https://www.elibrary.ru/title_about_new.asp?i 1605-8119 53 3 2025 1-218

RAR RUS 1-8 7006355365 0000-0002-6663-6357 Kuban State University Babeshko Vladimir

Krasnodar, Russia

57201387701 Southern Scientific Center RAS Evdokimova Olga

Rostov-on-Don, Russia

6602333282 0000-0003-1283-3870 Kuban State University Babeshko Olga

Krasnodar, Russia

57212310668 Kuban State University Evdokimov Vladimir

Krasnodar, Russia

Contact problems with a stamp in the form of an acute-angled wedge acting on an anisotropic composite layer In this paper, for the first time, the block element method provides an exact solution to the contact problem of the action of a rigid wedge-shaped stamp with an acute angle on a layer of composite material having arbitrary anisotropy. The research is based on the application of the block element method. In comparison with strip stamps, it contains an additively additional term describing the concentration of contact stresses at the angular point, that is, at the top of the stamp. The calculation of the indicator of the peculiarity of the concentration of contact stresses at this point is close to the values performed by numerical methods in a number of works. In the zone considered away from the top of the stamp, the exact solution turns into a solution for the case of a semi-infinite stamp. The developed method is applicable to composites of arbitrary anisotropies arising in linearly elastic materials and crystals of any cross sections that allow the construction of the Green function, and hence the two-dimensional Wiener-Hopf integral equations. The exact solution of two-dimensional Wiener-Hopf integral equations has made it possible, thanks to fractality, homeomorphism of stamp carriers and solution functions, to construct exact solutions to contact problems for wedge-shaped, sharply angled stamps. 10.18149/MPM.5332025_1 contact problems anisotropy composite Wiener-Hopf integral equation block element factorization wedge-shaped region with an acute angle https://mpm.spbstu.ru/article/2025.108.1/ 1_babeshko_va_et_al.pdf

RAR RUS 9-23 0000-0002-3339-8153 MBM University Kumari Emarti

Jodhpur, India

MBM University Choudhary Brajesh

Rajasthan, India

Static and dynamic analysis of trapezoidal cantilever plates Static and dynamic behaviour of trapezoidal cantilever plate are analysed in this work using ANSYS software. Static and dynamic analysis of trapezoidal cantilever plate has been carried out and studied the effect of change in taper ratio αt, aspect ratio a/b and varying tip to root width ratio c/b. It has been observed that at αt = 0.6 and c/b = 0.2, non-dimensional frequency of the trapezoidal cantilever plate is higher side, when both parameters varied. In bending analysis under uniformly distributed load when αt = 0.8 and c/b = 0.8 then tip deflection and stresses will be maximum, whereas under edge load when αt = 0.8 and c/b = 0.2 (smallest tip width) will have maximum deflection and stresses. Hence, present numerical results will be helpful for further researchers and designers to design safe thin-wall structures.   10.18149/MPM.5332025_2 trapezoidal cantilever plate modal analysis buckling bending beam https://mpm.spbstu.ru/article/2025.108.2/ 2_kumari.pdf

RAR RUS 24-36 56964798900 0000-0003-3336-8971 GIET University Gunupur Panda Manas R.

Rayagada, India

55482519400 0000-0001-7513-0078 VSSUT Burla Mishra Srimant K.

Odisha, India

58342484800 0000-0001-8231-6567 GIET University Gunupur Sahoo Prabin K.

Rayagada, India

Enhancing EDM performance of Monel-400 super alloy through process parameter optimization: RSM-based experimental and microstructural analysis A nickel-copper alloy Monel-400 renowned for its corrosion resistance and thermal properties finds extensive application in chemical, fitting, fastener, and marine industries. However, machining intricate, delicate components from this alloy using conventional methods presents significant challenges. EDM is a non-traditional process capable of producing precise, high-quality surfaces, which emerges as a viable alternative. The die-sinking EDM of Monel-400 are investigated with a particular focus on the machined surface microstructure. A Box-Behnken design was employed to evaluate the influence of discharge current, pulse-on time, and voltage gap on material removal rate, tool wear rate, and surface roughness. Results indicate that impact of peak current and pulse-on time are primary determinants of Monel-400 machining characteristics. While impact of peak current exhibited the most significant impact on MRR, pulse-on time was identified as the critical factor affecting tool wear rate and surface roughness. A comprehensive metallographic examination of the machined surface was conducted to elucidate wear mechanisms. 10.18149/MPM.5332025_3 EDM Monel-400 alloy microstructure RSM box behnken design SEM https://mpm.spbstu.ru/article/2025.108.3/ 3_panda_mr_et_al.pdf

