Effects of Spalling Fault on Dynamic Responses of Gear System Considering Three-dimensional Line Contact Elasto-hydrodynamic Lubrication

2021 ◽  
pp. 105930
Author(s):  
Liming Wang ◽  
Chunlong Deng ◽  
Jin Xu ◽  
Lei Yin ◽  
Wennian Yu ◽  
...  
Keyword(s):  
Hydrodynamic Lubrication ◽  
Three Dimensional ◽  
Gear System ◽  
Dynamic Responses ◽  
Line Contact

NONLINEAR IMPACT DYNAMIC ANALYSIS AND COMPARISON WITH EXPERIMENTAL DATA FOR THE SKID GEAR

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1403-1408 ◽  
Author(s):  
DONG-HYUN KIM ◽  
YU-SUNG KIM
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Landing Gear ◽  
Gear System ◽  
Dynamic Responses ◽  
Test Results ◽  
Dimensional Finite Element ◽  
Nonlinear Transient ◽  
Skid Landing Gear ◽  
Three Dimensional Finite Element

In this study, nonlinear crash analyses have been conducted for the skid landing gear of helicopter. The realistic configuration of skid landing gear system is considered. Detailed three-dimensional finite element model with variable thickness and material nonlinearity is constructed for required impact design conditions. Advanced computational approach is used to conduct nonlinear transient impact dynamic analyses for different collision models. Characteristics of impact dynamic responses due to the ground crash are practically investigated in detail. It is also shown that the exact consideration of friction effect is very important to accurately predict the crash behavior of the skid type landing gear system. Finally, two typical landing conditions are analyzed and correlated with drop test results.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

Simulation of Plasto-Elastohydrodynamic Lubrication in Line Contacts of Infinite and Finite Length

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Tao He ◽  
Jiaxu Wang ◽  
Zhanjiang Wang ◽  
Dong Zhu
Keyword(s):  
Surface Roughness ◽  
Finite Length ◽  
3D Model ◽  
Three Dimensional ◽  
Elastohydrodynamic Lubrication ◽  
Axial Direction ◽  
Contact Length ◽  
Line Contact ◽  
Line Contacts ◽  
3D Surface Topography

Line contact is common in many machine components, such as various gears, roller and needle bearings, and cams and followers. Traditionally, line contact is modeled as a two-dimensional (2D) problem when the surfaces are assumed to be smooth or treated stochastically. In reality, however, surface roughness is usually three-dimensional (3D) in nature, so that a 3D model is needed when analyzing contact and lubrication deterministically. Moreover, contact length is often finite, and realistic geometry may possibly include a crowning in the axial direction and round corners or chamfers at two ends. In the present study, plasto-elastohydrodynamic lubrication (PEHL) simulations for line contacts of both infinite and finite length have been conducted, taking into account the effects of surface roughness and possible plastic deformation, with a 3D model that is needed when taking into account the realistic contact geometry and the 3D surface topography. With this newly developed PEHL model, numerical cases are analyzed in order to reveal the PEHL characteristics in different types of line contact.

3-D elastic coupling vibration and acoustical radiation characteristics of cracked gear under elastic support condition

2015 ◽  
Vol 23 (9) ◽  
pp. 1548-1568 ◽  
Author(s):  
Shao Renping ◽  
Purong Jia ◽  
Xiankun Qi
Keyword(s):  
Dynamic Response ◽  
Support System ◽  
Three Dimensional ◽  
Elastic Support ◽  
Dynamic Responses ◽  
Tooth Root ◽  
Support Condition ◽  
Elastic Boundary ◽  
Root Crack ◽  
Elastic Disc

According to the actual working condition of the gear, the supporting gear shaft is treated as an elastic support. Its impact on the gear body vibration is considered and investigated and the dynamic response of elastic teeth and gear body is analyzed. On this basis, the gear body is considered as a three-dimensional elastic disc and the gear teeth are treated as an elastic cantilever beam. Under the conditions of the elastic boundary (support shaft), combining to the elastic disk and elastic teeth, the influence of three-dimensional elastic discs on the meshing tooth response under an elastic boundary condition is also included. A dynamic model of the gear support system and calculated model of the gear tooth response are then established. The inherent characteristics of the gear support system and dynamics response of the meshing tooth are presented and simulated. It was shown by the results that it is correct to use the elastic support condition to analyze the gear support system. Based on the above three-dimensional elastic dynamics analysis, this paper set up a dynamics coupling model of a cracked gear structure support system that considered the influence of a three-dimensional elastic disc on a cracked meshing tooth under elastic conditions. It discusses the dynamic characteristic of the cracked gear structure system and coupling dynamic response of the meshing tooth, offering a three-dimensional elastic body model of the tooth root crack and pitch circle crack with different sizes, conducting the three-dimensional elastic dynamic analysis to the faulty crack. ANSYS was employed to carry out dynamic responses, as well as to simulate the acoustic field radiation orientation of a three-dimensional elastic crack body at the tooth root crack and pitch circle with different sizes.

scholarly journals Improved Reliability of Bladed Disks due to Friction Dampers

1997 ◽  
Author(s):  
Walter Sextro ◽  
Karl Popp ◽  
Ivo Wolter
Keyword(s):  
Dry Friction ◽  
Three Dimensional ◽  
Line Contact ◽  
Two Dimensional ◽  
Centrifugal Forces ◽  
Friction Damper ◽  
Blade Vibration ◽  
Friction Dampers ◽  
Bladed Disk ◽  
Bladed Disk Assembly

