Engineering Computations

Guo, Yong; Yu, Ding-Hao; Li, Gang

doi: 10.1108/ec-07-2024-0698pmid: N/A

The nonlinear behavior of masonry structures is expressed via the global tangent stiffness matrix with large dimensions that needs to be updated and decomposed in real time, which reduces the calculation efficiency. The purpose of this paper is to propose an efficient nonlinear analysis method of masonry structures based on the inelasticity-separation concept and the discrete macro-element.Design/methodology/approachFirst, in the discrete macro-element model, each shear panel element interacts with other panels through interface elements to simulate the main failure modes of masonry walls, and the interaction is established by introducing multi-point constraints and relative displacement functions. Then, the inelasticity-separation concept is adopted to decompose the deformations of the shear panel elements and interface elements into linear-elastic and inelastic components, and the inelastic components are modeled using additional inelastic degrees of freedom. Thus, the global tangent stiffness matrix is expressed as a small-rank perturbation of the global linear elastic stiffness matrix, and the global governing equation is solved via the efficient mathematical Woodbury formula.FindingsConsequently, the updating and factorization of the global tangent stiffness matrix are avoided, and the computational effort of structural nonlinear analyses only focuses on the updating and factorization of a small-dimensional matrix representing the local inelastic behavior, which greatly improves the efficiency of the proposed method.Practical implicationsThe proposed method provides an effective structural analysis tool for design and performance evaluation of masonry structures.Originality/valueThis study proposes an efficient implementation of the discrete macro-element with the aim of speeding up the simulations through an inelasticity-separated strategy.

Zhu, Lili; Jiang, Haonan; Fan, Wenzhong; Wang, Guangxin

doi: 10.1108/ec-10-2024-0962pmid: N/A

The purpose of this paper is to analyze the influence of basic design parameters of nutation face gear transmission on the thermal elastohydrodynamic lubrication characteristics of grease lubrication, considering the influence of heat generated by frictional power loss between meshing tooth surfaces on the viscosity and density of lubricating grease in the flow and film thickness directions.Design/methodology/approachBased on the velocity separation method, the Reynolds equation corresponding to the constitutive equation of the Herschel Bulkley rheological model is given, and then the numerical calculation model of thermal elastohydrodynamic lubrication is established. Considering the influence of temperature rise between meshing tooth surfaces on the viscosity and density of lubricating grease in the direction of flow and film thickness, the multi-grid method is used to numerically solve the thermal elastohydrodynamic lubrication calculation model.FindingsBy comparing the thermal elastohydrodynamic numerical calculation results with the isothermal elastohydrodynamic numerical calculation results, the influence of the temperature rise between the meshing tooth surfaces on the film thickness and pressure in the lubrication area of the nutation gear transmission is obtained.Originality/valueBased on specific working conditions and performance parameters of the face gear and lubricating grease, the influence of basic design parameters of the face gear transmission on the thickness and pressure of the film in the thermal elastohydrodynamic lubrication area is obtained, which establishes a more reasonable basis for judging the gear failure of nutation face gear transmission.

Han, Wenping; Liu, Shankun; Zhang, Ling; Ma, Zhaosong; Han, Fei

doi: 10.1108/ec-02-2025-0098pmid: N/A

This study develops PERISOFT, a peridynamic (PD) simulation software, to overcome PD theory's high computational costs and limited engineering applications by coupling PD with classical continuum mechanics (CCM), enabling efficient simulation of material fracture, including crack initiation, propagation and branching.Design/methodology/approachBuilt on the GENVI platform, PERISOFT employs an adaptive PD-CCM coupling algorithm that dynamically transitions between local (CCM) and nonlocal (PD) domains based on stress strength or bond failure. It integrates four solving modes (finite element method (FEM), bond-broken induced peridynamic model (BIPD), strength-induced peridynamic (SIPD) and PD) to address static/dynamic problems.FindingsValidation via representative case studies demonstrates PERISOFT's capability to accurately model complex fracture patterns and provide quantitative mechanical insights. Beyond serving as an analytical tool, the platform offers extensibility for further development of PD theory, making it relevant to researchers in computational mechanics, material science and fracture modeling.Originality/valueAs a PD software leveraging the GENVI platform, PERISOFT bridges PD theory and engineering practice. Its adaptive coupling algorithm and hybrid solving modes offer a novel, flexible framework for multiscale fracture analysis, advancing computational mechanics and material failure research.

