| ultrasonic characterization of microstructure in powder metal alloy |
90 |
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| Authors:
B. R. Tittman; M. Abdel-Gawad; k. fertig
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 | the ultrasonic wave propagation characteristics were measured for in- 100, a powder metallurgy alloy used for aircraft engine components. this material was selected as a model system for testing the feasibility of characterizing the microstructure of a variety of inhomogeneous media including powder metals, ceramics, castings, and composites. the data were obtained for a frequency range from about 2-20 mhz and were statistically averaged over numerous volume elements of the ... |
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| Nonlinear Wave Propagation Study |
JUL 85 |
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| Authors:
J. R. Bulau; B. R. Tittman; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| In this document we report the results of combined high amplitude tensile and compressive loading experiments on four different rock types: Westerly granite, Boise sandstone, Berea sandstone, and Indiana limestone. The details of the stress-strain hysteresis loops are examined, with emphasis on investigating the elastic and inelastic properties of rocks at nonlinear amplitudes in both tension and compression. The results indicate that the mechanical behavior of rocks can be significantly ... |
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| THE ROLE OF CREEP RAYS IN THE SCATTERING FROM SPHEROIDAL CAVITIES AND INCLUSIONS IN SOLIDS |
OCT 81 |
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| Authors:
F. Cohen-Tenoudji; L. Ahlberg; B. R. Tittman; J. L. Opsal; V. V. Varadan
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| comparisons between theoretical and experimental results of the scattering of elastic waves are presented. these results are related to the properties of the different waves involved in the scattering process. for voids, when the shape of the defects are regular, the creeping waves are visible and easily related to geometry of the object; when the shape of the object is less regular or in the case of inclusion type defects, ... |
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| defect characterization by ultrasonic signal process techniques |
OCT 77 |
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| Authors:
R. K. Elsley; B. R. Tittman; h. l. nadler; L. A. Ahlberg
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| small defects in structural materials can be successfully characterized if ultrasonic waves scattered from them are captured and analyzed by simple signal processing algorithms. angular and frequency dependence of the scattered signals give information about the size, shape, orientation and material content of the defects. depending on how much is already known about a defect, a variety of algorithms can be used to estimate the unknown properties. in particular, a ... |
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| approach to a self-consistent calibration procedure of an ultrasonic system |
APR 77 |
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| Authors:
B. R. Tittman; D. O. Thompson
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| this brief note is intended to call attention to the potential application of theoretical scattering results to a self-consistent procedure for the calibration of ultrasonic inspection systems. the calibration procedure utilizes a quantitative comparison between the calibration measurement and an invariant theoretical expectation value. the needed theoretical and experimental techniques to accomplish the self-consistent calibration are outlined. included in the discussionis the concept of a goniometer used with a well-defined ... |
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| failure prediction in structural ceramics |
APR 77 |
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| Authors:
A. G. Evans; G. S. Kino; p. t. khuri-yakub; B. R. Tittman
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| the failure prediction requirements and the pertinent accept/reject criteria for structural ceramics are derived, and the available failure prediction techniques are examined vis-a-vis the failure prediction relations in order to highlight the capabilities and limitations of each technique. the need for additional techniques is thereby demonstrated. the capabilities of the ultrasonic technique are extensively evaluated in order to determine its ability to satisfy the deficiencies in the existing failure prediction ... |
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| quantitative estimation of defect properties by computerized ultrasonic methods |
APR 77 |
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| Authors:
r. l. elsley; B. R. Tittman
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| one of the challenges facing ultrasonic ndt is the need to quantitatively evaluate defects so as to reduce the number of parts rejected unnecessarily. it is therefore desirable to obtain accurate measure of size, shpe, orientation, and content of defects. to do this, we should collect as much information as possible and process that information by suitable methods. with this goal in mind, we have investigated small voids and inclusions ... |
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| apparatus for measuring internal friction q factors in brittle materials |
DEC 76 |
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| Authors:
B. R. Tittman; j. m. curnow
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| this report describes a flexural analog of the torsion pendulum for measuring young's modulus and the internal friction q factor on brittle materials. the design provides features to minimize fracture or chipping of the sample and reduces apparatus background damping sothat a sample q of greater than 1000 can be reliably measured. other features include strain amplitudes as low as 0000000.1, small size for use in an environmental chamber, and ... |
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