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Author: Andrew Rusinko
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659140419
Category :
Languages : en
Pages : 168
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Book Description
Mechanical vibrations of ultrasonic frequency exert a considerable influence upon the mechanical properties of metals, in particular, their deformation characteristics. The following three phenomena are considered: ultrasonic softening, ultrasonic hardening and the influence of preliminary ultrasonic treatment upon the steady-state creep of metals. Ultrasonic softening takes place when a ultrasonic loading is superimposed upon a static one, which results in the decrease of static load needed to deform the metal. Ultrasonic hardening occurs during the sonication of annealed material without a static loading. The ultrasonic hardening manifests itself in the increase of the yield strength of material due to the defects of crystalline structure nucleated and developed in acoustic field. Ultrasonic treatment consists of the ultrasonic irradiation of material and subsequent annealing. Materials treated in such a way can offer a considerable resistance to creep deformation. However, this tendency is not a monotonic function of the preliminary sonification parameters. A new theory, the synthetic theory of irrecoverable deformation, is employed to model the phenomena discussed above.
Author: Andrew Rusinko
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659140419
Category :
Languages : en
Pages : 168
Get Book Here
Book Description
Mechanical vibrations of ultrasonic frequency exert a considerable influence upon the mechanical properties of metals, in particular, their deformation characteristics. The following three phenomena are considered: ultrasonic softening, ultrasonic hardening and the influence of preliminary ultrasonic treatment upon the steady-state creep of metals. Ultrasonic softening takes place when a ultrasonic loading is superimposed upon a static one, which results in the decrease of static load needed to deform the metal. Ultrasonic hardening occurs during the sonication of annealed material without a static loading. The ultrasonic hardening manifests itself in the increase of the yield strength of material due to the defects of crystalline structure nucleated and developed in acoustic field. Ultrasonic treatment consists of the ultrasonic irradiation of material and subsequent annealing. Materials treated in such a way can offer a considerable resistance to creep deformation. However, this tendency is not a monotonic function of the preliminary sonification parameters. A new theory, the synthetic theory of irrecoverable deformation, is employed to model the phenomena discussed above.
Author: Alan R. Rosenfield
Publisher:
ISBN:
Category : Metals
Languages : en
Pages : 88
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Book Description
On June 21 a symposium was sponsored by the Bureau of Naval Weapons on the application of ultrasonic energy in the deformation of metals. At this session, a number of investigators actively working in the field reported informally on the results of their research. The reports revealed that the results achieved by incorporating ultrasonic transducers into conventional metalforming and-cutting operations are sufficiently promising that the technique merits further attention. Data are available to indicate that application of ultrasonic vibrations during metal working can increase speeds, lower forces, and improve surface finishes. All of these results have been obtained without any observed difference in properties between ultrasonically and conventionally fabricated parts. (Author).
Author: B. Langenecker
Publisher:
ISBN:
Category :
Languages : en
Pages : 57
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Book Description
High-intensity ultrasound at 20 kc/sec is used in studies of mechanisms metal deformation and treatment. Quantitative details ab6ut the experimental conditions are providedin the five parts of this report: (1) modes of intense ultrasonic stress waves in rods and bars, (2) conversion of acoustic energy into heat, (3) applications of ultrasound at high-strain-rate tensile tests, (4) measurements of internal friction during high-intensity ultrasonic radiation of metals, and (5) discussion of ultrasonic metal deformation along with a comparison between our observations and other reports on the subject of ultrasonic metal forming processes. (Author).
Author: B. Langenecker
Publisher:
ISBN:
Category :
Languages : en
Pages : 12
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Book Description
High-intensity ultrasound at 20 kc/sec is used in studies of mechanisms of metal deformation and treatment. Quantitative details about the experimental conditions are provided in the five parts of this report: (1) modes of intense ultrasonic stress waves in rods and bars, (2) conversion of acoustic energy into heat, (3) applications of ultrasound at high-strain-rate tensile tests, (4) measurements of internal friction during high-intensity ultrasonic radiation of metals, and (5) discussion of ultrasonic metal deformation along with a comparison between our observations and other reports on the subject of ultrasonic metal forming processes. (Author).
