Using Dynamic Analysis for Compact Gear Design

1999 ◽  
Vol 124 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Ping-Hsun Lin ◽  
Hsiang Hsi Lin ◽  
Fred B. Oswald ◽  
Dennis P. Townsend

This paper presents procedures for designing compact spur gear sets with the objective of minimizing the gear size. The allowable tooth stress and dynamic response are incorporated in the process to obtain a feasible design region. Various dynamic rating factors were investigated and evaluated. The constraints of contact stress limits and involute interference combined with the tooth bending strength provide the main criteria for this investigation. A three-dimensional design space involving the gear size, diametral pitch, and operating speed was developed to illustrate the optimal design of spur gear pairs. The study performed here indicates that as gears operate over a range of speeds, variations in the dynamic response change the required gear size in a trend that parallels the dynamic factor. The dynamic factors are strongly affected by the system natural frequencies. The peak values of the dynamic factor within the operating speed range significantly influence the optimal gear designs. The refined dynamic factor introduced in this study yields more compact designs than AGMA dynamic factors.

Author(s):  
Ping-Hsun Lin ◽  
Hsiang Hsi Lin ◽  
Fred B. Oswald ◽  
Dennis P. Townsend

Abstract This paper presents procedures for designing compact spur gear sets with the objective of minimizing the gear size. The allowable tooth stress and dynamic response are incorporated in the process to obtain a feasible design region. Various dynamic rating factors were investigated and evaluated. The constraints of contact stress limits and involute interference combined with the tooth bending strength provide the main criteria for this investigation. A three-dimensional design space involving the gear size, diametral pitch, and operating speed was developed to illustrate the optimal design of spur gear pairs. The study performed here indicates that as gears operate over a range of speeds, variations in the dynamic response change the required gear size in a trend that parallels the dynamic factor. The dynamic factors are strongly affected by the system natural frequencies. The peak values of the dynamic factor within the operating speed range significantly influence the optimal gear designs. The refined dynamic factor introduced in this study yields more compact designs than AGMA dynamic factors.


Author(s):  
L Xu ◽  
H Jin ◽  
X Hao

In this article, a three-dimensional dynamic model of the toroidal drive is given. By the model, equations of the relative displacements between different components and the dynamic equations for the drive are obtained. Changes of the mesh stiffness are analysed and the equation of periodical time-varying mesh stiffness is presented in Fourier series form. Under neglecting nonlinear items, time-varying mesh stiffness is changed into equivalent exciting load and linear dynamic equations of the drive are obtained. Then, the analytical equations of the forced response for the drive to mesh stiffness excitation are obtained, and the equations of the dynamic factors between a planet and worm or stator are given as well. By aforementioned equations, the forced frequency responses of the drive system to mesh stiffness variation are given, the variations of dynamic response for the worm as functions of the main parameters are presented, and the dynamic factor between a planet and worm is given as a function of operating speed.


2021 ◽  

Cable-supported pipe system (CSPS) provides a suitable system of structure for meeting the stringent structural requirements of pipeline bridges. However, due to a composite action of cable with truss and pipe members, the sudden failure of its structural member may lead to undesired vibratory response and collapse. The occurrence of a sudden break of the CSPS structural member is characterized by spontaneous dynamics and internal force rearrangement. The present study aims to investigate parametrically the collapse susceptibility and resistance of scaled down CSPS model in the event of a sudden break of the cable member by combined experimental and numerical procedures. The displacement of the structure, the pattern of internal force rearrangement, and dynamic responses were comparatively evaluated. Experimental results depict imminent cable failure under load and attendant dynamic response, but without a total collapse of the CSPS structure. Critical members causing large dynamic response amplitudes were identified and the mitigation of collapse was evaluated. Dynamic increasing factor (DIF) methods was utilized for the evaluation of the dynamic response of the sudden cable break resulting from the pattern of responses between the cable members and the rest of the CSPS structure. Comparison with provisions in other studies shows higher values DIF of the CSPS cable members which led to proposed evaluation using dynamic factor (DF). Thus, the dynamic factors for the sudden break of various cable members along the span and the errors were also estimated considering the parametric of design variables which will enable easy utilization during the structural process of CSPS.