Friction dampers are installed underneath the blade platforms to improve the reliability. Because of centrifugal forces the dampers are pressed onto the platforms. Due to dry friction and the relative motion between blades and dampers, energy is dissipated, which results in a reduction of blade vibration amplitudes. The geometry of the contact is in many cases like a Hertzian line contact. A three-dimensional motion of the blades results in a two-dimensional motion of one contact line of the friction dampers in the contact plane. An experiment with one friction damper between two blades is used to verify the two-dimensional contact model including microslip. By optimizing the friction dampers masses, the best damping effects are obtained. Finally, different methods are shown to calculate the envelope of a three-dimensional response of a detuned bladed disk assembly (V84.3-4th-stage turbine blade) with friction dampers.

Dynamic Analysis of Large-Scale Power House

2012 ◽  
Vol 446-449 ◽  
pp. 837-840
Author(s):  
Yu Zhao ◽  
Shu Fang Yuan ◽  
Jian Wei Zhang
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Large Scale ◽  
Three Dimensional ◽  
Dynamic Responses ◽  
Dynamic Loads ◽  
Element Analysis ◽  
Power House ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The underwater structure of power house is major structure under the dynamic loads of unit. The vibration problem is very common in operation. So the structures should have sufficient stiffness to resist dynamic loads of unit. This paper establishes three-dimensional finite element models with finite element analysis software—ANSYS. Dynamic characteristics of the power house and dynamic responses of structure under earthquake are analyzed. The results of the computation show that fluid-solid coupling may be ignored when studying dynamic characteristics of structures of the underground power house.

Calculation method of belt material parameters for finite element tire model

2021 ◽  
pp. 095440702110422
Author(s):  
Lu Zhang ◽  
Shaohua Wang ◽  
Bing Li
Keyword(s):  
Finite Element ◽  
Calculation Method ◽  
Complex Structure ◽  
Three Dimensional ◽  
Anisotropic Elasticity ◽  
Dynamic Responses ◽  
Reinforced Composites ◽  
Tire Model ◽  
Material Parameters ◽  
Vehicle Dynamic Simulation

The radial tire belt is composed of multi-layered fiber-reinforced cords with a very complex structure. Restricted by the computing speed, the simplified finite element (FE) tire model with equivalent belt is usually applied in the vehicle dynamic simulation. However, it is always difficult to obtain the material parameters of the equivalent belt. In this paper, a calculation method of equivalent belt material parameters for the simplified FE tire model is proposed based on the three-dimensional (3-D) anisotropic elasticity of the cord reinforced composites. The simulation results of the static radial stiffness, modal characteristics, and dynamic responses for the simplified FE tire model with parameters obtained by the calculation method were compared with experiment results. The results show that the deviation between the experiment and simulation is acceptable, and the validity of the calculation method is verified.

Dynamic Response of the Steel Bridge Deck Thin Surfacing due to Vehicle Load

2010 ◽  
Vol 148-149 ◽  
pp. 544-547
Author(s):  
Xun Qian Xu ◽  
Ye Yuan Ma ◽  
Guo Qing Wu ◽  
Xiu Mei Gao
Keyword(s):  
Dynamic Response ◽  
Bridge Deck ◽  
Three Dimensional ◽  
Coupled Model ◽  
Interface Layer ◽  
Dynamic Responses ◽  
Steel Bridge ◽  
Vehicle Load ◽  
Moving Vehicles ◽  
Space Technique

Basing on the coupled vibration theory, dynamic behavior of steel bridge deck thin surfacing under rand moving vehicles is studied. A three-dimensional coupled model is carried out for the steel bridges deck thin surfacing and vehicle. A method based on modal superposition and state space technique is developed to solve dynamic response generated by vehicle-surfacing interaction. The dynamic responses of an actual steel bridge deck thin surfacing are studied. The results show that adding epoxy asphalt as a sub coat can improve interface adhesion strength, which would be designed as the interface layer of steel deck thin surfacing.

Modeling and Kinematics Simulation of HT-CVT Based on Virtual Prototype Technology

2010 ◽  
Vol 44-47 ◽  
pp. 884-888
Author(s):  
Qing Gong Zhang ◽  
Hua Li ◽  
Jin Yao
Keyword(s):  
Hydrodynamic Lubrication ◽  
Three Dimensional ◽  
Gear Ratio ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Traction Drive ◽  
Kinematics Simulation ◽  
Contact Constraint ◽  
Variable Transmission ◽  
Angular Velocities

The three-dimensional model of a Half Toroidal Continuously Variable Transmission (HT-CVT) was established by CAXA solid design. The kinematics simulation of the HT-CVT was realized by replacing the traction drive of elasto-hydrodynamic lubrication (EHL) oil film with the contact constraint joints in ADAMS. The angular velocity curves of the power rollers and the output cone disk on the HT-CVT were obtained. Simulation results demonstrate the fluctuation of the angular velocities on the two power rollers and the output cone disk compares well with the conclusion derived from the actual gear ratio of the HT-CVT.

Sign in / Sign up

Export Citation Format

Share Document