RAR RUS 37-47 University of Djillali Liabes Hanifi Mohamed Amine Adda

Sidi Bel Abbes, Algeria

0000-0003-0576-9698 University of Djillali Liabes Zemri Mokhtar

Sidi Bel Abbes, Algeria

0000-0002-7276-7716 University of Djillali Merzoug Mohammed

Sidi Bel Abbes, Algeria

Effect of traverse speed on three-point bending behavior and surface quality of AA5083-H111 friction stir welds The FSW was developed to obtain a good joint in terms of surface quality, mechanical property and microhardness in aluminum and other alloy systems. This study investigates the effect of traverse speed on the three-point bending behavior and surface quality of friction stir welds in AA5083-H111 aluminum alloy by using with different parameters such as weld speeds (16, 20, 25, 30, 40, 50 and 63 mm/min) while maintaining constant rotational speed (1400 rpm) and tool geometry. The resulting welds were subjected to three-point bending tests to evaluate their mechanical performance, specifically focusing on yield strength, ultimate tensile strength, and ductility. Additionally, the investigation includes macrostructure, microhardness, and fracture toughness evaluations. The findings indicated that an augmentation in traverse speed led to elevated tensile strength and hardness levels due to enhanced material flow and bonding, while higher speeds led to increased surface roughness and reduced weld integrity. The study suggests that superior joints with favorable mechanical properties can be achieved by utilizing an intermediate rotational speed of 1400 rpm and a traverse speed of 20 mm/min. 10.18149/MPM.5332025_4 friction stir welding surface roughness aluminum 5083H111 parameters bending test https://mpm.spbstu.ru/article/2025.108.4/ 4_merzoug_m_et_al.pdf

RAR RUS 48-68 59485528600 0009-0002-3944-1922 Dayananda Sagar University Ganesha G.C.

Bangalore, India

57224355571 0000-0001-9997-550X Dayananda Sagar University Mukti Chaturvedi

Bangalore, India

57196120922 0000-0003-4133-5635 Dayananda Sagar University Arungalai Vendan Subbiah

Bangalore, India

57970941400 0009-0002-4255-7176 Dayananda Sagar University Sharanabasavaraj Radder

Bangalore, India

Polymer weld characterization and defect detection through advanced image processing techniques Welding defect detection in a radiographic image is vital in industrial non-destructive testing. It is significant in evaluating weld anomalies and surface and subsurface imperfections in welded joints.  Digital image processing techniques can make automation feasible in the weld microscopic image interpretation, thus reducing the instances of observational human errors in weld inspection. This technique will give more reliability, speed and reproducibility to the inspection system. This paper uses MATLAB image processing tools for weld defect detection using scanning electron microscope images of ultrasonically welded polymer samples. Image processing features of gray scaling, image resizing, histogram equalization, edge detection, thresholding, filtering, texture analysis, and image segmentation have been implemented for the detection and characterization of defects in weld scanning electron microscope images. Thorough insights into the structure of these defects are an essential step in appreciating the weld's quality. The approach is well-suited for defect detection of any welding technique. 10.18149/MPM.5332025_5 image processing weld defects scanning electron microscope analysis https://mpm.spbstu.ru/article/2025.108.5/ 5_ganesha_et_al.pdf

