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Simultaneous resonance of Duffing oscillator with fractional-order derivative

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Simultaneous resonance of Duffing oscillator with fractional...

第八届国际振动工程会议

作者： Hang Li Yongjun Shen Department of Mechanical Engineering Shijiazhuang Tiedao University State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University

Duffing-type oscillators can describe many issues in engineering vibration, such as the vertical vibration of pantograph carbon strip suspension system, the response of coupled pitch-roll ship and the nonlinear phenomena of rotor system, and the multiple-term frequency excitation is common case in these issues. For instance, the carbon belt suspension system of pantograph, it is excited by two kinds of harmonic excitations related to the distance between droppers and the span of catenary respectively. In this paper, the simultaneous resonance of fractional-order Duffing oscillator excited by two-term frequency is studied, and the fractional-order term is introduced due to the fact that many materials or devices in engineering exhibit obvious viscoelasticity, which could be accurately described by fractional-order *** approximately analytical solution of the system is obtained by the method of multiple scales, and the amplitude-frequency curve equation and phase-frequency curve equation of the steady-state response are derived from the analytical solution. Furthermore, Lyapunov’s first method is used to quantitatively calculate the stability condition of the steady-state response, based on this, the stability of the simultaneous resonance is analyzed. The effects of nonlinear factor and fractional-order term on the steady-state response is also analyzed by numerical simulation, and the general effects mechanism of the fractional-order term on the mass-spring-damping（MSD） system is revealed, i.e., the equivalent linear stiffness and equivalent linear damping of the fractional-order term are embodied simultaneously in the MSD system, and the focus and intensity of the effects are determined by fractional order and coefficient respectively.

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Principal resonance analysis of piecewise nonlinear oscillator with fractional differential

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Principal resonance analysis of piecewise nonlinear oscillat...

第八届国际振动工程会议

作者： Meiqi Wang Wenli Ma Enli Chen Shaopu Yang State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University School of Mechanical Engineering Shijiazhuang Tiedao University

To analyze the piecewise non-linear system with fractional order differential, we introduced fractional order into the two piecewise systems to accurately describe the stress relaxation of viscoelastic materials. We also established a non-linear dynamic model with non-linear stiffness, damping, and fractional order multi-piecewise points. Under periodic excitation,the equation of amplitude frequency relationship of the system was obtained using the average method, and the amplitude frequency response characteristics under different damping, stiffness,and fractional order parameters were provided. The influence of non-linear factors and fractional order terms on the stability of the system was studied. The chaotic behavior of the system under different parameter disturbances was studied, and the results indicate that the system presents chaotic behavior with the change of disturbance parameters. Moreover, the decrease of linear damping will subject the system to a wider range of chaotic state.

关键词： Principal resonance analysis of piecewise nonlinear oscillator with fractional differential

Design and evaluation of cab seat suspension system based on negative stiffness structure

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Journal of Southeast University(English Edition) 2021年第2期37卷 153-163页

作者： Liao Xin Zhang Ning Xing Haijun Zhang Wanjie School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang 050043 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang 050043 China School of Mechanical Engineering Southeast University Nanjing 211189 China

To improve the vibration-isolation performance of cab seats,the optimization model of the seat suspension system of construction machinery cabs is proposed based on the negative stiffness *** negative stiffness nonlinear kinetic equation is established by designing the seat negative stiffness suspension structure(NSS).Using MATLAB,the different parameters of the suspension system and their influences on the dynamic stiffness are *** ideal configuration parameter range of the suspension system is ***,the optimization model of NSS is proposed,and the vibration transmissibility characteristics are simulated and analyzed by different *** results show that the displacement and acceleration amplitudes of the optimized seat suspension system are evidently reduced,and the four-time power vibration dose value and root mean square calculation values in the vertical vibration direction of the seat decrease by 86%and 87%,*** effective amplitude transmissibility(SEAT)and the vibration transmissibility ratio values also ***,the peak frequencies of the vibration transmitted to the driver deviate from the key frequency values,which easily cause human ***,the design of the seat suspension system has no effect on the health condition of the driver after being *** findings also illustrate that the NSS suspension system has good vibration-isolation performance,and the driver's ride comfort is improved.

关键词： construction machinery negative stiffness structure seat suspension system dynamic properties ride comfort

Bearing fault diagnosis based on attention mechanism and deep residual network

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Bearing fault diagnosis based on attention mechanism and dee...

