Journal of Engineering and Thermal Sciences
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The design and finite element analysis of the mushroom picking flexible robotic arm
Full text linkThis article presents a robotic arm designed for mushroom picking in a greenhouse environment, taking into consideration the specific characteristics of Agaricus bisporus. The robotic arm was equipped with self-lifting and self-stretching functions, allowing it to move effectively within the restricted space of the greenhouse, while picking and placing Agaricus bisporus without causing any damage. The mechanical arm and flexible gripper were designed according to the growth environment and size of Agaricus bisporus. A finite element analysis was carried out on the flexible gripper, with the use of ABAQUS to construct a simulation model. The Yeoh model and the Mooney-Rivlin model are used as the research models, and tetrahedral linear elements C3D4H were used for meshing. By changing the positive and negative pressure of the gas inside the flexible gripper's airbag to simulate gripping and releasing actions, it was demonstrated that the deformation of the flexible gripper meets the requirements for picking actions under both the Yeoh model and the Mooney-Rivlin model. It was shown that a shear force greater than 3.2N is needed for the gripping and twisting of Agaricus bisporus within the flexible gripper to successfully complete the picking action. Finally, the experimental verification was carried out, proving the stability and feasibility of the mushroom picking robotic arm. And the design of flexible gripper control system, through the distributed computing and I/O structure, CANopen communication protocol, etc. makes the flexible gripper can perform accurate gripping tasks in complex environments, with high efficiency, reliable, flexible control performance, adaptable, and easy to expand and optimize
PSO-PPO-based reinforcement learning control strategy for active suspension systems under multiple operating conditions
Full text linkTo address the poor generalization capability and extended training duration of reinforcement learning (RL)-based active suspension control systems, this study proposes a PSO-PPO algorithm for multiple operating condition suspension control. The methodology initiates with establishing a 4-DOF suspension dynamic model under three characteristic driving conditions: constant-speed operation, vehicle launch, and emergency braking, which is subsequently converted into state-space representation. The novel PSO-PPO framework synergizes particle swarm optimization with proximal policy optimization to train condition-specific agents. Based on the trained optimal agents, the entropy weight method is applied to adjust the reward function weight coefficients to develop a generalized multi-condition controller. Finally, the control effectiveness of the PSO-PPO algorithm is validated through constant-speed, launch, emergency braking, and multi-condition concatenated scenarios. Simulation results demonstrate that the PSO-PPO algorithm achieves shorter training times while maintaining balanced performance in ride comfort, handling stability, and safety across all conditions
Magnetoelastic oscillation of current-carrying plates in an alternating magnetic field
Full text linkModern technological advancements, particularly in micro- and nanoelectronics, aerospace engineering, sensor systems, and robotics, necessitate a deeper understanding of how structural elements behave under various physical influences. One significant and relevant phenomenon is magnetoelastic interaction, which involves how the mechanical behavior of current-carrying elastic bodies is affected not only by external loads but also by internal electromagnetic processes. Current-carrying plates, commonly utilized in micro- and nanoelectronics, respond to external fields by altering their stress-strain states. To accurately model these processes, an integrated approach is required that considers mechanical, electromagnetic, and thermal effects caused by electrical currents. This paper focuses on the mathematical modeling and numerical study of transverse magnetoelastic oscillations in thin current-carrying plates subjected to an alternating magnetic field. The problem is formulated considering electromagnetic interactions, geometric nonlinearity, and external alternating currents. A comprehensive system of equations is developed that includes the equations of motion, Maxwell's equations, and the heat equation with Joule heating sources. For the numerical solution, the finite difference method using the Newmark scheme and discrete orthogonalization techniques are applied. Graphs illustrating stress and strain distributions are presented, and the effects of magnetic field frequency and external current on the system’s behavior are analyzed. This research is vital for designing reliable components in micro- and nano-electronics and aviation
