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Calculation of the technological parameters of constrained extrusion of unequal channels is considered, for plane deformation, with misalignment of the punch and matrix; the extruded material may be of hardening or nonhardening type. The analytical expressions obtained permit determination of the total and specific deforming forces and the height of the walls that are formed. [ABSTRACT FROM AUTHOR]

The propagation of shear waves inside/at the Earth’s crust during earthquake may cause the progression of punch in the rock medium. In this study, the movement of semi-infinite punch due to the propagation of the shear wave in a pre-stressed vertically transversely isotropic poro-viscoelastic medium has been analyzed. Based on Wiener–Hopf technique and two-sided Fourier integral transformations, the dynamic stress concentration due to moving punch is determined in closed form. The significant effects of various affecting parameters viz. velocity of moving punch, horizontal initial stress, vertical initial stress, anisotropy parameter, porosity, and viscoelasticity on dynamic stress concentration have been discussed. It is noteworthy that as the punch propagates with higher velocity, dynamic stress concentration in the considered poro-viscoelastic medium escalates. It is also found that horizontal tensile and vertical compressive initial stresses have an adverse impact on the dynamic stress concentration. On the other hand, the horizontal compressive and vertical tensile initial stresses have a favorable influence on the dynamic stress concentration. Also, its values increase with the increase of porosity, while it gets decreased as anisotropic parameter prevails in the considered medium. The behavior of dynamic stress concentration in three different types of pre-stressed vertically transversely isotropic poro-viscoelastic media viz. sandstone (a sedimentary rock), granite (an igneous rock), and marble (a metamorphic rock) has been compared. From this comparison, it is obtained that the dynamic stress concentration attains maximum value if the rock medium is marble and minimum value if the rock medium is sandstonel. Some graphical illustrations and numerical computations have also been established. Furthermore, some important properties are identified from the obtained dynamic stress concentration expressions. [ABSTRACT FROM AUTHOR]

The determination of the strain state of a workpiece in constrained extrusion of unequal channels is considered for plane deformation with misalignment of the punch and matrix. Formulas are obtained for the coordinates of the points and the plastic deformation under the punch close to the thick wall created, with hindered flow, for any punch pass. [ABSTRACT FROM AUTHOR]

The paper presents a research study into the effect of temperature on the properties of a mandrel and a punch during hot screw rolling and subsequent forging of 1000 medium-carbon structural steel vessels at the rolling and pressing line of the BF JSC NPO Pribor machine-building enterprise. According to the performed study, the main cause of downtimes in the technological production cycle and decreased geometric quality indicators of rolled products is related to deteriorated mechanical properties of the deforming tool. Significant temperature variations (more than 250°C) along the length of the piercing and pressing tool, made of 4Kh5MFS steel, during the hot pressure treatment were revealed. The main reasons leading to deterioration of the tool quality were established, including the loss of its strength and hardness, as well as an increase in the ductility of a piercing mandrel and a punch of up to 30 and 19%, respectively. The study identified rational ways to extend the service life of the most loaded processing tools and decrease the cost of vessels at the exit of the rolling and pressing line by 3–5%. [ABSTRACT FROM AUTHOR]

The determination of the strain state of a workpiece in constrained extrusion of unequal channels is considered for plane deformation with misalignment of the punch and matrix. Formulas are obtained for the coordinates of the points and the accumulated strain in the plastic deformation zone under the thick wall created. [ABSTRACT FROM AUTHOR]

On the basis of plastic flow theory, the determination of the kinematic and stress state of a workpiece in constrained channel extrusion is considered for plane deformation with misalignment of the punch and matrix. The forces and geometric parameters of the process are determined. Formulas are obtained for the extrusion parameters of unequal channels with a relatively thin horizontal floor. [ABSTRACT FROM AUTHOR]

On the basis of plastic flow theory, the determination of the kinematic and stress state of a workpiece in constrained channel extrusion is considered for plane deformation with misalignment of the punch and matrix. The flow rate and stress are determined in the plastic deformation region under the punch and close to the thick channel wall that forms. Formulas are obtained for the extrusion parameters of unequal channels with a thin horizontal floor. [ABSTRACT FROM AUTHOR]

