Investigations on Creep Groan Concerning Static and Dynamic Axle Bushing Properties

Research output: Chapter in Book/Report/Conference proceedingConference contributionResearchpeer-review

Abstract

The NVH performance of passenger car friction brake systems is an important product quality criterion. Brake creep groan, which is favoured by technological trends such as electrified powertrains and/or automated driving functionalities, has become a frequent inconvenience in that field. In order to develop and evaluate corrective measures against creep groan phenomena by simulative approaches, extensive and well parametrised models are essential. Axle bushings, which are an important part of this challenge, are treated within this work.
On one hand, creep groan of a MacPherson corner setup with floating calliper brake system has been investigated at a drum driven suspension and brake test rig. Experiments were conducted for different combinations of brake pressure and drum velocity. In order to estimate the in situ characteristics of built in axle elastomer components, interface forces between test rig and corner setup as well as related accelerations were measured. On the other hand, transient simulations with a non linear corner FE model have been carried out. Two typical manifestations of creep groan at different operating points were computed. These manifestations’ sensitivity towards viscous damping of the lower control arm hydro bushing has been analysed by a simple simulative parameter study.
Most of the test matrix experiments led to creep groan phenomena. The measured signals’ characteristics show a strong relation to the applied brake pressure. The interface forces indicate this via specific dynamic amplitudes at variable static levels. Thus, all involved axle bushings operate in different performance ranges. The radial direction of the lower control arm hydro bushing is affected in particular. High relevance of its non linear static elasticity concerning creep groan vibrations is already known from a former study. The current work also shows strong influences of the non linear dynamic stiffness and viscous damping respectively.
The simulative side offers potentials for a better physical conformance such as modelling and parameterisation of the suspension strut, determination and consideration of non linear dynamic bushing parameters or implementation of a well parametrised friction model.
Several works regarding creep groan test rig experiments have been published. In terms of its transient simulation, one paper has dealt with the basic FE model as well as the relevance of non linear static stiffness curves. Based on that, the present study provides additional experimental/simulative results and treats the influence of dynamic axle bushing properties.
In order to establish accurate virtual creep groan evaluation methods, holistic understanding of all relevant system influences is crucial. This study shows that axle bushings are of high relevance. Correlating results of the systematic test rig experiments and the transient non linear FEA indicate strong effects of the non-linear behaviour of hydro bushings.
Original languageEnglish
Title of host publicationProceedings of Eurobrake 2019
Number of pages14
Publication statusPublished - 21 May 2019
EventEuroBrake 2019: Europe's braking technology conference & exhibition - Dresden, Germany
Duration: 21 May 201923 May 2019

Conference

ConferenceEuroBrake 2019: Europe's braking technology conference & exhibition
CountryGermany
CityDresden
Period21/05/1923/05/19

Fingerprint

Bushings
Axles
Creep
Brakes
Damping
Experiments
Stiffness
Friction
Powertrains
Struts
Passenger cars
Parameterization
Elastomers
Elasticity
Finite element method

Fields of Expertise

  • Mobility & Production

Cite this

Investigations on Creep Groan Concerning Static and Dynamic Axle Bushing Properties. / Pürscher, Manuel; Huemer-Kals, Severin; Fischer, Peter.

Proceedings of Eurobrake 2019. 2019. EB2018-SVM-001.

Research output: Chapter in Book/Report/Conference proceedingConference contributionResearchpeer-review