Evaluation and modeling of airborne dust pollution in the Kamchik railway tunnel during train movements
Full text linkThis paper presents the results of a study on airborne dust pollution in the Kamchik Railway Tunnel caused by train movements. Field measurements were carried out to determine the concentrations of suspended particulate matter (PM10, PM2.5, PM1), as well as air temperature, pressure, and humidity in different sections of the tunnel – near the portals and in its central part. It was established that during train passages, the level of dust concentration increases by 6-10 times compared to background values, exceeding sanitary and hygienic standards. The main sources of dust generation were identified as frictional interactions between wheels and rails, braking processes, and the transportation of bulk materials. To reduce dust concentrations, engineering solutions are proposed, including the implementation of automatic water-based dust suppression systems, enhanced tunnel ventilation, and the use of hydrophobic surface coatings. The obtained results can be used to optimize ventilation modes and improve the operational safety of the Kamchik Railway Tunnel
Numerical modeling of reinforced concrete structures made of lightweight concrete using ANSYS
Full text linkIn this paper, extensive numerical investigations into reinforced concrete beam made of lightweight concrete are given, through the ANSYS finite element program. The main aim was to assess the load carrying capacity, stiffness and deformation characteristics of the beams of different concrete densities. There were seven beam specimens, which vary in the percentage ratio of lightweight to normal aggregates, and the material properties were duly incorporated in the model. Three-dimensional nonlinear finite element analysis was used to simulate the beams with a mesh size of 25 mm, and the results were compared with the experimental results. Results showed that when the concrete density was reduced the loadbearing capacity decreased gradually, as the concrete became normal weight (95 kN) and then fully lightweight (85.7 kN). Nevertheless, the plastic zone transition happened later in lightweight beams and this implies that the deformation resistance was more difficult than in normal-weight concrete. The load-deflection curve demonstrated the fact that lightweight concrete beams though less stiff in nature, are structurally reliable and competitive. This study highlights the possibility of the lightweight concrete to be used as a structural material in contemporary engineering practice and therefore seismic zones where minimized self-weight improves the overall safety and efficiency. The results are useful in understanding how to optimize and design the reinforced lightweight concrete members
The importance of using geosynthetic materials in ensuring anti-erosion stability of railway embankments
Full text linkRailway embankments are key elements of transport infrastructure whose stability depends on soil, hydrogeological, and climatic factors. Wind and rainfall erosion threaten slope integrity, causing soil loss and potential landslides. This study integrates field experiments and modeling to assess erosion mechanisms and the effectiveness of geosynthetic geomats for slope protection. Tests on the Bukhara-Miskin railway section determined wind and rainfall thresholds for soil displacement and evaluated geomat performance by slope stability, vegetation density, and runoff resistance. Reinforced slopes showed almost no soil washout, with vegetation density of 4000-5500 kg/ha – over 200 % higher than traditional seeding. Geomat use reduced erosion by up to 80 % and improved ecological resilience, offering a reliable, cost-effective, and sustainable solution for long-term railway slope stability
Dynamic response and lightweight design of winding drum based on CAE technology
Full text linkTo enhance the rationality of the anchor winch drum structure design and reduce costs and energy consumption, a lightweight design scheme was put forward based on multi-objective optimization technology. According to the working principle, load characteristics, and composition of the anchor winch, a parameterized coupled model of modal and strength was established using the finite element method, from which the stress, deformation, natural frequency, and mode shapes characteristics of the drum part were obtained. Under the premise of not changing the assembly dimensions and not causing structural interference, the dimensions of the cylinder, side panels, and ribs were determined as design variables, and corresponding sensitivity analysis was derived. The maximum stress, first-order equivalent stiffness, and mass were set as the optimization targets, and the Kriging model was used as an approximating function in the construction of mathematical model. The standard criteria for evaluating the precision of the response surface model were chosen as the coefficient of determination, adjusted coefficient of determination, and root mean square error. Under the condition of maintaining equivalent stiffness without degradation, two lightweight design schemes were obtained under the conditions of no less than the initial stress peak value and 1.5 times the stress peak value. The results show that it is possible to achieve a weight reduction rate of 14.1 % without increasing the stress peak value and without reducing the equivalent stiffness, effectively achieving the design goal of energy saving and cost reduction
