scholarly journals Dynamic Analysis of Helical Planetary Gear Sets under Combined Force and Moment Loading

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Yanfang Liu ◽  
Junbin Lai ◽  
Peng Dong ◽  
Xiangyang Xu
Keyword(s):  
Dynamic Model ◽  
Dynamic Behavior ◽  
Three Dimensional ◽  
Axial Loading ◽  
Planetary Gear ◽  
Combined Loading ◽  
External Loading ◽  
Parameter Method ◽  
Vibration Responses ◽  
The Moment

The dynamic behavior of a single-stage planetary gear set with helical gears of multishaft automotive automatic transmissions has been studied, in which one component of the planetary gear set is imposed by additional external vertical and axial loading from countershaft gear pair in addition to the moment. Under these combined loading conditions, the contributions of the deflections of the ring gear and the carrier cannot be neglected. A three-dimensional nonlinear time-variant dynamic model considering not only the transverse, torsional, axial, and rotational motions of the gears but also the elasticity of the mounted shafts has been developed by combining the lumped parameter method with finite element method. The natural modes and the forced vibration responses due to static transmission errors have been obtained. The proposed dynamic model is employed to describe the effects of the combined external loading condition and positioning on the dynamic behavior of a four-planet system.

Influence of the backlash generated by tooth accumulated wear on dynamic behavior of compound planetary gear set

2016 ◽  
Vol 231 (11) ◽  
pp. 2025-2041 ◽  
Author(s):  
Shijing Wu ◽  
Haibo Zhang ◽  
Xiaosun Wang ◽  
Zeming Peng ◽  
Kangkang Yang ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Planetary Gear ◽  
Tooth Wear ◽  
Transmission Error ◽  
Gear Transmission ◽  
Tooth Surface ◽  
Contact Ratio ◽  
The Impact

Backlash is a key internal excitation on the dynamic response of planetary gear transmission. After the gear transmission running for a long time under load torque, due to tooth wear accumulation, the backlash between the tooth surface of two mating gears increases, which results in a larger and irregular backlash. However, the increasing backlash generated by tooth accumulated wear is generally neglected in lots of dynamics analysis for epicyclic gear trains. In order to investigate the impact of backlash generated by tooth accumulated wear on dynamic behavior of compound planetary gear set, in this work, first a static tooth surface wear prediction model is incorporated with a dynamic iteration methodology to get the increasing backlash generated by tooth accumulated wear for one pair of mating teeth under the condition that contact ratio equals to one. Then in order to introduce the tooth accumulated wear into dynamic model of compound planetary gear set, the backlash excitation generated by tooth accumulated wear for each meshing pair in compound planetary gear set is given under the condition that contact ratio equals to one and does not equal to one. Last, in order to investigate the impact of the increasing backlash generated by tooth accumulated wear on dynamic response of compound planetary gear set, a nonlinear lumped-parameter dynamic model of compound planetary gear set is employed to describe the dynamic relationships of gear transmission under the internal excitations generated by worn profile, meshing stiffness, transmission error, and backlash. The results indicate that the introduction of the increasing backlash generated by tooth accumulated wear makes a significant influence on the bifurcation and chaotic characteristics, dynamic response in time domain, and load sharing behavior of compound planetary gear set.

Three-Dimensional Dynamic Model of TEHD Tilting-Pad Journal Bearing—Part I: Theoretical Modeling

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Junho Suh ◽  
Alan Palazzolo
Keyword(s):  
Heat Conduction ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Journal Bearing ◽  
Three Dimensional ◽  
Physical Parameters ◽  
Tilting Pad ◽  
Fluid Film Thickness ◽  
Three Dimensional Finite Element ◽  
Tilting Pad Journal Bearing