Pürscher, M, Huemer-Kals, S & Fischer, P 2019, Investigations on Creep Groan Concerning Static and Dynamic Axle Bushing Properties. in Proceedings of Eurobrake 2019., EB2018-SVM-001, EuroBrake 2019: Europe's braking technology conference & exhibition, Dresden, Germany, 21/05/19.
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N2 - The NVH performance of passenger car friction brake systems is an important product quality criterion. Brake creep groan, which is favoured by technological trends such as electrified powertrains and/or automated driving functionalities, has become a frequent inconvenience in that field. In order to develop and evaluate corrective measures against creep groan phenomena by simulative approaches, extensive and well parametrised models are essential. Axle bushings, which are an important part of this challenge, are treated within this work.On one hand, creep groan of a MacPherson corner setup with floating calliper brake system has been investigated at a drum driven suspension and brake test rig. Experiments were conducted for different combinations of brake pressure and drum velocity. In order to estimate the in situ characteristics of built in axle elastomer components, interface forces between test rig and corner setup as well as related accelerations were measured. On the other hand, transient simulations with a non linear corner FE model have been carried out. Two typical manifestations of creep groan at different operating points were computed. These manifestations’ sensitivity towards viscous damping of the lower control arm hydro bushing has been analysed by a simple simulative parameter study.Most of the test matrix experiments led to creep groan phenomena. The measured signals’ characteristics show a strong relation to the applied brake pressure. The interface forces indicate this via specific dynamic amplitudes at variable static levels. Thus, all involved axle bushings operate in different performance ranges. The radial direction of the lower control arm hydro bushing is affected in particular. High relevance of its non linear static elasticity concerning creep groan vibrations is already known from a former study. The current work also shows strong influences of the non linear dynamic stiffness and viscous damping respectively.The simulative side offers potentials for a better physical conformance such as modelling and parameterisation of the suspension strut, determination and consideration of non linear dynamic bushing parameters or implementation of a well parametrised friction model.Several works regarding creep groan test rig experiments have been published. In terms of its transient simulation, one paper has dealt with the basic FE model as well as the relevance of non linear static stiffness curves. Based on that, the present study provides additional experimental/simulative results and treats the influence of dynamic axle bushing properties.In order to establish accurate virtual creep groan evaluation methods, holistic understanding of all relevant system influences is crucial. This study shows that axle bushings are of high relevance. Correlating results of the systematic test rig experiments and the transient non linear FEA indicate strong effects of the non-linear behaviour of hydro bushings.

AB - The NVH performance of passenger car friction brake systems is an important product quality criterion. Brake creep groan, which is favoured by technological trends such as electrified powertrains and/or automated driving functionalities, has become a frequent inconvenience in that field. In order to develop and evaluate corrective measures against creep groan phenomena by simulative approaches, extensive and well parametrised models are essential. Axle bushings, which are an important part of this challenge, are treated within this work.On one hand, creep groan of a MacPherson corner setup with floating calliper brake system has been investigated at a drum driven suspension and brake test rig. Experiments were conducted for different combinations of brake pressure and drum velocity. In order to estimate the in situ characteristics of built in axle elastomer components, interface forces between test rig and corner setup as well as related accelerations were measured. On the other hand, transient simulations with a non linear corner FE model have been carried out. Two typical manifestations of creep groan at different operating points were computed. These manifestations’ sensitivity towards viscous damping of the lower control arm hydro bushing has been analysed by a simple simulative parameter study.Most of the test matrix experiments led to creep groan phenomena. The measured signals’ characteristics show a strong relation to the applied brake pressure. The interface forces indicate this via specific dynamic amplitudes at variable static levels. Thus, all involved axle bushings operate in different performance ranges. The radial direction of the lower control arm hydro bushing is affected in particular. High relevance of its non linear static elasticity concerning creep groan vibrations is already known from a former study. The current work also shows strong influences of the non linear dynamic stiffness and viscous damping respectively.The simulative side offers potentials for a better physical conformance such as modelling and parameterisation of the suspension strut, determination and consideration of non linear dynamic bushing parameters or implementation of a well parametrised friction model.Several works regarding creep groan test rig experiments have been published. In terms of its transient simulation, one paper has dealt with the basic FE model as well as the relevance of non linear static stiffness curves. Based on that, the present study provides additional experimental/simulative results and treats the influence of dynamic axle bushing properties.In order to establish accurate virtual creep groan evaluation methods, holistic understanding of all relevant system influences is crucial. This study shows that axle bushings are of high relevance. Correlating results of the systematic test rig experiments and the transient non linear FEA indicate strong effects of the non-linear behaviour of hydro bushings.

M3 - Conference contribution

BT - Proceedings of Eurobrake 2019

ER -