Mechanical Engineering, Engineering, Information Systems, Computer Engineering
16
Scopus Publications
Scopus Publications
Computerised analysis of non-conjugate spiral bevel gear mesh using an advanced and fast-converging tooth contact model Maksat Temirkhan, Andas Amrin Scientific Reports, 2025 The mathematical framework used to address the geometrically non-conjugate gear tooth contact problem in three-dimensional space represents a sophisticated task that requires substantial computational resources. The conventional approach to tooth contact analysis (TCA), involving five non-linear equations with five unknown parameters, uses an implicit model where convergence cannot be guaranteed. In recent years, researchers have proposed several new methods for analyzing gear tooth contact, offering more efficient alternatives to the conventional TCA model. However, most of these methods rely on a discretized approach, resulting in approximate solutions and the use of additional optimization algorithms, such as particle swarm optimization to find the initial contact or grid representation of the tooth surface composed of nodal points. This additional manipulation complicates the process of determining the contact trace and increases the computational load. Furthermore, most of these methods cannot be applied to all spiral gear tooth engagement cases involving complex misalignments and tooth surface modifications; they are limited to specific cases, such as pure-rolling gear drives, parallel axis contacts, or situations without axial misalignment. Moreover, the majority of these methods, like the conventional model, suffer from the challenge of determining proper starting values to run the iterative process required to solve the TCA non-linear equations, where a random choice of starting values might lead to the divergence of the numerical algorithm. To overcome this limitation and enhance the convergence properties, a novel TCA method has been introduced. This investigation contrasts the conventional and proposed novel model in terms of their convergence probability, accuracy, and computational speed, thereby contributing to a comprehensive understanding of the strengths and limitations inherent in these approaches. Compared to conventional and other TCA models suggested in the past few years, the proposed novel TCA method uses fundamental geometric principles to analytically reduce the non-linear meshing equations from five to two and decrease the number of unknown variables from five to two. This approach does not require the application of discretization methods or additional optimization algorithms. The iterative numerical calculation process can be initiated with any values, and the system will find all contact points exactly at once. Furthermore, the proposed model is applied to simulate the involute tooth contact of spiral bevel gears within a spherical coordinate system. This application aims to examine the impact of misalignment or profile modifications on the transmission error, path of contact, and stress.
Thermal, hardness, and tribological assessment of PEEK/CoCr composites Bakytzhan Sariyev, Andas Amrin, Aiat Mergenbay, H. Jeevan Rao, Aigerim Khabdulayeva, Christos Spitas, Boris Golman Scientific Reports, 2025 Poly(ether-ether-ketone) (PEEK) is a high-performance thermoplastic with excellent mechanical strength, thermal stability, and chemical resistance, making it attractive for applications like biomedical implants and prostheses. However, neat PEEK suffers from a high friction coefficient and pronounced wear in sliding contacts. In this work, composites of PEEK with Cobalt-Chromium (CoCr) alloy powder were fabricated by centrifugal powder compaction and vacuum sintering. Four composite compositions, with weight percentages of 10%, 20%, 30%, and 40% of CoCr, were produced. Scanning electron microscopy analysis confirmed uniform dispersion of CoCr particles within the PEEK matrix. Differential scanning calorimetry and thermogravimetric analysis showed that CoCr addition did not significantly alter PEEK's melting temperature or thermal stability. Microhardness increased with filler loading, with the 40% CoCr composite achieving a 40% hardness improvement over neat PEEK. Ball-on-disk tests against steel revealed that all composites exhibited significantly reduced wear loss by 84% compared to neat PEEK, while maintaining a friction coefficient typical for PEEK-steel contacts. Overall, the PEEK/CoCr composites demonstrate enhanced hardness and wear resistance while retaining PEEK's favorable thermal properties, suggesting their potential for applications requiring better tribological performance than unfilled PEEK.
