Journal of Mechanical Engineering, Automation and Control Systems
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Analysis of dynamic response characteristics of vehicle-mounted tank based on the finite element method
No full textThe vehicle-mounted tanks face prominent challenges in balancing dynamic safety, including vibration resistance and fatigue durability under complex transportation conditions. A rigid-flexible coupled finite element model, consisting of the base, tank body, and frame, was established. Vibration response analysis was conducted in accordance with ride comfort standards and road excitation requirements. Rigid-flexible coupled simulations were implemented with consideration of vertical acceleration inputs and road unevenness. For random vibration, power spectral density analysis demonstrated that the tank structure was prone to resonance in specific frequency bands. For structural optimization, key dimensions were selected as design variables, including vertical thickness, longitudinal thickness, middle width, and lateral width. An optimization mathematical model was established, and the Sequential Quadratic Programming (SQP) algorithm was adopted to solve the constrained nonlinear multi-objective optimization model. Through optimization calculations, the structure achieved 4.93 % reduction in mass, 37.3 % decrease in stress, and 37.1 % increase in the first-order natural frequency, thereby effectively balancing the requirements of lightweight design, structural strength safety, and anti-resonance performance. This study provided a comprehensive methodology for the dynamic analysis and optimization of vehicle-mounted tank containers, offered key technical support for advancing innovative studies in transportation and vibration engineering
Energy analysis of living stumps slope based on Hilbert-Huang Transform and marginal spectrum
Full text linkA large-scale shaking table model test on a slope with living stumps was designed and conducted. Under various types of seismic waves and excitation intensities, acceleration data from monitoring points on both sides of the living stumps were collected. Hilbert-Huang Transform (HHT) was innovatively applied to study the dynamic response of slopes with living stumps under seismic loading, overcoming the limitations of traditional Fourier Transform and Wavelet Transform. The variation patterns of Hilbert energy and marginal spectral characteristics under different seismic excitations were analyzed, providing new insights from both time-frequency domain and energy perspectives. The research conclusion showed that: (1) Under different seismic waves, the horizontal peak acceleration inside the living stumps slope shows the elevation amplification effect, and increases with the intensity of excitation. Additionally, the existence of living stumps causes a difference in horizontal acceleration on both sides, and the absolute value of the difference is positively correlated with elevation and excitation intensity. (2) Under different seismic waves, Peak of Hilbert energy spectrum (PSHEA) is positively correlated with excitation intensity and elevation. With the increase of elevation, the increase of PSHEA increases gradually when the excitation intensity increases. PMSA is positively correlated with excitation intensity, but at low frequencies (1-3 Hz), Peak of marginal spectrum (PMSA) is negatively correlated with elevation; while at high frequencies (7-11 Hz), PMSA is positively correlated with elevation. (3) With increasing elevation and excitation intensity, the total seismic Hilbert energy continues to accumulate and reaches the maximum at the top of the slope. During the propagation of seismic waves, the living stumps and the rock-soil composite play the characteristics of filtering the low-frequency components and amplifying the high-frequency components, causing the total seismic Hilbert energy in the low-frequency (1-3 Hz) component to gradually decrease and transfer to the high-frequency (7-11 Hz) component, resulting in a significant increase in seismic Hilbert energy in the high-frequency component. (4) The superposition of incident wave and reflected wave near the living stumps, and the absorption of seismic Hilbert energy by the living stumps make the PSHEA, PMSA, and total seismic Hilbert energy on the outside of the living stumps always smaller than the inside, resulting in different dynamic responses on either side of the living stumps. The living stumps show attenuation effect on seismic Hilbert energy, and the attenuation degree increases with the increase of excitation intensity and elevation. The study provides a theoretical basis for the seismic design of living stumps slopes
Dynamic detection and evaluation of wheel flats in heavy-haul railway wheelsets using wayside monitoring systems
Full text linkIn recent years, heavy-haul railways have become a critical direction for freight transport in China, with wheel flats in wheelsets posing significant threats to operational safety and infrastructure integrity. Traditional detection methods (e.g., manual inspection, TPDS) suffer from low efficiency or limited accuracy in characterizing flat features. To address this, this study develops a rigid-flexible coupling dynamic model for C80 wagons with K6 bogies, uniquely integrated with field data from the Truck Operation Detection System (TODS) to bridge simulation and engineering application gaps. Focusing on wheel-rail force responses under wheel flat conditions, we establish a quantitative mapping relationship between flat length, vehicle speed, and impact force through polynomial fitting of simulation data (10-80 km/h for empty/loaded vehicles). To validate feasibility, a 56-channel wayside monitoring system (TODS) is installed on a heavy-haul railway, calibrated via hydraulic loading to ensure measurement accuracy. Field tests (80,541 vehicles monitored) confirm that TODS can infer flat length from detected impact forces, with results consistent with TPDS alarms but offering finer characterization of flat dimensions. This work provides a practical solution for real-time wheel flat detection, enhancing maintenance efficiency and safety in heavy-haul operations
Fatigue performance analysis and reinforcement measures for foundation connection components of wind turbine towers
Full text linkIn recent years, frequent tower collapses have been mostly related to fatigue damage. Therefore, this paper systematically studies the fatigue resistance performance and reinforcement methods of tower foundation connection components through on-site tests and finite element analysis. The test analyzed the lifespan, stress-strain characteristics, crack development and mechanical properties of the connection components under fatigue loads; numerical simulation compared the fatigue life and safety of ordinary components, reinforced with steel mesh, C100 high-strength concrete components, and C40 and C100 composite components, etc., providing key basis for engineering reinforcement
