首页期刊导航|Iranian Journal of Science and Technology, Transactions of Mechanical Engineering
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Iranian Journal of Science and Technology, Transactions of Mechanical Engineering
Springer Verlag
Iranian Journal of Science and Technology, Transactions of Mechanical Engineering

Springer Verlag

半年刊

2228-6187

Iranian Journal of Science and Technology, Transactions of Mechanical Engineering/Journal Iranian Journal of Science and Technology, Transactions of Mechanical Engineering
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    Sensor-Less Sliding Mode Observer-Based Assistive Control of a Spherical Parallel Ankle Rehabilitation Robot Under Modeling Uncertainties

    Ahmadi A.Nopour R.Kamali Eigoli A.Taghvaeipour A....
    2407-2421页
    查看更多>>摘要：© The Author(s), under exclusive licence to Shiraz University 2025.This paper explores the field of robotic rehabilitation exercises using a spherical parallel robot, with an emphasis on assistive control strategy which has a wide range of applications in ankle rehabilitation robotics. While early in the rehabilitation process, passive control is more common, assistive control eventually takes over as the patient’s condition improves. Precise feedback of force and torque generated by the patient is essential for the implementation of assistive control topology. Force/torque sensors and electromyography sensors are just a few of the sensors that help monitor this interaction between the robot and human. But problems like sensor compatibility, positioning, dependability, and signal processing complexity appear. To circumvent the requirement for force and torque sensors, this study proposes a robust motion controller and a sensor-less strategy that employs a nonlinear observer utilizing the dynamics of the robot for assistive ankle rehabilitation applications. By utilizing the sliding mode controller, and the nonlinear observer, the paper improves the robot’s position control and the accuracy of active torque estimations in the presence of uncertainties arising from dynamic modelling of the robot and human–robot interaction. This interaction includes the foot’s mass and the hysteresis loop-shaped resistance torque of the ankle applied to the robot’s moving platform. Stability analysis of the whole system including the controller and the observer is conducted to demonstrate the robustness of the proposed control framework in the presence of modelling uncertainties. Co-simulations have been conducted to demonstrate the efficiency of the observer-based sliding mode controller in accurately estimation of the active torque and tracking the predefined trajectories in the presence of uncertainties.
      原文链接:
    • NETL
    • NSTL
    • Springer Nature

    Experimental Investigation of CNC Wire-Cut EDM Machining Accuracy on Vibration Characteristics of Non-Circular Gear Pairs

    Nguyen H.-P.Tran V.-T.Banh T.-L.Hoang M.-T....
    2423-2437页
    查看更多>>摘要：© The Author(s), under exclusive licence to Shiraz University 2025.The non-circular gear pair is designed to transmit motion at various speeds in a mechanical transmission system. The vibration characteristics significantly affect the performance and service life of the meshing gear pair. However, the vibration characteristics of non-circular gear pairs have not been extensively studied. Therefore, this study proposes an experimental investigation into the vibration response of a non-circular gear pair under different surface qualities, gear loading conditions, and rotation speeds. First, the tooth profile of a non-circular gear is designed using the proposed mathematical model and manufactured via CNC (computer numerical control) wire-cutting EDM (electrical discharge machining) with three machining parameters to produce three tooth profile quality levels: rough, semi-finished, and finished. The normal tooth profile error of the non-circular gear pair is calculated to verify the surface quality of the manufactured gear. The results show that the tooth profile error is within the allowable limits of gear manufacturing standards. An experimental device is then developed to simulate the operating conditions of a non-circular gear pair, including gear loading and rotation speed. The radial vibration of the gearbox system is measured using a vibration hub system and analyzed using the Mean Lab software to evaluate the variation in system vibration. The result indicates the influence of radial vibration on tooth surface quality, rotation speed, and gear loading.
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    • Springer Nature

    Research on the Impact Resistance and Energy Absorption Characteristics of the Improved Honeycomb Composite Structure Under Low-Velocity Impact Loading

    Wang Z.Wang H.Du X.
    2439-2456页
    查看更多>>摘要：© The Author(s), under exclusive licence to Shiraz University 2025.The impact resistance and energy absorption characteristics of the existing traditional honeycomb composite structures have not been fully explored, and in order to improve its mechanical performance under low-velocity impact loading, reasonable improvement is needed. In this study, an improved honeycomb composite structure is proposed by introducing a styrene-butadiene rubber (SBR) elastomer interlayer between the CFRP skin of the traditional composite structure and replacing the traditional hexagonal aluminum honeycomb core with a bio-inspired pomelo peel-like aluminum honeycomb core (Hg). First, drop-weight impact tests were conducted at 10 J impact energy to compare the impact resistance and energy absorption characteristics between traditional and improved honeycomb composite structures. Second, finite element models of the improved structure with five varying thickness configurations were established to analyze the influence of CFRP and SBR thickness on the impact resistance. Additionally, numerical simulations were performed by replacing the original hexagonal honeycomb core with Hg cores of varying aperture-to-wall thickness ratios (β) to analyze the influence of β on the energy absorption characteristics. The results demonstrated that the honeycomb composite structure exhibited significantly enhanced mechanical performance after the improvements and core replacement. Specifically, the impact resistance showed a strong dependence on the thickness of both the SBR interlayer and CFRP skin, while the energy absorption characteristics were closely related to the β of the Hg core.
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    • Springer Nature

