Open Access. Powered by Scholars. Published by Universities.®

Mechanical Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

1983

Manufacturing

Articles 1 - 8 of 8

Full-Text Articles in Mechanical Engineering

Rough Surface Effects Of Aluminum Castings On Ultrasonic Sizing Algorithms, Kent Lewis, Dale Fitting, Laszlo Adler Jan 1983

Rough Surface Effects Of Aluminum Castings On Ultrasonic Sizing Algorithms, Kent Lewis, Dale Fitting, Laszlo Adler

Review of Progress in Quantitative Nondestructive Evaluation

Several techniques for characterizing flaws and inclusions using ultrasonic scattering information have been developed in recent years. These algorithms assume a noise-free medium and are sensitive to perturbations in the acquired spectra. However, surface roughness and volumetric porosity effects alter the available data.

In order to determine the effects of surface roughness typical of aluminum castings on inversion accuracy, a sequence of experiments was performed. Ultrasonic backscattering data were acquired from spheroidal defects in flat, smooth surfaced, diffusion bonded titanium samples. Next, the scattering spectra were perturbed using theoretically or experimentally determined transmission spectra obtained from rough surfaced cast aluminum ...


Backscattering Of Ultrasonic Leaky Waves From Liquid-Solid Interfaces, Laszlo Adler, Ken Bolland, Michel De Billy, Gerard Quentin Jan 1983

Backscattering Of Ultrasonic Leaky Waves From Liquid-Solid Interfaces, Laszlo Adler, Ken Bolland, Michel De Billy, Gerard Quentin

Review of Progress in Quantitative Nondestructive Evaluation

It is well known that when a finite ultrasonic beam of a given spatial distribution is incident at the Rayleigh angle to a liquid-solid interface, the spatial distribution of the reflected field may be altered significantly. The “energy redistribution” is due to the interference between the specularly reflected beam and a surface wave which has leaked back to the water. The “shape” of the reflected field depends on the so-called Schoch displacement (which is characteristic of the interface) and on the width of the ultrasonic beam. It has also been observed that significant energy is scattered back to the transmitter ...


An Artificial Intelligence Approach To Ultrasonic Weld Evaluation, G. P. Singh, R. C. Manning Jan 1983

An Artificial Intelligence Approach To Ultrasonic Weld Evaluation, G. P. Singh, R. C. Manning

Review of Progress in Quantitative Nondestructive Evaluation

The inspection of butt-welded stainless-steel pipe joints in nuclear power plants is routinely performed using ultrasonic non-destructive evaluation methods. Field experience, based on conventional ultrasonic signal amplitude criteria, indicates that a large number of indications are recorded. Most of these are not due to cracks, but are inherent in the geometry of the specimen. Discrimination between crack and geometrical/weld (malignant vs. benign) indications is principally based on operator experience, variations in signal amplitude, and the location of the reflector. Field experience and round-robin tests show that indication discrimination is a very time-consuming process. Besides, significant variations in performance exist ...


Finite Element Modeling Of Ultrasonic Inspection Of Weldments, B. R. Dewey, B. F. Oliver, C. A. Pickard, L. Adler Jan 1983

Finite Element Modeling Of Ultrasonic Inspection Of Weldments, B. R. Dewey, B. F. Oliver, C. A. Pickard, L. Adler

Review of Progress in Quantitative Nondestructive Evaluation

High performance weldments for critical service applications require 100% inspection. Balanced against the adaptability of the ultrasonic method for automated inspection are the difficulties encountered with nonhomogeneous and anisotropic materials. This research utilizes crystals and bicrystals of nickel to model austenitic weld metal, where the anisotropy produces scattering and mode conversion, making detection and measurement of actual defects difficult.

Well characterized samples of Ni are produced in a levitation zone melting facility. Crystals in excess of 25 mm diameter and length are large enough to permit ultrasonic measurements of attenuation, wave speed, and spectral content. At the same time, the ...


High Frequency, Angle Beam Emats For Weld Inspection, G. A. Alers, D. T. Maclauchlan Jan 1983

High Frequency, Angle Beam Emats For Weld Inspection, G. A. Alers, D. T. Maclauchlan

Review of Progress in Quantitative Nondestructive Evaluation

Accompanying the requirements for higher quality welds in structural parts, there is a growing demand for more rapid and automatic methods for their nondestructive inspection. Conventional X-ray methods are inherently slow and are difficult to automate. Furthermore, they often present a safety hazard that adds mass and bureaucracy to the application of the method. Ultrasonics, on the other hand, can be very rapid, is easily made automatic, and does not present any safety problems. Its main drawbacks are the requirement for a carefully aligned transducer, a plumbing system to supply liquid couplant, and an educated operator to maintain the alignment ...


An Analysis Of Electromagnetic Acoustic Transducer Arrays For Nondestructive Evaluation Of Thick Metal Sections And Weldments, C. M. Fortunko, R. E. Schramm Jan 1983

An Analysis Of Electromagnetic Acoustic Transducer Arrays For Nondestructive Evaluation Of Thick Metal Sections And Weldments, C. M. Fortunko, R. E. Schramm

Review of Progress in Quantitative Nondestructive Evaluation

A new type of electromagnetic-acoustic transducer (EMAT) has been developed that may be particularly suitable for use as an element of ultrasonic arrays. The new transducer can generate and receive compact ultrasonic pulses that exhibit a component of polarization parallel to the free surface. In the plane of symmetry that is normal to the free surface and bisects the EMAT (the sagittal plane), the ultrasonic signals generated by the new transducer are SH waves. In addition, the new transducer can efficiently receive ultrasonic signals from a very wide range of direction in the sagittal plane. This property is required to ...


Progress In Non-Destructive Fatigue Crack Detection And Monitoring In Welded Pressure Vessels Subjected To External Pressure Cycling, I. M. Kilpatrick, J. M. Cargill Jan 1983

Progress In Non-Destructive Fatigue Crack Detection And Monitoring In Welded Pressure Vessels Subjected To External Pressure Cycling, I. M. Kilpatrick, J. M. Cargill

Review of Progress in Quantitative Nondestructive Evaluation

At the 1980 Review of Progress in Quantitative NDE the authors presented a paper outlining the NDE techniques then under development for fatigue crack detection and monitoring in welded structures (1). The present paper describes the progress made since then in applying the techniques to welded pressure vessels.


Theoretical And Experimental Developments In Ultrasonic Evaluation Of Periodic Surfaces, Alain Jungman, Laszlo Adler, R. Roberts, J. D. Achenbach Jan 1983

Theoretical And Experimental Developments In Ultrasonic Evaluation Of Periodic Surfaces, Alain Jungman, Laszlo Adler, R. Roberts, J. D. Achenbach

Review of Progress in Quantitative Nondestructive Evaluation

Most ultrasonic NDE experiments and their theoretical models deal with perfectly smooth interfaces, but true materials generally exhibit rough interfaces. As an approach to include the ultrasonic scattering which occurs on the different interfaces along the beam path, the reflection factors of acoustic waves diffracted by periodic surfaces is investigated theoretically and experimentally by looking at the frequency dependence of the reflected signal. Mode conversion bulk and surface waves are shown to be the result of strong coupling between the incident wave and the geometry of the grating. As a consequence, the geometrical parameters of the interface can be obtained ...