Drawing Of Sheets Research Articles

Learning Languages in a Creative Way: Young Children Using the Computer in Discovering the Written Word and the Spoken Language

Abstract The computer is the same sort of aid as drawing sheets or coloured crayons, by which children communicate their messages, their stories, and their wishes to us. Its creative application actually speeds up the rate of learning, and provides maximum opportunity for those skills to unfold which, if traditional means were used, would probably come to the surface much later. If the appropriate software is available, it is possible to create a pedagogical environment which centres on the children themselves, an environment where they can discover the world of the written language at their leisure, learn to read and write at their own pace, even, moreover, in a language different from their own. By using the software Fairy‐Tale World, children can print their drawings and texts and, at the same time, they can learn several hundred foreign words easily.

Leonardo da Vinci: The Anatomy of Man

This volume consists of reproductions of 23 sheets of the anatomical drawings of Leonardo da Vinci (1452-1519) together with explanatory discussions of their content and significance. These were selected from the extensive collection of his anatomical works in the Royal Library at Windsor Castle. They formed the basis for an exhibition that was organized in 1992. Leonardo conducted extensive anatomical dissections in humans. Most of his written records are lost, but several hundred heavily annotated drawings have been preserved. The majority came into the possession of the British monarchy in the early 17th century. Their significance was not recognized until well into the 19th century. The contributions of Andrei Vesalius (1514-1564) had been recognized long before those of Leonardo were acknowledged. Leonardo's anatomical studies began as a companion to his work as an artist. His insatiable curiosity and demand for the primacy of direct observation (the Aristotelian and Hippocratic method)

Finite deformations of anisotropic polymers

A model for the thermomechanical behavior of anisotropic polymers under finite deformations below the glass-transition temperature is developed. The anisotropy is deformation-induced and the principal axes of the plastic stretch tensor are used to define the local axes of orthotropy at each material point of the deforming polymer. The formulation is based on a multiplicative decomposition of the deformation gradient tensor into elastic and plastic parts. An expression for the plastic spin, which is the average spin of the continuum as seen by an observer spinning with the axes of orthotropy, is derived. The numerical implementation of the model in a finite-element program is discussed and an algorithm for the numerical integration of the elastoplastic equations is developed. The problems of plane strain drawing and extrusion of polymeric sheets are solved using the finite-element method.

Simulations of earing in aluminum single crystals and polycrystals

Simulations of earing during the deep drawing of single crystals and of polycrystalline sheets have been performed. The anisotropic constitutive properties responsible for the earing phenomenon are derived from crystal plasticity models. These models account for the evolution of anisotropy at finite strains. The behavior of the polycrystalline materials was specified by ascribing part of the behavior to the dominant crystal orientations. The remaining volume fraction was characterized by isotropic plasticity. A detailed finite-element model and a simplified model of the deforming flange adequately capture the behavior of the single-crystal cups. Calculations depicting the drawing of polycrystalline sheets give earing predictions which are in reasonable agreement with the experiments. Less satisfactory agreement is obtained from solutions using a phenomenological yield surface description.

Roman Distance Slabs: two 17th century drawings based on fieldwork by John Adair, FRS and their inter-relationship and context.

Summary Two entirely separate sheets of drawings of Roman sculptured stones, chiefly “distance slabs” (1) from the Antonine Wall or associated features, and both dating to the 1690s, are described and discussed. It is found that these drawings, although in different hands, are the result of fieldwork by the cartographer John Adair (d.1718). Adair's interest and researches on Roman Scotland are outlined, and further links with the Oxford antiquarian circle are noted.