Nguyen, Tuan Anh

doi: 10.1108/ec-02-2025-0128pmid: N/A

An integrated nonlinear control solution is introduced in this paper to improve the performance of an electric power steering (EPS) system.Design/methodology/approachThis algorithm is established based on combining two robust nonlinear control techniques: sliding mode control (SMC) and backstepping control (BSC). The phase difference phenomenon is improved by adjusting the input of the BSC technique based on a proportional-integral (PI) controller, whose parameters are optimally calculated by a genetic algorithm (GA). This new combination produces a robustly stable algorithm called SMC-BSC-PI-GA with control signals chosen to satisfy the Lyapunov stability condition.FindingsThe algorithm’s performance is evaluated by simulation, which is performed in the MATLAB–Simulink interface for two specific cases. Based on the paper findings, the controlled objects, steering column angle (SCA) and steering motor angle (SMA), obtained from the SMC-BSC-PI-GA algorithm, follow the reference value with negligible error (approximately zero in some cases). The energy consumption efficiency of this controller is improved, while the phase difference phenomenon is wholly eliminated, and the influence of chattering is negligible. Controller performance is guaranteed in all investigated cases, even when speed and driver torque change.Originality/valueThis integrated nonlinear algorithm can decline systematic errors (for controlled objects), reduce energy consumption and eliminate the influence of disturbances, which are the problems that exist for other algorithms.

Çalık, İsmet

doi: 10.1108/ec-02-2025-0107pmid: N/A

The aim of this study is to determine the behavior of masonry stone minarets, which are important and delicate examples of historical monuments that are a common value of humanity, under the effects of earthquakes and to examine the size-damage relations of the February 6, 2023 Kahramanmaras earthquakes, the history of Gaziantep and the minarets. With the results obtained from this study, damage limits and risks related to the dimensions of existing masonry stone minarets before possible earthquakes can be evaluated.Design/methodology/approachWithin the scope of the study, the minarets of the mosques damaged due to the Kahramanmaras Earthquakes in Gaziantep were examined observationally. The damages, damaged areas and damage–collapse situations are revealed. The sizedamage relationships of the minarets were examined and the damage relationships of their slenderness and structural features were revealed using statistical approaches.FindingsAs a result, it was determined that the roof-top minarets exhibited the most risky behavior in the form of collapse and cracks with slenderness values below 10%. It has been determined that the cracks occurred between 10–6% of the slenderness values of adjacent minarets while the collapse behavior occurred below the slenderness value of 6. Also, the separated minarets exhibited a more resistant behavior and there were no damages observed above the 8% slenderness level. In this study, suggestions were made regarding the measures that can be taken to shed light on restoration works.Research limitations/implicationsThe research is based on the behavior of masonry stone minarets in Gaziantep province under the effect of Kahramanmaras earthquakes. Masonry stone minarets, similar examples of which are widely seen, reveal the size–damage relationship, provided that the ground properties are not recorded. With this study, data that can be referenced in terms of size–damage relationship of similar structures under the influence of earthquakes have been obtained.Originality/valueThe research includes field data of the historical minarets of Gaziantep, which were damaged under the influence of the earthquake, some of which were destroyed and some of which were damaged. The unique nature of the study is the on-site examination of the behavior of historical minarets after the earthquake, as well as the access and recording of a large number of data such as their dimensions and photographs. Recording the limited opportunities of historical buildings for experimental studies and structural observations in the post-earthquake situation will serve as a reference for other researchers.

Dai, Ning; Geng, Dajiang; Yuan, Jianyi; Zhai, Guangyao; Chen, Yanqiang

doi: 10.1108/ec-07-2024-0664pmid: N/A

This study aims to introduce a new version of the Drucker–Prager model (DPM) to effectively capture the strain-softening effects in geotechnical materials.Design/methodology/approachIn this study, small step size convergence and limited computational efficiency were used during the numerical implementation of the new model.FindingsThe amalgamation of direct measurement, equation solving and optimization theory proves to be a highly effective approach for determining the parameters of intricate constitutive models.Originality/valueThe conventional DPM is an ideal plastic model but lacks the capability to represent material softening effects, rendering it fundamentally inadequate. In contrast, the new model can effectively capture material softening effects, rendering it better suited for describing geotechnical materials exhibiting softening behavior.

Li, Na; Zhang, Haipeng; Zhou, Xin; Duan, Zhenyu

doi: 10.1108/ec-11-2024-0996pmid: N/A

The main objective is to investigate the correlations among the unsteady flow, nonlinear aerodynamic damping, amplitude response and heat transfer characteristics of a piezoelectric fan under various spatial confinement conditions.Design/methodology/approachFor this purpose, the multidisciplinary coupling analysis method for fluid–thermal–structure interaction (FTSI) has been studied and validated.FindingsThis study’s findings are as follows: (1) piezoelectric fan in the non-vacuum environment exhibit significant amplitude decay due to aerodynamic damping, causing a reduction in maximum amplitude by almost 50% compared to that in a vacuum. Furthermore, the effect of confined space cannot be ignored. When the sidewall gap d1 is approximately 1 mm, the maximum amplitude of the fan blade decreases by 60%. (2) The analysis based on FTSI demonstrates that there is interaction between blade deformation and aerodynamic damping, which results in corresponding changes in the induced jet and heat transfer characteristics.Originality/valueTheoretical analysis and FTSI simulation studies have been carried out to explore the correlations among the unsteady flow, nonlinear aerodynamic forces, amplitude response and heat transfer characteristics of piezoelectric fans under various spatial confinement conditions. The analysis based on bidirectional fluid–solid interaction demonstrates a significant interaction between blade deformation and aerodynamic damping, which results in corresponding changes in the induced jet and heat transfer characteristics.

