This paper deals with the classical and Bayesian estimations of step-stress partially accelerated life test model under type-I censoring for the inverse Weibull lifetime distribution. In classical estimation, the maximum likelihood estimates of the distribution parameters and the acceleration factor were obtained. In addition, approximate confidence intervals of the parameters were constructed based

When employing end milling for the thin-walled elements, in particular aircraft gas-turbine engines, it is possible to observe their forced vibrations due to the machining discontinuity. The authors present the calculation method for determining the best performance of discontinuous milling of the given elements, which minimizes the forced vibrations’ level and provides the required quality of the

This paper proposes an analytical model for the stress-strain state in a welded joint with a hard single-V butt weld. Analytical expressions for the stress-strain state in both the hard weld and the mild main material subjected to elasto-plastic deformation are proposed. In order to verify the proposed expressions, a finite element simulation of the stress-strain state in a welded joint with a hard

Based on experimental studies of specimens of 12Kh18N10T stainless steel under a rigid (strain-controlled) deformation process, which includes a sequence of monotonic and cyclic loading modes, some features and differences between isotropic and anisotropic hardening under monotonic and cyclic loading are found. To describe these features in terms of the theory of plasticity (the Bondar model), the

A method is examined that permits the ballistic coefficient (BC) of a bullet to be converted based on universal expressions: in the Ciacci law and the air drag law of 1943, i.e., within the framework of laws that extend to the territories of the former USSR countries; to the standards G7 and G1, i.e., within the framework of standards that are the most-used worldwide; in the air drag law of 1943 and

Experimental results are presented for damage accumulation in 10GN2MFA and 15Kh2MFA steels studied with the LM-hardness method at different stress states under cyclic loading at room and elevated temperatures that are consistent with the service conditions of structure elements. Damage accumulation kinetics is examined at primary and secondary creep stages in view of the multiaxial stress state and

The use of a damping system is one of the seismic protection systems that improve the seismic response of structures. The proposed methodology estimates the location (which bay and which floor) where the dampers must be placed to dissipate the maximum energy. The goal is the cost reduction comparing the optimal place to a uniform damper placement (one damper per floor). The historical analysis of two

The paper presents a procedure for determining the design parameters of multilayer thick-walled structures with a local load on the inner surface portion located near the end face. The design provides for the use of two layers, of which the outer layer can have a smaller height. The procedure involves obtaining numerical results of calculating the stress state of the inner cylinder, their approximation

The fracture resistance of domestic and foreign nanolaminate ceramics was studied by the EF (edge fracture) method. This method provides for indentor chipping of rectangular specimen edges, which permits evaluating such fracture resistance characteristics, as chipping resistance and edge toughness. There is no way of experimental determining the stress intensity factor effected as the penetration of

In the present study, closed-cell aluminum foams of varying porosities (65–75%) were produced through the stir casting technique using TiH2 (1 wt.%) as a foaming agent. Under the uniaxial compressive loading, the compressive stress-strain responses of these foams were examined. The finite element (FE) models of the foam were elaborated using the ABAQUS FE simulation software and realized via the ABAQUS

Results of experimental investigation of mechanical characteristics of ULTEM 9085 thermoplastic, produced by additive manufacturing, i.e., the method of layer-by-layer application of a molten polymer thread, are presented. Flat specimens were tensile tested within the temperature range of (–40) –150°C. Temperature dependencies of ultimate strength, relative elongation at break, elastic modulus, and

The statistical analysis performed on the defectiveness of rails in the Kiev subway railway shows that the main cause of the occurrence of most defects is the contact fatigue of the rail material. The paper presents modern concepts of crack growth in the railhead. It has been found that one of the most promising directions of studying the stress-strain state of rails and the crack growth process is

The procedure for the material damage assessment by the LM-hardness method, consisting of the in-service scratching of structure element surfaces and employing portable instruments for its implementation, is described. These instruments can provide the rapid analysis of damage of a structural element to be diagnosed, continuous measurement of axial displacements of the embedded scratching tip, moving

The fretting fatigue behavior in Al–Zn–Mg alloy is investigated under conditions of various equivalent stress amplitudes of cyclic multiaxial loadings and the same contact pressure with a point contact. The ANSYS finite element analysis is used to analyze stress distribution by a numerical study using the 3D finite element method. Fretting regions’ morphology and fracture of specimens are characterized

The effect of hydrogen at a pressure of up to 35 MPa and a content of up to 29 ppm on the strength, ductility, short-term and long-term static crack resistance of four KhN43MBTYu (EP-915VD) alloy modifications with different heat treatment modes and chemical composition has been studied. It has been found that the critical stress intensity factor KIc in the presence of hydrogen, just as the ductility