Author(s):  
Fatih Güven

Gears are commonly used in transmission systems to adjust velocity and torque. An integral gear or an interference fit could be used in a gearbox. Integral gears are mostly preferred as driving gear for a compact design to reduce the weight of the system. Interference fit makes the replacement of damaged gear possible and re-use of the shaft compared to the integral shaft. However, internal pressure occurs between mating surfaces of the components mated. This internal pressure affects the stress distribution at the root and bottom land of the gear. In this case, gear parameters should be re-considered to assure gear life while reducing the size of the gear. In this study, interference fitted gear-shaft assembly was examined numerically. The effects of rim thickness, profile shifting, module and fit tolerance on bending stress occurring at the root of the gear were investigated to optimize gear design parameters. Finite element models were in good agreement with analytical solutions. Results showed that the rim thickness of the gear is the main parameter in terms of tangential stress occurring at the bottom land of the gear. Positive profile shifting reduces the tangential stress while the pitch diameter of the gear remains constant. Also, lower tolerance class could be selected to moderate stress for small rim thickness.


1993 ◽  
Vol 115 (1) ◽  
pp. 111-119 ◽  
Author(s):  
A. B. Palazzolo ◽  
S. Jagannathan ◽  
A. F. Kascak ◽  
G. T. Montague ◽  
L. J. Kiraly

The vibrations of a flexible rotor are controlled using piezoelectric actuators. The controller includes active analog components and a hybrid interface with a digital computer. The computer utilizes a grid search algorithm to select feedback gains that minimize a vibration norm at a specific operating speed. These gains are then downloaded as active stiffnesses and dampings with a linear fit throughout the operating speed range to obtain a very effective vibration control.


2021 ◽  
Vol 18 (3) ◽  
pp. 172988142110177
Author(s):  
Jia Yonghao ◽  
Chen Xiulong

For spatial multibody systems, the dynamic equations of multibody systems with compound clearance joints have a high level of nonlinearity. The coupling between different types of clearance joints may lead to abundant dynamic behavior. At present, the dynamic response analysis of the spatial parallel mechanism considering the three-dimensional (3D) compound clearance joint has not been reported. This work proposes a modeling method to investigate the influence of the 3D compound clearance joint on the dynamics characteristics of the spatial parallel mechanism. For this purpose, 3D kinematic models of spherical clearance joint and revolute joint with radial and axial clearances are derived. Contact force is described as normal contact and tangential friction and later introduced into the nonlinear dynamics model, which is established by the Lagrange multiplier technique and Jacobian of constraint matrix. The influences of compound clearance joint and initial misalignment of bearing axes on the system are analyzed. Furthermore, validation of dynamics model is evaluated by ADAMS and Newton–Euler method. This work provides an essential theoretical basis for studying the influences of 3D clearance joints on dynamic responses and nonlinear behavior of parallel mechanisms.


2015 ◽  
Vol 23 (9) ◽  
pp. 1548-1568 ◽  
Author(s):  
Shao Renping ◽  
Purong Jia ◽  
Xiankun Qi

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.


2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Ying Yan ◽  
Gengping Li ◽  
Jinjun Tang ◽  
Zhongyin Guo

Operating speed is a critical indicator for road alignment consistency design and safety evaluation. Although extensive studies have been conducted on operating speed prediction, few models can finish practical continuous prediction at each point along alignment on multilane highways. This study proposes a novel method to estimate the operating speed for multilane highways in China from the aspect of the three-dimensional alignment combination. Operating speed data collected in field experiments on 304 different alignment combination sections are detected by means of Global Positioning System. First, the alignment comprehensive index (ACI) is designed and introduced to describe the function accounting for alignment continuity and driving safety. The variables used in ACI include horizontal curve radius, change rate of curvature, deflection angle of curve, grade, and lane width. Second, the influence range of front and rear alignment on speed is determined on the basis of drivers’ fixation range and dynamical properties of vehicles. Furthermore, a prediction model based on exponential relationships between road alignment and speeds is designed to predict the speed of passenger cars and trucks. Finally, three common criteria are utilized to evaluate the effectiveness of the prediction models. The results indicate that the prediction models outperform the other two operating speed models for their higher prediction accuracy.


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