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Abstract In addressing the finite element model and actual structural error of the sprayer boom truss, this study aims to achieve high-precision dynamic characteristics, enhance simulation credibility, make informed optimization decisions, and reduce testing costs. The research investigates the dynamic behavior of the sprayer boom truss through modal experiments and finite element simulations. Initially, modal parameters of the sprayer boom are obtained through experimental testing, validating their reasonableness and reliability. Subsequently, Ansys Workbench18.0 simulation software was employed to analyze the finite element model of the sprayer boom, revealing a maximum relative error of 11.93% compared to experimental results. To improve accuracy, a kriging-based response surface model was constructed, and multi-objective parameter adjustments using the MOGA algorithm reduce the maximum relative error to 4.6%. Sensitivity analysis further refines the model by optimizing target parameters, resulting in a maximum relative error of 4.96%. These findings demonstrate the effective enhancement of the corrected finite element model’s precision, with the response surface method outperforming sensitivity analysis the maximum relative error between the updated finite element model and experimental results was within the engineering allowable range, confirming the effectiveness of the updated model.

Abstract A wealth of practical cases indicates that the fatigue failure of subway bogies primarily stems from the modal resonance of the structure. If the modal characteristics of the entire vehicle, including equipment and bogies, are mismatched, rail vehicles may experience abnormal vibrations and noise. Therefore, it is imperative to conduct modal analysis and matching design for subway vehicle bogies to ensure smooth operation, reduce structural vibrations and noise, and enhance vehicle safety and ride comfort. Modal identification methods under the ambient l excitations during vehicle operation were employed to identify the modal parameters of the bogie structure before and after wheel reprofiling and under different load conditions. According to the test results, wheel reprofiling has minimal impact on the modal parameters of the structure, but with an increase in load, the modal frequencies of each order generally increase. This is associated with boundary constraint states, such as the increased stiffness of the bogie air spring with an increase in vehicle load. By comparing the test results with simulation analysis results of the bogie structure under free and constrained states, it is evident that simulating realistic boundary constraint conditions is crucial to ensure the accuracy of the finite element model. Based on frequency isolation criteria and vibration isolation theory, a frequency planning basis for the bogie structure was established. The study found that as the vehicle load increases, changes in the boundary conditions of the bogie affecting the elastic modal frequencies of the structure may have a certain impact on matching design, and may even better comply with the requirements of frequency management equations. This provides a new direction for subsequent scholars researching modal matching design.

A wealth of practical cases indicates that the fatigue failure of subway bogies primarily stems from the modal resonance of the structure. If the modal characteristics of the entire vehicle, including equipment and bogies, are mismatched, rail vehicles may experience abnormal vibrations and noise. Therefore, it is imperative to conduct modal analysis and matching design for subway vehicle bogies to ensure smooth operation, reduce structural vibrations and noise, and enhance vehicle safety and ride comfort. Modal identification methods under the ambient l excitations during vehicle operation were employed to identify the modal parameters of the bogie structure before and after wheel reprofiling and under different load conditions. According to the test results, wheel reprofiling has minimal impact on the modal parameters of the structure, but with an increase in load, the modal frequencies of each order generally increase. This is associated with boundary constraint states, such as the increased stiffness of the bogie air spring with an increase in vehicle load. By comparing the test results with simulation analysis results of the bogie structure under free and constrained states, it is evident that simulating realistic boundary constraint conditions is crucial to ensure the accuracy of the finite element model. Based on frequency isolation criteria and vibration isolation theory, a frequency planning basis for the bogie structure was established. The study found that as the vehicle load increases, changes in the boundary conditions of the bogie affecting the elastic modal frequencies of the structure may have a certain impact on matching design, and may even better comply with the requirements of frequency management equations. This provides a new direction for subsequent scholars researching modal matching design. [ABSTRACT FROM AUTHOR]

Gantry five-axis machine tools have garnered acclaim for their robustness, cost-effectiveness, and accuracy in fabricating intricate workpieces. In the era of Industry 4.0, these tools necessitate heightened flexibility, precision, and cognitive capabilities to meet contemporary industrial requisites and accommodate escalating processing demands. This study delved into a comprehensive analysis of a gantry five-axis machine tool via the finite element method, encompassing static, modal, spatial accuracy analysis, and topological optimization, to grasp the structural attributes of the entire apparatus. Modal experiments were conducted to validate the numerical findings, with experimental and analytical errors falling within an acceptable range, ranging from 11 to 2.5% respectively. The analysis outcomes facilitated the identification of structural vulnerabilities and resonance frequencies, enabling the avoidance of these frequencies during machining, thereby enhancing machining precision and work piece value. Utilizing ANSYS mechanical, topology optimization of the column was executed, achieving objectives such as weight reduction, augmented rigidity, and enhanced natural frequencies in contrast to the original design. Lattice optimization was applied to the spindle, aiming to elevate the fundamental frequency and diminish mass. This approach yielded a notable frequency increase from 580 to 736 Hz and nearly halved the mass. Spatial accuracy analysis facilitated the detection of component errors at various machine positions, enabling input to the machine tool's controller for error compensation, thereby enhancing precision. This comprehensive investigation underscores the significance of advanced analytical techniques and optimization strategies in fortifying the performance and efficacy of gantry five-axis machine tools in modern industrial settings. [ABSTRACT FROM AUTHOR]

Accurate calculation of the mode shape and natural frequency of the motor stator is the basis for reducing motor noise and vibration. At present, scholars have disputes about the setting of stator core and winding material property parameters. In this paper, the modal simulation analysis and experimental test of a 2.2 kW permanent magnet brushless DC motor stator system are carried out. First, to give the stator core and the winding materials, The finite element software is used to analyze the relationship between the motor modal frequency and the parameters of the anisotropic materials. According to the modal frequency variation law, a method for correcting the parameters of the anisotropic materials based on the modal frequency is proposed. The method can complete the finite element model parameter correction of the stator. Secondly, the modal experiment is carried out by hammering method to verify the accuracy of the finite element model and determine the effectiveness of the method for correcting the equivalent material parameters. And by this method, the stator material parameters of the stator can be quickly determined. The error of this experiment and simulation is within 3%, achieving the purpose of experiment and simulation benchmarking.

The vibration problem during the operation of rice transplanter is the most common phenomenon. In order that the static and dynamic characteristics of the rice transplanter chassis can meet the requirements of more stable operation, the research took the 2ZG-6DK rice transplanter as the research object to carry out a vibration reduction optimization study. In the research, the Pro/Engineer 5.0 software was first used to model the chassis of the rice transplanter. The constructed finite element model was revised by using the structural parameter revision method and the mixed penalty function method. The model was imported into ANSYS Workbench to solve the modal frequency and vibration shape of the rice transplanter chassis. Based on the MAC (modal assurance criterion) criterion, modal tests were carried out to verify the accuracy of the finite element theoretical analysis. Through the analysis of the characteristics of the external excitation frequency, the chassis is structurally optimized to avoid resonance caused by the natural frequency of the chassis falling within the road excitation frequency range. The final optimization results showed that the first four orders of modal frequencies of the chassis were adjusted to 32.083 Hz, 33.751 Hz, 42.517 Hz, and 50.362 Hz, respectively, in the case that the chassis mass was increased by 6.714 kg (8.8%). They all avoid the range of road excitation frequency (10-30 Hz) so that the rice transplanter can effectively avoid the resonance phenomenon during operation. This study can provide a reference for the design and optimization of chassis structure of transplanter. [ABSTRACT FROM AUTHOR]