Showing papers on "Deformation (meteorology) published in 1980"
TL;DR: In the early Miocene, the Indo-Australian plate deformation appeared analogous to the buckling of an elastic plate with brittle failure at its surface as mentioned in this paper, and the onset of intraplate deformation in the late Miocene was connected to the Himalayan orogenic stage of the collision between India and Asia.
Abstract: Intraplate seismicity, deformed oceanic crust and sediments, and local areas of abnormally high heat flow characterize significant internal deformation of the Indo–Australian plate in the northeastern Indian Ocean. The deformation appears analogous to the buckling of an elastic plate with brittle failure at its surface. Itis not clear whether the Indo–Australian plate can be resolvedinto two component parts or whether a new convergent plate boundary is likely to form in the deformed region. The onset of intraplate deformation in the late Miocene seems to be connected to the Himalayan orogenic stage of the collision between India and Asia.
276 citations
TL;DR: In this paper, the pressure distribution over the area of contact between spheres undergoing linear deformation is calculated for non-linear deformation problems, such as Meyer hardness, creeping indentation and hot pressing of aggregates.
183 citations
TL;DR: In this paper, case II diffusion in glassy polymers is considered in terms of a deformation model, where the process is controlled by the mechanical response of the glass just ahead of the sharp front to an osmostic swelling stress.
182 citations
156 citations
TL;DR: The main lithological features and structural relations of the South Armorican Shear Zone (S.A.S.Z) are described and the evolution of physical conditions during deformation is outlined in this paper.
148 citations
TL;DR: In this paper, a thermodynamic theory of deformation using internal variables is adapted to rigid viscoplastic materials, and the formulations for finite element discretization are given specifically for metal forming problems.
135 citations
121 citations
108 citations
TL;DR: In this paper, a review of the use of threshold stresses and back stresses to characterize fluid flow, diffusional creep, superplastic deformation, power law creep in relatively pure metals and dislocation creep in dispersion-strengthened materials is examined.
106 citations
Journal Article•
106 citations
TL;DR: In this article, the finite element formulations for coupled analysis of deformation and heat transfer are applied to the problems of solid cylinder compression and ring compression, and the results of ring compression of aluminum at elevated temperature are compared with experimental observations as well as with calculated results not including the temperature effects.
TL;DR: In this paper, the transition from smoothly distributed asperity contact to a condition where the surfaces are supported by a few thermal asperities is discussed, including wear, cooling and hydrodynamic lubrication.
TL;DR: In this article, various phenomena associated with the large deformation compression of metal tubes between rigid plates are examined, and the relevance of these observations and the resulting theory to other plasticity problems involving bending as the primary mode of deformation is discussed.
TL;DR: In this paper, a general collective model is presented that includes all possible cases, like vibrational, rotational andγ-unstable nuclei, illustrated by the potential energy surface (PES), describing all deformation effects of the nucleus.
Abstract: A general collective model is presented that includes all possible cases, like vibrational, rotational andγ-unstable nuclei. Collective properties are illustrated by the Potential-Energy-Surface (PES), describing all deformation effects of the nucleus. The model is applied to the case of92238U, where very high-spin states are known from experiment.
TL;DR: In this paper, several strategies for numerical time-integration of some stiff constitutive models of inelastic deformation are presented for the integration of one such model for the case of uniaxial deformation under various prescribed histories of stress or strain.
Abstract: Several strategies for numerical time-integration of some stiff constitutive models of inelastic deformation are presented in this paper. Numerical results and comparisons are presented for the integration of one such model for the case of uniaxial deformation under various prescribed histories of stress or strain. A simple one step Euler type integration scheme with automatic time-step control, which can be easily adapted to the solution of multiaxial boundary value problems, appears promising.
TL;DR: In this paper, it is shown that tensile stresses in the drying outer shell usually overcome tensile strength of concrete, thus crack formation takes place and the internal stress is redistributed.
TL;DR: In this article, the authors investigated the possibility of the change of type of the differential equations governing finite plane elastostatics for incompressible elastic materials, and the related issue of the existence of equilibrium fields with discontinuous deformation gradients.
