Advances in Mechanical Engineering

Gao, Jin; Han, Peifeng

doi: 10.1177/16878132231175751pmid: N/A

A rigid-flexible dynamics model is built. In view of established 7-DOF vibration model, the expressions of the output indexes are derived and the influence mechanism of suspension parameters on ride comfort is revealed. The effects of different vehicle speeds on ride comfort on bump road are studied in the frequency and time domains by analyzing the suspension dynamic disturbance by taking the vertical acceleration of the foot floor and seat rail, the wheel dynamic loads, and the suspension dynamic deflections of the suspension as the objects of analysis. The effects of dynamic changes in the suspension spring and damper parameters on the time and frequency domain response indices are analyzed. Two window functions are used on the bump road to process and analyze the time domain charts of the front and rear of foot floors and seat rails in the vertical direction, and the Rms values of the global and local vibrations of the foot floor and seat rail obtained are used as one of the evaluation indicators of ride comfort. The evaluation index of the total vehicle considering local and global vibration is determined, and the suspension parameters are collaboratively optimized by genetic algorithm to improve vehicle ride comfort.

Shahrjerdi, Ali; SafariFard, Ali

doi: 10.1177/16878132231168277pmid: N/A

The present study examines the effect of the thickness, cutouts numbers, and different cutouts shapes on the ratcheting behavior of 304 steel sheets under cyclic axial loading. The cutout shapes considered here are circular, triangular, and square cutouts. The effect of the number of circular cutouts in 304 steel sheets on ratcheting behavior is investigated. The Instron 8502 device is used to perform the experiments in which the cyclic axial loading is applied to six specimens with different cutouts and thicknesses at ambient temperature. The obtained results highlight the fact that reducing the thickness and increasing the number of cutouts in the sheets are attributed to the rise in the ratcheting displacement. Accordingly, the ratcheting displacement is more striking in the sheets with triangular cutouts. Notably, a numerical analysis is considered using the isotropic/kinematic nonlinear hardening model and FEM in ABAQUS software. Since a good agreement is seen between the numerical and experimental results, the analysis conducted in this study is reliable in terms of accuracy and authenticity.

Jiang, Fan; Li, Kai; Wu, Honghua; Luo, Shihui

doi: 10.1177/16878132231169618pmid: N/A

The latest international survey shows that slow computational speed is still a significant issue for air brake models. Fluid dynamics air brake models can be more accurate but are slower in computing speed. Empirical models are reported as effective and more efficient. This article developed a new experimental based empirical air brake model that is more comprehensive and can be used to simulate both pneumatically and electronically controlled air brake systems, as well as locomotive air brake systems and brake systems for radio-based distributed power trains. Multiple functions were used to simulate various characteristics of brake cylinder pressures, which enables the model to capture more details. An activating algorithm was developed to further improve the computational efficiency. Case studies were conducted to compare the simulation results with experimental data. Simulation results and experimental data had good agreements regarding brake delays, force patterns and cylinder pressure amplitudes. The empirical air brake model is about 70 times faster than a fluid dynamics model and 7.4 times faster than real-time.

Yang, Po-Yuan; Chang, Ping-Yueh

doi: 10.1177/16878132231175000pmid: N/A

To build a synchronization error prediction model for the machine tool efficiently, a robust whale optimization algorithm (RWOA) method proposed in this study is applied to the hyperparameter optimization of its model. The proposed RWOA method integrated a non-linear time-invariant inertia weighting (NTIW) method and a Taguchi-based adaptive parameter exploration (ATPE) to improve the performance of WOA and promote robustness. The NTIW method can improve the performance of other algorithms, so this study used the NTIW method in the WOA. In addition, the Taguchi method can get an excellent combination of variables with optimal values and stable performance, making the WOA robust. First, to verify the validity of the proposed RWOA method, 13 benchmark functions were used in this study. The results of the benchmark function tests include the mean, standard deviation, and p-value of the t-distribution test. The results show that 11 of the 13 functions differ significantly. In other non-significant difference functions, the means and standard deviations obtained by the proposed RWOA are considerably better than those obtained by WOA. Since the product cost of machine tools is higher, if a prediction model can be built effectively, it can reduce the cost. Therefore, in this study, the proposed RWOA was used to explore the best hyperparameter combination for the model. From the results, the model’s average MAPE (mean absolute percentage error) was 7.2604% for training data and 9.2603% for the testing data under 30 modeling runs. For the best one in 30 models, the MAPE was 6.8384% for the training data and 6.7372% for the testing data. This model was also introduced into the actual machine in this study, and the experimental results showed the MAPE 6.3447%. The proposed RWOA method effectively explores a suitable synchronization error model for the tool machine.

Parsi, Behzad; Abouzarkhanifard, Aylar; Zhang, Lihong

doi: 10.1177/16878132231158983pmid: N/A

In this paper, we propose a new method to use cost-effective multi-sheet off-the-shelf piezoelectric material (e.g. PZT) as an actuator for micropumps. Instead of one customized single PZT sheet that is typically expensive, multiple commercially available PZT sheets are utilized to decrease the cost of fabrication. For this purpose, we have derived analytic equations for expressing the natural frequency and mode shape of the actuator. The FEM simulations are utilized to verify the analytic equations. Thanks to their high accuracy, we can utilize the derived analytic equations as fitness functions of genetic algorithm (GA) for the optimization purpose of PZT physical aspects. Our experimental measurement results show that the GA is capable of optimizing multiple physical parameters of the piezoelectric actuator. Moreover, one-way compliant microflaps are presented for the first time to act as one-way valves for a PZT micropump aided by our proposed multi-sheet PZT actuator. The flow rate of this configuration is compared with a single-sheet PZT actuator in order to demonstrate the effect of the optimized PZT actuators in the practical applications of micropumps.