2021 International Conference on Computer engineering and Artificial Intelligence, ICCEAI 2021

作者： Ma, Xinna Qi, Lin Zhao, Meng Shijiazhuang Tiedao University College of Information Science and Technology State Key Laboratory of Mechanical Behavior and Ystem Safety of Traffic Engineering Structures Shijiazhuang China Shijiazhuang Tiedao University College of Information Science and Technology Shijiazhuang China

ISBN: (纸本)9781665439602

A bearing fault diagnosis model based on the deep residual network is proposed for the situation that the model recognition rate is low and the classification effect is poor due to the large difference of fault sample distribution in the actual working condition. Firstly the collected bearing fault signals are constructed as fault samples, reconstructs the one-dimensional time series signals into grayscale maps, and initially obtains the input data which is suitable for the deep residual network. To solve the situation of insufficient effective samples, data augmentation by sliding sampling is used to expand the bearing vibration dataset;the samples are further divided into training and testing sets as the input of ResNet101, and data normalization is used to make the training and testing sets learn the same distribution to shorten the training time;then a hybrid attention mechanism is introduced at the appropriate parts to effectively suppress the redundant features and enhance the feature extraction capability of the model. And then a softmax classifier is used for fault classification to achieve intelligent fault diagnosis of rolling bearings. Finally, the Western Reserve University bearing dataset (CWRU) is used to verify the effectiveness of the model. The experimental results show that the proposed bearing fault diagnosis method based on hybrid attention mechanism and residual network can achieve more than 99 % diagnostic accuracy, and it achieves good generalization performance on the high-speed rail wheel pair dataset with an accuracy above 94 %. © 2021 IEEE.

关键词： Failure analysis

The Effect of High-Temperature Deformation Twinning on the Work Hardening Behavior of Fe-38mn Alloy During Hot Shear-Compression Deformation

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SSRN 2023年

作者： Sang, Deli Xin, Xiaoli Fu, Ruidong Li, Yijun Jing, Lei College of Materials Science and Engineering Shijiazhuang Tiedao University Hebei Shijiazhuang050000 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Hebei Shijiazhuang050043 China State Key Laboratory of Metastable Materials Science and Technology Yanshan University Hebei Qinhuangdao066004 China Northwest Institute for Nonferrous Metal Research Xi’an710016 China

The effect of high-temperature deformation twinning on the work hardening behaviors of Fe-38Mn alloy during hot shear-compression deformation was investigated. The flow curves for hot shear-compression deformation of Fe-38Mn alloy exhibit the characteristics of continuous work hardening. The deformation was uniform shear-compression deformation with no significant strain localization, but the shear action gradually increased with the increase of strain rate. Benefited from such deformation characteristics, the dynamic microstructure evolution was pioneered by "bulged" mechanism and had geometric and sub-grain migration characteristics, which was continuous dynamic recrystallization in nature and accompanied by a large number of micro-shear bands and deformation twins. Particularly, the work hardening rate curve is classified into five stages considering the deformation twinning during hot shear-compression deformation. © 2023, The Authors. All rights reserved.

关键词： Shear bands

Model Test and Numerical Simulation Study on Soil Arching Effect Evolution Of Pile - Supported Reinforced Embankment

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SSRN 2024年

作者： Wang, Xin Yang, Guang-Qing Li, Hao-Ran Hebei GEO University Hebei Shijiazhuang050030 China The 6410th Factory of the People's Liberation Army of China Hebei Shijiazhuang050307 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Hebei Shijiazhuang050043 China Shijiazhuang Tiedao University Hebei Shijiazhuang050043 China

The mechanical behavior of pile-supported reinforced embankment is complex, and the shape of soil arch has not been unified. It is of great scientific value to further study the mechanism of soil arch effect. Through three-dimensional model test, this paper studies the influence of embankment filling properties, pile spacing and horizontal reinforcement on soil arching effect. Based on the stress monitoring results of foundation surface and embankment internal, the formation process and evolution mechanism of soil arching effect in cohesive soil embankment were studied. The arch axis expressions of the central area between four piles and the strip area between two piles were proposed by numerical simulation. The results show: The differential settlement of pile-soil has a great influence on the degree of soil arching effect. The increase of pile spacing promotes the soil arching effect to a certain extent, but too large pile spacing will increase the settlement of roadbed;The cohesion of embankment has a certain promoting effect on load transfer. With the increase of cohesion, the differential settlement of pile-soil decreases gradually;Under the action of the reinforcement, the internal structure of the soil arch changes;The height of soil arch is related to the net spacing of pile cap. The maximum height of soil arch in the strip area between two piles is 1.10(s-a), and the maximum height of soil arch in the central area between four piles is 1.64(s-a). © 2024, The Authors. All rights reserved.