This paper is focused on a new modeling method of three-dimensional (3D) thermo-elasto-hydro-dynamic (TEHD) cylindrical pivot tilting-pad journal bearing (TPJB). Varying viscosity Reynolds equation and 3D energy equation are coupled via lubricant temperature and viscosity relationship. Three-dimensional finite element method (FEM) is adopted for the analysis of: (1) heat conduction in shaft and bearing pad, (2) thermal deformation of shaft and pad, (3) flexible bearing pad dynamic behavior, and (4) heat conduction, convection, and viscous shearing in thin lubricant film. For the computational efficiency, modal coordinate transformation is utilized in the flexible pad dynamic model, and pad dynamic behavior is represented only by means of modal coordinate. Fluid film thickness is calculated by a newly developed node based method, where pad arbitrary thermal and elastic deformation and journal thermal expansion are taken into account simultaneously. The main goal of this research is to provide more accurate numerical TPJB model than developed before so that the designers of rotating machinery are able to understand the bearing dynamic behavior and avoid unpredicted problem by selection of physical parameters.

Pressure-Plus-Moment Limit-Load Analysis for a Cylindrical Shell Nozzle

1987 ◽  
Vol 109 (3) ◽  
pp. 297-301 ◽  
Author(s):  
C. J. Tabone ◽  
R. H. Mallett
Keyword(s):  
Cylindrical Shell ◽  
Three Dimensional ◽  
Limit Load ◽  
Element Model ◽  
Combined Loading ◽  
Inelastic Behavior ◽  
Limit Loads ◽  
Out Of Plane ◽  
Load Analysis ◽  
The Moment

A finite element model of a nozzle in a cylindrical shell is analyzed for three cases; pressure, out-of-plane moment and combined pressure plus out-of-plane moment. The model uses three-dimensional finite elements and the analysis considers inelastic behavior at small displacements. Load versus displacement behavior is given for the three cases. Estimates of limit loads are obtained based upon extrapolation of load versus inverse displacement data curves. An interaction expression is used to show the effect of the combined loading for a case in which an internal pressure reduces the moment capability of the nozzle by 35 percent.

scholarly journals Dynamic Analysis of Planetary Gear with Root Crack in Sun Gear Based on Improved Time-Varying Mesh Stiffness

2020 ◽  
Vol 10 (23) ◽  
pp. 8379
Author(s):  
Jian Shen ◽  
Niaoqing Hu ◽  
Lun Zhang ◽  
Peng Luo
Keyword(s):  
Fault Diagnosis ◽  
Dynamic Model ◽  
Theoretical Basis ◽  
Planetary Gear ◽  
Vibration Response ◽  
Gear System ◽  
Transition Curve ◽  
Parameter Method ◽  
Time Varying ◽  
Mesh Stiffness

The time-varying mesh stiffness (TVMS) is the crucial parameter of the dynamic model of the gear system. Accurate calculation of TVMS is essential for effective fault diagnosis of the gear system. A mesh stiffness improved method considering both the gear tooth transition curve and deformation of the gear body is presented in this paper, and the stiffness calculation expressions under healthy and crack states are given, respectively. Based on the lumped parameter method, the dynamic model of planetary gear with crack in sun gear is constructed, and the vibration response is solved. The simulation results show when the tooth root cracks appear, the vibration response of the tooth has obvious shock response characteristics. The characteristic frequency and frequency multiplication of sun gear fault can be found obviously by envelope analysis. The simulation signal and the test signal obtained by the drivetrain dynamics simulator gearbox test rig are compared and verified. The comparison and verification results show that the proposed TVMS calculation method and the dynamic model are accurate, which can provide a certain theoretical basis for the fault diagnosis of planetary gear with crack fault. The test results are consistent with the numerical analysis results, which provides a theoretical basis for the fault diagnosis of tooth crack.

