https://www.elibrary.ru/title_about_new.asp?i 1605-8119 54 2 2026 1-196

RAR RUS 1-16 Institute for Problems of Mechanical Engineering RAS Belyaev F.S.

St. Petersburg, Russia

St. Petersburg State University Volkov A.E.

St. Petersburg, Russia

St. Petersburg State University Gorbachenko D.F.

St. Petersburg, Russia

St. Petersburg State University Evard M.E.

St. Petersburg, Russia

Numerical study of the influence of the reverse martensitic transformation completion degree on the cyclic stability of a shape memory alloy-based actuator Despite all the advantages of shape memory alloy-based actuators, their widespread adoption is hampered by a significant drawback: a gradual decline in performance with repeated actuation. The ways to overcome this drawback are explored. Based on microstructural modeling, the influence of the degree of completion of the reverse martensitic transformation on the operational stability of a torsion actuator with a working body made of a TiNi alloy was investigated. The existence of a critical transformation threshold (~ 75 %) has been identified: exceeding it leads to significant loss of work output, while limiting the transformation to this level ensures practical stabilization of the working cycle parameters. A compromise in the influence of the transformation degree was revealed: reducing it improves the stability of the actuator parameters but reduces the work output per cycle. Based on the obtained results, criteria for selection of an optimal operating mode for actuators intended for long-term cyclic operation were formulated. http://dx.doi.org/10.18149/MPM.5422026_1 shape memory alloys thermomechanical actuator functional fatigue martensitic transformations microstructural modeling https://mpm.spbstu.ru/article/2026.113.1/ 1_belyaev_et_al.pdf

RAR RUS 17-25 Belgorod National Research University Borisov S.I.

Belgorod, Russia

Belgorod National Research University Dolzhenko P.D.

Belgorod, Russia

Belgorod National Research University Nikitin I.S.

Belgorod, Russia

Belgorod National Research University Kalinenko A.A.

Belgorod, Russia

Belgorod National Research University Zuiko I.S.

Belgorod, Russia

Belgorod National Research University Kaliuzhnaya E.V.

Belgorod, Russia

Shandong University Shi L.

Jinan, China

Shandong University Wu Ch.

Jinan, China

Belgorod National Research University Mironov S.Yu.

Belgorod, Russia

Partitioning of a microstructure produced during laser powder bed fusion of 17-4 PH steel This study focused on the characterization of a complex microstructure in 17-4 PH martensitic steel produced during laser powder bed fusion. Due to the specific nature of the LPBF process, the additive material undergoes an extremely high cooling rate (~ 106 K/s) and pronounced thermal cycling. This usually gives rise to the complex microstructures consisting of δ-ferrite, austenite, and martensite. In this work, a two-step approach was developed for the partitioning of the δ-ferrite and martensite phases. The elaborated method was based on the electron backscatter diffraction technique and involved a two-factor filtration of the electron backscatter diffraction data using the distinct differences between the δ-ferrite and martensite in stored energy and grain size. From experimental observations, it was shown that the proposed technique was highly effective for an analysis of the complex microstructures produced during LPBF of 17-4 PH martensitic steel. 10.18149/MPM.5422026_2 martensitic steel additive manufacturing electron backscatter diffraction microstructure martensite δ-ferrite https://mpm.spbstu.ru/article/2026.113.2/ 2_borisov_et_al.pdf

RAR RUS 26-40 https://orcid.org/0009-0004-4685-4420 GIET University Mohanty N.

Gunpur, Odisha, India

https://orcid.org/0000-0003-1027-6644 GIET University Patnaik T.K.

Gunpur, Odisha, India

https://orcid.org/0000-0002-4980-1242 International PranaGraf Mintech Research Centre (IGMRC) Dash T.

Bhubaneswar, Odisha, India

https://orcid.org/0000-0003-4633-6434 CSIR-Institute of Minerals and Materials Technology Bajpai S.