Atomistic Modeling of Graphene Oxide and Epoxy Resin Composite for Wind Turbine Applications , Adilkhan Zhiyengali, Kuanysh Abzhaparov, , Gaukhar Kabdrakhimova, , Fatima Abuova, , Almira Zhakupova, , Maksat Temirkhan, , Bakytzhan Sariyev, , Christos Spitas, , Nurlan Almas, , Andas Amrin, and Es Materials and Manufacturing, 2025 This study integrates classical all-atom molecular dynamics (MD) simulations and density functional theory (DFT) calculations to explore bisphosphate interactions in carbon fiber reinforced polymers (CFRP) composed of graphene oxide and epoxy resin for wind turbine applications.This research addresses the growing need for durable and reliable materials in renewable energy technologies.MD simulations reveal favorable interaction energies between bisphosphate and the
Critical Assessment on the Stability and Convergence of the Conventional Gear Tooth Contact Analysis Maksat Temirkhan, Andas Amrin, Christos Spitas, Bakytzhan Sariyev, Chingis Kharmyssov Proceedings of Engineering and Technology Innovation, 2024 Mathematical modeling of gear engagement is crucial during design to ensure optimal performance in manufacturing. This study reproduces the conventional tooth contact analysis (TCA) model, highlighting convergence issues in parallel-axis gears and limitations in local synthesis methods. The research critically analyzes the TCA method, which solves five nonlinear equations to assess performance and accuracy. Simulations replicate the conditions of previous studies to ensure valid comparisons. Initial guess values are randomly generated within a specific range to guide the iterative process toward convergence, with this range progressively narrowed to improve computational efficiency and accuracy. Results indicate that the TCA approach is highly sensitive to initial guess values, particularly the starting angular position. Convergence issues arise from the complexity of nonlinear equations and multiple roots. This can lead to divergence or reverting to the initial guess when values deviate significantly from the true solution.
Convergence and accuracy problems of the conventional TCA model – Critical analysis and novel solution for crowned spur gears Maksat Temirkhan, Andas Amrin, Vasilios Spitas, Christos Spitas Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science, 2024 In this work the quasi-static model of the three-dimensional geometrical non-conjugate contact problem for two [Formula: see text] surfaces is studied. The set of contact equations is formulated by using a new parameterisation that enables to reduce the conventional system of five nonlinear equations with five unknown position and contact parameters to just two nonlinear equations with two changeable parameters. The novel model is computationally efficient and demonstrates increased accuracy and stability of the numerical solution, compared to the conventional model described by Litvin, which suffers from convergence problems and requires a high computational effort. The new model is implemented to spur gear with crowned tooth surfaces to parametrically estimate the susceptibility to diverse misalignments of the contact pressure, transmission error and path of contact.
ANALYSIS OF RHEOLOGICAL PROPERTIES IN PE FIBER-REINFORCED FLY ASH GEOPOLYMER FOR ADDITIVE MANUFACTURING B. Sariyev, A. Amrin, A. Jexembayeva, M. Konkanov Herald of the Kazakh British Technical University, 2024 The leading edge of construction advancements is represented by 3D printing which creates durable and elaborate structures and minimizes resource wastage. As a viable substitute for regular cement materials highlights the ecological benefits and strong mechanical traits of fly ash geopolymers. This study investigates how the addition of polyethylene (PE) fibers alters these properties and how varying concentrations influence the flow behavior and capability of producing the composite material. The analysis of non-Newtonian behavior in these fiber-reinforced geopolymers is conducted using the Herschel-Bulkley model. By precisely measuring critical rheological factors such as viscosity and flow behavior researchers can evaluate how they influence 3D printing processes. This research reveals that adding PE fibers boosts the material’s strength and improves resistance against cracking while also elevating the viscosity and yield stress that can hinder its passage through the printer’s nozzle. An optimal blend of fiber content emerges from controlled tests that align increased durability with controllable extrusion flow and structure reliability. The results offer deep practical applications that reveal methods for producing geopolymers that can maintain strength while meeting the exacting requirements of 3D printing methods. Research deepens the grasp of how adding fibers alters the properties of geopolymers and enriches the overall dialogue on green building materials. It opens doors for subsequent analysis of complex fiber systems and creative additive practices to boost the effectiveness and resilience of construction materials in practical use.