Information is provided regarding the density distribution of seals made of cast-iron composites and the particle motion in cold molds on cold pressing. The influence of the mold's shaping kinematics on the density distribution over the height of the sleeve-type seal is assessed. The deviation from the mean workpiece density over the height is less in bidirectional pressing than in unidirectional pressing. The relation between the pressure on the workpiece and the compaction mechanism is analyzed for different pressing procedures. [ABSTRACT FROM AUTHOR]

On the basis of plastic flow theory, the determination of the kinematic and stress state of a workpiece in constrained channel extrusion is considered for plane deformation with misalignment of the punch and matrix. The flow rate and stress are determined in the plastic deformation region under the thick channel wall that forms. Formulas are obtained for the extrusion parameters of unequal channels with a thin horizontal floor. [ABSTRACT FROM AUTHOR]

The determination of the kinematic and stress state of a workpiece in completely constrained extrusion of unequal channels is considered for plane deformation with misalignment of the punch and matrix. The forces and geometric parameters of the process are determined. Formulas are obtained for the extrusion parameters of unequal channels with a relatively thin horizontal floor. [ABSTRACT FROM AUTHOR]

Formulas are derived for the geometric parameters that characterize the deformation of structural elements in extruded material. [ABSTRACT FROM AUTHOR]

The importance of predicting the fibrous structure of extruded parts is established. Some incorrect statements about channel extrusion in the literature are noted. A correct sequence for the analysis of fibrous structure is formulated. [ABSTRACT FROM AUTHOR]

New methods are proposed for controlling the shaping process in free channel extrusion with misalignment of the punch and matrix, so as to obtain the required wall height. Comparison with experimental results shows that the formulas obtained are highly accurate. [ABSTRACT FROM AUTHOR]

Methods are proposed for controlling the shaping process in free channel extrusion with misalignment of the punch and matrix, so as to obtain the required wall height. Comparison with experimental results shows that the formulas obtained are highly accurate. [ABSTRACT FROM AUTHOR]

Channel extrusion is studied experimentally for hardening materials. Comparison of the experimental and theoretical results shows that the formulas are highly accurate. [ABSTRACT FROM AUTHOR]

Channel extrusion is studied experimentally for nonhardening materials. Comparison of the experimental and theoretical results shows that the formulas are highly accurate. [ABSTRACT FROM AUTHOR]

Formulas are derived for the geometric parameters that characterize the deformation of structural elements in extruded material. Analysis of experimental data and theoretical results shows that the formulas are highly accurate. [ABSTRACT FROM AUTHOR]

Formulas are derived for the most important parameters of channel extrusion. [ABSTRACT FROM AUTHOR]

Attention focuses on determining the deformed state of the workpiece in free channel extrusion. The formulas obtained permit calculation of the accumulated strain at a specified point of the plastic-deformation region and the extruded channel walls for any working path of the punch. [ABSTRACT FROM AUTHOR]

Attention focuses on determining the deformed state of the workpiece in free channel extrusion. The formulas obtained permit calculation of the accumulated strain at a specified point of the plastic-deformation region and the extruded channel walls for any working path of the punch. [ABSTRACT FROM AUTHOR]

On the basis of the complete set of plastic-flow equations, the extrusion force, the maximum pressure at the matrix wall, and the wall height in channel extrusion are determined, taking account of the elastic deformation of the matrix. [ABSTRACT FROM AUTHOR]

On the basis of the complete set of plastic-flow equations, the kinematic and stress state of workpiece in channel extrusion is determined in the case of plane deformation when the punch and matrix are misaligned (noncoaxial). [ABSTRACT FROM AUTHOR]

