Meshing Stiffness and Tooth Root Stress for Internal Cylindrical Gears With Thin Rim

2003 ◽  
Author(s):  
Jean-Pierre de Vaujany ◽  
Miche`le Guingand ◽  
Didier Remond
Keyword(s):  
3D Model ◽  
Statistical Design ◽  
Tension Stress ◽  
Tooth Root ◽  
Meshing Stiffness ◽  
Cylindrical Gears ◽  
Maximal Tension ◽  
Experiment Method ◽  
Internal Gear ◽  
Root Stress

The main objective of this study is to quantify the influence of the deformation of the rim of an internal gear on the meshing stiffness and the stress distribution in tooth fillets. The 3D model used is based on a method derived from the Finite Prism Method. Tooth bending effects and contact deformations are processed simultaneously. Scientific use of the software has resulted in formulating an equation to calculate the maximal tension stress in the tooth root. This formula has been obtained by using the statistical design of experiment method.

The Combined Influence of Helix Angle and Total Contact Ratio on the p-FEM Calculated Tooth Root Stress in Cylindrical Gears

2000 ◽  
Author(s):  
Andrea Piazza ◽  
Maurizio Uberti
Keyword(s):  
Transverse Section ◽  
Helix Angle ◽  
Tooth Root ◽  
Finite Element Method Analysis ◽  
Contact Ratio ◽  
Profile Modification ◽  
Cylindrical Gears ◽  
Angle Correction ◽  
Method Analysis ◽  
Root Stress

Abstract Many parametrical studies about the effect of the helix angle on the maximum tooth root stress on cylindrical gears were conducted by means of a p-FEM (polynomial Finite Element Method) analysis, using models that comprehend all the contacting teeth and the adjacent ones. The studies were conducted in a way that the helix angle was varied from 0 to 35 degrees, keeping the transverse section constant (i.e. twisting the gears). Many non-HCR existing spur and helical gearsets, with different transverse contact ratio εα, transmission ratio, pressure angle, correction factor, and facewidth to module ratio were examined. Neither profile modification, nor crowning were considered. For each gearset the maximum p-FEM-calculated tooth root stress in both pinion and gear drops considerably when the total contact ratio εγ reaches the value of 2, with a minimum noticed around εγ = 2.1 ÷ 2.4; then the stress rises monotonically except for a non-remarkable drop when εγ reaches the value of 3. The p-FEM results were also compared with those based on ISO 6336-3 method B and AGMA 2001, showing noticeable differences.

scholarly journals Investigation of the Nominal Tooth Root Stress for External, Cylindrical Gears with Symmetric and Asymmetric Profile

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Bending Strength ◽  
Critical Cross Section ◽  
Tooth Root ◽  
Gear Design ◽  
Cylindrical Gears ◽  
Basic Issue ◽  
Root Stress

The determination of tooth bending strength is a basic issue in gear design. This work presents the change of nominal tooth root stress of external toothed, cylindrical gears depending on the geometry used. The nominal tooth root stress is analyzed with using finite element simulations. The numerical calculations are executed in Abaqus. The imported geometries are produced by our own program in MATLAB. The boundary conditions to the models are defined accordance with the most significant analytical methods used in practice. This approach allows mapping direct correlation analysis by these calculations. The optimization of computational capacity used is also considered. In addition to the examination of the significant tooth stress value of symmetrical element pairs, the position of the critical cross-section is also analyzed. The effect of the asymmetric design of the tooth profile on the nominal tooth root stress is also presented in our investigations. The purpose of the numerical simulations carried out here is to determine the effect of the coast side angle on the magnitude of the significant tooth root stress and the position of the critical cross-section.

Multi-Objective Topology Optimization for Bevel Gear and Geometrical Reconstruction

2013 ◽  
Vol 278-280 ◽  
pp. 139-142
Author(s):  
Xiang Bian ◽  
Zong De Fang ◽  
Kun Qin ◽  
Lifei Lian ◽  
Bao Yu Zhang
Keyword(s):  
Topology Optimization ◽  
Optimization Method ◽  
Tooth Root ◽  
Multi Objective Optimization ◽  
Direct Optimization ◽  
Multi Objective ◽  
Gear Modification ◽  
Parametric Cad ◽  
Straight Lines ◽  
Root Stress

Usually the gear modification is a main measure to reduce the vibration and noise of the gears, but in view of the complexity of the gear modification, topology optimization method was used to optimize the structure of the gear. The minimum volume was set as the direct optimization goal. To achieve the target of reducing contact stress, tooth root bending stress and improving flexibility, the upper bound of the stress and lower bound of the flexibility were set appropriately, thus realizing multi-objective optimization indirectly. A method for converting topology result into parametric CAD model which can be modified was presented, by fitting the topology result with simple straight lines and arcs, the model can be smoothed automatically, after further regulating, the geometry reconstruction was finished. After topology optimization, the resulting structure and properties of the gear are consistent with cavity gear. While reducing the weight of the gear, the noise can be reduced and its life would be extended through increasing flexibility and reducing tooth root stress.

scholarly journals Frequency and Vibration Characteristics of High-Speed Gear-Rotor-Bearing System with Tooth Root Crack considering Compound Dynamic Backlash