Bhubaneswar, Odisha, India

https://orcid.org/0009-0009-6555-960X International PranaGraf Mintech Research Centre (IGMRC) Biswal S.K.

Bhubaneswar, Odisha, India

B4C reinforced Al nanocomposite development by powder metallurgy route: revolutionizing material for the future An effective powder metallurgy route has been used to develop new Al/B4C (0, 0.5, and 1 wt. %) nanocomposites. Following 4 h of optimized mechanical milling, particle size measurements verified for the pure Al, Al/B4C (0.5 wt. %), and Al/B4C (1 wt. %) samples as 65, 54, and 51 nm, respectively and these values are well corroborated to the crystal size measurement by XRD for the respective samples. Then the compacted (at 200 MPa) samples were sintered at an argon atmosphere at 550 °C for 3 h. Because of the homogeneous dispersion of 1 wt. % B4C in Al, the intensity of the Al peaks is significantly reduced in the XRD pattern of Al/1 wt. % B4C composite, which indicates the proper composite formation between Al and B4C. It is marked that the reinforcement of B4C enhanced the morphology of pure Al. Reinforcement of only 1 wt. % B4C in Al was found to enhance its microhardness value from 45 to 112 VHN (about 148 % increment). 10.18149/MPM.5422026_3 aluminium boron carbide XRD microhardness https://mpm.spbstu.ru/article/2026.113.3/ 3_mohanty_et_al(1).pdf

RAR RUS 41-56 0000-0003-3780-5104 Southern Federal University Nesterov S.A.

Rostov-on-Don, Russia

Identification of the variable characteristics of a functionally graded elastic pipe with voids Using the Cowin-Nunziato model, a coefficient inverse problem for inhomogeneous poroelastic bodies is formulated, and operator equations of the 1st kind for its solution are derived. As an example, an inverse problem for a functionally graded elastic pipe with voids is considered using additional information measured in the domain of transient loading. To solve the direct transient problem, a combined method is used: transition to the Laplace transform space, followed by solution of the boundary value problem using the shooting method and inversion using an expansion in shifted Legendre polynomials. The solution to the direct problem was verified by comparing it with the solution obtained in the finite element package FlexPDE for a homogeneous pipe. The influence of the heterogeneity laws of the Lamé moduli, coupling modulus, pore diffusion modulus, density, and pore stiffness modulus on the radial displacement was investigated. For reconstruction of physical and mechanical characteristics the iteration approach is applied. Two methods discretization of operator equations (a collocation method and a projection method) are proposed. The initial approximation is defined among the constants as the average of the maximum and minimum values of the material properties. Refinement of physical and mechanical characteristics in projection method was carried out in stages: (1) among constants; (2) linear functions; (3) quadratic functions. Computational experiments were conducted to reconstruct variable properties both at internal points of the pipe and in the class of power functions. A comparative analysis of the effectiveness of the proposed discretization schemes is performed. 10.18149/MPM.5422026_4 elastic pipe with voids Cowin-Nunziato theory functionally graded material identification variable physical and mechanical properties integral equation 1st kind iterative approach https://mpm.spbstu.ru/article/2026.113.4/ 4_nesterov.pdf

RAR RUS 57-69 0000-0001-7544-6056 Peter the Great Saint-Petersburg Polytechnic University Lobachev M.I.

St. Petersburg, Russia

Dynamic effects of a hollow cylinder quasi-force-free magnet This study investigates mechanical stresses induced by a unipolar sinusoidal pulse in a hollow cylindrical conductor, which serves as a key element of the base part of a quasi-force-free configuration pulsed magnet. The aim of the work is to assess transient mechanical effects not accounted for by static models. The applied method determines the system's natural frequencies and solves the dynamic axisymmetric problem of elasticity theory using Laplace transforms. The results include the calculated spectrum of natural frequencies; it is shown that the stress response exhibits quasistatic behavior for millisecond-duration pulses, whereas dangerous stress magnification requires microsecond pulses which are consistent with the single-degree-of-freedom model predictions. In conclusion, the adequacy of static models for designing magnets with millisecond-range pulses is confirmed, and the development of a methodology for analyzing complex multilayer magnets is proposed. 10.18149/MPM.5422026_5 quasi-force-free magnet hollow cylinder dynamic response Lorentz force von Mises stress natural frequencies pulsed magnetic field https://mpm.spbstu.ru/article/2026.113.5/ 5_lobachev.pdf

RAR RUS 70-82 0000-0003-2950-8775 Kallam Haranadha reddy Institute of Technology Suresh B.

