Showing papers on "Deformation (meteorology) published in 1986"
597 citations
Book•
01 Jan 1986
TL;DR: The authors' solutions was introduced using a want to work as a complete on the internet digital library that provides use of great number of PDF file e-book assortment that provides many different types of e-guide along with other literatures from your paperwork data source.
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590 citations
TL;DR: In this paper, the deformation behavior associated with the R-phase (rhombohedral phase) transition and the subsequent martensitic transformation was studied systematically in Ti-Ni alloys by tensile testing over a wide temperature range.
Abstract: Deformation behavior associated with theR-phase (rhombohedral phase) transition and the subsequent martensitic transformation was studied systematically in Ti-Ni alloys by tensile testing over a wide temperature range covering belowM
f to aboveT′
R (>Af). Since the deformation and transition characteristics showed a strong dependence on thermo-mechanical treatment and Ni-content, internal structures were examined by electron microscopy in specimens with various Ni-content and thermo-mechanical treatment. As a result precipitates and/or dislocations were revealed in the specimens in which theR-phase transition occurs. Based on the above results, the effects of thermo-mechanical treatment and Ni-content on the deformation and transition characteristics were clarified for both theR-phase transition and the martensitic transformation.
425 citations
TL;DR: In this article, a new framework for considering the localization of deformation and illustrate it for the case of hyperelastic materials is proposed, where strain-induced localized deformation patterns are accounted for by adding a second deformation gradient-dependent term to the expression for the strain energy density, leading to equilibrium equations which remain always elliptic.
Abstract: By utilizing methods recently developed in the theory of fluid interfaces, we provide a new framework for considering the localization of deformation and illustrate it for the case of hyperelastic materials. The approach overcomes one of the major shortcomings in constitutive equations for solids admitting localization of deformation at finite strains, i.e. their inability to provide physically acceptable solutions to boundary value problems in the post-localization range due to loss of ellipticity of the governing equations. Specifically, strain-induced localized deformation patterns are accounted for by adding a second deformation gradient-dependent term to the expression for the strain energy density. The modified strain energy function leads to equilibrium equations which remain always elliptic. Explicit solutions of these equations can be found for certain classes of deformations. They suggest not only the direction but also the width of the deformation bands providing for the first time a predictive unifying method for the study of pre- and post-localization behavior. The results derived here are a three-dimensional extension of certain one-dimensional findings reported earlier by the second author for the problem of simple shear.
361 citations
TL;DR: In this article, the authors investigated the mechanisms of hydrogen "embrittlement" of nickel by performing in situ straining experiments in a highvoltage electron microscope equipped with an environmental cell.
329 citations
01 Jan 1986
TL;DR: In this paper, the authors compared the fracture behavior of normal weight and lightweight concrete with respect to their envelope curves, material stiffness and degradation during post-peak cycles, and residual compressive deformation on crack closure.
Abstract: For modelling fracture behaviour of concrete various types of deformation controlled uniaxial tests were performed on normal weight and on lightweight concrete. These two types of concrete were compared with respect to their envelope curves, material stiffness and degradation during post-peak cycles, and residual compressive deformation on crack closure. Differences in behaviour were explained on the basis of the properties of the aggregates which result in specific fracture surfaces. Based on narrow specimens with uniform stress distribution, unique stress deformation curves were determined and the descending branches were modelled. These models were applied to calculate the stress distribution in wide specimens with a sawcut. The total force was in good agreement with the experiment. Probable reasons for the different behaviour of lightweight and normalweight concrete are discussed.
307 citations
267 citations
TL;DR: The relationship between phase changes and hydrogen transport parameters was modeled using various assumptions about the microstructure and the effective solubility and diffusivity values were discussed in terms of dislocation trapping and transport as mentioned in this paper.
246 citations
TL;DR: It is demonstrated that surface deformation mediated by contamination plays a major role in images of graphite obtained by a scanning tunneling microscope in air, where abnormally high atomic corrugations are observed.