The authors present the results of experimental investigations of strength and plasticity characteristics, as well as fracture nature, of the specimens of different steels under tension after ion nitriding in hydrogen (nitrogen with hydrogen) and hydrogen-free (nitrogen with argon) environments. The obtained characteristics are compared with those before nitriding. It is established that during ion

Special features of computational assessment of dimensional change of WWER-1000 reactor core baffle during the reactor operation are discussed. The paper gives results of computational analysis of a change in shape of core baffle, which was performed by applying up-to-date approaches of modeling the irradiation-induced swelling of constrained austenitic steels under the action of neutron irradiation

The following correction should be made to the article entitled “Milling-Related Brittle Fracture Mechanisms of a SiCp/Al Composite” by H. J. Zhang, J. G. Li, and J. G. Du, Vol. 52, No. 1, 81–89, 2020, https://doi.org/10.1007/s11223-020-00152-3.

The spatial axisymmetric creep problem for complex-shaped bodies of rotation from functionally graded materials is considered. For the variational problem statement, the Lagrangian-form functional is defined for kinematically possible displacement rates. For the main unknown creep parameters, namely displacements, stresses, and strains, the Cauchy problem in time scale is formulated for the spatial

In this article, a constant-stress partially accelerated life test model of high reliability products and materials with type-II censored data from the linear failure rate distribution is considered. Two different methods of estimation likelihood and Bayesian are used to estimate the unknown parameters of the model. The maximum likelihood estimates of the model parameters are obtained using the Newton–Raphson

The effect of contact conditions and the gap between the metal and composite layers on the stress-strain state and strength of a two-layer metal composite cylinder under internal explosive loading in air is numerically studied. It is accepted that in the absence of a gap between the metal and composite layers, there is no interference. The problem was considered on the basis of the general equations

Limiting cyclic stress diagrams of welded joints of a low-carbon and low-alloy steels of different strength levels are analyzed under conditions that they contain the same level of steady residual stresses. For tests of butt-welded joints as an example, a procedure for calculating the endurance limit at different values of limiting steady residual stresses is proposed. Limiting cyclic stress diagrams

A system for recording the contraction of cylindrical specimens under static compression loading was developed based on the original cantilever-type extensometer and the L-Card E-440 analog-todigital converter with Power Graph software for data acquisition and pre-processing. 26H2MF and St12T steels’ stress–strain diagrams in compression at elevated temperatures were constructed. The influence of temperature

Structural features, mechanical properties, and stressed state of welded joints of the TiAl system intermetallic compound (Nb, Cr, Zr) after electron-beam welding and subsequent electron-beam local heat treatment are determined. It was shown that stresses generated immediately after welding contributed to the appearance of cold cracks in the weld. Residual stresses in welded joints were determined

The paper considers one of the topical problems of the targeted control of the properties of the material of products in the zones under critical loads, which lead to their failure or loss of performance. The processes for the diffusion saturation of the surface layers of parts (chemical heat treatment) are an effective method for the strengthening treatment of parts of complex geometric shape. The

The methods for low-cycle fatigue testing and cyclic crack growth testing of 10GN2MFA steel at 20 and 270°C are described. Based on test results, fatigue crack growth rate curves are plotted and the characteristics of low-cycle plastic deformation and fracture are found. A difference in the kinetics of low-cycle plastic deformation is shown – the cyclic softening at 20°C and hardening at 270°C – which

This paper describes the experimental and theoretical investigation on ultimate strength of cold-formed steel built-up square stub columns under axial compression. In total, fifteen stub columns were tested by varying the cross-sectional dimensions of specimens. Local buckling, distortion, and interaction of these buckling modes were observed. The strengths obtained from the experiment are compared

The paper provides results of the study of correctness of the mathematical model that includes the influence of stresses on irradiation-induced swelling of metal in the problems of elastic-plastic deformation mechanics. The present-day approaches to modeling irradiation-induced swelling, which take into account a damaging dose, irradiation temperature, and the effect of the stress state on the swelling

The structure nonuniformity a VT23 titanium alloy after shock and vibration loading is established to lead to larger plasticity of the material and changes in fracture mechanisms. Localization of deformation processes influences the sizes and quantitative distribution of tear dimples on the fracture surface. The approach was advanced to detect tear dimples on the fracture surface of the alloy, in particular

A MEPR Calculator program is described that provides automatic computations of the longitudinal elastic modulus and Poisson’s ratio of structural materials in accordance with operating test standards. The deformation diagram of the material with a clear-cut linear section is examined. The program permits of valuating the agreement between calculated and experimental data with the coefficients of determination