Punches without the use of instruments/objects are a common type of body violence and as such a frequent subject of medicolegal analyses. The assessment of the injuries occurred as well as of the potential of the assault to produce severe body harm is based on objective traces (especially the documented injuries of both parties involved) as well as the—often divergent—descriptions of the event. Quantitative data regarding the punching characteristics that could be used for the assessment are rare and originate mostly in sports science. The aim of this study was to provide physical data enabling/facilitating the assessment of various punching techniques. A total of 50 volunteers took part in our study (29 males and 21 females) and performed severe punches with the fist, with the small finger edge of the hand (karate chop), and with the open hand with both the dominant and the non-dominant hands in randomized order. The strikes were performed on a boxing pad attached to a KISTLER force plate (sampling frequency 10,000 Hz) mounted on a vertical wall. The punching velocity was defined as the hand velocity over the last 10 cm prior to the contact to the pad and ascertained by using a high-speed camera (2000 Hz). Apart from the strike velocity, the maximum force, the impulse (the integral of the force-time curve), the impact duration, and the effective mass of the punch (the ratio between the impulse and the strike velocity) were measured/calculated. The results show a various degree of dependence of the physical parameters of the strikes on the punching technique, gender, hand used, body weight, and other factors. On the other hand, a high degree of variability was observed that is likely attributable to individual punching capabilities. In a follow-up study, we plan to compare the "ordinary" persons with highly trained (boxers etc.) individuals. Even though the results must be interpreted with great caution and a direct transfer of the quantitative parameters to real-world situations is in general terms not possible, the study offers valuable insights and a solid basis for a qualified forensic medical/biomechanical assessment. [ABSTRACT FROM AUTHOR]

Theoretical analyses of extrusion are reviewed in the case where the punch and matrix are misaligned. It is found that the formulas obtained do not permit successful design of extrusion processes. [ABSTRACT FROM AUTHOR]

Deep drawing is one of the important sheet-forming processes. Several process parameters are responsible for producing defect-free products of deep drawing. Out of those parameters, blank holder force is one of the widely studied process parameters, which significantly influence deep drawing. In the present study, the effect of velocity of the punch on deformation behavior of aluminum alloys is investigated. FEM simulation is conducted using commercially available software ABAQUS. It is found through FEM simulation that effective stress increases by nearly 56% with an increment in punch velocity from 150 to 350 mm/s. Besides this, equivalent plastic strain increases by five times on increment in punch velocity from 150 to 350 mm/s. von Mises stress and equivalent plastic strain found to be maximum at flange radii region (die corner) at all velocities of punch. Wrinkling is found to be absent during deformation (loading step) at all punch velocities. Wrinkling is obtained in deep drawn cups after unloading of the punch at all punch velocities except the lowest velocity of 150 mm/s. The phenomenon of wrinkling was found to be pronounced with increment in velocity of the punch after unloading of the punch. For prevention of wrinkling tendency during deep drawing, the velocity of punch should be less than 200 mm/s. Besides this, punch force, effective stress, and equivalent plastic strain found to increase nonlinearly due to increment in punch stroke. It is gathered through FEM simulation that wrinkling phenomenon increases with increment in punch velocity due to unloading of the punch during deep drawing. [ABSTRACT FROM AUTHOR]

The stamping of eyelets in brackets by plastic deformation is analyzed. The eyelet geometry and the basic requirements on the stamping process are determined. The force required for deformation of the metal in final shaping is established. [ABSTRACT FROM AUTHOR]

The formulas here proposed may be used to take account of how the hardening of deformable material affects not only the stress state and forces in extrusion but also the results of the process. [ABSTRACT FROM AUTHOR]