RAR RUS 69-78 0000-0002-7682-9830 University of Tyumen Ganopolskij Rodion

Tyumen, Russia

0000-0003-0347-3930 University of Tyumen Fedorov Konstantin

Tyumen, Russia

0000-0001-7790-9958 Irkusk Oil Company LLC Folomeev Alexey

Irkutsk, Russia

General model of the carbonate acidizing process with different injection rate The process of dolomite rock acidizing is considered. Theoretical analysis considers three regimes of the chemical reaction: face and uniform dissolution and wormhole formation. The general model integrates two analytical solutions of the face and uniform dissolution and semi empirical model of wormhole formation. The analytical solutions consider in the paper, appropriate data on semi empirical approach was extracted from Fredd and Fogler investigations. These solutions had been transferred to the dependence of skin factor from the specific acid injection rate, slug volume and acid concentration. The approximation of the dependence involves two Gauss functions and matches to the appropriate asymptotes (low and high injection rates) and describes the wormhole local minimum in the vicinity of critical injection rate. The proposed approximation dependence may be used in different codes for a reservoir acid treatment process. It could be the basis of the process optimization procedure with maximum productivity increase criteria and determination of optimal impact parameters such as acid slug volume and concentration, injection rate and etс. 10.18149/MPM.5332025_6 dolomite hydrochloric acid face and uniform dissolution wormhole formation reservoir acidizing analytical solution https://mpm.spbstu.ru/article/2025.108.6/ 6_ganopolskij_rm_et_al.pdf

RAR RUS 79-93 0000-0002-4438-7249 SIR C R Reddy College of Engineering Sunil Ratna Kumar Khandavalli

Vatluru, Andhra Pradesh, India

0000-0003-2856-7204 St. Ann's College of Engineering and Technology Devireddy Siva Bhaskara Rao

Andhra Pradesh, India

0000-0001-5622-4140 St. Ann's College of Engineering and Technology Gopala Rao Thellaputta

Andhra Pradesh, India

0000-0002-4694-3341 Lakireddy Bali Reddy College of Engineering Sudheer Kumar Battula

Andhra Pradesh, India

0000-0003-2200-0629 RVR& JC College of Engineering Bala Prasad Katuru

Andhra Pradesh, India

Influence of alkali treatment and fiber percentage on the mechanical and thermophysical properties of gypsum composites filled with hemp fiber The influence of alkali treatment and fiber percentage on the physical, mechanical and thermal properties of hemp fiber reinforced gypsum composites are examined. Short hemp fibers (15 mm in length) were subjected to alkali treatment using 5, 10, and 15 wt. % NaOH concentrations for 5 h. Both untreated and NaOH treated hemp fiber reinforced gypsum composites were fabricated with fiber percentages of 3, 6, 9, 12, and 15 vol. % through the hand layup process. The fabricated composite samples were evaluated for density, water absorption, compressive strength, flexural strength, and thermal conductivity. The composite with 10 wt. % NaOH treated fibers, and 12 vol. % fiber content showed significant improvements, with a 337 % increase in flexural strength, a 136 % increase in flexural modulus, and a 109.8 % increase in compressive strength compared to pure gypsum. The results for thermal conductivity indicate that NaOH concentration has a minimal effect on enhancing thermal resistance compared to the influence of fiber percentage. SEM analysis of untreated and treated fibers revealed surface modifications and changes in fiber characteristics due to NaOH treatment. The results showed that stronger NaOH treatments and higher fiber content negatively impacted fiber suitability, stiffness, and overall composite properties. 10.18149/MPM.5342025_7 alkali treatment gypsum composite hemp fiber scanning electron microscopy mechanical properties thermal conductivity water absorption https://mpm.spbstu.ru/article/2025.108.7/ 7_devireddy_siva_bhaskara_rao_et_al.pdf

RAR RUS 94-115 59122315900 0000-0002-1572-2108 Kurukshetra University Kumar Rajneesh

