from the inside and outside diameters of the barrel with a plurality of transducers aligned to reflect ultrasound waves from the outside and the inside surfaces of the gun barrel. Change in time for the return of waves from the inside surface indicates the change in thickness of plating on the inside of the barrel. The change is calculated by measuring the change in time for the wave to return to its source, and multiplying by the sound velocity.

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Rensselaer, NY, United States of America

Julius Frankel