Abstract: This investigation is concerned with the possibility of the change of type of the differential equations governing finite plane elastostatics for incompressible elastic materials, and the related issue of the existence of equilibrium fields with discontinuous deformation gradients. Explicit necessary and sufficient conditions on the deformation invariants and the material for the ellipticity of the plane displacement equations of equilibrium are established. The issue of the existence, locally, of “elastostatic shocks”—elastostatic fields with continuous displacements and discontinuous deformation gradients—is then investigated. It is shown that an elastostatic shock exists only if the governing field equations suffer a loss of ellipticity at some deformation. Conversely, if the governing field equations have lost ellipicity at a given deformation at some point, an elastostatic shock can exist, locally, at that point. The results obtained are valid for an arbitrary homogeneous, isotropic, incompressible, elastic material.
TL;DR: In this paper, the effects of deformation which induces martensite in austenitic stainless steel with deformation alone noticeably increases the kinetics of sensitization only at temperatures where undeformed samples are readily sensitized.
Abstract: This paper compares the effects of deformation which induces martensite in austenitic stainless steel with deformation which does not on the sensitization and corrosion susceptibility of these alloys. We show that deformation which induces martensite causes rapid sensitization at temperatures below 600 °C, leads to extensive transgranular corrosion, and can produce rapid healing. The martensite is also an area of extensive carbide precipitation. Deformation alone noticeably increases the kinetics of sensitization only at temperatures where undeformed samples are readily sensitized. Without the presence of martensite, intergranular corrosion is always the predominant corrosion path, rapid healing is not observed, and most carbides precipitate along the grain boundaries.
TL;DR: In this article, the stress relaxation behavior of molten PMMA under large tensile deformations has been studied and the time dependence of the relaxing stress was found to be approximatively the same at all deformations.
Abstract: The stress relaxation behaviour of molten PMMA under large tensile deformations has been studied. Maximum values of the extension ratio were larger than 3.5. Similarly with previous results, the time dependence of the relaxing stress was found to be approximatively the same at all deformations. The deformation dependence was compared with the predictions of a theory byDoi andEdwards as well as with a modification of that theory which proves to agree better with the experimental results.
TL;DR: Uniaxial unconfined compression tests were carried out on frozen saturated Ottawa sand containing about 20% by weight of water, at temperatures between −2 and − 15°C, and at strain rates varying be...
Abstract: Uniaxial unconfined compression tests were carried out on frozen saturated Ottawa sand containing about 20% by weight of water, at temperatures between −2 and − 15°C, and at strain rates varying be...
TL;DR: In this article, the microstructural changes which occur during the extrusion of a commercial aluminium alloy (AA 5456) have been investigated at macroscopic, microscopic, and substructural magnifications.
Abstract: The microstructural changes which occur during the extrusion of a commercial aluminium alloy (AA 5456) have been investigated at macroscopic, microscopic, and substructural magnifications. Light microscopy has established that the deformation zone is not fully established until a short time after the peak or breakthrough pressure has occurred and that thereafter cylinder wall/billet shear is important in determining deformation. Light microscopy also reveals that recrystallized grains are present both at original grain boundaries and within grains when the deformation is advanced. Electron microscopy reveals that those grains contain a substructure and are thus dynamically recrystallized grains. The bulk of the material continues to deform with dynamic recovery as the operative mechanism. The deformation is thus duplex with dynamic recrystallization considerably modifying the structure normally observed in aluminium alloys. It is concluded that this occurs primarily because of the high solute addi...
TL;DR: In this article, a plate-type theory is developed for the flexural-extensional vibratory response and static voltage deformation of heterogeneous piezoelectric circular transducers.
Abstract: A plate‐type theory is developed for the flexural‐extensional vibratory response and static voltage deformation of heterogeneous piezoelectric circular transducer elements. Known results for homogeneous disks and bimorphs are shown to be special cases of the theory. Application is made to the design of simply supported metal‐piezoceramic unimorph disks, and thin piezoceramic bimorph benders possessing metallic electrodes of non‐negligible thickness.
TL;DR: In this article, a tie chain length distribution model was used to quantitatively interpret the IR data, and the observed long lifetimes of highly stressed chains suggest a reappraisal of existing fracture theories.
Abstract: Infrared (IR) spectroscopy was used to study molecular deformation processes in polymers as a function of stress, strain, time and temperature. Stress-induced frequency shifts were found to depend on temperature and morphology. Deformation of viscoelastic polypropylene was examined in terms of time dependent molecular stress distributions, orientation changes, conformational variations, and chain fracture. A tie chain length distribution model was used to quantitatively interpret the IR data. Molecular deformation processes of creep and stress relaxation were found to be opposite in nature, Observed long lifetimes of highly stressed chains suggest a reappraisal of existing fracture theories.