State-of-the-art and some of the future challenges for selectable- and fixed-ratio gear transmissions Andas Amrin, Maksat Temirkhan, Hamza Bin Tariq, Amin Amani International Journal of Powertrains, 2024 Geared transmissions are as ubiquitous, as they are essential to nearly every mechanical powertrain. There is a large and growing body of research on gear geometry, with a focus on manufacturing, errors and accuracy, on gear strength, lubrication, efficiency, noise and vibration, for practically all known embodiments of parallel axes, intersecting axes and non-intersecting axes- spatial configurations. Configurations of planetary transmissions are also studied extensively - not least in terms of topology due to their importance to automatic transmissions, and to a lesser but growing extent also cycloidal transmissions, strain-wave transmissions and other exotic but singular architectural configurations are subject to continued research and development. This research and development landscape is far from exhaustive, however; we argue that an extensive part of the - at this time conceivable - design space is largely unexplored: not only in terms of gear contact geometry and associated kinematic and dynamic response and function, but mostly in terms of topology and architecture, either alone or in combination with geometry. We reason, map and anticipate significant innovations and lay a roadmap for future research and technology development. We also make the essential links to use cases from the fields of aerospace engineering, automotive engineering, robotics, and energy.
Assessment of contact forces and stresses, torque ripple and efficiency of a cycloidal gear drive and its involute kinematical equivalent Hamza Tariq, Zhaksylyk Galym, Andas Amrin, Christos Spitas Mechanics Based Design of Structures and Machines, 2024 In this paper, we assess and compare a conventional cycloidal drive and its involute-tooth kinematical equivalent via finite element (FE) and dynamical multi-body analysis. The analysis of the stiffer conventional cycloidal configuration reveals multiple points of contacts, although some of these have little contribution to the torque transmission. Significant non-torque loads are self-induced, with contact forces constantly changing in magnitude and orientation, consistently with the contact characteristics of the cycloid. In the involute alternative, the stress concentration was more localized to two or three points of contact, according to the involute contact ratio, leading to increased stresses. The contact forces remained constant relative to the tangential direction, as per the constant involute pressure angle, contributing to desirable torque loads. The torque ripple was found to have two components, one at the tooth engagement frequency (fz) and one at the high-speed shaft rotation frequency (fn), the former being more pronounced in the conventional cycloidal case, while the latter being larger for the cycloidal drive with involute teeth. Moreover, both analytical calculations and the multi-body dynamics simulations suggest that the involute-tooth design is more efficient compared to the conventional cycloidal-tooth design.
Kelvin-Voigt lumped parameter models for approximation of the Power-law Euler-Bernoulli beams Dongming Wei, Almir Aniyarov, Dichuan Zhang, Christos Spitas, Daulet Nurakhmetov, Andas Amrin Alexandria Engineering Journal, 2023 The purpose of this research is to initiate an investigation of the nonlinear material strain-rate damping effects on the amplitude and frequencies of some Euler-Bernoulli Beams. It is well known that the dynamic behaviors of most heat-treated metals can be modelled by using the power-law strain-rate dependent constitutive equations. Lumped parameter models for approximations of dynamic vibration of the power-law Euler-Bernoulli Beam subject to power-law strain-rate damping and concentrated loads are formulated. Analytic formulas of the lumped parameters, including effective the train-rate damping, are derived. The lumped-parameters are also evaluated numerically by a low-order Galerkin Method to validate and compare the lumped parameter model with another numerical model. Numerical examples made of some heat-treated aluminum and stainless-steel alloys are presented to illustrate the implications of the aforementioned lumped-parameter models on the dynamics of the beams. The results obtained in this work cover with the classical results in the literature for linear the materials as special cases. The novel lumped parameter models can provide useful insights for crashworthiness analysis of structures of heat treated metals and thermal plastics.
