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Mechanical Engineering Commons

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

1983

Ames Laboratory

Structures and Materials

Articles 1 - 5 of 5

Full-Text Articles in Mechanical Engineering

Progress On Ultrasonic Flaw Sizing In Turbine Engine Rotor Components: Bore And Web Geometries, James H. Rose, T. A. Gray, R. Bruce Thompson, J. L. Opsal Jan 1983

Progress On Ultrasonic Flaw Sizing In Turbine Engine Rotor Components: Bore And Web Geometries, James H. Rose, T. A. Gray, R. Bruce Thompson, J. L. Opsal

Review of Progress in Quantitative Nondestructive Evaluation

The application of generic flaw sizing techniques to specific components generally involves difficulties associated with geometrical complexity and simplifications arising from a knowledge of the expected flaw distribution. This paper is concerned with the case of ultrasonic flaw sizing in turbine engine rotor components. The sizing of flat penny shaped cracks in the web geometry will be discussed and new crack sizing algorithms based on the Born and Kirchhoff approximations will be introduced. Additionally we propose a simple method for finding the size of a flat, penny shaped crack given only the magnitude of the scattering amplitude. The bore geometry ...


Absolute Determination Of Stress In Textured Materials, R. Bruce Thompson, John F. Smith, S. S. Lee Jan 1983

Absolute Determination Of Stress In Textured Materials, R. Bruce Thompson, John F. Smith, S. S. Lee

Review of Progress in Quantitative Nondestructive Evaluation

The continuum theory of elastic wave propagation in deformed, anisotropic solids is reviewed with emphasis on those features which might be used to distinguish between stress induced changes in ultrasonic velocity and changes due to material anisotropy, such as would be produced by preferred grain orientation in a polycrystalline metal As noted by previous authors, one such feature is the difference in velocity of two shear waves, whose directions of propagation and polarization have been interchanged. In particular, when these directions fall along the symmetry axes of a rolled plate (assuming orthorhombic symmetry) and these are also the directions of ...


The Clamping Force Of Heat Shrinkable Fittings, David K. Rehbein, B. J. Skillings, J. F. Smith, Donald O. Thompson Jan 1983

The Clamping Force Of Heat Shrinkable Fittings, David K. Rehbein, B. J. Skillings, J. F. Smith, Donald O. Thompson

Review of Progress in Quantitative Nondestructive Evaluation

A number of alloys exhibit a phenomenon which has come to be known as ‘shape memory’. Without exception these alloys undergo a rather special type of martensitic transformation which results from one or another of the elastic constants1–7 weakening with changing temperature to the point that at the transformation temperature the transforming phase becomes both mechanically and thermodynamically unstable. ‘Shape memory’ is exhibited in the following way. A specimen at a temperature above the martensitic transformation is shaped to some desired form. The specimen is then cooled below its transformation temperature and deformed. Subsequent heating of the specimen through ...


Elastic Wave Scattering From Multiple Voids (Porosity), Donald O. Thompson, Samuel J. Wormley, James H. Rose, R. Bruce Thompson Jan 1983

Elastic Wave Scattering From Multiple Voids (Porosity), Donald O. Thompson, Samuel J. Wormley, James H. Rose, R. Bruce Thompson

Review of Progress in Quantitative Nondestructive Evaluation

The purpose of the work described in this paper is the development of an ultrasonic measurement technique which provides a convenient way to detect dilute porosity conditions in materials and to extract certain properties of the flaw distribution which are important in failure prediction. Use has been made entirely of ultrasonic backscatter measurements; thus, the technique differs considerably from other investigations which lead to porosity determinations in that no reliance is placed upon either attenuation measurements or precise ultrasonic velocity measurements [1,2]. The technique thus possesses a distinct advantage for practical implementation, i.e., it is a “one-sided” measurement ...


The Middle Ground Of The Nde R&D Spectrum, H. M. Burte, Dale E. Chimeti, R. Bruce Thompson, Donald O. Thompson Jan 1983

The Middle Ground Of The Nde R&D Spectrum, H. M. Burte, Dale E. Chimeti, R. Bruce Thompson, Donald O. Thompson

Review of Progress in Quantitative Nondestructive Evaluation

Our keynote talk today has several objectives: First, we want to call attention, as some of us have before, to the interdisciplinary nature of NDE science and technology and some approaches for fostering R&D in such a situation. Next, we want to describe the objective of the DARPA, Air Force (and now Navy) core program for developing a science base for NDE and how it has evolved during the past two years. Some changes have indeed taken place; we feel that they were both necessary and evolutionary. Many of you are probably familiar with these changes by now but there may be some residual concerns or questions in your minds. Since I was the initiating influence behind most of them, it is appropriate for you to hear me say what they are and what they aren’t, and to have an opportunity to question ...