Response Sensitivity and the Assessment of Nonlinear Vibration Using a Nonlinear Lateral–Torsional Coupling Model of Vehicle Transmission System

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Chang L. Xiang ◽  
Yi Huang ◽  
Hui Liu
Keyword(s):  
Model Updating ◽  
Direct Method ◽  
Transmission System ◽  
Torsional Stiffness ◽  
Differential Sensitivity ◽  
Design Stage ◽  
Partial Amplitude ◽  
Response Sensitivity ◽  
Mass Eccentricity ◽  
Torsional Coupling

The eigensensitivity analysis does not meet the increasing industrial requirements of the dynamic performance of a vehicle transmission system. To reduce vibration, it is necessary to include response sensitivity in the guideline in the design stage. In this study, we developed a nonlinear lateral–torsional coupling spur gear system model considering the effect of time-varying mesh stiffness, clearance, mass eccentricity, and transmission error. Then the dynamic response sensitivity to system parameters was systematically analyzed by taking the shaft torsional stiffness, for example. The equation of response sensitivity was deduced by a direct method (DM) based on the fitting of the clearance function curve using a polynomial function. In allusion to the characteristic of the aperiodicity of response sensitivity curves of the nonlinear system in the time domain, a novel assessment method—differential sensitivity based on the root mean square (RMS) of response is proposed. This method provides statistical results in a certain range, thus avoiding the inaccuracy of the partial amplitude. The vibrational energy of modified system (MS) can also be estimated. All the abovementioned characteristics make it possible to provide the theoretical support for dynamic modification, model updating, and optimal design.

Comparison of Numerical Methods for Determining Torsion Stiffness of Automotive Chassis

2011 ◽  
Author(s):  
Steven Tebby ◽  
Ebrahim Esmailzadeh ◽  
Ahmad Barari
Keyword(s):  
Finite Element Analysis ◽  
Analytical Approach ◽  
Torsional Stiffness ◽  
Design Stage ◽  
Element Analysis ◽  
Detailed Design ◽  
Vertical Displacements ◽  
Comparison Of The Results ◽  
Torsion Stiffness

The torsion stiffness of an automotive chassis can be determined using an analytical approach based purely on geometry, using an experimental method, or alternatively by employing a Finite Element Analysis (FEA) process. These three methods are suitable at different design stages and combined together could prove to be practical methods of determining the torsion stiffness of a chassis. This paper describes and compares two distinct FEA processes to determine the torsion stiffness of an automotive chassis during the detailed design stage. The first process iteratively applies forces to the model and records displacements, while the second process gradually applies vertical displacements in place of force to determine the torsional stiffness threshold. Each method is explained and supported with a case study to provide a basis of comparison of the results.

A new torsional vibration coupling model for transmission system in diesel generator

2021 ◽  
pp. 146808742110689
Author(s):  
Bin Chen ◽  
Yunbo Hu ◽  
Yibin Guo ◽  
Zhijun Shuai ◽  
Chongpei Liu ◽  
...  
Keyword(s):  
Fault Diagnosis ◽  
Torsional Vibration ◽  
Coupling Model ◽  
Transmission System ◽  
System Matrix ◽  
Diesel Generator ◽  
Lumped Mass ◽  
Proposed Model ◽  
Torsional Coupling ◽  
Vibration Coupling

The coupling between the crankshaft and the camshaft is neglected before in fault diagnosis which may lead to incomplete fault information. In this paper, a new torsional coupling model of a diesel generator transmission system is proposed for fault diagnosis. The natural frequency and forced torsional vibration response of the model are obtained by the system matrix method and Newmark-β method. For the system without considering the lumped mass of camshafts, some key natural frequencies are lost. The vibration dynamics are compared for the transmission system with and without the new coupling model. And important frequency responses are missed in the spectrums of the forced torsional vibration without the new coupling model. Finally, the new coupling model is implemented in fault diagnosis and the cause of an unusual vibration fault is deduced in the simulation, which confirms the feasibility of the proposed model in fault diagnosis.

scholarly journals Design of Eco-Efficient Body Parts for Electric Vehicles Considering Life Cycle Environmental Information

2020 ◽  
Vol 12 (14) ◽  
pp. 5838
Author(s):  
Lars Reimer ◽  
Alexander Kaluza ◽  
Felipe Cerdas ◽  
Jens Meschke ◽  
Thomas Vietor ◽  
...  
Keyword(s):  
Life Cycle ◽  
Conceptual Design ◽  
Electric Vehicles ◽  
Ghg Emissions ◽  
Torsional Stiffness ◽  
Design Stage ◽  
Body Parts ◽  
Electricity Mix ◽  
Use Phase ◽  
Structural Parts