Conformal cooling channels introduced into manufacturing tools is fast becoming an industry standard, as it has proven to significantly reduce cycle time during operation. Introducing conformal cooling channels into a metal tool (such as a hot forming punch or injection moulding core) is a challenge on its own and often requires expertise in both additive and subtractive processes to execute efficiently. Another issue is that of the inherent constraints of both the additive and subtractive processes, which prohibit the effective use of these processes for manufacturing of specific tool designs. Thus, often a balance needs to be met, where a hybrid process is sought to utilise the advantages of both processes while limiting the disadvantages. This study suggests a viable process chain for manufacturing a large hybrid tool using milling and selective laser melting processes. A large (745 × 174 × 78.7 mm) hot forming punch with conformal cooling channels was produced by splitting the tool into four sections to fit into the build envelope of the M2 cusing machine from Concept Laser GmbH. Various considerations and challenges are highlighted. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the etiology of punctal stenosis based on the histopathological features of puncta and clinical correlations in punctal stenosis patients. Methods: A retrospective review was conducted of 69 cases from 38 patients who were diagnosed with punctal stenosis. Slit-lamp examination, the lacrimal irrigation test, dacryocystography, and spectral domain-optical coherence tomography were performed for the evaluation of punctal occlusions. For treatment, punctoplasty using a punch biopsy with or without silicone tube insertion and histopathological examinations were performed. Results: The pathological features of the punctal membranes were classified into two types of epithelia: squamous (95.7%, 66/69) and columnar (4.3%, 3/69). The squamous epithelial specimens were divided into three groups: fibrous tissue (66.8%, 48/69), goblet cells (21.8%, 48/69), and keratinization (4.3%, 3/69). Most of the subepithelial pathology was fibrosis (82.6%, 57/69), and inflammation was noted in 17.4% (12/69) of the patients. Subepithelial fibrosis was the most common pathological feature in patients exhibiting stenosis with a squamous epithelium, while inflammation was more strongly correlated with patients with a columnar epithelium. However, there was no correlation between the histopathological findings and treatment outcomes. Conclusion: Our histopathological findings suggest that primary fibrosis of the stenotic punctum was caused by intrinsic inflammation of the puncta rather than spreading from the conjunctiva or eyelid. Punctoplasty was effective in treating punctal stenosis, regardless of the epithelial type. [ABSTRACT FROM AUTHOR]

The present work is a contribution in analyzing dimensional deviations in ellipsoidal thin-layer steel heads used for high-pressure air brake reservoirs. The dimensional deviations are attributed to the thickness distribution during the drawing process with regard to input geometrical parameters such as punch and die diameter, and also die and punch fillet. The aim of the present work is therefore optimizing the input data in order to respect the initial geometrical requirement. Investigation has been carried out using FEM code Abaqus, on a case example produced by the Algerian truck company according to G.R.C E81-102 standard. FEM simulations followed the process of deep drawing and concerned the effect of the most influencing factors such as the die corner radius, the punch corner radius, and the blank radius. Dimensional deviations are analyzed in terms of variations of thinning along the true dish path and hence engineering models of the corresponding true strain in the straight zone, the knuckle zone, and the crown zone of the dish are proposed. [ABSTRACT FROM AUTHOR]

Two laser-induced shock wave pressures, 4.5 and 6.5 GPa, were applied to punch LC4CS aluminum sheet respectively, and the influence of different pressures on fracture behaviors was investigated. The code ANSYS/LS-DYNA, dynamic finite element software, was employed to investigate the sheet fracture behaviors during the punching process. The experimental results display that the punching quality manufactured by higher peak pressure of shock wave is better than that by lower one. The finite element method visualizes the punching process, including sheet deformation, cracks growth, and plug flying away. The computational analysis results reveal that the time to punch the sheet with higher peak pressure of shock wave is shorter than that with lower one, and the edge of punched hole resulted from the higher peak pressure is smoother than that from the lower one, which are consistent well with the experimental results. [ABSTRACT FROM AUTHOR]