Kurukshetra, India

55929083700 0000-0003-3651-5498 Kurukshetra University Singhal Pooja

Kurukshetra, India

Temperature-dependent phase leg and non-local thermoelastic damping and frequency shift in thermoelastic plates Thermoelastic damping and frequency shift are critical factors influencing the performance and stability of micro- and nano-scale resonators, such as those employed in MEMS and NEMS devices. Traditional thermoelastic models often overlook important scale-dependent behaviors, thermal relaxation effects, and material property variations with temperature, leading to inaccuracies at small scales. To address these limitations, the present study investigates thermoelastic damping and frequency shift in a Kirchhoff plate resonator by incorporating non-local elasticity theory, the dual-phase lag heat conduction model, and temperature-dependent material properties. In order to investigate thermoelastic damping and frequency shift of Kirchhoff plate resonator, the current work takes into account the influence of non-local, dual phase leg, and temperature dependent properties on thermoelastic theory. The governing equations, comprise equations of motion and heat conduction equation which include a temperature-dependent property, a dual-phase leg model along with non-local parameters are formulated with the assistance of Kirchhoff-Love plate theory. Under the simply supported boundary conditions, thermoelastic damping and frequency shift are analysed. The derived amounts are graphically displayed with different thickness and length values. The current work additionally deduces a specific example of interest. Results are graphically presented to illustrate key trends, and a specific numerical example is discussed to demonstrate the applicability of the model. This study enhances the accuracy of thermoelastic analysis in micro-scale resonator design by integrating advanced theoretical considerations often neglected in conventional models. 10.18149/MPM.5332025_8 thermoelastic Kirchhoff Love plate theory non local dual phase-lag model TDP model frequency shift thermoelastic damping https://mpm.spbstu.ru/article/2025.108.8/ 8_rajneesh_kumar_pooja_singhal.pdf

RAR RUS 116-121 57209463744 0000-0002-5479-3064 St. Petersburg State University Saitova Regina

St. Petersburg, Russia

7004876952 0000-0003-0745-1683 St. Petersburg State University Arutyunyan Alexander

St. Petersburg, Russia

Creep and long-term strength of high-entropy alloys High-entropy alloys are a new class of metallic alloys without a principal component. These materials are attractive because of their unique structures and properties, including mechanical ones. Some high-entropy alloys based on refractory metals are considered as advanced high-temperature materials. In this regard, the study and description of the behavior of such materials under conditions of creep, fatigue and long-term strength is of great interest. In the work, to describe the creep and long-term strength of high-entropy alloys a damage conception is used. A system of interconnected kinetic equations for the creep rate and damage parameter is formulated. A compressible medium is considered, and the mass conservation law is taking into account. The damage parameter is specified in the form of the ratio of the current density of the material to the initial one. The analytical solutions of these equations are obtained. The theoretical creep and long-term strength curves are plotted and compared with the experimental results for CrMnFeCoNi and CrFeCoNi alloys. The experimental results are in good agreement with the theoretical ones. 10.18149/MPM.5332025_9 creep damage parameter high-entropy alloys long-term strength https://mpm.spbstu.ru/article/2025.108.9/ 9_saitova_rr_et_al.pdf

RAR RUS 122-139 0009-0005-1059-2948 Indian Institute of Technology (BHU) Varanasi Choudhury Debendra Nath

Varanasi, India

55419719200 0000-0001-8876-909X Indian Institute of Technology (BHU) Varanasi Panda Saroja Kanta

Varanasi, India

Evaluating the impact of functionalized graphene integration on thermal properties of CFRP composites This study highlights the improvement in the thermal properties of CFRP composites modified with lower concentrations of graphene reinforcement (ADG-NH2/epoxy/CFRP). Thermal properties such as storage modulus, loss modulus, damping factor and glass transition temperature of the composites were investigated through dynamic mechanical analysis with a temperature scan range of 30 to 200 °C and thermogravimetric analysis measurements. Five symmetrical CFRP composite laminates were prepared through a hand layup process assisted by vacuum bagging technique using various wt. % proportions (0.25, 0.5, 0.75 and 1) of ADG-NH2/epoxy along with a neat epoxy. A slight increase of ~ 2 % in the glass transition temperature Tg was observed for the modified composites. It was observed that the ADG-NH2 composites showed ~54 % increment in storage modulus E', ~ 41 % increase in loss modulus E'' compared to neat epoxy CFRP laminate composites. Thermal stability values were determined through integral procedural decomposition temperature measurement and an enhancement from 389.1 to 411.9 °C was observed. Morphological properties of fracture surfaces were characterized by SEM micrographs and XRD analysis. 10.18149/MPM.5332025_10 composite CFRP amine functionalized graphene DMA TGA SEM XRD https://mpm.spbstu.ru/article/2025.108.10/ 10_debendra_nath_choudhury_sk_panda.pdf