Planetary Gear Train Dynamics

1994 ◽  
Vol 116 (3) ◽  
pp. 713-720 ◽  
Author(s):  
A. Kahraman
Keyword(s):  
Dynamic Behavior ◽  
Linear Time ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Planetary Gear ◽  
Gear Train ◽  
Planetary Gear Train ◽  
Gear Teeth ◽  
Linear Time Invariant ◽  
Mesh Phasing

A model to simulate the dynamic behavior of a single-stage planetary gear train with helical gears is developed. The three-dimensional dynamic model includes all six rigid body motions of the gears and the carrier. The generic nature of the formulation allows the analysis of a planetary gear set with any number of planets. Planets can be arbitrarily spaced (equally or unequally) around the sun gear. The model is also capable of handling different planet meshing conditions which are functions of number of gear teeth and planet positions. The linear time-invariant equations of motion are solved to obtain the natural modes and the forced vibration response due to static transmission errors. The proposed model is employed to describe the effects of the planet mesh phasing conditions on the dynamic behavior of a four-planet system.

scholarly journals Evaluation of Undrained Bearing Capacities of Wide-Shallow Bucket Foundation with Honeycomb Bulkheads in Clay

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Qingshan Wang ◽  
Xun Han ◽  
Yunfei Guan ◽  
Yongyong Cao ◽  
Wenxuan Li
Keyword(s):  
Shear Strength ◽  
Three Dimensional ◽  
Offshore Wind ◽  
Combined Loading ◽  
Vertical Load ◽  
Bucket Foundation ◽  
Failure Envelopes ◽  
Soil Shear Strength ◽  
New Type ◽  
The Moment

As a new type of offshore wind foundation, the wide-shallow bucket foundation with honeycomb bulkheads mainly bears vertical, horizontal, and moment loads. As yet, no systematic study has been conducted regarding the effects of honeycomb bulkheads on the undrained bearing capacities of the wide-shallow bucket foundation. In this study, a large number of three-dimensional (3D) finite element (FE) analyses were performed to investigate the undrained bearing capacities of the wide-shallow bucket foundations with and without honeycomb bulkheads, thereby evaluating the influence of honeycomb bulkheads on the bearing capacities under different conditions. The results show that under uniaxial loading, the uniaxial bearing capacities of the wide-shallow bucket foundation are basically unaffected by the honeycomb bulkheads in homogeneous clay. For nonhomogeneous clay, the moment bearing capacity will be considerably enhanced with the increase in soil shear strength heterogeneity. Under combined loading, the honeycomb bulkheads will enhance the combined bearing capacities only in nonhomogeneous clay. The enhancement effects will increase with the increase in soil shear strength heterogeneity but decrease with the increase in vertical load. Besides, the simplified equations for calculating the uniaxial bearing capacities of the wide-shallow bucket foundation with honeycomb bulkheads are also proposed considering the influence of embedment ratio and soil shear strength heterogeneity. At last, the parameters of an approximating expression are fitted to predict the failure envelopes of this foundation under combined loading.

The dynamic behavior of fractal-like tubes with Sierpinski hierarchy under axial loading

2021 ◽  
Author(s):  
Qiang He ◽  
Yonghui Wang ◽  
Hang Gu ◽  
Jun Feng ◽  
Honggen Zhou
Keyword(s):  
Dynamic Behavior ◽  
Axial Loading

Dynamic Modeling of the Torsional Vibration of the Slewing Mechanism of a Hydraulic Excavator

2012 ◽  
Vol 253-255 ◽  
pp. 2102-2106 ◽  
Author(s):  
Xu Juan Yang ◽  
Zong Hua Wu ◽  
Zhao Jun Li ◽  
Gan Wei Cai
Keyword(s):  
Torsional Vibration ◽  
Natural Frequencies ◽  
Planetary Gear ◽  
Moment Of Inertia ◽  
Hydraulic Excavator ◽  
Planetary Gear Trains ◽  
Vibration Model ◽  
Gear Trains ◽  
The Moment ◽  
Relationship Of

A torsional vibration model of the slewing mechanism of a hydraulic excavator is developed to predict its free vibration characteristics with consideration of many fundamental factors, such as the mesh stiffness of gear pairs, the coupling relationship of a two stage planetary gear trains and the variety of moment of inertia of the input end caused by the motion of work equipment. The natural frequencies are solved using the corresponding eigenvalue problem. Taking the moment of inertia of the input end for example to illustrate the relationship between the natural frequencies of the slewing mechanism and its parameters, based on the simulation results, just the first order frequency varies significantly with the moment of inertia of the input end of the slewing mechanism.

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