关键词： Piles

Evolution of Pore-Fracture and Permeability During Co2+O2 In-Situ Leaching Process of Fractured Sandstone

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SSRN 2024年

作者： Niu, Qinghe He, Jiabin Yuan, Wei Chang, Jiangfang Wang, Wei Yuan, Junhong Wang, Qizhi Zheng, Yongxiang Shang, Songhua Key Laboratory of Roads and Railway Engineering Safety Control Shijiazhuang Tiedao University Ministry of Education Shijiazhuang050043 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Hebei Technology and Innovation Center on Safe and Efficient Mining of Metal Mines Shijiazhuang050043 China State Key Laboratory of Nuclear Resources and Environment East China University of Technology Nanchang330013 China School of Transportation Inner Mongolia University Hohhot010021 China School of Civil Engineering Hebei University of Science and Technology Shijiazhuang050018 China

This work is organized to reveal the influence mechanism and law of CO2+O2 in situ leaching on pore permeability characteristics of stimulated deposits. Results show that geochemical reactions during the CO2+O2 ISL process are complex, the dolomite and potassium feldspar are dissolved, while the clay mineral precipitates are formed. The response characteristics and mechanisms of pore-fracture structures differ between the single and multi-fractured samples during the CO2+O2 ISL process. The pore number density of the single-fractured sample increases while porosity decreases, causing larger pores to evolve into smaller ones. While the porosity and fracture volume of the multi-fractured sample increase significantly. The permeability characteristics of fractured samples are consistent with the evolution of pore-fracture structures. The multi-fractured sample possesses a higher fracture compression coefficient and lower PLR due to the larger compressive space, the self-supporting effect of fracture network and the scouring effect of leaching solution. Although creating a single fracture in reservoir stimulation can enhance the original deposit permeability, the conductivity will gradually decline during the subsequent CO2+O2 ISL process. Optimizing reservoir stimulation techniques to create complex fracture networks within deposits can enhance overall permeability and weaken the permeability reduction effect, ensuring the efficient extraction of uranium resources. © 2024, The Authors. All rights reserved.

关键词： Fracture

Optimization of the Evaluation Indexes for the Low-Temperature Performance of Asphalt Mixture Based on Relaxation Characteristics of Thermal Cracking Mechanism

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SSRN 2022年

作者： Sun, Zhiqi Qi, Haonan Yi, Jie Li, Shaohua Tan, Yiqiu Ren, Jianying Xu, Yongli State Key Laboratory of Mechanical behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Key Laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures Shijiazhuang Tiedao University Hebei Shijiazhuang050043 China School of Transportation Science and Engineering Harbin Institute of Technology Harbin150090 China State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology China School of Civil Engineering Northeast Forest University Harbin150090 China

Thermal cracking behavior of asphalt pavement includes thermal contraction, low temperature relaxation and low temperature damage. A great quantity of theoretical and experimental studies on the characterization of low-temperature performance had mostly focused on characterizing low-temperature performance with low-temperature relaxation or low-temperature failure performance, resulting in incomplete evaluation of low-temperature performance of asphalt mixtures. Considering the relaxation performance is one of the key factors in the thermal cracking mechanism of the asphalt mixture, the evaluation indexes were established and optimized according to the relationship between the viscoelastic characteristics and the relaxation performance. Combined with the relationship among the low-temperature performance obtained by Thermal Stress Restrained Specimens Test (TSRST) and the evaluation indexes, then the evaluation indexes for the low-temperature performance of asphalt mixture were preferably selected. Firstly, according to the conversion of viscoelastic information in the time domain and frequency domain, the relationship between viscoelastic characteristics and relaxation characteristics was analyzed. Secondly, depending on the characteristics of relaxation characteristics in time, the relaxation rate and the cumulative stress per unit strain rate were proposed as evaluation indexes to characterize the long-term and short-term relaxation characteristics of asphalt mixtures, respectively. Finally, the relationship between asphalt binders and asphalt mixtures with different evaluation indexes and low temperature performance was analyzed. The results showed that relaxation rate, stored shear modulus and cumulative stress per unit strain rate (below -20 °C) apply to the evaluation of low-temperature performance among gradation types, and the average slope of complex modulus and the average slope of relaxation rate-temperature curve with temperature apply to the evaluation

关键词： Asphalt mixtures

A Novel Dynamic Data Driven Tire Model

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Research Square

Research Square 2021年

作者： Zhang, Junning Yang, Shaopu Lu, Yongjie Key Laboratory of Mechanical behavior System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China

In the study of vehicle dynamics, the accurate description of tire mechanical characteristics is the basis and key of vehicle dynamics simulation. An innovative tire model is proposed based on fuzzy algorithm and a sinusoidal membership function is used to design fuzzy rules. In order to ensure the accuracy of tire behavior calculation, this model is driven by a small amount of experimental data of tire mechanical characteristics. This tire model consists of four layers of fuzzy systems, each of which has a knowledge base. The data in knowledge base Ⅰ is obtained by experiments, and the data of knowledge base Ⅱ is computed by the upper system, and so is the later system. Then, the input signal, the change rate of side slip angle and slip rate, is considered to improve the calculation accuracy of the model. The proposed fuzzy tire model can accurately predict the longitudinal force, lateral force and self-aligning torque of the tire under unknown conditions. Finally, by comparing the fuzzy tire model with the experimental data, it is found that the maximum RRMSE (Relative Root Mean Square Error) value is not more than 0.14. It is proved that the model can accurately describe the tire mechanical characteristics under combined conditions. © 2021, CC BY.

关键词： Membership functions