The aims of this finite elemental stress analysis (FEA) study were to evaluate the effects of loading direction, crown coverage, and adjacent teeth on stress distribution in premolar tooth models restored using fiber-post restoration. Three 3D premolar tooth FEA models were created as follows: Model 1: sound tooth; Model 2: tooth-model including root filling, fiber-post and composite resin restoration;

The paper presents the experimental results of investigations using different types of glass by the Rockwell indenter scratching of the specimen surface till its edge chipping (S+EF method). The peculiar features of the materials’ fracture are determined as a result of fractography analysis of the empirical data. It is proposed to classify chips under two different groups. The first group is characterized

The assemblies of a ship-to-shore portal crane after 33 years of service were studied on the possible loss of the initial brittle fracture resistance level by rolled steel sheets. Strain gauge measurements were used to predict the level of operating stresses. The latter and a decrease in the Charpy impact strength were established to be distinctly related. Transverse specimens are shown to generally

Leveling essentially aims to improve the flatness of steel plates but also causes a significant reduction in the magnitude of residual stresses and their equalization. In this study, the results of residual stress measurements by use of a Stresscan 500C device (based on the Barkhausen magnetoelastic noise method) for steel sheets made of S235 and S355 steel without leveling and after roller leveling

The authors present the results of the numerical experiments on the determination of the effect of shrouding coupling parameters in the rotor blades on their forced vibrations using an assembly of two blades as an example. The task is solved in the variation of the inclination angle of the shrouded flanges as the parameter of their contact interaction and amplitude of the kinematic excitation of vibrations

In this study, residual stresses in hot-extruded Al-6061 rods with different cross-sectional reduction were investigated using the contour method. The contour method was used to provide a twodimensional map of residual stresses. The residual stresses were evaluated along the radius of the rods with different cross-sectional reduction before and after annealing heat treatment, and the uncertainty of

This paper considers both likelihood and Bayesian estimations of a constant-stress partially accelerated life test model with type-I censored data from the linear failure rate distribution. The maximum likelihood estimates of the model parameters are obtained using Newton–Raphson technique. The posterior means and posterior variances are obtained under the squared error loss function using Lindley’s

D16AT aircraft Al-alloy was evaluated. The friction stir hole expansion (FSHE), solid mandrel cold working and symmetric cold expansion (SCE) methods were compared. The results are summarized on the basis of fatigue tests, S–N curves, X-ray diffraction, and microstructural analysis. Under the high-cycle fatigue, SCE provides more than 66 times longer fatigue life as compared to the solid mandrel method

SiCp/Al composites were machined with carbide cutting tools, the surface morphology of the materials was examined with SEM and EDXS. The SiCp removal in the aluminum matrix was studied on the basis of the brittle fracture theory. The fracture and shear removal mechanisms of SiCp were demonstrated, the conditions of SiCp brittleness-ductility removal were revealed. The SiCp/Al milling was investigated

The development of bimetallic materials is one of the modern lines of research. The differences in the properties of components can impart special mechanical characteristics to the material, which provides its most effective functioning in different fields of application. The stretching deformation mechanism of a Cu-Al sheet was set, and a calculation model of warping deformation was constructed, which

The concrete compression strength is an effective characteristics among other properties of practical significance. Although coring testing on such members as columns is not recommended. But sometimes, for determining the concrete strength in the column, this method should be applied to the reinforced concrete one. Coring in a reinforced concrete column creates a cylindrical cavity in it, which has

The additive friction stir process provides a new approach to additive manufacturing by depositing and coating of a variety of similar and dissimilar materials with imparting them exceptional mechanical properties. During this process, the filler material can be deposited layer-by-layer on the substrate effected by heat and plastic deformation due to friction between the filler rod and substrate. For

A subsea oil and gas pipeline repair clamp and circumferential sealing structure are designed. Based on the principle of equal contact pressure on the contact surface and the thick-walled cylinder calculation, a formula for the contact pressure between the sealing ring and the outer wall of the pipeline is derived. An axisymmetric finite element model is constructed for circumferential sealing with

The mechanisms of dynamic recovery and dynamic recrystallization significantly affect the mechanical behavior and microstructure of the materials deformed at high temperatures. The modified Kocks and Mecking (K–M) model was used to assess the evolution of dislocation density of pure copper under high-temperature compression. The relationship between the deformation conditions and model parameters was

The effect of the second-phase particle precipitation on the recrystallization texture of high-strength and fine-grain interstitial-free steel was studied. It is shown experimentally that the sizes of second-phase particles increase and their number decreases with holding time and annealing temperature. The texture is mainly influenced by the size, number, and distribution of the particles. Finely

To the article “Effect of Porosity Parameters on the Strength of Gas Turbine Compressor Blades Made of Titanium Alloys,” by D. V. Pavlenko, Vol. 51, No. 6, pp. 887–899, November, 2019.

