Torsional vibration absorbers in heavy-duty truck powertrains
Doktorsavhandling, 2020

The heavy-duty vehicle manufacturers face large challenges when it comes to reducing CO2 emissions from vehicles. The ongoing development of more efficient combustion engines leads to an increase in torsional vibrations. Experience within the industry indicates that the conventional single mass flywheel (SMF) and clutch will not be enough to protect the gearbox and rear driveline from engine induced vibrations in the future; more advanced technology will be needed.

The work presented in this thesis focuses on simulation and analysis of torsional vibration absorbers for heavy-duty truck applications. Different multiple-mass flywheels are analysed, including dual mass flywheels (DMFs), power split vibration absorbers (PSVAs) and DMFs combined with tuned vibration absorbers (TVAs). DMFs have been used in smaller vehicles for many years, but the use in heavy-duty commercial applications is to date very limited. The other two vibration absorbers studied in this work have not yet been industrialised.

The vibrations absorbers are analysed by means of simulations. Methodologies for efficient simulations in time- and frequency-domain have been developed and are presented in the thesis. The frequency-domain methods used include the harmonic response and a harmonic balance method, combined with an arc-length continuation scheme. For models with many gap-activated springs, a time-domain approach is proposed, where the dynamics problem is reformulated as a linear complementary problem (LCP).A detailed DMF model, including internal parts, friction and clearances, is presented for time-domain studies requiring high accuracy. The model is correlated based on test rig measurements.

The torsional vibrations in typical heavy-duty truck powertrains with the different multiple-mass flywheels are simulated in a large engine load and speed range. The results are analysed and compared to corresponding conventional powertrains. It is evaluated how different design parameters affect the torsional vibrations and the feasibility of the concepts for heavy-duty use is studied. The simulations show that the torsional vibration amplitudes are generally significantly lower with a DMF than with an SMF, but under some conditions significant resonance excitation can occur. The PSVA and DMF equipped with a TVA can reduce vibrations further than a corresponding DMF within limited speed ranges, but lead to higher vibration amplitudes outside these ranges.



torsional vibrations

dual mass flywheel



tuned vibration absorber

power split vibration absorber

heavy-duty truck






Opponent: Professor Gaëtan Kerschen, Department of Aerospace and Mechanical Engineering, University of Liège, Belgium


Lina Wramner

Chalmers, Mekanik och maritima vetenskaper, Dynamik

Wramner L., Sub-harmonic resonance excitation in heavy-duty truck powertrains with piecewise linear dual mass flywheels

Analysis of power split vibration absorber performance in heavy-duty truck powertrains

Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering,; Vol. 234(2020)p. 2509-2521

Artikel i vetenskaplig tidskrift

Dual-mass flywheels with tuned vibration absorbers for application in heavy-duty truck powertrains

Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering,; Vol. 234(2020)p. 2500-2508

Artikel i vetenskaplig tidskrift

Numerical Algorithms for Simulation of One-Dimensional Mechanical Systems With Clearance-Type Nonlinearities

Journal of Computational and Nonlinear Dynamics,; Vol. 14(2019)

Artikel i vetenskaplig tidskrift

Vibration dynamics in non-linear dual mass flywheels for heavy-duty trucks

Proceedings of ISMA2018 International Conference on Noise and Vibration Engineering,; (2018)p. 1935-1947

Paper i proceeding

Vibrations in vehicles lead to noise and wear. In extreme cases vibrations can also cause components to break. Vehicle manufacturers therefore spend a lot of resources trying to reduce vibrations. Combustion engines are a major source of vibration.  Currently, there is a high focus on improving the energy efficiency of combustion engines. With higher peak cylinder pressure and lower operating speeds, it is expected that the vibrations from the engines increase. Therefore, the vibration handling must also be improved.

In heavy-duty trucks, a flywheel and a clutch with a spring damper are installed between the engine and the gearbox. These components work as vibration absorbers and reduce the level of vibration, but with future engines it is expected that more advanced technology will be required.

This thesis explores different vibration absorbers that can be used to limit the level of vibrations transmitted to the gearbox in heavy-duty trucks. The work comprises development of simulation methodology as well as evaluations of the functionality and design requirements of the absorbers.

A dual mass flywheel is a well-known vibration absorber. It consists of two flywheels connected by springs. The springs can temporarily store energy when there is a peak in the load and then release the energy when the load is lower. The analyses presented in the thesis show that a significant overall reduction of vibrations can be obtained if the conventional flywheel in a heavy-duty truck is replaced by a dual mass flywheel. There are some operating conditions, though, at which relatively high vibrations can occur. These conditions are high-lighted in the thesis and the parameters affecting these vibrations are studied.

The power split vibration absorber and the dual mass flywheel with tuned vibration absorber are two novel concepts that both can provide additional vibration reduction for engine rotational speeds within a small interval. The work shows that a major design challenge with both these vibration absorbers is to obtain this high reduction speed interval at the usually critical low engine operating speeds. Moreover, vibrations at engine speeds outside this interval might reach unacceptable levels. Designs well adapted to heavy-duty applications would probably require a significantly larger installation space than what is needed for a dual mass flywheel.

Trade-offs between different requirements and the performance at different operating conditions are necessary. Nevertheless, the work presented shows that there is a potential for a significant overall reduction of vibrations into the gearbox with the vibration absorbers analysed. This can enable further improvements in combustion engine efficiency.

Minskade transmissionsvibrationer – minskad energiåtgång och miljöpåverkan ihop med ökad konkurrenskraft

Energimyndigheten (ScaniaCVAB), 2016-04-01 -- 2020-03-31.




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Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4747




Opponent: Professor Gaëtan Kerschen, Department of Aerospace and Mechanical Engineering, University of Liège, Belgium

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