Abstract: We demonstrate that surface deformation mediated by contamination plays a major role in images of graphite obtained by a scanning tunneling microscope in air. Atomic resolution has been obtained with the surface compressed by as much as 100 \AA{}, where abnormally high atomic corrugations, up to 24 \AA{}, are observed. Calculation of the deformation profile reveals that the force necessary to deform the surface must be spread over several thousand square angstroms. The measured deformation is negligible in vacuum with a clean sample and tip, and the corrugation is 0.9 \AA{}.
215 citations
TL;DR: In this paper, an attempt to date the individual deformation episodes, over 50 conventional K-Ar and 1140 Ar/39Ar incremental gas release analyses have been carried out on fine grained white micas separated from samples whose structural settings were well known.
201 citations
Book•
01 Jan 1986
TL;DR: In this paper, the authors present a review of the development of ideas regarding oceanic frontogenesis in the literature and present a classification of frontal zones and fronts of the World Ocean.
Abstract: 1. The Subject and Methods of Research.- 1.1. Historical summary of the development of ideas regarding oceanic fronts.- 1.2. Definitions, terminology and criteria.- 1.3. Classification of frontal zones and fronts of the World Ocean.- 1.4. Modern methods of frontal research.- 2. General Physical Description of the Phenomenon.- 2.1. How frequently are fronts encountered in the ocean?.- 2.2. General background of spatial variability in temperature and salinity near the surface of the ocean.- 2.2.1. Composite spectrum of spatial variability of the temperature field in the ocean.- 2.2.2. Spatial variability of salinity.- 2.3. Main physical parameters of frontal zones and interfaces.- 2.4. On the conditions of frontogenesis in the ocean and in the atmosphere.- 2.5. The concepts of deformation field and frontogenesis.- 2.6. On numerical modelling of oceanic frontogenesis.- 2.7. Problems of general frontal dynamics.- 2.8. Factors controlling the evolution of fronts.- 2.8.1. The effect of wind on near-surface fronts.- 2.8.2. Wave-like instability at fronts.- 2.9. On the two important functions of Ekman boundary layers.- 3. Characteristic Features of Oceanic Fronts.- 3.1. Eddies and fronts in the ocean.- 3.1.1. Frontogenesis in synoptic eddies.- 3.1.2. Eddy generation at fronts.- 3.1.3. Frontal systems of Gulf Stream rings.- 3.2. Peculiarities of coastal upwelling fronts.- 3.3. Salinity fronts originating from river discharge into coastal areas of the ocean.- 3.3.1. Open-sea discharge fronts.- 3.3.2. Estuarine fronts.- 3.4. Coastal fronts with tidal mixing.- 3.5. Surface phenomena of a frontal nature.- 4. Fronts and the Structure of the Ocean.- 4.1. On the multifrontal structure of frontal zones.- 4.2. Thermohaline finestructure near oceanic fronts.- 4.2.1. Characteristics of the thermohaline finestructure of frontal zones.- 4.2.2. The formation, evolution and destruction of frontal intrusions.- 4.3. Characteristic features of the three-dimensional spatial structure of frontal zones (as in the example of the Gulf Stream).- 4.4. Cross-frontal transfer.- 4.4.1. Estimates of double-diffusive heat and salt transport.- 4.4.2. Role of the density increase due to mixing.- 5. Problems for Future Research and the Concerns of Associated Disciplines.- 5.1. Some generalizations.- 5.2. Research on the physics of frontal phenomena in the ocean and associated problems of other disciplines.- 5.3. Future research tasks.- References.
TL;DR: It is shown how to use the results of this analysis to obtain the constitutive relations, as well as the associated material parameters, from the corresponding experiments, to give a detailed account of the deformation and interaction of the fluid and solid phases in the tissue.
Abstract: The dynamic finite deformational behavior of a biphasic model for soft hydrated tissue is examined. In the case of uni-axial confined compression the displacement and stress fields are derived for steady-state permeation, creep, and stress-relaxation. It is shown how to use the results of this analysis to obtain the constitutive relations, as well as the associated material parameters, from the corresponding experiments. It is also shown that the solutions from the theory go much farther, giving a detailed account of the deformation and interaction of the fluid and solid phases in the tissue.