Guntur, Andhra Pradesh, India

0000-0002-8584-5752 VR Siddhartha School of Engineering, Siddhartha Academy of Higher Education (Deemed to be University) Naresh P.

Vijayawada, Andhra Pradesh, India

0000-0003-1301-3057 Lakireddy Bali Reddy College of Engineering Sobhanachalam P.

Mylavaram, Andhra Pradesh, India

0000-0002-7892-3871 Krishna University Dr. MRAR College of PG Studies Rao Narasimha N.

Nuzvid, India

0000-0002-4565-2622 Kallam Haranadha reddy Institute of Technology Rani Ch.

Guntur, Andhra Pradesh, India

0000-0001-9209-702x Univ. College of Engineering and Technology, Acharya Nagarjuna University Srinivasa Reddy M.

Nagarjuna Nagar Andhra Pradesh, India

Interpretation of macroscopic and microscopic optical properties of Sm3+ doped ZnF2-PbO-B2O3 glass systems The preparation and spectroscopic investigation of Sm2O3 doped ZnF2−PbO−B2O3 glasses. XRD patterns confirmed their amorphous nature are reported. From measured densities, various physical parameters – including molar volume, optical band gap, refractive index, electronic polarizability and optical basicity were systematically evaluated and presented. Optical absorption spectra show well defined Sm3+ transitions from 6H5/2-6FJ where  levels. The optical band gaps are found to be minimal for the glass containing 2.0 mol. % Sm2O3. Judd-Ofelt analysis yielded Ω2 > Ω4 > Ω6 with bonding parameter δ highest at 2.0 mol. % Sm2O3, indicating a less covalent environment. Overall, the linear variation of physical and optical properties reflects the compositional role of Sm2O3. These results provide useful for potential laser-host applications. 10.18149/MPM.5422026_6 borate glasses Sm doped glasses optical parameters JO parameters FTIR spectra lead contained glasses https://mpm.spbstu.ru/article/2026.113.6/ 6_suresh_et_al.pdf

RAR RUS 83-100 0009-0003-2749-3546 Saveetha School of Engineering, SIMATS Solairaju J.A.

Chennai, Tamil Nadu, India

0000-0003-4912-5579 Saveetha School of Engineering, SIMATS Thanikodi S.

Chennai, Tamil Nadu, India

Processing structure property relationship of flax/hemp/glass hybrid laminates: multifactor effects of TiO₂, SiC, and fiber sequencing on mechanical and thermal performance This study investigates the mechanical, moisture resistance, and thermal behavior of hybrid flax/hemp/glass fiber reinforced epoxy composites incorporated with TiO₂ and SiC nanoparticles. The composites were fabricated using compression molding with different stacking sequences and varying nanofiller contents to evaluate their influence on tensile strength, flexural strength, microhardness, fracture toughness, water absorption, and thermal stability. The results indicate that both fiber stacking configuration and hybrid nanoparticle reinforcement significantly influence the performance of the composites. Among the tested configurations, the Sequence-3 laminate containing 2 wt. % SiC and 3 wt. % TiO₂ exhibited the best overall performance. Compared with the baseline composite, this optimized structure demonstrated a 33 % increase in tensile strength, 18 % improvement in flexural strength, 22 % enhancement in microhardness, and 9 % increase in fracture toughness, indicating improved load transfer and crack resistance. In addition, the incorporation of hybrid nanoparticles reduced water absorption by approximately 18 %, enhancing moisture resistance of the composite system. Thermogravimetric analysis further confirmed improved thermal stability, with delayed degradation temperatures attributed to the barrier effect and strong interfacial bonding provided by SiC and TiO₂ nanoparticles. Overall, the synergistic interaction between hybrid fibers and nanofillers significantly improves the structural, thermal, and environmental performance of the composites, demonstrating their potential as sustainable lightweight materials for advanced engineering and structural applications. 10.18149/MPM.5422026_7 nanoparticles hybrid fiber mechanical strength thermal properties sustainable https://mpm.spbstu.ru/article/2026.113.7/ 7_solairaju_ja_et_al.pdf