During the occurrence of earthquake, the shear wave propagates in the rocks present inside/at the Earth’s crust. The propagation of shear wave may lead to the progression of punch present inside the rock medium. As a result of this, substantial stress accumulated at the vicinity of propagating punch inside rock medium which significantly affects the stability of various geological and human-made structure and, hence, may cause failure of structure. Therefore, the analysis of stress concentration at the vicinity of punch moving due to shear wave propagation has become prominent in the area of seismology. In the present paper, an analytical perspective has been employed to discuss the influence of velocity of moving punch associated with the propagation of shear wave on developed dynamic stress concentration (DSC) in three types of pre-stressed vertical transversely isotropic (VTI) poroelastic media viz. granite (an igneous rock); sandstone (a sedimentary rock); and marble (a metamorphic rock). The closed form expression of DSC for the force of constant intensity has been derived with the aid of Weiner-Hopf technique along with Galilean and two-sided Fourier integral transformations. The noticeable influence of different affecting parameters (viz. velocity of moving punch associated with the shear wave propagation, horizontal compressive/tensile initial stresses, vertical compressive/tensile initial stress, porosity, and anisotropy parameter) on dynamic stress concentration has also been reported. Numerical computation and graphical illustrations have been carried out for the aforementioned three different types of porous rocks to investigate the profound impact of affecting parameters on DSC. Moreover, some noteworthy peculiarities have also been derived from the obtained expression of dynamic stress concentration. [ABSTRACT FROM AUTHOR]

The article presents a detailed analysis of the degradation phenomena and mechanisms of selected forging punches made of UNIMAX tool steel. Analyzed punches are used in the manufacture of a constant velocity joint boot forging (CVJB) applied in motorcars with front axle drive. The thorough analysis concerned the punches used in the fourth forging operation after a multi-operational process of forging at elevated temperatures, due to the lowest durability equaling only 4000 forgings. A comparison was made of 5 variants of surface thermo-chemical treatment including 2 types of nitriding (with a low and high potential) and 2 different coatings: CrN and AlCrTiN as well as a punch with and without additional thermo-chemical treatment. The performed complex analysis included a macroscopic analysis combined with scanning of the working surfaces, numerical modeling, microstructural tests, SEM microscopic tests, and microhardness measurements. The obtained results make it possible to select of the optimal variant of thermo-chemical surface treatment which improves the durability of these tools. In particular, the analysis included the manner and areas of wear of the punches as well as their resistance to the particular degradation mechanisms. [ABSTRACT FROM AUTHOR]

A method is proposed for measuring the profile of the pipe blank in shaping. In the production of welded large-diameter straight-seam pipe, the blank breaks away from the bending roller in the deforming region. Such breakaway is investigated in a bending system. Experiments show that, in the breakaway zone, the blank has complex curvature. Software is developed for calculating the coordinates and radii of curvature of the blank surface from photographs of the deformation region. The profile of the pipe blank is plotted with allowance for the change in curvature at breakaway from the bending roller. Breakaway is taken into account in calculating the radius of curvature after unloading. [ABSTRACT FROM AUTHOR]

The kinematic and stress state associated with the insertion of a punch in a half-space is considered. [ABSTRACT FROM AUTHOR]

The equilibrium of an elastic plane with a wedge-like cut and an internal or edge crack on the symmetry axis was studied in [1] in the case of punch indentation in the lateral faces of the cut at a distance from the cut tip. In [1], the systemof singular integral equations of the problemwas solved numerically by the mechanical quadrature method. In this paper, the generalized Wiener-Hopf method [2] is used to obtain the analytic solution of a similar problem in the case of an edge crack under punch pressure on parts of the cut lateral faces adjacent to the cut tip. Some special cases of this problem were considered earlier without a crack [3, 4] or a punch [5, 6]. [ABSTRACT FROM AUTHOR]

The dynamic contact problem of a plane punch motion on the boundary of an elastic half-plane is considered. The punch velocity is constant and does not exceed the Rayleigh wave velocity. The moving punch deforms the elastic half-plane penetrating into it so that the punch base remains parallel to itself at all times. The contact problem is reduced to solving a two-dimensional integral equation for the contact stresses whose two-dimensional kernel depends on the difference of arguments in each variable. A special approximation to the kernel is used to obtain effective solutions of the integral equation. All basic characteristics of the problem including the force of the punch elastic action on the elastic half-plane and the moment stabilizing the punch in the horizontal position in the process of penetration are obtained. A similar problem was considered in [1] and earlier in the 'mode of steady-state motions' in [2, 3] and in other publications. [ABSTRACT FROM AUTHOR]