Theoretical assessment of the mechanical properties of fiber concrete using the dispersion analysis method
Full text linkThis paper examines how the type of fiber and the amount of fiber in concrete impacts the mechanical characteristics of fiber-reinforced concrete (FRC) by both experimental testing and statistical modelling. Basalt, polypropylene, and steel fiber reinforced concrete specimen were cast at different percent ratios (0, 0.1, 0.2 and 0.3) and subjected to laboratory conditions to measure compressive strength. At every dose and fiber type, three specimens were tested, and average values of the strengths were computed. OriginPro was used to fit the data in polynomial regression models (second degree) to quantify the connections between the parameters of this fiber and compressive strength. The most important statistical indicators provided in the assessment of the model accuracy were coefficients of determination (R2), adjusted R2, F-statistics, p-values, and residual analysis. The results revealed that the models were all characterized by high predictive accuracies (R2= 0.72, 0.93) and found to be significant using ANOVA (p< 0.0001). Results validated that the type of fiber along with the dosage were critical in the effectiveness of strength with optimal amount enhancing performance and loads beyond or below those levels decreasing the matrix bonding. The produced models offer a predictive predicting model that would be helpful in FRC mixture optimization. The study presents significant information in the field of structural engineering where a newly established structure will be needed to have superior durability, dependability, and load capacity
Enhancing sound absorption of Helmholtz resonance metamaterials with extended microperforated neck
Full text linkTo enhance sound absorption of Helmholtz resonance metamaterials in low frequency region with simple structure and engineering practicability, according to the well-established acoustic absorption theory of micro-perforated panel, a novel designed Helmholtz resonance metamaterial with extended microperforated neck is proposed, and a theoretical modelling method is developed by using the transfer matrix method which is validated by finite element simulation. Both theoretical calculation and finite element simulation results show that sound absorption performance of proposed Helmholtz resonance metamaterial is improved significantly compared to that of Helmholtz resonator with normal neck, and the resonant absorption coefficient is close to 1. The influence of geometric parameters of microperforated neck is also investigated in detail, and some meaningful conclusions are drawn. This work provides a perfect solution for low-frequency noise control with Helmholtz resonance metamaterials
Study on the compaction and dynamic properties of loess enhanced by waste tyre rubber particles
Full text linkThis study investigates the compaction and dynamic properties of rubber particle-loess from Inner Mongolia through laboratory tests, including compaction tests and dynamic triaxial tests. Four rubber particle sizes (10 mesh, 20 mesh, 40 mesh, and 100 mesh) and four contents (5 %, 10 %, 15 %, and 20 % by volume) were tested under varying conditions: confining pressures of 50 kPa, 100 kPa, and 200 kPa, and freeze-thaw cycles of 0, 1, 3, 6, and 9. The tests aimed to simulate environmental conditions relevant to infrastructure in Inner Mongolia's loess regions. Results revel that adding 5 % 40-mesh rubber particles maximized dynamic shear modulus, damping ratio, and compactness. The dynamic shear modulus exhibited strain-softening behavior, which decreased with increasing dynamic strain, rubber content, and freeze-thaw cycles, but increased with confining pressure. The damping ratio showed a non-linear relationship with moisture content, showing a minimum at optimum moisture and increasing with freeze-thaw cycles while decreasing with confining pressure. Notably, the damping ratio of rubber particle-loess consistently exceeded that of plain soil. These results highlight the potential of waste tire rubber particles as an eco-friendly material to enhance loess engineering properties, particularly in cold regions with significant freeze-thaw effects. The study provides a theoretical basis for improving loess stability and seismic performance in geotechnical applications