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A finite strain viscoplastic constitutive model for rubberwith reinforcing fillers
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. Scania.ORCID iD: 0000-0002-1036-6837
Scania.
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.ORCID iD: 0000-0001-5760-3919
(English)Manuscript (preprint) (Other academic)
Abstract [en]

A three dimensional viscoplastic constitutive model for finite strains in aco-rotational explicit scheme is developed and implemented using finite elementsthat captures the amplitude dependency, commonly referred to as theFletcher-Gent effect, and frequency dependency of rubber with reinforcingfillers. The multiplicative split of the deformation gradient is utilized andthe plastic flow rule stems from an extension to finite strains of a boundarysurface model with a vanishing elastic region. The storage and loss modulusfor a 50 phr carbon black filled natural rubber are captured over a largerange of strain amplitudes, 0.2 − 50% shear strain, and frequencies, 0.2 − 20Hz. In addition, bimodal excitation is replicated accurately, even though thismeasurement data is not included when obtaining material parameters. Thiscapability is essential when non-sinusoidal loading conditions are to be replicated.By separating the material and geometrical influence on the propertiesof a component, the design engineers have the capability to evaluate more concepts early in the design phase. This also reduces the need of complexprototypes for physical testing, thereby saving both time and money.

Keyword [en]
Finite strains, Viscoplastic material, Polymeric material, Finite elements, Fletcher-Gent effect
National Category
Textile, Rubber and Polymeric Materials
Research subject
Vehicle and Maritime Engineering
Identifiers
URN: urn:nbn:se:kth:diva-184890OAI: oai:DiVA.org:kth-184890DiVA: diva2:917491
Note

QS 2016

Available from: 2016-04-06 Created: 2016-04-06 Last updated: 2016-04-06Bibliographically approved
In thesis
1. Modelling the viscoplastic properties of carbon black filled rubber: A finite strain material model suitable for Finite Element Analysis
Open this publication in new window or tab >>Modelling the viscoplastic properties of carbon black filled rubber: A finite strain material model suitable for Finite Element Analysis
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

An increased environmental awareness, legal demands and the large part of total costs attributable to fuel cost are all incentives for the automotive industry to reduce fuel consumption. The optimal driveline to enable this reduction depends on the operational conditions and the available infrastructure. Moreover, special care is needed when developing the driveline isolators, since the demands on noise, vibration and harshness (NVH) are the same regardless of driveline. To this end, computer aided calculations can be used in order to evaluate a large number of configurations. However, these calculations are only, at best, as good as the material models employed. In the foreseeable future, rubber with reinforcing fillers will be used in vibration isolators in order to obtain the desired properties of these components. However, the stiffness and damping of rubber with reinforcing fillers are highly non-linear functions, and the available material models in commercial software and in the literature are often insufficient. Therefore, a finite strain viscoplastic material model is derived in the time domain and implemented as a user defined material model in Abaqus Explicit. The model captures the strain amplitude and frequency dependency of the storage and loss modulus for a carbon black filled natural rubber. The model is accurate over a wide range of shear strain amplitudes and frequencies, 0.2-50 % and 0.5-20 Hz, respectively, using only 5 material parameters. In addition, the model correctly captures the response from bimodal excitations. The implementation in Abaqus Explicit enables component characteristics to be evaluated early in the development phase, with material parameters derived from simple test specimens. The improved accuracy of simulations of these components can aid engineers develop more optimized solutions faster than with conventional methods.

Abstract [sv]

En ökad miljömedvetenhet, juridiska krav och den stora delen av de totala kostnaderna som kan hänföras till bränslekostnader är alla incitament för fordonsindustrin att minska bränsleförbrukningen. Den optimala drivlinan för att möjliggöra denna minskning beror på driftförhållanden och den tillgängliga infrastrukturen. Dessutom ställs höga krav på utvecklingen av drivlineisolatorer, eftersom kraven på buller och vibrationer (NVH) är desamma oavsett drivlina. För detta ändamål kan datorstödda beräkningar användas för att utvärdera ett stort antal konfigurationer. Dessa beräkningar är, i bästa fall, endast så bra som de använda materialmodellerna. Inom en överskådlig framtid kommer gummi med förstärkande fyllmedel användas i vibrationsisolatorer för att erhålla de önskade egenskaperna hos dessa komponenter. Men styvheten och dämpningen i gummi med förstärkande fyllmedel är kraftigt icke-linjära funktioner, och de tillgängliga materialmodellerna i kommersiella programvaror och i litteraturen är ofta otillräckliga. Därför är en viskoplastisk materialmodell för finita deformationer framtagen i tidsdomänen och implementeras som ett användardefinierat material i Abaqus Explicit. Modellen fångar töjningsamplitud- och frekvensberoendet av lagrings- och förlustmodulen för ett kimröksfyllt naturgummi. Den är korrekt över ett brett intervall av skjuvtöjningsamplituder och frekvenser, 0.2-50% respektive 0.5-20 Hz, och kräver endast 5 materialparametrar. Dessutom fångar modeller responsen från bimodala excitationer. Implementeringen i Abaqus Explicit gör att komponentegenskaper kan utvärderas tidigt i utvecklingsfasen, med materialparametrar som härrör från enkla provkroppar. Den förbättrade noggrannheten i simuleringar av dessa komponenter kan hjälpa ingenjörer att utveckla mer optimerade lösningar snabbare än med konventionella metoder.

Place, publisher, year, edition, pages
Stockholm: US-AB, 2016. xii, 55 p.
Series
TRITA-AVE, ISSN 1651-7660 ; 2016:12
Keyword
reinforcing fillers, rubber, finite strain, viscoplastic, förstärkande fyllmedel, gummi, finita töjningar, viskoplastisk
National Category
Vehicle Engineering
Research subject
Vehicle and Maritime Engineering
Identifiers
urn:nbn:se:kth:diva-184879 (URN)978-91-7595-902-3 (ISBN)
Public defence
2016-04-29, D2, Lindstedtsvägen 5, 10044 Stockholm, KTH Campus, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

QC 20160406

Available from: 2016-04-06 Created: 2016-04-06 Last updated: 2016-04-06Bibliographically approved

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