Enhancing the Carrying capacity of complex mountain railway sections through the optimization of train mass standards
Full text linkIt is known that the current train mass standards for railway sections often do not allow locomotives to fully utilize their tractive power. This limits the throughput and Carrying capacity of the railway sections. This article examines the issues of increasing the carrying capacity of freight trains by optimizing train mass standards, using the “Angren-Pop” railway section, which has the most complex profile in “Uzbekistan Railways” JSC, as an example. Updated optimal train mass standards have been proposed for freight trains operating on the “Angren-Pop” railway section, and experimental tests have been carried out based on these standards, followed by their implementation in practice. Based on traction calculations, the interstation travel times of trains for the updated mass standards have been determined. Methods for effectively increasing the transport capacity of the section have been recommended by implementing measures such as increasing the train mass standards and interstation running speeds of freight trains, as well as systematically organizing the use of electric locomotives with high tractive power
Experimental thermal fatigue crack on brake disc of heavy vehicle
Full text linkBrake system reliability is critical for the safety and performance of heavy vehicles, including semi-trailers, passenger buses, and industrial transport units. This study investigates the thermal fatigue failure mechanisms in brake discs (BDs), which are subjected to extreme operational conditions. The primary motivation is to enhance brake disc durability and reduce the risk of catastrophic failures by understanding the interplay between material properties, thermal stress, and fatigue resistance. A comprehensive experimental approach was employed, including visual inspections, chemical composition analysis, metallurgical structure examination, hardness testing, and tensile strength evaluation. The study compares brake discs that have undergone extensive service with those in an undamaged state to identify critical degradation patterns. The results indicate that temperature fluctuations and cyclic thermal stresses induce crack formation and propagation, with rough graphite inclusions significantly reducing fatigue strength. Furthermore, deviations in silicon and carbon content were found to impact material integrity, contributing to premature failure. The findings of this research provide actionable insights for optimizing brake disc design, material composition, and manufacturing processes. By modifying graphite distribution, refining alloy compositions, and improving thermal resistance, future brake systems can achieve greater durability and reliability. These advancements will directly enhance braking efficiency, reduce maintenance costs, and improve overall vehicle safety
Complex fault diagnosis in wind turbine bearings: a hybrid approach combining the improved feature mode decomposition and convolutional neural networks
Full text linkThe complex noise interference and diverse fault-induced signals in vibration data from wind turbine equipment pose significant challenges for bearing fault diagnosis, including cumbersome methodologies, prolonged processing times, and compromised accuracy. To address these limitations, this study proposes a novel composite fault diagnosis framework that integrates Feature Mode Decomposition (FMD), Fast Spectral Kurtosis (FSK), and Convolutional Neural Network (CNN). While conventional Empirical Mode Decomposition (EMD) exhibits limited noise robustness and struggles to extract subtle fault signatures in composite failure scenarios, our approach employs FMD to decompose fault-related intrinsic mode functions (IMFs)and further filters the IMF components using fast spectral cliffs with enhanced feature separability. Subsequently, the Short-Time Fourier Transform (STFT) is applied to derive time-frequency representations, followed by Fast Spectral Kurtosis analysis to identify optimal demodulation bands for non-stationary signals. The energy spectrum of denoised signals is converted into grayscale images, serving as input to a tailored CNN architecture for hierarchical feature learning. Experimental validation demonstrates that this hybrid methodology achieves a fault recognition accuracy of 98 % under compound fault conditions, outperforming conventional EMD-based approaches in terms of noise immunity and diagnostic precision. Comparative analysis reveals an 8 % improvement in detection reliability over standalone deep learning models, particularly in low signal-to-noise ratio (SNR) environments. The proposed framework offers a robust solution for multi-fault identification in industrial Bearing machinery, demonstrating superior generalization capability across varying operational conditions
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
Key construction technologies for in-situ reconstruction of a continuous girder bridge onto a steel truss arch bridge
Full text linkThis study explains the challenges of reconstructing a continuous beam bridge and its effects on the performance of adjacent structures. Combined in-situ demolition and modification of continuous beam bridges with the new construction of steel truss arch bridges, an integrated construction method is established. Taking a bridge as a construction platform, the temporary fixation technology is used for the tie beam hook. Various erection techniques of the bridge and tie beam construction support frame, as well as the construction techniques of Truss steel arch and wind bracing are studied and explored. In addition, the method of simultaneous disassembly and construction methods of crossbeams are also studied. Finally, a new technology is developed to reconstruct Truss arch bridge on continuous beam bridges
Field evaluation of the geotechnical behavior of lime-ground cushions in the Republic of Tajikistan
Full text linkThe article presents the methodology for conducting field tests of lime-soil cushions to examine the technology of their construction, gain strength, their operation under rigid stamps, and the characteristics of stress-strain state development. The results of field studies showed that the lime-soil mixture can be used as a structural material in the preparation of bases on loess- loess soils in the conditions of the Republic of Tajikistan. Field tests showed that the lime-soil mixture achieved a dry density of 1.53-1.56 t/m3, while the deformation modulus increased by 5-10 times compared to natural loess soils