Showing papers on "Deformation (meteorology) published in 1968"
TL;DR: In this paper, the frequency-magnitude relation of microfracture deformation was studied and the dependence of the parameter b on rock type, stress, and confining pressure was found to depend primarily on stress.
Abstract: During the deformation of rock in laboratory experiments, small cracking events, i.e., microfractures, occur which radiate elastic waves in a manner similar to earthquakes. These radiations were detected during uniaxial and triaxial compression tests and their frequency-magnitude relation studied. They were found to obey the Gutenberg and Richter relation log N = a + b M
Where N is the number of events which occurred of magnitude M , and a and b constants. The dependence of the parameter b on rock type, stress, and confining pressure was studied. It was found to depend primarily on stress, in a characteristic way. The frequency-magnitude relation for events which accompanied frictional sliding and deformation of a ductile rock was found to have a much higher b value than that observed in brittle rock. The Gutenberg and Richter formulation of the frequency-magnitude relation was derived from a statistical model of rock and crustal deformation. This analysis demonstrates the basis of similarity between rock deformation experiments in the laboratory and deformation of the crust.
1,415 citations
Journal Article•
TL;DR: In this paper, the conditions générales d'utilisation (http://www.numdam.org/conditions) are defined, i.e., toute utilisation commerciale ou impression systématique is constitutive d'une infraction pénale.
Abstract: L’accès aux archives de la revue « Annali della Scuola Normale Superiore di Pisa, Classe di Scienze » (http://www.sns.it/it/edizioni/riviste/annaliscienze/) implique l’accord avec les conditions générales d’utilisation (http://www.numdam.org/conditions). Toute utilisation commerciale ou impression systématique est constitutive d’une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright.
781 citations
TL;DR: In this paper, a new experimental method which increased the sensitivity of detection by several orders of magnitude over that of previous studies was used, and the pattern of crack occurrence for a wide variety of rocks and at confining pressures up to 5 kb was found to be closely related to the stress-strain behavior.
Abstract: The cracking that occurs during the deformation of rock in compression was studied by detecting and analyzing the radiated elastic waves. A new experimental method which increased the sensitivity of detection by several orders of magnitude over that of previous studies was used. The pattern of crack occurrence for a wide variety of rocks and at confining pressures up to 5 kb was found to be closely related to the stress-strain behavior. Dilatancy in the region above half the fracture stress was found to be directly proportional to cracking. Microfracturing, i.e. cracking, of brittle rock was compared with the microfracturing observed in frictional sliding and in the deformation of ductile rock. Cataclastic deformation of marble was found to be similar to frictional sliding in this respect but distinctly different than brittle deformation. The marble was found to undergo a gradual transition from cataclastic to fully plastic flow as confining pressure was increased in tests up to 4 kb. A model of deformation of an inhomogeneous brittle material is introduced which predicts the observed microfracturing activity and inelastic stress-strain behavior of rock. According to this model, microfracturing events in the dilatant region below about 95% of the fracture stress can be considered randomly independent. At higher stresses, where a rapid acceleration of activity is observed, the events cannot be considered independent and are correlated with the formation of the fault.
601 citations
TL;DR: Magnetic anomalies and fracture zones make distinctive patterns when the direction of sea floor spreading changes as has occurred repeatedly in the north-eastern Pacific as mentioned in this paper, where the mode of deformation is such that the spreading centres between transform faults become uniformly reoriented essentially perpendicular to the faults.
Abstract: Magnetic anomalies and fracture zones make distinctive patterns when the direction of sea floor spreading changes as has occurred repeatedly in the north-eastern Pacific. The mode of deformation is such that the spreading centres between transform faults become uniformly reoriented essentially perpendicular to the faults.
300 citations
TL;DR: In this paper, an approximate analysis of the viscous deformation of a thin circular diaphragm clamped at the periphery and subjected to one-sided hydrostatic pressure is presented.
168 citations
156 citations
01 Jan 1968
TL;DR: Statistical measurements of deformation structures and refractive indices in experimentally shock loaded quartz specimens with different crystallographic orientations were performed in this article, showing that the deformation structure of the quartz specimens varied with different orientations.
Abstract: Statistical measurements of deformation structures and refractive indices in experimentally shock loaded quartz specimens with different crystallographic orientations
136 citations
TL;DR: In this paper, simple ideas of the structure of oriented polymers are used to explain the main features of the deformation behavior, including the change in the extinction direction within a deformation band, and they are of a sufficiently general nature to be applicable to all oriented linear polymers.
Abstract: Polyethylene terephthalate sheet which had been oriented by drawing was subsequently deformed in tension where the primary variable was the angle between the stress and the initial drawing direction. The beginning of yielding was marked by the formation of a narrow deformation band which had the following important characteristics: (1) the shear strain in the band was about 200%, (2) the direction of the band was nearly but definitely not parallel to the initial drawing direction and (3) the direction of optical extinction under crossed polarizers rotated from the initial drawing direction toward the axis of stress. Simple ideas of the structure of oriented polymers are used to explain the main features of the deformation behaviour, including the change in the extinction direction within the deformation band. These ideas are of a sufficiently general nature to be applicable to all oriented linear polymers.