Xin, Ma; Zui-Cha, Deng; Xu-Wei, Tie

doi: 10.1108/ec-02-2025-0106pmid: N/A

The purpose of this paper is to investigate the inverse problem of recovering two-dimensional spatial heat sources in thermal energy management based on the Crocco-type degenerate parabolic equation.Design/methodology/approachUnlike classical parabolic equations, the mathematical model discussed in the paper belongs to the Crocco-type equation, characterized by the absence of the second-order derivative with respect to x. Moreover, to better capture the discontinuity of the source term coefficients, this study employs the total variation regularization method to address the problem.FindingsBy transforming the original problem into an optimal control problem, a necessary condition of the control functional is derived. Combined with the a priori estimate of the forward problem, the global uniqueness and stability of the minimizer are obtained. For numerical verification, the Gauss–Jacobi iterative scheme is used to deal with the nonlinear term and the Euler equation is also derived. Numerical experiments indicate that the proposed algorithm is stable and effective, achieving successful reconstruction of the heat source distribution within the building.Practical implicationsThis study enhances thermal energy management by precisely reconstructing heat source distributions, thereby optimizing energy efficiency and thermal comfort, with particular emphasis on irregular heat source configurations.Originality/valueThe paper first applies total variation regularization to Crocco-type parabolic equations to address inverse source problems in thermal energy management, optimizing energy utilization and enhancing thermal comfort.

Öztürk, Burak

doi: 10.1108/ec-01-2025-0056pmid: N/A

This study aims to enhance the safety and reliability of tibial tray designs used in total knee arthroplasty by analyzing the effects of region-specific cooling rates and geometric parameters on mechanical properties. Through an integrated experimental and computational approach, the study highlights the critical influence of thermal gradients during manufacturing.Design/methodology/approachThe mechanical behavior of tibial tray materials was evaluated using hardness and tensile tests under varying cooling conditions. Finite Element Method (FEM) simulations were conducted to assess stress distribution and safety factors under physiological loading. Multi-objective optimization was performed using Response Surface Methodology (RSM) and Monte Carlo simulations to identify optimal geometric configurations.FindingsCooling rates were found to significantly affect mechanical properties, with hardness ranging from 320 to 597 HV and tensile strength between 390 and 616 MPa. FEM results showed maximum stress values of 3.18–6.14 MPa and average polyethylene safety factors of 6.4. Optimization via RSM revealed that material volume could be reduced from 9,387 mm3 to 3,754 mm3 through geometric refinement.Originality/valueThis research presents a novel combination of experimental and simulation-based methods—FEM, RSM, and Monte Carlo—to evaluate and optimize tibial tray design. Unlike prior studies, it quantitatively links cooling rate variations to mechanical performance and introduces a validated multi-objective framework that balances material efficiency with structural safety.

Öztürk, Burak; Aydın, Kutay; Uğur, Levent

doi: 10.1108/ec-12-2024-1138pmid: N/A

The main objective of the study is to increase energy efficiency and to determine the optimum rotational speeds in production processes. In this direction, the ideal production parameters were determined using experimental measurements and artificial neural network (ANN) analyses.Design/methodology/approachIn this study, the threading performances of two different types of pipe fittings made of (Spheroidal graphite cast iron) GGG44 spheroidal graphite cast iron are investigated experimentally by considering energy efficiency. Experimental studies were carried out on elbow and tee-type fittings and energy consumption and torque values were measured. The experimental results were modeled using the ANN method. Afterward, optimum production parameters were determined.FindingsAs a result, it was found that the best threading parameter in terms of maximum energy efficiency is 34 revolutions per minute (rpm) rotational speed value. When force, torque, cutting tool life and energy efficiency outputs are considered together, the optimum threading condition was obtained at 30 rpm rotational speed.Originality/valueThe production of pipe fittings has high energy costs in the manufacturing sector due to the large amount of threading operations and the high torque required. These machines increase energy consumption by producing high torque while operating at low rotational speeds. Research on optimising energy consumption is of great importance both in terms of reducing costs and sustainability. For these reasons, the study focuses on optimising energy consumption in the mass production of pipe fittings by mounting an inverter on manual threading machines and obtaining energy consumption and required torque values at different rotational speeds.HighlightsThreading performance of GGG44 pipe fittingsMeasurement of cutting power, cutting force and torqueArtificial neural network (ANN) modeling and determination of optimum threading parameters