Lumbosacral spine imaging: Physioanatomic method

Noninvasive evaluation of low back and leg pain has progressed rapidly over the past decade. The development of computed tomography, single-photon emission-computed tomographic bone scan, and magnetic resonance imaging has markedly increased diagnostic accuracy in detecting pathologic conditions. With this increased accuracy has come recognition of a 50% prevalence of underlying abnormalities in patients between 20 and 60 years old who have no symptoms. When such patients have a back injury, subsequent imaging will show in half of the population studied abnormalities that are not related to an acute injury. Degeneration of the spine progresses in all patients throughout their lifetime, and nearly all of the population will have back discomfort at some time. Political- and judicial-based compensation for back injuries related to accidents and on-the-job injuries provides an incentive for patients not to improve on therapy and to exaggerate symptoms, further complicating the clinical evaluation of their condition. The goal of physioanatomic noninvasive and invasive imaging evaluation presented in the following chapters is to increase specificity by differentiating pain generators from asymptomatic underlying pathologic conditions. When used with intensive conservative management and psychologic testing, this physioanatomic approach has resulted in much better treatment outcomes in our experience. The physioanatomic approach is quite simple, consisting of rigorous correlation of pathologic changes demonstrated by noninvasive imaging modalities (computed tomography, single-photon emission-computed tomographic bone scan, and magnetic resonance), or invasive modalities (diskography-enhanced computed tomography, nerve root block, and facet block) with the patient's symptoms to evaluate whether the symptoms and the pathologic lesion are concordant or discordant. Patient symptoms and history are evaluated by use of a pain drawing and information sheet. The patient's pain pattern is categorized into a nonspecific pattern or into one of four recognizable pathway patterns (radicular, dorsal ramus, polyneuropathy, and sympathetic). Because each spinal lesion is typically manifested primarily via one of the four symptom pathways, the distribution of expected symptoms from each pathologic feature can be compared with the patient's pain drawing, and an assessment of the significance of imaged lesions can be made. The patient's presenting symptoms are also used to determine the most cost-effective and efficacious use of initial diagnostic imaging evaluation. In a minority of patients the findings on noninvasive imaging either will not correlate with the patient's symptoms or will demonstrate multiple abnormalities that could account for the patient's symptoms. In these patients, invasive techniques are extremely helpful in defining a pain generator or pain generators. Such evaluation is typically performed only after intensive conservative management has failed and the patient is a surgical candidate. This physioanatomic invasive evaluation improves surgical planning and treatment outcomes in our experience.

Friction in deep drawing of aluminium sheet

A new testing device has been developed to investigate the mechanism of friction and lubrication in the deep-drawing process. The frictional force occurring in the flange part of the cup was measured directly. The relevant factors likely to affect the frictional resistance at the tool-metal interface include the clamping force, the drawing speed and the viscosity of the lubricant. One additional factor related to the frictional behaviour is the characteristics of a lubricating layer in the flange area. The mechanisms can be assessed by examining optical micrographs of the worn surface and the variation in the surface roughness on the flange during the deep-drawing process.

Formability characterisation of aluminum cladded deep drawing sheets for automotive catalytic converters and simular parts

Aluminium cladded steel sheets are not resistant to ageing. Therefore, it should be expected that both the mechanical properties and the press performance or ductility of them will be depending on time after skin-pass rolling. Results of investigations over a range of 100 days between skin-pass rolling and testing are delivering on the one hand a significant change of the material properties. But, on the other hand a nearly constant press performance is observed over the same range.

A Formable Advanced Thermoplastic Composite Sheet Based on an Excess Filament Length Concept

The development of a formable or stampable advanced thermoplastic com posite sheet is described. This unique sheet structure is based on an excess filament length concept that enables excellent sheet drawability, making possible the fabrication of com plex shapes while maintaining high advanced composite properties. The analysis of two fiber structures are presented—namely, sine wave and straight/zig-zag fiber patterns. Data is presented to show the dependence of sheet property on fiber structure. Results of theo retical analyses for the prediction of sheet properties of known fiber structures are also presented. In general the straight/zig-zag fiber structure gives higher mechanical proper ties than the sine wave structure. Reasons for these property differences are suggested. Ex amples of parts formed to demonstrate the concept of fabricating complex shapes of high properties are shown. Even though the sheets before forming have lower strength, when the fibers straightened out upon forming, properties obtained were equivalent to those of straight continuous fiber composites.