Quench and partition (QP) steel is a class of third-generation high-strength steels with effective ductility. The uniaxial tensile test was used to evaluate fundamental mechanical parameters. These parameters for QP980 are shown to be much higher than those for HSLA450 and DP590. Then the forming limit diagram of QP980 was constructed using bulging test results. The forming limit of QP980 was not seriously

The temperature influence on the structural and mechanical properties of AISI 420 stainless steel is studied. The iron-based alloy underwent normalizing at three temperatures 975, 1025, and 1075°C for 1 h, followed by annealing at temperatures ranging from 250 to 650°C for 2 h. At both treatment stages, steel is air-cooled. The material was examined with nanoindentation, macrohardness, scanning electron

Free and fixed plate blade root states were simulated with finite element analysis to reveal the crack effect on the natural vibration frequency of the blade. Natural vibration frequencies are obtained for blades with different crack locations and lengths. The crack is found to reduce the blade stiffness and to affect its natural vibration frequency. The longer the crack, the greater the change of

A Co–Cr–Ni–W–C alloy was manufactured and cold-rolled to investigate the effect of the latter. Its microstructure, precipitates, and mechanical properties are presented. An M6C carbide, Co3W intermetallic compound and α-Co matrix were selected as the main phase constituents. During cold rolling, the alloy was deformed mainly by dislocation slipping at a small reduction, but some microtwins were formed

Two main cracks appear on the upper end of the inner hole of a hammer anvil after 130 hours’ impact. The fracture morphology, microstructure, metallographic microscopy results and nonmetallic inclusions of the cracked anvil are analyzed. The chemical composition and mechanical properties of the anvil are examined. In its material, carbon content is shown to be higher than the highest limit of 40CrMnMo

Bearings, as a key part of a vehicle transmission system, were extensively studied to improve their abrasion resistance and fatigue life. Mixtures of hard ceramic particles, namely, molybdenum disulphide (MoS2) and graphite particles (PC), were sprayed with a high-pressure inert gas onto the surface of AISI52100 bearing steel, forming the lubricant film. The morphology and phase composition of the

The effect of the surface protection with insulating materials of the two types on the bending and compressive strengths, internal temperature, mass loss, and relative dynamic elastic modulus of hydraulic concrete was studied. In comparison with unprotected concretes, the surface protection can delay the temperature drop of the concrete bulk and increase its final temperature. Polyurethane and polystyrene

Reflective cracking is the main problem of the asphalt concrete overlay on a functional airfield cement concrete pavement. It can reduce the serviceability and service life of the airfield pavement. The improvement effect of an epoxy asphalt geogrid stress-absorbing layer on the reflective cracking resistance of the asphalt concrete overlay on the functional airfield cement concrete pavement was studied

A method of cutting coal with three drums was advanced, a three-drum shearer was designed, and the free mode and restrained model under prestress of the third drum were analyzed in large mining with ANSYS Workbench 14.0 to solve the damage problem of the cutting blade in a large mining face. The vibration modes caused by its own structural characteristics are obtained, and the dynamic response of all

The impact of the rotation speed on the microstructure and mechanical properties of Super304H/T92 friction weld joints was studied. The properties of weld joints are shown to be adequate, with their strength and impact toughness meeting the requirements. With an increase in the rotation speed (1200–1800 rpm), the heat and number of precipitated carbide phases in the heat-affected zone of the weld joints

The paper presents the results of simulations and experimental investigations on natural frequencies and oscillation modes of pairwise-shrouded cooled turbine blades and their rings with allowance for a possible frequency mistuning and the assured contact of mating surfaces of the root and shroud platform halves. As the research object, the high-pressure turbine wheel of an aircraft bypass turbojet

Outcomes of the stress state investigations are presented for cylindrical hydroacoustic piezoceramic transducers on their operation in the shielded electroacoustic systems, which is defined by the maximum amplitudes of their vibration velocities and physical parameters of piezoceramic materials. The calculation model of the shield–transducer system takes account of the coupling between the electric

Investigation results are presented to improve the structural strength (cold crocking resistance) of weld joints in high-strength steels with the yield limit over 600 MPa. The effect of arc, laser, and hybrid laser-arc welding conditions on the weld metal structure and diffusion hydrogen saturation of build-up and fused base metals was experimentally studied. The diffusion hydrogen saturation of build-up

The quantitative method of evaluating the parameters of tear dimples and their conglomerates was proposed with examination of their fractographic images. The method is based on calculating the correlation coefficient distribution field of pixel intensity for compatible image areas. The 17G1S-U steel specimen fractograms produced with a REM-106I scanning electron microscope were studied. The zones of