The reduction of greenhouse gas (GHG) emissions over the entire life cycle of vehicles has become part of the strategic objectives in automotive industry. In this regard, the design of future body parts should be carried out based on information of life cycle GHG emissions. The substitution of steel towards lightweight materials is a major trend, with the industry undergoing a fundamental shift towards the introduction of electric vehicles (EV). The present research aims to support the conceptual design of body parts with a combined perspective on mechanical performance and life cycle GHG emissions. Particular attention is paid to the fact that the GHG impact of EV in the use phase depends on vehicle-specific factors that may not be specified at the conceptual design stage of components, such as the market-specific electricity mix used for vehicle charging. A methodology is proposed that combines a simplified numerical design of concept alternatives and an analytic approach estimating life cycle GHG emissions. It is applied to a case study in body part design based on a set of principal geometries and load cases, a range of materials (aluminum, glass and carbon fiber reinforced plastics (GFRP, CFRP) as substitution to a steel reference) and different use stage scenarios of EV. A new engineering chart was developed, which helps design engineers to compare life cycle GHG emissions of lightweight material concepts to the reference. For body shells, the replacement of the steel reference with aluminum or GFRP shows reduced lifecycle GHG emissions for most use phase scenarios. This holds as well for structural parts being designed on torsional stiffness. For structural parts designed on tension/compression or bending stiffness CFRP designs show lowest lifecycle GHG emissions. In all cases, a high share of renewable electricity mix and a short lifetime pose the steel reference in favor. It is argued that a further elaboration of the approach could substantially increase transparency between design choices and life cycle GHG emissions.

A direct method for model updating with incomplete measured data and without spurious modes

2007 ◽  
Vol 21 (7) ◽  
pp. 2715-2731 ◽  
Author(s):  
Joao Carvalho ◽  
Biswa N. Datta ◽  
Abhijit Gupta ◽  
Maitreya Lagadapati
Keyword(s):  
Model Updating ◽  
Direct Method ◽  
Measured Data ◽  
Spurious Modes ◽  
A Direct Method

scholarly journals Research on Torsional Property of Body-In-White Based on Square Box Model and Multiobjective Genetic Algorithm

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yanmei Meng ◽  
Yuan Liang ◽  
Qinchuan Zhao ◽  
Johnny Qin
Keyword(s):  
Genetic Algorithm ◽  
Shear Stiffness ◽  
Box Model ◽  
Torsional Stiffness ◽  
Design Stage ◽  
Multiobjective Genetic Algorithm ◽  
First Order ◽  
Body In White ◽  
Torsional Frequency ◽  
Square Box

In order to assess the performance of a vehicle in the conceptual design stage, a square box model was proposed to predict the torsional stiffness and the first-order torsional frequency of Body-in-White. The structure of Body-in-White was decomposed into eight simple structural surfaces, from which a square box model was constructed. Based on the finite element method, modified shear stiffness of each simple structure surface was calculated and the torsional stiffness was obtained. Then, simple structural surfaces of Body-in-White were constructed into an eight degree-of-freedom series spring system to calculate the first-order torsional frequency. Furthermore, a multiobjective genetic algorithm was used to determine the thickness and structural reinforcement of panels with small stiffness, so as to achieve the goal of increasing the stiffness while reducing the mass of the panel. The result shows that the optimal values of thickness are reduced by around 9.9 percent without affecting their performance by the proposed method. Compared to the prediction results obtained with the complicated numerical simulation, the relative error of the square box model in predicting the torsional stiffness is 6.04 percent and in predicting the first-order torsional frequency is 0.95 percent, indicating that the prediction model is effective.

Sensitivity Analysis of Parameters for FPSO Model Updating

2020 ◽  
Author(s):  
Qihao Wu ◽  
Min Zhang ◽  
Tian’en Yang ◽  
Nuoya Xu ◽  
Junrong Wang ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Model ◽  
Model Updating ◽  
Direct Method ◽  
Unit Length ◽  
Parameter Sensitivity ◽  
Irregular Waves ◽  
Sensitivity Analyses ◽  
Mooring Line ◽  
Restoring Force

Abstract This paper presents parameter sensitivity analysis for a FPSO numerical model updating. Generally, model test data are considered a better presentation of physical phenomena than its numerical counterpart. To minimize the discrepancy, model updating is of pragmatically importance. Model updating of a certain FPSO can be achieved by specific steps. In each step, the required properties of numerical model and test results are matched by means of tuning of the related parameters. To avoid inefficiency and physical meaning loss resulting from large modification of parameters which are insensitive to objective properties, parameter sensitivity analyses using the direct method are conducted in this paper. The investigated parameters mainly are the FPSO’s mooring line length, mooring line mass per unit length, mooring line cross-sectional area, fairlead position, FPSO hydrostatic stiffness, FPSO mass properties, linear and quadratic damping coefficients. According to the different stages of FPSO model updating, the objective functions are set to be the FPSO’s mooring line pretension, mooring system horizontal restoring force, the natural periods of the FPSO’s 6 degree of freedom motions and the standard deviation of motion response spectra under irregular waves.