RAR RUS 101-110 0009-0001-9233-1549 Shri Govind Guru University Pandya T.P.

Godhra, India

0009-0005-4455-3891 Shri Govind Guru University Jani M.P.

Godhra, India

Gujarat University Vyas S.M.

Ahmedabad, India

Gujarat University Pavagadhi H.B.

Ahmedabad, India

Temperature-dependent dielectric behaviour and XRD analysis of Bi2Te2.8Se0.2 X-ray diffraction and temperature-dependent dielectric measurements were used to examine the structural and dielectric characteristics of Bi2Te2.8Se0.2, a promising thermoelectric material. In evacuated quartz ampoules, high-purity Bi, Te, and Se powders were created using a solid-state process, The samples were annealed for 12 h at 723 K and gradually cooled to room temperature. A highly crystalline rhombohedral structure (space group R3̅m) with little lattice distortion (microstrain ~3.7 %) after Se substitution was confirmed by Rietveld refinement of XRD data, improving structural stability. Because Se has a larger atomic radius than pure Bi₂Te₃, the unit cell volume increased slightly. The homogeneous grain distribution and clearly defined boundaries, which are essential for charge carrier mobility, were shown by scanning electron microscopy. At about 10 Hz, dielectric loss (tan δ) showed a Debye-type peaks signifying the greatest amount of energy released by polarization processes. At the peak frequency, the imaginary electric modulus verified relaxation dynamics with relaxation time τ = 0.016 s. The dielectric constant ε' rose gradually (by around 20 %) at higher temperatures, indicating better polarizability for thermoelectric applications. In comparison to undoped versions, this work demonstrates the originality of Se-doping in Bi₂Te₃ for adjustable dielectric characteristics, attaining better efficiency (potential ZT > 1.2) with reduced synthesis costs. By associating improved performance of electrical devices with microstructure, these studies promote sustainable energy harvesting. 10.18149/MPM.5422026_8 thermoelectric materials semiconductor bismuth selenium telluride dielectric properties x-ray diffraction crystal growth Bi2Te2.8Se0.2 material https://mpm.spbstu.ru/article/2026.113.8/ 8_pandya_t_et_al.pdf

RAR RUS 111-128 0000-0001-6655-1495 Universidad San Pablo-CEU, CEU Universities Maciá Torregrosa M.E.

Madrid, Spain

0009-0005-3497-5468 Universidad San Pablo-CEU, CEU Universities Pinilla Hernandez M.I.

Madrid, Spain

0000-0002-9573-6162 Universidad San Pablo-CEU, CEU Universities Camacho Diez J.

Madrid, Spain

0000-0003-1639-2208 Universidad San Pablo-CEU, CEU Universities Machín Hamalainen C.

Madrid, Spain

Universidad CEU San Pablo Gonzalez-Lezcano R.A.