60 citations
Patent•
10 Oct 1968
TL;DR: A frangible item is packed into a container by pouring therein all round the item a packing material to fill the space between the item and the walls of the container, the packing material comprising a mass of open-ended hollow bodies of expanded framed plastics material which interlock with each other when subjected to pressure as discussed by the authors.
Abstract: 1,262,346. Packaging frangible articles. FREE FLOW PACKAGING CORP. 4 Feb., 1969, No. 5909/69. Heading B8C. [Also in Divisions B5 and C3] A frangible item is packed into a container by pouring therein all round the item a packing material to fill the space between the item and the walls of the container, the packing material comprising a mass of open-ended hollow bodies of expanded framed plastics material which interlock with each other when subjected to pressure. The plastics material may be an alkenyl aromatic or olefine polymer or a polyurethane. The bodies may be shaped as shown in Figs. 1, 2, 3 and 10-17 and may be used to pack a carton as shown in Figs. 5-7 wherein a klystron tube 88 is in carton 86. In Fig. 7 a blow at 96 is absorbed by deformation and compacting of the hollow bodies at 94: 90 shows vibration of the carton on floor 92 of a transporter.
TL;DR: The deformation microstructures associated with aluminium after shock loading and cold rolling at room temperature and at liquid nitrogen temperature are presented and discussed in this paper, where a high density of point defects is produced by shock loading aluminium and it is observed that vacancy-produced dislocation loops are more numerous than those produced by interstitial clustering.
Abstract: The deformation microstructures associated with aluminium after shock loading and cold rolling at room temperature and at liquid nitrogen temperature are presented and discussed. A high density of point defects is produced by shock loading aluminium and it is observed that vacancy-produced dislocation loops are more numerous than those produced by interstitial clustering. Comparison is made with the response of copper and nickel to shock and it is shown that aluminium does not form dislocation cell structures as these metals do under similar loading conditions. The temperature of deformation has little effect on the microstructure in the low pressure range, but as pressure increases the temperature of deformation becomes more important. Mechanisms for the production of defects are discussed.
TL;DR: In this article, a slip line field was constructed for the deformation of a rigid perfectly-plastic wedge compressed by a flat rigid die and subsequently sheared by a force acting tangentially to the face of the die.
Abstract: A slip-line field has been constructed for the deformation of a rigid perfectly-plastic wedge compressed by a flat rigid die and subsequently sheared by a force acting tangentially to the face of the die. An associated velocity field is suggested. Consistency between the slip-line field, the velocity field and the changing profile of the wedge as deformation proceeds is closely, though not exactly, preserved. The progressive deformation has been found, using these fields, by an incremental graphical construction. The deformation and the growth of the area of contact between the wedge and the die face under the action of a constant normal force and increasing tangential force are found to agree well with experiment. The theoretical contact area growth supports Tabor's empirical expression for ‘junction growth’ in the build-up of static friction between metallic surfaces.
TL;DR: In this paper, a specific form of deformation occurs; during the early stages the molecules and the lamellae become oriented at an angle of 30° to the draw direction, and the number of molecules so oriented increases with increasing draw up to about 150% deformation.
Abstract: Wide-angle X-ray diffraction, small-angle X-ray diffraction, and electron microscopy have been applied to the study of the deformation of spherulitic polyoxymethylene at 125°C. The results show that a specific form of deformation occurs; during the early stages the molecules and the lamellae become oriented at an angle of 30° to the draw direction (the molecular axes are therefore tilted within the lamellae). The number of molecules so oriented increases with increasing draw up to about 150% deformation, after which the molecular axes tilt further, into the draw direction. The mechanism of deformation is seen to differ in different sectors of a spherulite. Folds are retained in the fully drawn material.
TL;DR: In this paper, a diffusion equation is obtained that describes the mechanical dispersion of a dilute mixture of solid particles within an ice matrix that is undergoing deformation, and it is shown that within the limits of time intervals and strain-rates appropriate to the movement of glaciers and ice sheets, the dispersal distance usually is no larger than a distance about one order of magnitude greater than the size of the particles themselves.
Abstract: A diffusion equation is obtained that describes the mechanical dispersion of a dilute mixture of solid particles within an ice matrix that is undergoing deformation. It is shown that within the limits of time intervals and strain-rates appropriate to the movement of glaciers and ice sheets, the dispersal distance usually is no larger than a distance about one order of magnitude greater than the size of the particles themselves.
TL;DR: In this paper, a theory for the small deformations superposed on the large deformation of an elastic rod is given, and some aspects of material and geometrical symmetry are discussed.