TL;DR: The results reveal an analogy with the tensile properties of cartilage and indicate that the collagen network is mainly responsible for controlling the "instantaneous" deformation, while the proteoglycans play an indirect role by modulating the stiffness of the collagennetwork through their osmotic pressure.
TL;DR: This study proposes a mathematical model of skin deformation based on the finite element method which facilitates the modeling of complex structures by analyzing them as an aggregate of smaller elements.
Abstract: Skin flap design has traditionally been based on geometric models which ignore the elastic properties of skin and its subcutaneous attachments. This study reviews the theoretical and experimental mechanics of skin and soft tissues (I) and proposes a mathematical model of skin deformation based on the finite element method (III). Finite element technique facilitates the modeling of complex structures by analyzing them as an aggregate of smaller elements. This paper gives the results of an animal model developed to study the deformation and mechanical properties of skin, including its viscoelastic properties (hysteresis, creep, and stress relaxation). A new skin extensometer, constructed with digital stepper motors and controlled with a microcomputer, is described to measure these properties for both skin and its subcutaneous attachments. Deformation grids quantitated from photographs with a digitalizing tablet are presented, and computer software is introduced to standardize and analyze them (II). The mathematical model is used to simulate wound closures such as the ellipse and rectangular advancement flap. In addition, a series of mathematical experiments performed to simulate deformation of a strip of skin are described; the relationships between the various elastic constants are investigated; and a comparison of these simulations with actual deformation is presented. Limitations of the model and areas for future investigation are discussed (III).
TL;DR: In this article, a novel mode of deformation of circular tubes axially compressed on to a die is examined experimentally with regard to its energy absorbing capacity, where the tube splits as a number of axial cracks are produced and the strips so formed are bent into curls.
TL;DR: In this paper, the dominant deformation mechanism within foreland thrust sheets is the displacement of blocks of weakly deformed rock on discrete, mineral-coated minor faults, such minor faults are members of families or populations of consistently oriented structures.
TL;DR: In this article, a thermo-rheological model of the deformation of the continental lithosphere was used to examine intraplate continental deformation, including brittle-ductile transition depth and flexural rigidity.
Abstract: Summary A thermo-rheological model of lithosphere deformation, incorporating the elastic, ductile and brittle behaviour of lithosphere material, has been used to examine intraplate continental lithosphere strength, brittle-ductile transition depth and flexural rigidity. These parameters are critically dependent on crust and mantle rheology and consequently on geothermal gradient, crustal thickness and lower crustal composition. For lithosphere subjected to a lateral tectonic force, creep in the lower crust and mantle leads to stress release, and the subsequent stress redistribution generates stresses in the upper lithosphere sufficient to cause brittle fracture. The extent of creep in the lower crust and mantle and the degree of upper lithosphere stress amplification (which together determine bulk lithosphere strength) increase with geothermal gradient. For significant lithosphere extension, under maximum likely levels of available tectonic stress, a lithosphere surface heat flow of 60 mW m−2 or greater is required, while for compressive lithosphere deformation, heat flow must exceed 75 mW m−2. Similarly flexural rigidity increases with increase in the thermal age of the lithosphere at the time of loading. The depth of the brittle-ductile transition decreases with increase in geothermal gradient. For a limited range of gradients (expressed by heat flow q = 50–55 mW m−2) multiple brittle-ductile transitions may exist in the middle and lower crust and upper mantle, with important tectonic implications (e.g. for intra-crustal detachments and crust-mantle decoupling). Lithosphere strength in extension and compression, and flexural rigidity, are both controlled by the quartzo-feldspathic rheology of the crust for thermally young lithosphere and by the olivine rheology of the mantle for older lithosphere. Lithosphere strength is therefore critically influenced by the thickness of the crust (decreasing with increase in crustal thickness) and by the composition of the lower crust, particularly for lithosphere with intermediate heat flows.
Patent•
17 Apr 1986
TL;DR: In this paper, the authors proposed a method of using a computer graphic system for free-form deformation of geometric models based on the use of a control-point grid which is imposed on the model and which can then be moved by a system designer to specify a deformation to a particular region of the model.
