Thermal effect is a crucial factor leading to failure of gear system. However, the lack of comprehensive nonlinear dynamics model limits the further study of thermal effects. The constitutive ...relation of beam element considering steady-state temperature is reconstructed, and thermal node load is formulated. Considering the influences of thermal expansion and temperature on material properties, a more comprehensive dynamic model of gear-rotor-bearing system is established based on the finite element node method. Nonlinear friction, high-speed gyroscopic effect, thermal-related time-varying meshing stiffness (TVMS) and thermal backlash are included in the model. The effects of temperature and bearing type on the vibration response of gear system are analyzed. The results show that the system motion changes from period to chaos with the temperature increase in part of the speed range. The appropriate backlash could restrain the chaotic motion caused by temperature rise. Moreover, the temperature significantly increases the axial bearing force, and the appropriate bearing could reduce the axial displacement. This research can further understand the influence of temperature on the dynamic response of gear system and guide the design of gear system.
Purpose
The purpose of this paper is to investigate the dynamic responses of a spur gear pair with unloaded static transmission error (STE) excitation numerically and experimentally and the ...influences of the system factors including mesh stiffness, error excitation and torque on the dynamic transmission error (DTE).
Design/methodology/approach
A simple lumped parameters dynamic model of a gear pair considering time-varying mesh stiffness, backlash and unloaded STE excitation is developed. The STE is calculated from the measured tooth profile deviation under the unloaded condition. A four-square gear test rig is designed to measure and analyze the DTE and vibration responses of the gear pair. The dynamic responses of the gear transmission are studied numerically and experimentally.
Findings
The predicted numerical DTE matches well with the experimental results. When the real unloaded STE excitation without any approximation is used, the dynamic response is dominated by the mesh frequency and its high order harmonic components, which may not be result caused by the assembling error. The sub-harmonic and super-harmonic resonant behaviors are excited because of the high order harmonic components of STE. It will not certainly prevent the separations of mesh teeth when the gear pair is under the condition of high speed and heavy load.
Originality/value
This study helps to improve the modeling method of the dynamic analysis of spur gear transmission and provide some reference for the understanding of the influence of mesh stiffness, STE excitation and system torque on the vibration behaviors.
Fault feature extraction plays a significant role in bearing fault diagnosis, especially in incipient fault period. Recently, deep neural network has been favored by many researchers due to its ...excellent hierarchical feature extraction capabilities. The existing diagnosis methods based on deep neural network mostly take original condition monitoring data as input and further convert fault diagnosis into pattern recognition issues. Although it improves the level of intelligent diagnosis, it is still confronted with practical problems. Since deep neural network includes many non-linear mapping layers, the extracted fault-related features show a high degree of abstraction, which reduces the practical level of this technology. Aimed at this problem, a mining method of understandably weak fault information is proposed based on deep neural network inversion estimation. From perspective of neuron response degree, this method mines the most sensitive input pattern that maximizes the neuron's activation value of network output layer in the original input feature space. It can intuitively mine the weak fault information from the original signal. Two bearing experiments verify the effectiveness and reliability of the proposed method.
Low-risk transmission performance including elastic deformation, loaded contact pattern, load distribution and loaded transmission error is of paramount significance to the actual manufacturing for ...non-orthogonal aviation spiral bevel gears. The advanced digital twin technology is introduced into tooth flank grinding. A new digital twin modeling considering low-risk transmission performances is proposed. In the modeling, low-risk transmission performance driven simulation, sensitivity analysis and robust control are developed, respectively Firstly, data-driven tooth surface modeling is developed by simulating free-form tooth surface grinding including gear tilt method and pinion double helical method. With local geometric boundary setup meshing stiffness is determined by using local Rayleigh–Ritz solution. Then, to deal with the sensitivity of gear assembly, an improved tooth contact analysis (TCA) is developed. Moreover, numerical loaded tooth contact analysis (NLTCA) is performed to build a bridge between of low-risk performances and hypoid generator parameters. The low-risk transmission performance driven control model is established by using hypoid generator parameters modification. Finally, sensitivity analysis strategy-based robust control model is solved by using Levenberg–Marquardt method for accurate hypoid generator parameters having modification amount. The provided numerical instance can verify the proposed method.