By the slip-line method, analytical formulas are derived for the upsetting force and the length of the internal transition zone. The calculation results obtained for specific upsetting conditions correspond to experimental data. The proposed method of determining the parameters for upsetting of the ends of drilling pipe have been successfully used in industrial conditions. [ABSTRACT FROM AUTHOR]

General solutions for the problems of an elastic half-space and an elastic half-plane, respectively, subjected to a symmetrically distributed normal force of arbitrary profile are analytically derived using a simplified strain gradient elasticity theory (SSGET) that contains one material length scale parameter. Mindlin's potential function method and Fourier transforms are employed in the formulation, and the half-space and half-plane contact problems are solved in a unified manner. The specific solutions for the problems of a half-space/plane subjected to a concentrated normal force or a uniformly distributed normal force are obtained by directly applying the general solutions, which recover the existing classical elasticity-based solutions of the Flamant and Boussinesq problems as special cases. In addition, the indentation problems of an elastic half-space indented by a flat-ended cylindrical punch, a spherical punch, and a conical punch, respectively, are solved using the general solutions, leading to hardness formulas that are indentation size- and material microstructure-dependent. Numerical results reveal that the displacement and stress fields in a half-space/plane given by the current SSGET-based solutions are smoother than those predicted by the classical elasticity-based solutions and do not exhibit the discontinuity and/or singularity displayed by the latter. Also, the indentation hardness values based on the newly obtained half-space solution are found to increase with decreasing indentation radius and increasing material length scale parameter, thereby explaining the microstructure-dependent indentation size effect. [ABSTRACT FROM AUTHOR]

Analytical solutions for the problems of an elastic half-space and an elastic half-plane subjected to a distributed normal force are derived in a unified manner using the general form of the linearized surface elasticity theory of Gurtin and Murdoch. The Papkovitch-Neuber potential functions, Fourier transforms and Bessel functions are utilized in the formulation. The newly obtained solutions are general and reduce to the solutions for the half-space and half-plane contact problems based on classical linear elasticity when the surface effects are not considered. Also, existing solutions for the half-space and half-plane contact problems based on simplified versions of Gurtin and Murdoch's surface elasticity theory are recovered as special cases of the current solutions. By applying the new solutions directly, Boussinesq's flat-ended punch problem, Hertz's spherical punch problem and a conical punch problem are solved, which lead to depth-dependent hardness formulas different from those based on classical elasticity. The numerical results reveal that smoother elastic fields and smaller displacements are predicted by the current solutions than those given by the classical elasticity-based solutions. Also, it is shown that the out-of-plane displacement and stress components strongly depend on the residual surface stress. In addition, it is found that the new solutions based on the surface elasticity theory predict larger values of the indentation hardness than the solutions based on classical elasticity. [ABSTRACT FROM AUTHOR]

Blanking of sheet steels is one of the most frequently used processes in the manufacturing industry. During blanking processes, the wear of punches occurs due to the cyclic contact of the opposite surfaces. Therefore, the punch is exposed to high stresses and requires high resistance against wear. When worn tools are used, the tool surface directly affects the quality of sheet products and causes some surface defects. The PVD coating of the punch with a surface layer of improved hardness and low friction may reduce wear. The aim of the present study is to characterize the tool wear of AlCrN coated punch used for the sheet-steel blanking. The worn punch surfaces were examined by scanning electron microscopy. The results showed that wear take place due to the abrasion, adhesion, and delamination along sliding flank surfaces. Edge rounding and fracture of cutting edges were also observed. After blanking tests, the tool wear volume of punches and the burr height of blanked parts were also measured. The wear volumes were determined by means of profile measurements of the worn punch carried out after the completion of a large amount of blanked parts. [ABSTRACT FROM AUTHOR]