    Enhancing Energy Absorption and Crashworthiness of Optimized Re-entrant Auxetic Structures

    Roosta A.Rouzegar J.Rahmanian S.
    2457-2480页
    查看更多>>摘要：© The Author(s), under exclusive licence to Shiraz University 2025.This research aims to design and optimize novel auxetic structures inspired by simple re-entrant geometries to enhance crashworthiness and energy absorption characteristics. Three auxetic structures, namely curved, splitted, and peanut, are introduced and evaluated alongside traditional re-entrant structures through experimental and numerical analyses. Finite element method simulations using Abaqus/CAE software are conducted, complemented by quasi-static tests on the structures to derive force–displacement diagrams. Energy absorption parameters—total energy absorption (EA), specific energy absorption (SEA), and crush force efficiency (CFE)—are determined and compared between structures. The results demonstrate the alignment of numerical and experimental approaches, with the peanut structure exhibiting the highest EA and SEA, and the curved structure displaying the highest CFE. Additionally, the presence of foam within the structures is experimentally and numerically examined, leading to increased energy absorption in most cases. Through Taguchi design of experiments, an optimization process was conducted on the curved structure, considering four geometric variables and different objective functions. By introducing a new objective parameter termed ‘absorber efficiency’ combining CFE and SEA, an optimized structure achieving a balanced performance in both aspects is obtained.
      原文链接:
    • NETL
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    • Springer Nature

    Finite Element Implementation of Continuum Damage Mechanics for SLM AlMgScZr Cantilever Under Random Vibration Loading

    Zha Z.Yin H.Yang Y.Li P....
    2481-2499页
    查看更多>>摘要：© The Author(s), under exclusive licence to Shiraz University 2025.Vibration fatigue loading can degrade the elastic properties of selective laser melting (SLM) aluminum alloys, resulting in a reduction of the structure’s natural frequency, which is essential for the analysis of structural integrity and design of the structure. To account for the vibration-induced natural frequency degradation, continuum damage mechanics (CDM) is applied based on the finite element method (FEM) for the cantilever beam under random vibration fatigue loading, simulating elastic modulus degradation and natural frequency reduction due to the fatigue damage evolution. Vibration fatigue tests on SLM aluminum alloy cantilever beams assess natural frequency degradation across various power spectral density (PSD) magnitudes. Fractography analysis is conducted to investigate the mechanism of vibration fatigue failure. The predicted natural frequency degradation closely aligns with experimental measurements, and the vibration fatigue life predictions fall within an acceptable two-fold range, validating the fatigue damage analysis.
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    • Springer Nature

    A Rapid Surrogate Model for Collision Risk Prediction in Real-Time Optimization of Slender Flexible Manipulators with Obstacle Avoidance

    Makhdoomi P.Mardani A.Pashaei M.H.
    2501-2520页
    查看更多>>摘要：© The Author(s), under exclusive licence to Shiraz University 2025.This paper addresses a fundamental question in motion planning for slender manipulators: how can an optimal tip-point trajectory be determined while accounting for collision risk across all points of the manipulator's body hull without proximity sensors? Additionally, is it feasible to develop an offline-trained point-to-point motion strategy that minimizes the risk of collision? An enhanced surrogate model based on a matrix of multi-layer perceptron neural networks, designed to estimate the nonlinear vibration zones surrounding the desired configuration of the manipulator hull is the proposed solution. The system is structured around fundamental components, including a single-type link, revolute joint, and cable, whose mechanical simplicity and slender form inherently lead to high-amplitude fluctuations that must be mitigated in point-to-point movements. A key limitation of conventional optimization approaches lies in their inability to achieve real-time responsiveness due to the complex interaction between obstacle detection, multi-degree-of-freedom system dynamics, and control mechanisms. This study introduces a novel surrogate model trained for rapid and reliable response, enabling real-time path optimization based on kinematics and geometry while integrating neural networks to estimate vibration zones associated with specific kinematic configurations. The surrogate model, trained offline to incorporate dynamic effects, ensures comprehensive risk assessment across the manipulator hull for all point-to-point tasks. By leveraging reinforcement Q-learning, the proposed approach facilitates efficient real-time motion planning, delivering a fast and viable solution for collision-free path optimization.
      原文链接:
    • NETL
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    • Springer Nature