FFG-61 Prototype Digital Technical Library

USS Ingraham (FFG-61) is the prototype ship for NavSea's Advanced Technical Information System (ATIS). ATIS is a digital technical library, which holds on optical disks the ship's 2,000 technical manuals and 73,000 drawing sheets. It contains a detailed ship's configuration index (derived from SCLSIS) to lead the user to the proper drawing or manual, and it replaces the ship's aperture cards and the second (library) copy of the technical manuals. ATIS, and the data standards established and tested through ATIS development, will be the technical library portion of micro-SNAP and SNAP III. It also forms an important part of NavSea's plans to utilize EDMICS data. This paper describes the goals and technical concepts behind the development of ATIS. Problems encountered, solutions developed, and lessons learned are detailed. Special attention was paid to the application of the Computer Aided Acquisition and Logistic Support (CALS) standards, problems caused by conflicts and ambiguities in those standards, and recommendations for future application and tailoring of the standards. Original program goals are compared with actual operational experiences. Plans for future expansion are outlined, including applications of this technology in the availability planning and execution process. A comparison is developed among the various methods of optical imaging and their costs and benefits.

Investigation of Factors Affecting the Coefficient of Friction and Surface Properties with a Sheet Drawing Test

Abstract The purposes of this study are to examine systematically the effect of tribological factors on the coeffocient of friction and surface features of drawn sheet, and to propose a method for predicting and controlling the surface brightness before sheet drawing. Aluminum sheet drawing experiments are carried out, by changing the drawing speed and viscosity of lubricant. From the experimental results, it is seen that since all the data fall on a single brightness versus calculated entrance oil film thickness curve, the surface brightness howeveris predictable using the entrance oil film thickness. The coefficent of friction is not significantly dependent on the lubricant viscosity and drawing speed.

Finite element simulation of deep drawing of stainless steel sheet with deformation-induced transformation

Plastic deformation and temperature distribution in deep drawing of stainless steel sheets with deformation-induced martensitic transformation are simulated by using the rigid-plastic finite element method and the finite element method for heat conduction. The variation of the martensite content is obtained from the calculated strain and temperature. To take the flow stress expressed by a complicated function of strain-rate into consideration, the rigid-plastic finite element method is formulated on the basis of the equilibrium of nodal forces without using the functional. The forming limit in axi-symmetruc deep drawing of austenitic stainless steel sheets is determined by the occurrence of localized necking. Effects of the punch speed and the temperature on the formability are examined.

Hot deep drawing of titanium sheet

Commercial purity titanium (IMI 125) and a Ti–Cu alloy (IMI 230) in sheet form have been deep drawn at room temperature and at elevated temperatures. Cylindrical cups drawn at room temperature and at temperatures up to about 550°C develop four ear peaks at about 45° to the rolling direction (RD). When drawing is carried out at temperatures above 600°C, two ear peaks are formed at 90 and 270° to RD. The change in anisotropy is attributed to the temperature dependence of crystallographic slip modes, the high temperature behaviour being associated with basal plane slip. Drawing with a temperature gradient (cold punch, heated die) enables high drawing ratios to be achieved.MST/1352

Hot deep drawing of titanium sheet

Hot deep drawing of titanium sheet

An Interpretation of the Speed Dependence of the Coefficient of Friction under the Micro-PHL Condition in Sheet Drawing

In the previous work, the authors confirmed the occurence of the so-called micro-hydrodynamic lubrication mechanism using a newly developed sheet drawing apparatus with a transparent quartz die. In order to search possibility of this mechanism to reconcile low friction and smooth surface finish in metal forming operations, the speed dependence of the coefficient of friction is examined under the same experimental conditions. The increase in the coefficient of friction with increasing drawing speed is then interpreted in terms of the measured volume of the surface pockets trapping lubricant.

