Limitations of Smoothening Functions for Automotive Vibro-Impact Problems

Nonlinear torsional models are used to analyze automotive transmission rattle problems and find solutions to reduce noise, vibration and dynamic loads. The torsional stiffness and inertial distribution of such systems show that the underlying mathematical problem is numerically stiff. In addition, t...

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Main Authors: Zhiwei Zhang, Rajendra Singh, Ashley R. Crowther
Format: Article
Language:English
Published: Wiley 2011-01-01
Series:Shock and Vibration
Online Access:http://dx.doi.org/10.3233/SAV-2010-0582
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author Zhiwei Zhang
Rajendra Singh
Ashley R. Crowther
author_facet Zhiwei Zhang
Rajendra Singh
Ashley R. Crowther
author_sort Zhiwei Zhang
collection DOAJ
description Nonlinear torsional models are used to analyze automotive transmission rattle problems and find solutions to reduce noise, vibration and dynamic loads. The torsional stiffness and inertial distribution of such systems show that the underlying mathematical problem is numerically stiff. In addition, the clearance nonlinearities in the gear meshes introduce discontinuous functions. Both factors affect the efficacy of time domain integration and smoothening functions are widely used to overcome computational difficulties and improve the simulation. In this paper, alternate smoothening functions are studied for their influence on the numerical solutions and their impact on global convergence and computation times. In particular, four smoothening functions (arctan, hyperbolic-cosine, hyperbolic-tan and quintic-spline) are applied to a five-degree-of-freedom generic torsional system with two backlash (clearance) elements. Each function is assessed via a global convergence metric across an excitation map (a design of experiment). Regions of the excitation map, along with multiple solutions, are studied and the implications to assessing convergence are critically examined. It is observed that smoothening functions do not lead to better convergence in many cases. The smoothening parameter needs to be carefully selected, or over-smoothened solutions may be found. The system studied is representative of a typical automotive rattle problem and it was found that benefits were limited from applying such smoothening functions.
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spelling doaj-art-e8f19d2d662e4ec1911fc7bf57afd8ba2025-02-03T05:45:22ZengWileyShock and Vibration1070-96221875-92032011-01-01181-239740610.3233/SAV-2010-0582Limitations of Smoothening Functions for Automotive Vibro-Impact ProblemsZhiwei Zhang0Rajendra Singh1Ashley R. Crowther2Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Leicestershire LE11 3TU, UKAcoustics and Dynamics Laboratory, Mechanical Engineering Department, The Ohio State University, Columbus, OH, USAAcoustics and Dynamics Laboratory, Mechanical Engineering Department, The Ohio State University, Columbus, OH, USANonlinear torsional models are used to analyze automotive transmission rattle problems and find solutions to reduce noise, vibration and dynamic loads. The torsional stiffness and inertial distribution of such systems show that the underlying mathematical problem is numerically stiff. In addition, the clearance nonlinearities in the gear meshes introduce discontinuous functions. Both factors affect the efficacy of time domain integration and smoothening functions are widely used to overcome computational difficulties and improve the simulation. In this paper, alternate smoothening functions are studied for their influence on the numerical solutions and their impact on global convergence and computation times. In particular, four smoothening functions (arctan, hyperbolic-cosine, hyperbolic-tan and quintic-spline) are applied to a five-degree-of-freedom generic torsional system with two backlash (clearance) elements. Each function is assessed via a global convergence metric across an excitation map (a design of experiment). Regions of the excitation map, along with multiple solutions, are studied and the implications to assessing convergence are critically examined. It is observed that smoothening functions do not lead to better convergence in many cases. The smoothening parameter needs to be carefully selected, or over-smoothened solutions may be found. The system studied is representative of a typical automotive rattle problem and it was found that benefits were limited from applying such smoothening functions.http://dx.doi.org/10.3233/SAV-2010-0582
spellingShingle Zhiwei Zhang
Rajendra Singh
Ashley R. Crowther
Limitations of Smoothening Functions for Automotive Vibro-Impact Problems
Shock and Vibration
title Limitations of Smoothening Functions for Automotive Vibro-Impact Problems
title_full Limitations of Smoothening Functions for Automotive Vibro-Impact Problems
title_fullStr Limitations of Smoothening Functions for Automotive Vibro-Impact Problems
title_full_unstemmed Limitations of Smoothening Functions for Automotive Vibro-Impact Problems
title_short Limitations of Smoothening Functions for Automotive Vibro-Impact Problems
title_sort limitations of smoothening functions for automotive vibro impact problems
url http://dx.doi.org/10.3233/SAV-2010-0582
work_keys_str_mv AT zhiweizhang limitationsofsmootheningfunctionsforautomotivevibroimpactproblems
AT rajendrasingh limitationsofsmootheningfunctionsforautomotivevibroimpactproblems
AT ashleyrcrowther limitationsofsmootheningfunctionsforautomotivevibroimpactproblems