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A Verified and Validated Model for Simulation-Driven Design of Heavy Duty Truck Synchronizers
KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.). Scania CV AB, Sweden.ORCID iD: 0000-0002-6644-7441
FS Dynamics, Stockholm, Sweden.
KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).ORCID iD: 0000-0002-2578-9453
2015 (English)In: ASME Proceedings | ASME 2015 Power Transmission and Gearing Conference, ASME Press, 2015, Vol. 10, V010T11A045Conference paper (Refereed)
Abstract [en]

The strong market trend toward lower fuel consumption for heavy road transports requires more frequent gear shifting and increased gear shift performance, i.e. shorter shift time. Increased shift performance means higher loads for the synchronizer which brings component and shifting process optimization more into focus.

Traditionally, synchronizer development has relied on physical testing of complete synchronizers in general gearbox test rigs or in specialized synchronization test rigs leaving much of the causes of the observed effects unclear. This paper presents a generalized FE-based thermomechanical simulation model to be used for model-based synchronizer analysis and design. The model is targeted for studies of how different external loads and the values of different synchronizer design parameters affect the temperature transient in the friction lining. Recommendations of how major modeling complications should be treated are presented. The developed simulation model is verified and validated with a combination of analytical means and transient temperature measurements of bulk and surface temperatures. The applicability of the presented model, as well as its limitations, are discussed and exemplified with different design cases.

Place, publisher, year, edition, pages
ASME Press, 2015. Vol. 10, V010T11A045
Keyword [en]
Atmospheric temperature, Gears, Optimization, Reliability analysis, Stress analysis, Synchronization, Temperature measurement
National Category
Vehicle Engineering
URN: urn:nbn:se:kth:diva-182350DOI: 10.1115/DETC2015-47318ISI: 000380413500045ScopusID: 2-s2.0-84979008641ISBN: 978-0-7918-5720-5OAI: diva2:904228
ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE 2015, Boston, United States, 2 August 2015 through 5 August 2015

QC 20160218

Available from: 2016-02-18 Created: 2016-02-18 Last updated: 2016-09-07Bibliographically approved
In thesis
1. On synchronization of heavy truck transmissions
Open this publication in new window or tab >>On synchronization of heavy truck transmissions
2016 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Gear shifts are becoming more and more important as engines are adapted to low speed high torque working conditions. Synchronizers are key components for successful gear shifts. To adapt the synchronizers to new working conditions due to adaptations to new engines, improved development tools are needed. The presented thesis describes the development of two types of numerical models for the synchronization process, namely fluid-structure interaction to simulate the pre-synchronization phase and thermomechanical FE models to simulate the main synchronization phase. A methodology for developing friction models based on a combination of physical testing and numerical simulations is presented. Additionally, a comprehensive gear shift and synchronizer frame of reference section is presented.

In paper A, two numerical fluid-structure interaction simulation models for assessing the pre-synchronization phase are presented. Simulations show that the synchronizer functionality is highly dependent on the gear shift maneuvering system, and that grooves in the synchronizer surface have a positive effect on the oil evacuation during the pre-synchronization phase.

Paper B describes the development of a numerical thermomechanical model for simulating the main synchronization phase. Two parameter studies were performed, one based on external loads and one based on synchronizer geometry. The effect on the temperature increase from differences in thermal properties between molybdenum and carbon friction linings are presented.

In paper C, a verification and validation methodology for highly transient thermomechanical processes was presented. Numerical verification, bulk temperature measurement, surface temperature measurement and qualitative visual inspection were combined to verify and validate the simulation model presented in paper B.

In paper D, a methodology combining physical testing with an thermomechanical simulation model to develop a friction model was exemplified by a molybdenum coated synchronizer. A simplified thermal model was developed to remove the dependence of full finite element thermal models. The friction models shows good agreement with measured data.

Abstract [sv]

Betydelsen av växlingar i en växellåda har ökat, och synkroniseringsenheter är viktiga komponenter för snabba och robusta växlingar. För att anpassa synkroniseringsenheterna till nya arbetsförhållanden och laster krävs nya utvecklingsverktyg. Denna avhandling innehåller två typer av numeriska modeller för att simulera synkroniseringsförloppet. Multifysikmodeller som kopplar samman oljeflöde och solida kroppar används för att simulera försynkroniseringsfasen. En termomekanisk modell används för att simulera synkroniseringsfasen. En metod för att utveckla friktionsmodeller under synkroniseringsfasen genom att kombinera fysisk provning med numerisk simulering presenteras. Dessutom finns ett utförligt kapitel om synkroniserings- och växlingsteori.

I artikel A presenteras två olika "Fluid-Structure interaction" ("Interaktion mellan vätskeflöde och solida kroppar") för att simulera försynkroniseringsfasen. Simuleringarna visar att synkroniseringsenheter är väldigt beroende av de aktuatorer de är kopplade till, samt att oljedräneringsspår i kontaktytan har en positiv effekt för försynkroniseringsförloppet.

Artikel B beskriver utvecklingen av en termomekanisk modell för att simulera synkroniseringsförloppet. Två parameterstudier utfördes, en där de externa lasterna utvärderas, och en där geometrin på synkroniseringsenheten utvärderas. Effekten av skillnaden i termiska egenskaper hos molybden och kolfiber utvärderas också.

Artikel C beskriver metodik för verifiering och validering av termomekaniska simuleringar av starkt transienta förlopp. En kombination av numerisk verifiering, temperaturmätning i materialet, yttemperaturmätning samt kvalitativ visuell bedömning används för att verifiera och validera simuleringsmodellen som utvecklades i artikel B.

I artikel D beskrivs en metodik för att kombinera fysiska prover med en uppdaterad termomekanisk simuleringsmodell för att beskriva friktionsbeteendet under synkronisering. Metoden exemplifieras med en molybdenbelagd synkroniseringsenhet. En förenklad termisk modell utvecklas för att kunna beskriva friktionsbeteendet utan att använda tidskrävande finita elementmodeller. Den nya friktionsmodellen överensstämmer väl med uppmätt data.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2016. ix, 38 p.
TRITA-MMK, ISSN 1400-1179 ; 2016:02
synchronization, synchronizers, gear shift, gearbox, synkronisering, växling, växellåda
National Category
Other Mechanical Engineering
Research subject
Machine Design
urn:nbn:se:kth:diva-181108 (URN)978-91-7595-851-4 (ISBN)
2016-03-08, Sal Gladan, Brinellvägen 85, KTH, Stockholm, 10:00 (English)

QC 20160218

Available from: 2016-02-18 Created: 2016-01-29 Last updated: 2016-02-18Bibliographically approved

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Häggström, DanielSellgren, UlfBjörklund, Stefan
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