Numerical and Experimental Investigations of Deep Drawing of Metal Sheets

Results of a comprehensive study on deep drawing are presented. The numerical results are based on finite element procedure developed for simulation of arbitrarily shaped, 3-D forming operations. The elastic-plastic material description with Hill’s anisotropic model is employed allowing for elastic effects, unloading, and multistage processes. By applying a proper computational model of large strain and large rotation plasticity, reliable results were obtained even using relatively simple material and friction laws. Predicted values of the press force, strain distributions, and flange reduction are compared with the corresponding results from axisymmetric deep draw experiments for a wide range of materials used in real forming applications including a deep drawing quality steel, brass, high strength steel, stainless steel, and aluminum. The parametric study shows the sensitivity of the solution on material parameter variations. Presented results can be considered as a set of benchmark problems.

The stretching of a thin viscous inclusion and the drawing of glass sheets

A thin, two-dimensional inclusion of a highly viscous fluid is deformed by an external Stokes flow—a suggested mechanism by which the Earth’s oceanic crust is entrained and thinned by the mantle. The method of matched asymptotic expansions is applied with the small expansion parameter being the inverse aspect ratio of the inclusion. The kinematic condition and continuity of shear and normal stresses lead to boundary conditions for the biharmonic equation governing the outer flow in the two cases of stretching by a pure shear and by a simple shear flow. The evolution of the inclusion can then, in principle, be determined. The equations governing the drawing of glass sheets may be derived as a limiting case, and any asymmetry in the centerline of the sheet is deformed over a short time scale before stretching occurs. Several examples are computed, showing how the straightening of the sheet can be slowed down by constraints on the gradients at the two ends. It is shown that an inclusion with smooth initial data cannot break up in a finite time.

Research on the tool-workpiece compatibility in deep drawing. 2nd report. Assessment of compatibility from the standpoint of contact ratio and frictional shearing stress at die profile radius.

Experimental equipment used to assess the tool-workpiece compatibility in deep drawing is designed and built. In this construction, a die is divided into two coaxial parts and the one with die profile radius can be rotated so that the meridian component of frictional force reduces with increasing its peripheral velocity. A sophisticated procedure, which clarifies contact ratio and frictional shearing stress in the tool-workpiece interface using experimental results and theoretical relationships, is introduced. By means of experimental drawing of copper and stainless steel sheets with three kinds of die materials (carbide, die steel, and aluminum bronze), the response of the contact ratio and frictional shearing stress to changes in blank holding force, drawing ratio and ironing ratio, is evaluated. Consequently, a deeper understanding of the phenomenon acquired, and it is confirmed that the contact ratio and the frictional shearing stress behave independently to determine the tool-workpiece compatibility.

Deep drawing of polypropylene sheets under differential heating conditions

AbstractMeans of improving the deep drawability of thermoplastic sheets were explored by introducing temperature gradients in the deforming material during deep drawing of initially flat sheets. The specific experimental procedure consisted of either limiting the heating to the flange section of the deforming sheet or exposing the entire material to higher temperatures. At the same time, the initial blank size and the clamping force at the flange section were varied systematically. Both polypropylene and polypropylene with 40 percent calcium carbonate in the form of sheet were tested up to 130°C. It is demonstrated that the draw‐ability increases markedly with increasing temperature gradient between the flange and punch sections. The results of measured strain distribution in the deformed part indicate that the magnitude of temperature difference between the flange and punch sections determines the relative amount of deep drawing and stretching in the wall of the formed part, which in turn dictates the drawability of the material.

Modification of a surface profile's horizontal spacing during strip drawing

Stylus profilometry is used to quantify surface damage resulting from single-pass strip drawing (SD) of different deep-drawing quality steel sheets. Simple straightforward methods are presented to determine and follow the penetration depth, real bearing area A r , average summit density and average summit length as a function of normal load F N . By comparing the real horizontal spacing during SD with the corresponding parameters resulting from a fictitious levelling down, based on purely topological aspects of the virgin sheets prior to SD, the plastic deformation resulting from the ironing action of the dies is quantified. The variation in A r as a function of F N in SD turns out to depend mainly on the topology of the virgin sheets. The corresponding variation in the average summit length clearly shows an important contribution due to plastic deformation of the surface profile.