Abstract: A method of using a computer graphic system for free-form deformation of geometric models. The method is based on the use of a control-point grid which is imposed on the model and which can then be moved by a system designer to specify a deformation to a particular region of the model. Displacement of control points on the grid provides the designer with an intuitive appreciation for the resulting affect in terms of deformation on the specified region of the geometric model. The free-form deformation of the model is accomplished through the use of a trivariate vector rational polynomial in which the displaced control points represent coefficients of the polynomial. The method provides a powerful and highly flexible technique that can be adapted and used in the environment of virtually any presently known solid modeling system, such as CSG or B-rep. The method can be used to deform surface primitives of any type or degree, such as planes, quadrics, parametric surface patches or implicitly defined surfaces. Single or successive deformations can be applied both globally and locally, and local deformations can be imposed using the method of the present invention with any desired degree of derivative continuity. It is also possible to use the method of the present invention to deform a solid geometric model in such a way that its volume is preserved.
TL;DR: In this paper, the conditions for which the initial disturbance will amplify as the lithosphere extends are evaluated for a range of rheological parameters, and the associated pattern of near-surface deformation is determined.
TL;DR: This study proposes a mathematical model of skin deformation based on the finite element method which facilitates the modeling of complex structures by analyzing them as an aggregate of smaller elements.
Abstract: Skin flap design has traditionally been based on geometric models which ignore the elastic properties of skin and its subcutaneous attachments This study reviews the theoretical and experimental mechanics of skin and soft tissues (I) and proposes a mathematical model of skin deformation based on the finite element method (III) Finite element technique facilitates the modeling of complex structures by analyzing them as an aggregate of smaller elements This paper gives the results of an animal model developed to study the deformation and mechanical properties of skin, including its viscoelastic properties (hysteresis, creep, and stress relaxation) A new skin extensometer, constructed with digital stepper motors and controlled with a microcomputer, is described to measure these properties for both skin and its subcutaneous attachments Deformation grids quantitated from photographs with a digitalizing tablet are presented, and computer software is introduced to standardize and analyze them (II) The mathematical model is used to simulate wound closures such as the ellipse and rectangular advancement flap In addition, a series of mathematical experiments performed to simulate deformation of a strip of skin are described; the relationships between the various elastic constants are investigated; and a comparison of these simulations with actual deformation is presented Limitations of the model and areas for future investigation are discussed (III)
TL;DR: In this article, a three-dimensional numerical model for predicting beach evolution was developed by improving a wave calculation method and sediment transport formulas, which includes wave refrasurement and wave propagation.
Abstract: A three-dimensional numerical model for predicting beach evolution has been developed by improving a wave calculation method and sediment transport formulas. The wave computation includes wave refr...
01 Jan 1986
TL;DR: In this article, the authors trace the development of tectonic models for the Indo-Australian plate to illustrate techniques for the analysis of such deformation and identify anomalous seismicity near the Ninetyeast and Chagos-Laccadive Ridges demonstrated the existence of the deformation.
TL;DR: In this article, a convective co-ordinate system is used to take into account the effect of geometric change during one step in the incremental analysis of a planar anisotropic rigid-plastic sheet metal.
TL;DR: Tselentis et al. as mentioned in this paper measured the rates of crustal deformation in the Gulf of Corinth (central Greece) as determined from seismicity, and found that the deformation rate in the area is about 1 mm/r.
TL;DR: In this paper, a simplified, economical and highly accurate method for large deformation, postbuckling, analyses of frame-type structures is presented, using the concepts of polardecomposition of deformation.
Abstract: In this paper, a simplified, economical and highly accurate method for large deformation, post-buckling, analyses of frame-type structures is presented. Using the concepts of polar-decomposition of deformation, an explicit expression for the tangent stiffness matrix of a member/element of the frame, that accounts for the nonlinear bending-stretching coupling, is derived in closed form, at any point in the load-deformation path. The ranges of validity of the present simplified approach are discussed. Several example problems to demonstrate the feasibility of the present approach, over ranges of deformation that are well beyond those likely to occur in practical large frame structures, are included.