01 Jan 1968
TL;DR: In this article, an elastic-viscoplastic theory based on dislocation dynamics is presented for an internally pressurized thick walled sphere, where the total deformation consists of elastic and plastic components throughout the deformation history.
Abstract: The constitutive equations that have been developed for the dynamic behavior of materials presuppose the existence of a reference “static” yield criterion. An alternative formulation motivated by the work on dislocation dynamics considers the total deformation to consist of elastic and plastic components throughout the deformation history. This procedure permits the consideration of large deformations (finite strains) in a direct manner. The present paper outlines an elastic-viscoplastic theory based on this approach and includes numerical results for an internally pressurized thick walled sphere.
TL;DR: In this article, the authors show that the usual exponential laws describing stress deformation of soils can be replaced by hyperbolic functions and derive expressions for tractive effort and rolling resistance of crawler tractors.
TL;DR: In this paper, small-angle light scattering (SALS) was used to identify the sign of birefringence of spherulites too small to be seen in the optical microscope.
Abstract: The submicroscopic morphology of uniaxially deformed isotactic polypropylene films has been examined by small-angle light scattering (SALS), electron microscopy, optical microscopy, small-angle x-ray scattering (SAXS), wide-angle x-ray diffraction, birefringence, sonic modulus, and density methods. Several new interpretations and extensions of existing theories are developed and verified experimentally as follows. (1) The Vv SALS pattern is shown to be a new tool for the identification of the sign of the birefringence of spherulites too small to be seen in the optical microscope. The theoretical dependence of the Vv SALS pattern is developed and verified experimentally with patterns from isotactic polypropylene, polyethylene, Penton, nylon 6,6, poly(ethylene terephthalate), and nylon 6,10. (2) Intraspherulitic lamellar behavior during deformation can be identified from the SAXS pattern. This includes quantitative evaluation of the long spacing between lamellae and their average orientation. (3) The two-phase sonic modulus theory is valid over the wide range of deformations, crystallinities, processing temperatures, and molecular weights used in this study. The deformation of isotactic polypropylene films drawn at 110 and 135°C. has been characterized quantitatively in terms of an integrated picture of mass movement on all morphological levels: the molecular, the interlamellar, and the spherulitic. At both temperatures, the spherulites deform affinely with extension, whereas the deformation mechanisms within the spherulite depend on the location of the radii with respect to the applied load. During spherulite deformation, lamellar orientation and separation processes predominate, whereas at high extensions, fibrillation occurs and crystal cleavage processes predominate. The noncrystalline region orients throughout the draw region. At 135°C. non-orienting relaxation processes appear in the noncrystalline region which retard the rate of molecular orientation with extension.
TL;DR: In this paper, the authors studied the nature of obstacles to dislocation motion in copper single crystals by determining their effective retarding force-distance relationship as a function of solute content (up to 7 a/o silicon) and state of deformation.
Abstract: The nature of obstacles to dislocation motion in copper single crystals has been studied by determining their effective retarding force–distance relationship as a function of solute content (up to 7 a/o silicon) and state of deformation. The obstacle energy is found to be 0·67 ev ± 0·06 ev, independent of solute content and state of deformation. While the rate-controlling barrier is independent of solute content and state of deformation, the athermal portion of the internal retarding force is observed to increase with state of deformation but to decrease markedly with increasing solute content. The results are consistent with a dislocation intersection mechanism which is discussed in detail.
TL;DR: The structural style of cryptoexplosion structures, together with features that suggest shock deformation, supports the belief that they are the eroded roots of impact craters.
Abstract: The pattern of deformation in central uplifts of Sierra Madera and other well-known cryptoexplosion structures indicates that inward as well as upward movement of strata formed the uplifts. This kind of movement is incompatible with structures not of impact origin with which they have been compared. The structural style of cryptoexplosion structures, together with features that suggest shock deformation, supports the belief that they are the eroded roots of impact craters.
Patent•
03 Dec 1968
TL;DR: In this article, a tank for use in storing low-temperature liquefied gas has an inner vessel composed of a thin film construction suspended from the top wall of an outer vessel, and is constructed so that corrugations vertically formed on the sidewall of said inner vessel may be contracted under the low temperature loaded condition.
Abstract: A tank for use in storing low-temperature liquefied gas has an inner vessel composed of a thin film construction suspended from the top wall of an outer vessel, and is constructed so that corrugations vertically formed on the sidewall of said inner vessel may be contracted under the low-temperature loaded condition to approach a smooth configuration in close contact with a heat-insulating layer provided between said outer and inner vessels. At the curved bottom corner of said inner vessel, an increase in length is produced along the outer top part of each corrugation due to the difference in length between the outer top part and inner top part of each corrugation, and said increased length appears as an additional corrugation. To prevent collapse of the additional corrugation, when the vessel is loaded, a part of the heat-insulating layer is eliminated to form a recess for the outer part of the additional corrugation, thereby providing it with a smooth deformation.