•The free-form tooth flank grinding for the new non-orthogonal aerospace spiral bevel gears.•NLTCA for establishing data-driven function relation.•Tooth flank geometric accuracy control by considering loaded contact deformation predication.•Optimal control strategy by selecting a small of machine settings based on sensitivity analysis.•Digital twin modeling considering both geometric and low-risk transmission performances.
The linear filtering model is widely adopted because it can effectively control the areal autocorrelation function (AACF). However, these methods either constrain only half of the AACF or add the ...assumption of symmetry along one coordinate axis, which leads to a limited scope of applicability of the model. In this paper, a new AACF constraint for all spatial information is present. The new constraint function can provide objectives for all AACFs, and thus both isotropic rough surfaces, anisotropic surfaces of arbitrary orientation, and cross-textured surfaces can be reconstructed. The numerical experimental results show that the AACF fits well for isotropic as well as arbitrarily oriented anisotropic surfaces. For cross-textures surfaces, the errors are significant, indicating that the linear filtering model still has potential for improvement.
•The generalized form of the optimization objective of the linear filter reconstruction model is presented.•Rough surface reconstruction problems with arbitrary texture orientations merged into a unified model.•L-BFGS algorithm is adopted to solve the optimization problem in the reconstructed model.
•Numerical prediction methods for elastic behavior of anisotropic and quasi-isotropic webs are proposed.•The iterative calculation methods of meshing behavior for two hybrid metal-composite gears are ...unified.•The calculation accuracy and efficiency of the proposed method are verified.•Detailed discussion on effects of hybrid gears replacing full metal gears.•Multi-parameter design to reduce mesh stiffness fluctuations.
Thin-web structures are the primary strategy for lightweight gears in the aerospace and automotive fields, but current research mainly focuses on metal thin web, lacking understanding of the application of anisotropic and quasi-isotropic composite thin-web gears. Focusing on accurate and efficient calculations of mesh stiffness and load sharing ratio, this work develops a unified numerical analysis method to assess the meshing behavior of the two hybrid metal-composite gears. Multi-scale numerical prediction methods for elastic properties of anisotropic composite and homogeneous laminated webs are established, and two tooth-loading deformation calculation methods for metal-composite-metal gear bodies with different web widths are developed separately. A numerical analysis method is proposed by unifying the iterative calculation process of the two hybrid gears through deformation coordination relationships, which is also applicable to full metal gears. Finally, extensive comparisons with the finite element method (FEM) and existing numerical method verify the proposed analytical method (PAM). The investigation results reveal the impact of replacing full metal gears with these two hybrid gears on the meshing behavior and further elucidate the advantages of using composite webs for micro and macro parameters design in adjusting the mass and stiffness and reducing mesh stiffness fluctuations. This work provides a new analytical method for the structural design and performance assessment of lightweight hybrid metal-composite gear systems.
Aiming at the actual working conditions of high temperature， high speed and heavy oil mist of the accessory transmission gear of aero engine， a set of the gear dynamic transmission error test system ...is designed and developed based on the principle of the quadruple subdivision of magnetic grid sensor. In this system， the real-time rotation angel of the driving gear and driven gear is respectively measured at the same time by magnetic grid sensor， through the high-speed data acquisition， storage devices of NI and the producer/consumer design pattern of LabVIEW for real-time acquisition and storage of the high-frequency data. Finally， the digital counting method is used to obtain the gear dynamic transmission error curve. The measuring speed of the testing system can reach 40 000 r/min， which is doubled the measurable speed of the previous test system， it can provide data support for vibration analysis and tooth surface design of higher-speed accessories transmission gear.
Analysis of the dynamic meshing force of face gear is the important content in the design of face gear drive with high quality.Based on the secondary development of CATIA and the principle of gear ...machining,the 3Dgeometric modeling of face gear for finite element analysis is obtained.Based on basic theory of contact dynamics,the reasonable finite element analysis model is built and the reasonable parameters are determined.The finite element simulation analysis and study of the dynamic meshing of face gear are carried out by using the ABAQUS,the variation law of the tooth surface contact force and the tooth root bending stress of face gear in the process of continuous mesh and the association law of the among the speed,load and tooth surface dynamic meshing are obtained.It will be provide some reference value for dynamic performance analysis of high-performance face gear drive.
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