Author: W. H. Frandsen
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
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Book Description
Intense ultrasound having power levels up to 100 w/sq cm at 20 kc is used in studies of mechanisms of metal deformation and treatment. To provide accurate quantitative information about the underlying experimental conditions, Part 1 of this progress report describes detailed investigations of modes of propagation of intense ultrasonic stress waves in rods and bars. Part 2 will be concerned with measurements of conversion of acoustic energy into heat and kinetic energy of lattice imperfections. Parts 3 and 4 will illustrate experiments in which high strain rate tensile tests, and intense pulsed ultrasound were applied. A discussion of ultrasonic metal deformation will be given in the final Part 5 along with a comparison of our observations with results and viewpoints from other reports on this subject. (Author).
Author: B. LANGENECKER
Publisher:
ISBN:
Category :
Languages : en
Pages : 14
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Book Description
High-intensity ultrasound at 20 kc/sec is used in studies of mechanisms of metal deformation and treatment. Quantitative details about the experimental conditions are provided in the five parts of this report: (1) modes of intense ultrasonic stress waves in rods and bars, (2) conversion of acoustic energy into heat, (3) applications of ultrasound at high strain rate tensile tests, (4) measurements of internal friction during highintensity ultrasonic radiation of metals, and (5) discussion of ultrasonic metal deformation along with a comparison between our observations and other reports on the subject of ultrasonic metal forming processes. (Author).
Author: Donald Ray Culp
Publisher:
ISBN:
Category : Ultrasonic waves
Languages : en
Pages : 186
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Book Description
Author: B. Langenecker
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
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Book Description
Author: O. V. Abramov
Publisher: Springer
ISBN:
Category : Science
Languages : en
Pages : 520
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Book Description
Ultrasound in Liquid and Solid Metals focuses on the effect of intensive ultrasound on metals, including the analysis of the development of cavitation and acoustic flows in melts, mechanism of metals' spraying and crystallization, the formation of dislocation structure in crystals, diffusion, phase transformation, and plastic deformation. Physical fundamentals of intensive ultrasound effects are covered, and detailed discussions are presented on the engineering principles of equipment and material design for the practical use of ultrasound in the refining of melts, crystallization of ingots and molds, pulverization, plating, pressure working of metals, surface strengthening, and other processes.
Author: Minghao Cai
Publisher:
ISBN:
Category : Deformations (Mechanics)
Languages : en
Pages : 263
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Book Description
Abstract: The present dissertation summarizes the results of research and development for elastic-plastic deformation of metals by nonlinear stress waves. The focus of the present work is the development of a new theoretical and numerical framework to simulate nonlinear stress waves in solids. The application of the new method focuses on modeling the plateau stage of a novel ultrasound welding process. Superimposed by ultrasonic vibrations, metal specimens under static loading experience remarkable transitory softening, which has been called the Blaha effect or the Acousto-Plastic Effect (APE). Previous microscopy studies showed that the metals experience significant plastic deformation and the morphology resembles the Kelvin-Helmholtz instability waves in the presence of shear stresses. The present research addresses the need to understand the APE beyond phenomenological descriptions in the literature. Theoretical and numerical studies have been performed to understand the unusual metal deformation induced by ultrasonic vibrations. A comprehensive continuum mechanics model for macroscopic description of nonlinear stress waves in solids has been developed, including conservation laws of mass, momentum, and energy in the Eulerian frame, in conjunction with a set of transport equations for stress components, which have been derived based on the elastic-plastic constitutive relation employed. The present approach aims to directly address the dynamic nature of the processes rather than treating transitory metal softening by proposing "effective constitutive relations" to relate the nominal "static stress" to the nominal "static strain." Various forms of the governing equations have been systematically derived. The eigensystem of each set of model equations has been analyzed in details with clear presentation of the analytical forms of eigenvalues and the associated eigenvector matrices. To solve these governing equations for the nonlinear stress waves, the space-time Conservation Element and Solution Element (CESE) method has been used. Numerical results of one- and two-dimensional elastic and elastic-plastic stress waves are reported in the dissertation. The numerical results are validated by a series of comparison between the one-dimensional numerical results of elastic and elastic-plastic waves and the available analytical solutions, experimental results and published numerical works.