Research on dynamic load sharing characteristics of double input face gear split-parallel transmission system

2021 ◽  
pp. 095440622110263
Author(s):  
Shuai Mo ◽  
Yuling Song ◽  
Zhiyou Feng ◽  
Wenhao Song ◽  
Maoxiang Hou
Keyword(s):  
Load Sharing ◽  
Transmission System ◽  
Torsional Stiffness ◽  
Research Trend ◽  
Face Gear ◽  
Parallel Transmission ◽  
Input Face ◽  
Lumped Parameter ◽  
The Face ◽  
Dynamic Load Sharing

The face gear power-split system has huge superiorities over the traditional transmission form in the application of modern rotorcraft, and it has become the research trend of the industry in recent years. Thus this paper took the double input face gear split-parallel transmission system used in the rotorcraft as the research target, and established its dynamics model through the lumped parameter theory. Based on the Newtonian second law, the dynamics equations were built and solved to gain the meshing forces and load sharing coefficients of the transmission system. Simultaneously, the impacts of the eccentric errors, support stiffness, and torsional stiffness on the load sharing characteristics were studied. The results show that the meshing forces and load sharing coefficients of each gear pair have periodic changes; the eccentric errors of each drive stage gear have only a significant effect on the corresponding drive stage. Moreover, the changes in the support stiffness of the split-torque shafts and double gear shafts mainly affect the load distribution of the parallel stage, and the shaft torsional stiffness is less sensitively to maintain load balance. In addition, the increment of the shaft stiffness increases the load sharing coefficients of the corresponding gear pairs.

scholarly journals Bifurcation and Chaos Analysis of the Spur Gear Transmission System for One-Way Clutch, Two-Shaft Assembly

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Zhihui Liu ◽  
Hongzhi Yan ◽  
Yuming Cao ◽  
Yuqing Lai
Keyword(s):  
Excitation Frequency ◽  
Transmission Error ◽  
Spur Gear ◽  
Transmission System ◽  
Gear Transmission ◽  
Torsional Stiffness ◽  
System Response ◽  
Gear Mesh ◽  
Gear Transmission System ◽  
The Impact

A four-degree-of-freedom nonlinear transverse and torsional vibration model of spur gear transmission system for one-way clutch, two-shaft assembly was developed, in which the one-way clutch was modeled as a piecewise nonlinear spring with discontinuous stiffness, considering the factors such as the time-varying gear mesh stiffness, static transmission error, and nonlinearity backlash. With the help of bifurcation diagrams, time domain response diagrams, phase plane diagrams, and Poincaré maps, the effects of the excitation frequency and the torsional stiffness of one-way clutch on the dynamic behavior of gear transmission system for one-way clutch, two-shaft assembly are investigated in detail by using Runge-Kutta method. Numerical results reveal that the system response involves period-1 motion, multiperiodic motion, bifurcation, and chaotic motion. Large torsional stiffness of one-way clutch can increase the impact and lead to instability in the system. The results can present a useful source of reference for technicians and engineers for dynamic design and vibration control of such system.

Dynamic Instability of Cantilever Beams With Open Cross-Section

2016 ◽  
Author(s):  
Júlio C. Coaquira ◽  
Paulo B. Gonçalves ◽  
Eulher C. Carvalho
Keyword(s):  
Composite Structures ◽  
Dynamic Instability ◽  
Nonlinear Oscillations ◽  
Equations Of Motion ◽  
Beam Theory ◽  
Torsional Stiffness ◽  
Phase Portraits ◽  
Large Displacements ◽  
Torsional Coupling ◽  
Thin Walled

Structural elements with thin-walled open cross-sections are common in metal and composite structures. These thin-walled beams have generally a good flexural strength with respect to the axis of greatest inertia, but a low flexural stiffness in relation to the second principal axis and a low torsional stiffness. These elements generally have an instability, which leads to a flexural-flexural-torsional coupling. The same applies to the vibration modes. Many of these structures work in a nonlinear regime, and a nonlinear formulation that takes into account large displacements and the flexural-flexural-torsional coupling is required. In this work a nonlinear beam theory that takes into account large displacements, warping and shortening effects, as well as flexural-flexural-torsional coupling is adopted. The governing nonlinear equations of motion are discretized in space using the Galerkin method and the discretized equations of motion are solved by the Runge-Kutta method. Special attention is given to the nonlinear oscillations of beams with low torsional stiffness and its influence on the bifurcations and instabilities of the structure, a problem not tackled in the previous literature on this subject. Time responses, phase portraits and bifurcation diagrams are used to unveil the complex dynamic.

Sign in / Sign up

Export Citation Format

Share Document