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Jie Liu ◽  
Weiqiang Zhao ◽  
Weiwei Liu
Keyword(s):  
Time Domain ◽  
Crack Depth ◽  
Transmission System ◽  
Gear System ◽  
Time Varying ◽  
Tooth Root ◽  
Meshing Stiffness ◽  
The Time Domain ◽  
Center Distance ◽  
Root Crack

Considering the microstructure of tooth surface and the dynamic characteristics of the vibration responses, a compound dynamic backlash model is employed for the gear transmission system. Based on the fractal theory and dynamic center distance, respectively, the dynamic backlash is presented, and the potential energy method is applied to compute the time-varying meshing stiffness, including the healthy gear system and the crack fault gear system. Then, a 16-DOF coupled lateral-torsional gear-rotor-bearing transmission system with the crack fault is established. The fault characteristics in the time-domain waveform and frequency response and statistics data are described. The effect of crack on the time-varying meshing stiffness is analyzed. The vibration response of three backlash models is compared. The dynamic response of the system is explored with the increase in crack depth in detail. The results show that the fault features of countershaft are more obvious. Obvious fluctuations are presented in the time-domain waveform, and sidebands can be found in the frequency domain responses when the tooth root crack appears. The effect of compound dynamic backlash on the system is more obvious than fixed backlash and backlash with changing center distance. The vibration displacement along meshing direction and dynamic meshing force increases with the increase in crack depth. Backlash and variation of center distance show different tendencies with increasing crack depth under different rotational speeds. Amplitude of the sidebands increases with crack depth increasing. The amplitude of multiplication frequency of rotational frequency has an obvious variation with growing crack depth. The sidebands of the multiplication frequency of meshing frequency show more details on the system with complex backlash and crack fault.

Study on Experiment Modeling of Human-Gun System

2014 ◽  
Vol 644-650 ◽  
pp. 2137-2142
Author(s):  
Jian Wang ◽  
Yan Liu ◽  
Zhi Guang Zhang ◽  
Zhan Jiang Yu ◽  
Bao Gui Wang ◽  
...  
Keyword(s):  
Parameter Identification ◽  
Dynamic Simulation ◽  
Test Data ◽  
Main Part ◽  
3D Model ◽  
Quality Test ◽  
High Quality ◽  
Model Parameter ◽  
Interaction System ◽  
Experiment Method

A new kind of human-imitate shooting platform is needed, so that the automation and standardization of small arm experiment could be realized. And the main part of shooting platform design is the modeling of human-gun interaction system. The main object of this paper is modeling human-gun interaction system by testing the model of the system. Firstly, the testing scheme is promoted for testing interaction between gun and human shoulder, and high quality test data is collected. Then, the model parameter of human-gun system is calculated by the method of model parameter identification. 3D model of human-gun system is built. At last, the dynamic simulation is made by ADAMS. And human-gun model built by experiment method is verified.

Viscoelastic Tooth Root Stress Analysis on Fiber Reinforced Thermoplastic Poly-Imide (TPI) Gears

2000 ◽  
Author(s):  
Gong Donghui ◽  
Ichiro Moriwaki ◽  
Kenji Saito
Keyword(s):  
Carbon Fiber ◽  
Stress Analysis ◽  
Power Transmission ◽  
Hysteresis Loss ◽  
Tooth Root ◽  
Fiber Reinforced ◽  
Standard Specimens ◽  
Sufficient Strength ◽  
Root Stress ◽  
Poly Imide

Abstract Although thermoplastic poly-imide (TPI) gears do not have sufficient strength for power transmission, carbon fiber reinforcement greatly improves the strength of TPI gears. Previous experimental research showed that although standard specimens made from carbon fiber reinforced (CFR) TPI has 2.4 times strength in static bending than specimens made from natural TPI, gears made from CFR-TPI yields bending fatigue strength about 10 times greater than gears made from natural TPI. The present paper explains this phenomenon using viscoelastic tooth root stress analysis. The experiments indicated that the natural TPI gears showed much larger viscoelasticity than the CFR-TPI gears. Thus, tooth root stresses were calculated for cases of large and small viscosity moduli. These calculations showed tooth root stress increased with the increase in the viscosity modulus. Also, viscoelasticity may induce heat due to hysteresis loss, and this heat should reduce gear durability. The increase in tooth root stress and the heat due to hysteresis loss must make the durability of the natural TPI gears very small. Therefore, the CFR-TPI can yield much more durable gears than the natural TPI.

Tooth Root Stresses of Helical Gear Pairs With Unequal and Offset Face Widths

2011 ◽  
Author(s):  
Carlos H. Wink
Keyword(s):  
Load Distribution ◽  
Element Model ◽  
Helical Gear ◽  
The Other ◽  
Gear Pair ◽  
Tooth Root ◽  
Pair Member ◽  
Face Width ◽  
The Face ◽  
Root Stress

In this study, tooth root stresses of helical gear pairs with different combinations of face width increase and offsets were analyzed. Contact face width was kept constant. The variables studied were face width and gear faces offset. The well-known LDP – Load Distribution Program was used to calculate tooth root stresses using a finite element model. The results presented show that the face width increase and offset have a significant influence on tooth root stresses. In some cases, increasing face width of one gear pair member resulted in significant increase of tooth root stress of the other member. For gear pairs with unequal and offset face widths, tooth root stresses were mostly affected when face widths were increased to the same direction of the contact line travel direction.

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