    A Predictive Model for Fatigue Performance in Spot Welded and Bolted Joints

    Teke I.T.Ertas A.H.Baykara C.Akbulut M....
    2521-2546页
    查看更多>>摘要：© The Author(s), under exclusive licence to Shiraz University 2025.This study examines the fatigue behavior of spot-welded and bolted single-lap joints through an integrated framework combining experimental testing, finite element analysis (FEA), and regression modeling. The investigation focuses on how geometric parameters—such as plate width, length, thickness, and overlap length—affect fatigue life under variable loading conditions. Fatigue tests serve as the foundation for developing a predictive model for low-cycle fatigue, while FEA provides detailed insights into stress concentrations at critical regions like weld nuggets and bolt holes. Results show that bolted joints, particularly those using M4 fasteners, exhibit superior fatigue performance due to more uniform stress distribution and reduced localization. Submodel-based FEA confirms these findings, revealing that bolted configurations better disperse stresses compared to the high gradients observed near spot welds. This combined approach enhances fatigue life prediction accuracy and offers practical guidance for optimizing joint geometry in automotive, aerospace, and mechanical engineering applications.
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    • Springer Nature

    Fabrication of Aluminum Alloy Foams from Sheets Using Clad-Chip Extrusion Technique

    Suzuki R.Fujiwara K.Hangai Y.Nishida S....
    2547-2555页
    查看更多>>摘要：© The Author(s), under exclusive licence to Shiraz University 2025.This work demonstrates a new technique for the easy fabrication of aluminum alloy foams from inexpensive alloy sheets instead of expensive powders. In this process, a clad-chip extrusion method is used to provide the precursor materials. Two A1050 aluminum alloy sheets are stacked with titanium hydride powder in between and are then roll-bonded at a 50% reduction ratio. The laminated sheets are subsequently cut into squares to produce clad-chips, from which a foamable precursor is obtained via extrusion. Another foamable precursor is produced for comparison. This precursor is produced from chips of the same size. The chips are cut from an as-received A1050 aluminum alloy sheet. Both precursors are used in foaming tests at 700 °C in an electric furnace, after which the porosities of the aluminum alloy foams are ascertained. The clad-chip precursor expands during heating and provides a foam with a maximum mean porosity of 51%. In contrast, the as-received chip precursor expands minimally and provides a maximum mean porosity of just 20%. It is clear that aluminum alloy foams can be easily obtained from sheets using this clad chip extrusion precursor method.
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    • NETL
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    • Springer Nature

    On the Generation of Curve-Face Gear Composite Mechanism: Modelling and Dynamic Simulation

    Dong C.Yang X.Wang F.Liu Y....
    2557-2573页
    查看更多>>摘要：© The Author(s), under exclusive licence to Shiraz University 2025.To investigate the motion characteristics of a curve-face gear (CFG) composite mechanism, a geometric and kinematic model was developed based on the gear envelope principle. The axial motion behavior of the theoretical model was analyzed, and the effects of structural parameters were examined through dynamic simulations. The internal velocity distribution and the influence of working condition parameters on dynamic meshing force and torque were studied. Tooth surface contact stresses and load distribution were assessed using finite element simulations. The results indicate that increasing the eccentricity of the driving gear leads to greater fluctuations in axial displacement, velocity, and acceleration. A higher CFG order corresponds to a shorter fluctuation period. The discrepancy between theoretical and simulated axial displacement was 2.44%, confirming the validity of the model. The amplitude of dynamic meshing force and torque increases with higher damping and decreases with greater stiffness. Increases in rotational speed and load torque significantly raise the amplitude and frequency of force fluctuations. The tooth contact primarily occurs on the inner side of the gear surface. The specially designed pitch curve of the CFG reduces peak elastic deformation of the driven gear and leads to a more uniform distribution of contact force and pressure.
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    • Springer Nature

    Research on the Modeling and Application of Drone Vibration Isolation Systems in Humid Steam Environments

    Cheng Z.Zhang X.Wei S.
    2575-2590页
    查看更多>>摘要：© The Author(s), under exclusive licence to Shiraz University 2025.This study investigates a specific quadrotor unmanned aerial vehicle (UAV) with the aim of supporting rescue missions in humid, vapor-laden environments following heavy rainfall and flooding. The vibrational excitation on rotor blades caused by water droplets in such conditions is first analyzed through theoretical derivation and simulation. Subsequently, dynamic models and motion differential equations for the vibration isolation system are developed for both hovering and cruising states. Based on calculations, the isolator parameters are determined to be k = 5574 N/m and c = 5.8 N·s/m. Finally, finite element simulations and experimental tests are conducted to compare the vibration responses of the original system and the system with vibration isolation. The results indicate that the designed UAV vibration isolation system, when operating in a humid steam environment, reduces the resonance frequency by 33%, the acceleration resonance amplitude by 60%, and the lift amplitude by 50% compared to the original system. These improvements contribute to enhanced post-disaster rescue efficiency.
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    • NETL
    • NSTL
    • Springer Nature