RAR RUS 140-148 Nagpur Institute of Technology Bhaiswar Jitendra

Nagpur, India

36481198900 Bhalerao Science College Saoner Dongre Sunil

Saoner, India

Nagpur Institute of Technology Meghe Dhiraj

Nagpur, India

Structural and thermal changes in the polyaniline lead sulphide nanocomposite In this study, composite films of PbS nanoparticles and PANI were used. The PbS/PANI samples were analyzed using XRD, UV-visible, FT-IR and TEM. Furthermore, the effects of PbSNPs on their optical, structural and thermal parameter were determined using DTA, UV-Visible and XRD. The UV and XRD confirmed the successful synthesis of PbS/PANI Nanocomposite. The TEM indicated homogeneous dispersion of PbS in PANI with average diameter of particle is 20nm. Besides, the broadness and reduction of PANI in XRD peaks intensity with increasing PbS is attributed to the intermolecular interactions of PANI and PbS and indicates the successful incorporation of PbS in PANI. The thermal stability was enhanced at different weight percentages of PbS nanoparticle indicated in DTA analysis. The structural changes in the Pbs nanocomposite observed in the XRD. 10.18149/MPM.5332025_11 DTA thermal analysis polyaniline Pbs TEM nanocomposite https://mpm.spbstu.ru/article/2025.108.11/ 11_bhaiswar_jitendra_et_al.pdf

RAR RUS 149-164 59513744400 0009-0006-3586-0723 Alexandria University Samir Noha

Alexandria, Egypt

15071308200 0000-0003-0391-5946 Alexandria University Abdou Mohamed A.

Alexandria, Egypt

0000-0002-3330-0822 Alexandria University Awad Emad

Alexandria, Egypt

Effect of electromagnetic waves on the thermoelastic Hookean unbounded domains based on fractional Fourier law An analytical framework for time-fractional magneto-thermoelasticity in unbounded domains, focusing on heat conduction in materials exhibiting non-classical thermal behavior, are presented. Thermal transport is strongly influenced by temperature and the internal structure of the medium; in the presence of imperfections such as inclusions, voids, or microstructural defects, the heat transfer process often deviates from conventional diffusion laws. To model these complex phenomena, fractional calculus is employed, and the governing equations are reformulated using dimensionless variables. Analytical solution in the Laplace–Fourier domain was derived, with temperature distribution expressed in terms of Mittag-Leffler and Fox H-functions. The use of uncoupled thermoelastic theory allows for a simplified treatment by decoupling thermal and mechanical fields. Finally, numerical inversion techniques are used to reconstruct time-domain solutions for displacement and stress, demonstrating how fractional-order parameters influence both thermal wave propagation and material response. 10.18149/MPM.5332025_12 Maxwell's equations thermoelasticity fractional derivative uncoupled theory https://mpm.spbstu.ru/article/2025.108.12/ 12_n_samir_m_a__abdou_e__awad.pdf

RAR RUS 165-176 15052027100 0000-0002-5061-7880 Hanoi National University of Education Nguyen Quang Hoc