Madrid, Spain

Numerical simulation of flexural breaking load resistance tests in mortars with recycled polyethylene terephthalate This study investigates the flexural behavior of mortars modified with recycled polyethylene terephthalate through numerical simulations developed in SolidWorks Simulation using a linear dynamic approach. Prismatic specimens measuring 40 × 40 × 160 mm3 with recycled polyethylene terephthalate contents of 10 and 20 % were evaluated under three temperature levels (20, 150, and 350 °C) and two curing conditions: ambient and water curing. A linear dynamic finite element model was developed in SolidWorks Simulation to reproduce the bending response and analyze the temporal evolution of Von Mises stresses, principal stresses, and stress distribution patterns. The numerical model incorporated experimentally determined mechanical properties and breaking loads as input parameters. The results indicate that increasing recycled polyethylene terephthalate content reduces the stiffness and load-bearing capacity of the mortar, particularly at elevated temperatures, due to the thermal softening of the polymer and the weakening of the interfacial transition zone. Water curing enhances mechanical performance by promoting matrix hydration and improving the capacity for stress redistribution, thereby mitigating the adverse effects of thermal exposure. The numerical simulations showed strong agreement with experimental observations and successfully captured the evolution of stress localization and failure mechanisms under different thermal and curing conditions. These findings highlight the combined influence of recycled polyethylene terephthalate content, curing regime, and temperature on the structural performance of modified mortars and confirm the suitability of linear dynamic finite element analysis for investigating bending behavior in polymer-modified cementitious materials. 10.18149/MPM.5422026_9 RPET bending finite elements sustainable mortars thermal behavior dynamic simulation https://mpm.spbstu.ru/article/2026.113.9/ 9_macia_torregrosa.pdf

RAR RUS 129-139 0000-0002-0090-5745 RUDN University Hematibahar M.

Moscow, Russia

0000-0002-2773-4114 Moscow State University of Civil Engineering Kharun M.

Moscow, Russia

0000-0002-2279-1240 Far Eastern Federal University Fediuk R.S.

Vladivostok, Russia

0000-0002-1196-8004 Peter the Great St. Petersburg Polytechnic University Vatin N.I.

St.Petersburg, Russia

Perm Military Institute of the National Guard Troops of the Russian Federation Lymarev V.N.

Perm, Russia

Far Eastern Federal University Fediuk G.R.

Vladivostok, Russia

Gomel State Medical University Alexeiko L.N.

Gomel, Republic of Belarus

Effect of acoustic vibration frequency of concrete during hydration on mechanical properties While extensive research has focused on the sound absorption properties of concrete, the effect of external acoustic vibration loads on its hydration process, mechanical performance, and microstructure remains a significant scientific gap. This study investigates the influence of applying acoustic vibrations at varying frequency ranges during the critical hydration period. A conventional concrete mixture was subjected to acoustic vibrations across five frequency ranges for 24 h during hydration, using a setup with two loudspeakers at constant sound intensity. A control sample was cured without any vibrations. The mechanical performance was evaluated through compressive and tensile strength tests at 7, 14, and 28 days Microstructural analysis was conducted using scanning electron microscopy on selected samples. The results demonstrated a clear negative impact on mechanical properties. The control sample achieved the highest compressive (37.2 MPa) and tensile (3.6 MPa) strengths at 28 days. The application of acoustic vibrations generally reduced strength, with the reduction being more severe at higher frequencies. The sample E (104–2·104 Hz) showed the most significant decline, with compressive and tensile strengths 42.4 % and 22.2 % lower than the control, respectively. However, the effect was found to be frequency-dependent. Sample C (103–5·103 Hz) exhibited a relatively smaller reduction in strength compared to other treated samples, suggesting a less detrimental impact within this specific range. The study concludes that external acoustic vibrations during hydration disrupt the microstructure formation, leading to a decrease in the mechanical strength of concrete. No beneficial effects were observed within the tested parameters. 10.18149/MPM.5422026_10 acoustic vibrations concrete hydration mechanical properties compressive strength tensile strength microstructure frequency dependence early-age concrete https://mpm.spbstu.ru/article/2026.113.10/ 10_hematibahar_et_al.pdf

RAR RUS 140-166 Peter the Great St. Petersburg Polytechnic University Borovkov A.I.

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Vafaeva Kh.M.

St. Petersburg, Russia

0000-0002-1196-8004 Peter the Great St. Petersburg Polytechnic University Vatin N.I.