Endonasal endoscopic dacryocystorhinostomy (EEDCR) has been popularized as a minimally invasive technique. Although preliminary reports revealed less success in comparison with external approaches, recent endonasal endoscopic surgeries on various types of DCR have preserved advantages of this technique while diminishing the failures. We described our experience on EEDCR, including the main advantages and disadvantages of it. Hundred consecutive cases of lachrymal problems underwent EEDCR utilizing simple punch removal of bone, instead of powered instrumentation or lasers. The medial aspect of the sac was removed in all of patients, while preserving normal mucosa around the sac. Hundred cases of EEDCR were performed on 81 patients, with 19 bilateral procedures. Nine procedures were performed under local anesthesia. Based on a mean 14 months follow-up, 95 cases were free of symptoms, revealing 95% success rate. The punch technique diminishes the expenses of powered or laser instrumentation with comparable results. It seems that preserving normal tissues and creating a patent rhinostomy with least surgical trauma and less subsequent scar, plays the most important role in achieving desirable results. [ABSTRACT FROM AUTHOR]

The problem of contact interaction between a punch with rectilinear base and an elastic wedge with one fixed face is studied with regard for the friction in the contact zone. By using the Wiener-Hopf method, we obtain the analytic solution of the problem. The results of evaluation of the contact stresses and displacements of points of the free face of the wedge are presented. [ABSTRACT FROM AUTHOR]

The production molding of multicomponent articles consisting of several granular compositions in a multiocular molding tool, which makes it possible to execute all required production operations on the basis of an automated robotized system, is examined. An example is given for implementation of the production molding of multicomponent combined articles on the basis of the automated robotized system. Procedures are cited for calculation of the pressure and selection of the optimal rate of pressing as a function of the physico-mechanical properties of the compositions that enter into the multicomponent article, and the properties of the material of the molding tool. [ABSTRACT FROM AUTHOR]

We consider the axisymmetric contact problem on the indentation of a round punch with plane base into an elastic half-space. Roughness is taken into account in the framework of the well-known model in which the local surface displacements are proportional to some power of the contact pressures at the same point. To study the problem, we use the theory of nonlinear integral equations of Hammerstein type together with the mathematical technique of orthogonal Legendre polynomials and the contraction mapping principle. We obtain an approximate analytic solution of the problem, numerically analyze the results, and reveal typical laws of variation of the main mechanical variables. [ABSTRACT FROM AUTHOR]

The physical bases of quasi-isostatic compaction and the kinetics of elastically compacting elements in a pressing regime are studied, making it possible to establish the reasons for compact breakage and to create in molds a reliable construction for anti-breakage devices providing preparation of unbroken articles and high quality. A design theory is developed for scale dimensions of compacting elements. Calculation equations are provided for their original dimensions. [ABSTRACT FROM AUTHOR]

This paper is concerned with the stationary plane contact of an insulated rigid punch and a half-space which is elastically anisotropic but thermally conducting. The frictional heat generation inside the contact region due to the sliding of the punch over the half-space surface and the heat radiation outside the contact region are taken into account. With the help of Fourier integral transform, the problem is reduced to a system of two singular integral equations. The equations are solved numerically by using Gauss-Jacobi and trapezoidal-rule quadratures. The effects of anisotropy and thermal effects are shown graphically. [ABSTRACT FROM AUTHOR]

A high-pressure apparatus, whose cavity is formed by openings of two oppositely located calipers surrounded by an angular body, has been considered. Parameters, at which the pressure created in the cavity is kept by the forces of friction without the use of a press, have been defined. A scheme of a plant that allows a group of apparatuses to be driven by one press has been suggested. [ABSTRACT FROM AUTHOR]

Brief information is given about the development of high-pressure apparatuses starting in the thirties of the last century. The devices developed by the members of the Bakul Institute for Superhard Materials, National Academy of Sciences of Ukraine, in the second half of the 20th century are discussed in more detail. [ABSTRACT FROM AUTHOR]

A mathematical formulation is given and a solution is found to the quasistatic contact problem of thermoelasticity for a rigid heat-conducting punch moving over an elastic layer with fixed base. The interaction is accompanied by heating due to frictional forces obeying Amonton’s law. The problem is reduced to a system of integral equations with time-varying limits of integration. The structure of these equations depends on the type of thermal and physical conditions on the contact surface. An algorithm is proposed for the numerical solution of this kind of equations. The variation in the contact pressure and contact area with time is studied [ABSTRACT FROM AUTHOR]