Hanoi, Vietnam

57857641400 0000-0002-6090-5755 Dai Nam University Tran Ky Vi

Hanoi, Vietnam

Vietnam National University Quach Si Gia Khoa

Hanoi, Vietnam

Hanoi-Amsterdam High School for the Gifted Doan Quang Tuan

Hanoi, Vietnam

Hanoi-Amsterdam High School for the Gifted Nguyen Ngoc Phuong Anh

Hanoi, Vietnam

Hanoi National University of Education Nguyen Thi Sao Mai

Hanoi, Vietnam

Mac Dinh Chi High School Nguyen Duc Hien

Gia Lai, Vietnam

59249944400 0009-0009-1367-1093 Vietnam National University Tran Anh Tuan

Hanoi, Vietnam

Elastic deformation and elastic wave velocity in metals (Au, Cu) and interstitial alloy (CuSi) with FCC structure A model for face centered cubic binary interstitial alloys and advance the theory of elastic deformation and wave propagation within these alloys using the statistical moment method are presented. The theory extends to include the elastic properties and wave dynamics of pure metals as a subset. The numerical simulations for metals like Au and Cu, as well as the CuSi alloy are conducted. The results obtained for Au and Cu were validated against experimental data and existing calculations. For the CuSi alloy, numerical predictions offer insights that could be confirmed by future experiments. 10.18149/MPM.5332025_13 FCC binary interstitial alloy elastic deformation elastic wave propagation statistical moment method https://mpm.spbstu.ru/article/2025.108.13/ 13_nguen_et_al.pdf

REV RUS 177-218 0000-0002-9212-2579 Lomonosov Moscow State University Khokhlov Andrew

Moscow, Russia

North-Eastern Federal University Okhlopkova Aitalina

Yakutsk, Russia

North-Eastern Federal University Sleptsova Sardana

Yakutsk, Russia

North-Eastern Federal University Lazareva Nadezhda

Yakutsk, Russia

North-Eastern Federal University Tarasova Praskovia

Yakutsk, Russia

Moscow Aviation Institute (National Research University) Babaytsev Arseny

Moscow, Russia

Moscow Center of Fundamental and Applied Mathematics Shaporev Artemii

Moscow, Russia

Lomonosov Moscow State University Gulin Vyacheslav

Moscow, Russia

Systematic all-round examination of the viscoelastoplastic properties of nanocomposites with increased wear resistance based on polytetrafluoroethylene. Part 1 A description of the technology for manufacturing composites with increased wear resistance based on polytetrafluoroethylene is given. The composites were obtained by introducing mechanically activated layered silicates (kaolinite, serpentine, bentonite) and magnesium spinel as fillers. The main results of the study on wear resistance, structure and chemical composition of friction surface using electronic microscopy and infrared spectroscopy and mechanical test data are presented, including families of tensile-to-failure curves at different strain rates, loading and unloading curves at different rates, and creep and recovery curves for different stress levels obtained in tests of pure PTFE and six PTFE composites particulate-filled with serpentine and magnesium spinel with a mass fraction ranging from 1 to 5 %. The first part of the article describes the objectives and system of quasi-static testing programs for polymers and composites for a comprehensive study of their viscoelastoplastic properties (a set of all effects observed in tests), the possibilities of describing them using several physically nonlinear constitutive relations of viscoelastoplasticity (one of which takes into account the mutual influence of structure evolution and the deformation process), and the methodology for analyzing test data and selecting adequate constitutive relations for their modeling. In particular, the signs of physical nonlinearity of material behavior are considered, i.e. indicators of inapplicability of the linear integral Boltzmann-Volterra viscoelasticity relation that can be detected in tests using different loading programs, and methods for outlining the range of linearity of viscoelastic material behavior. The tests for preliminary diagnostics of the type of material behavior are described, if we characterize it by the categories elastic, viscoelastic, viscoplastic, elastic-viscoplastic, and the methodology for selecting an adequate model to describe the behavior of a particular material. In the second part of the article, a primary analysis of the expression of hereditary properties of materials is carried out, in particular, speed sensitivity, the ability to flow under constant stress, creep and recovery after unloading, and the influence of the composition, state and proportion of fillers on them. 10.18149/MPM.5332025_14 polytetrafluoroethylene nanocomposites wear resistance viscoelastoplastic properties stress-strain curves family strain rate sensitivity failure strains loading and unloading curves creep and recovery curves https://mpm.spbstu.ru/article/2025.108.14/ 14_khokhlov_et_al_(part_1).pdf