St.Petersburg, Russia

Kazakhstan Multidisciplinary Institute of Reconstruction and Development Republican State Enterprise on the Right of Economic Use Nuguzhinov Zh.S.

Karaganda, Republic of Kazakhstan

Topological data analysis and graph signal processing: quantitative defect assessment and localization of structural inhomogeneities in composites from nondestructive testing data The aim of the study is to develop and perform a preliminary evaluation of a method for diagnosing and locating internal defects in multilayer polymer composite materials using non-destructive testing data. A method combining topological data analysis and graph-signal processing is proposed. To demonstrate the potential feasibility of this method, an analysis of synthetic ultrasonic signals was conducted. A set of 81 ultrasonic signals, representing various locations of internal defects in the composite material, was used. Topological data analysis enabled the identification of informative topological features and distinguished defective from defect-free cases with a silhouette score of 0.471. The results show the potential of using topological data analysis to automate the structural monitoring of internal defects in multilayer polymer composite materials. 10.18149/MPM.5422026_11 topological data analysis graph signal processing nondestructive testing composite materials structural inhomogeneities defect localization signal interpretation structural health monitoring https://mpm.spbstu.ru/article/2026.113.11/ 11_vafaeva_khm_et_al.pdf

RAR RUS 167-180 University of Brothers Mentouri Constantine 1 Nebatti R.

Constantine, Algeria

University of Brothers Mentouri Constantine 1 Kadja M.

Constantine, Algeria

Badji Mokhtar University – Annaba Mechighel F.

Annaba, Algeria

CFD evaluation of the hydrodynamic and thermal performances of a counter-flow heat exchanger A heat exchanger is a device that facilitates the transfer of energy between two fluids through a solid barrier. Simulations were performed in a turbulent flow regime to investigate the two-dimensional forced convective heat transfer of the nanofluid water / Al2O3 within a counter-flow heat exchanger. This study is numerical and was conducted using a single-phase approach with constant thermophysical properties. Conduction through the interface was taken into account in the computations. The results unequivocally showed an improvement in the overall coefficient of heat transfer depending on the Reynolds number along with the type of fluid. The use of nanofluid significantly increases total heat transfer in contrast to the pure base fluid; however, this is accompanied by an increase in friction coefficients, leading to higher pumping costs. 10.18149/MPM.5422026_12 сomputational fluid dynamics fully developed turbulent flow double tube heat exchanger numerical convective heat transfer overall heat transfer coefficient https://mpm.spbstu.ru/article/2026.113.12/ 12_nebatti_r_et_al.pdf

RAR RUS 181-196 Institute of Engineering and Technology Lucknow Mohit K.

Lucknow, India

0000-0002-7399-8823 Institute of Engineering and Technology Lucknow Singh S.K.

Lucknow, India

Institute of Engineering and Technology Lucknow Mishra A.

Lucknow, India

Structural health monitoring of two storey steel frame using accelerometer sensor: a numerical and experimental study External forces generated due to earthquakes, wind, and blasts cause damage to the structure by which its structural integrity gets compromised. A method is to be developed to find the current state of the structure after the damage has occurred. This can be done by finding the natural frequency of the structure using modal analysis. In this study, a two-storey steel frame bolted structure has been studied experimentally on a one-dimensional shake table. Results obtained through the experiment have been verified using the numerical study of the same structure. COMSOL Multiphysics was used for additional numerical analysis, and the various eigenfrequencies and mode shapes were identified. Additionally, numerical research was carried out to simulate damages ranging from 10 mm to 20 mm, and the findings indicate that the natural frequencies decrease as the damage increases. Thus, Modal analysis can be used to determine the current state of the structure. For various mode shapes, the experimental and numerical frequency variations are 0.37, 1.61, and 3.16 %, respectively. 10.18149/MPM.5422026_13 experimental modal analysis COMSOL Multiphysics shake table accelerometer damage study numerical study https://mpm.spbstu.ru/article/2026.113.13/ 13_kumar_m_et_al.pdf