Weiwei, Liu; Kai, Cheng; Jiang, Liu

doi: 10.1177/16878132231174760pmid: N/A

The determination of Initial Track Tension (ITT) is an important issue for the moving performance of tracked vehicle under soft ground. At the present time, however, the selection of ITT only according to a moving performance or an operating condition under hard ground. Focus on this, a novel approach for determination of ITT without changing the basic vehicle parameters is proposed in this paper, which can improve the moving performance under soft ground comprehensively. Analytical models for predicting ground pressure under tracked vehicle on soft ground including ITT were used based on the track-soil coupling relationship, movement characteristics and turning characteristics of an articulated track vehicle, which applied to the straight driving condition, steering-driving condition and climbing condition. The intrinsic mechanisms between the ITT and the Mean Maximum Pressure (MMP) under roadwheels were revealed. The stresses produced by the action of track and sprocket, roadwheels, idle wheel, soil respectively were studied in consideration of the vehicle-soil mechanics theory and strength theory. The stress state and changes for an element of the track were investigated. What’s more, the relationship between the ITT and fatigue life of the track was explained in detail based on the Miner’s rule. On this basis, an optimal study for the ITT was performed taking advantage of NSGAII, which used the MMP under roadwheels and fatigue life of track as optimization objectives. And then, the determination principles of the ITT were presented, and it was identified by an articulated track vehicle. The results are significant to the prediction and control of the moving performance of track vehicle under soft ground.

Liu, Yingjie; Cui, Dawei

doi: 10.1177/16878132231170766pmid: N/A

Accurate knowledge of the vehicle dynamics response is a critical aspect to improve handling performance while ensuring safe driving at the same time. However, it poses a challenge since not all the quantities of interest can be directly measured due to cost and/or technological reasons. Therefore, combining the principle of robust filtering and unscented particle filtering algorithm, a filter estimation method of vehicle state is proposed to estimate driving state parameters of a vehicle. The adaptive robust unscented particle filter (ARUPF) is used to realize the longitudinal and lateral velocity as well as the side slip angle of the vehicle. The CarSim and Matlab/Simulink co-simulation platform is established to verify the estimation algorithm. The results show that based on the adaptive robust unscented particle filter algorithm, the vehicle driving states can be estimated, the measurement parameters can be effectively filtered, and the estimation accuracy is higher.

Yan, Lu; Qin-Xiao, Chen; Cheng, Zhong; Xian, Tao; En-Jie, Ding; Ke, Liu; Juan, Du; Xiao-Chun, Tong

doi: 10.1177/16878132231172489pmid: N/A

Mechanical equipment often works on variable speed condition, its corresponding vibration signal presents multi-component, modulation coupling with fast time-varying instantaneous frequency (IF), how to effectively compute IF and realize fasting varying non-stationary signal decoupling separation plays an important role in mechanical system fault diagnosis. In this paper, a sparse representation method called multi-scale chirp sparse representation (MSCSR) is introduced to identify, extract, and trend IF for achieving a highly concentrated time-frequency energy. Simulation demonstrates that the proposed method performs better than traditional IF estimation method. Furthermore, an adaptive time-varying filter is constructed using the extracted instantaneous frequency to decouple non-stationary fast signal. Ultimately, by rapid instantaneous frequency fluctuation experiment, the effectiveness of proposed method for fast strong time-varying signal is validated, it can effectively extract rapid oscillation instantaneous frequency, and the error is less than 10%.

Hicham, Fakiri; Abdelhamid, Hadjoui

doi: 10.1177/16878132231176190pmid: N/A

This work presents the eigenfrequencies of a study on the fluid-structure interaction for a pipe with a circular section, under pressure constraints in laminar, incompressible and irrotational flow, followed by a comparison between stiffness coupling and bar coupling with different geometric ratio Radius/Length; Radius/Thickness, as a frequency geometric identity of the pipe in the industry. The realization of this study is to have better coupling, where we use the relations of mechanical behaviour of the solid on displacement-stress and for the fluid, we use the Navier-Stokes equations in cylindrical coordinates under the speed-stress form transformed into displacement by the Galerkin-Temp theory. Either the force of the fluid will be distributed on the internal surface of the cylinder by the coupling (interface) between fluid and solid. To obtain the results of the eigenfrequencies we used the hierarchical finite element method (HFEM) for both mechanical and fluid entities. For the natural frequencies, we apply the hierarchical finite elements of the Legendre polynomial which is defined in a well-known interval, thanks to this mathematical calculation we arrive at the general equations of motion matrix form of the solid, the interface and the fluid. The calculation was carried out by a MATLAB programme which determines the eigenfrequencies of the evolved system by different geometric and physical parameters mentioned. We validated this work by a table of comparison between the experimental values and the values of the programme.

Han, Rui; Trostmann, Erik; Dunker, Thomas

doi: 10.1177/16878132231170771pmid: N/A

As a result of the ongoing upgrading of the manufacturing industries, higher and higher requirements are being proposed for assembly precision. In particular, in the industries that involve assembly of large-sized products, it is hoped that assembly accuracy can still be guaranteed as the product size increases. The emergence of the indoor Global Positioning System (iGPS) will enable this demand to be met. In this work, we have conducted in-depth research on the measurement principles and the dynamic measurement performance of the iGPS measurement system. In addition, based on the motion equation for the tracked target, an analytical method to calculate the compensation amount required for dynamic measurements is proposed. This method is suitable for accurate measurement of the actual trajectory of a target in real time when the theoretical trajectory of this tracked target is known. We set up a simulation environment in MATLAB and tested the proposed method. The simulation testing proved that the method can compensate effectively for errors in iGPS dynamic measurement.