드라이브라인 댐퍼 1D 모델링

반용운 부장(타타대우) / 김석산(Altair)

Driveline Damper 1D Modeling

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Agenda

• Why MBD(Model Based Development)

• Torsional Damper System : Dry Clutch

• Modeling

• Vibration analysis

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Why MBD(Model Based Development)

Commercial Vehicle Driveline Configurations

• There are several kinds of configurations

• Driveline parts should be studied about NVH performance

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Commercial Vehicle Driveline and Damper

• Damper system(clutch) is important starting point to design driveline NVH performance

• NVH performance should be studied for time domain but this analysis is a time consuming process if we use CAD based 3D analysis

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Commercial Vehicle Driveline and Damper

• Clutch is made up of serval parts

• The manufacturing process analysis is hard process

• Compression, release, non-linear property, pretension and etc.

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Model Based Development

• Before detail 3D design

• Use specification and analyze system performance

• After 3D design and test

• Make model based model by using the part’s test results

• Build system model and then do the problem analysis or find improved design

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Activate : System analysis

• Activate is good to study the model based model for time domain NVH system analysis

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Activate : Signal-based Library

• Signal-based Library

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Activate : Physical-component library

• Physical-component library

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Torsional Damper System : Dry Clutch

Clutch system assembly

• Torsional damper : Dry clutch system

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• Role of the clutch system

• Transfer the engine torque to the driveline

• Damper system for torsional vibration

• Reduce engine torque/acceleration oscillation

• Torsional stiffness and slip

• It has an effect for the driveline NVH

• jerk, clonk, judder and etc.

• Make smooth gear shift

Fly wheelClutch discClutch cover

Diaphragm spring

How it works

• How the clutch system work

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[Normal force]

[Tangential : Friction torque]

• Normal force

• Friction material

• Geometry design

Clutch clamp load

• Diaphragm spring has dominant role for the clamp load

• It control the clutch disc slip for gear shift

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Torsional stiffness and hysteresis

• Hub is connected to the transmission input shaft.

• Damper springs work as the parallel connection.

• Hysteresis effect appears.

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Modeling

Clutch system design parameters

• Pre damper range

• Working range : -2° ~ +6°

• Torsional stiffness : 0.07 kgf m/deg

• Hysteresis torque : 0.425 kgf

• Main damper range

• Working range : -2° ~ -9° , +6° ~ +14°

• Torsional stiffness : 8.84 kgf m/deg

• Hysteresis torque : 8.5 kgf

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Spring system modeling

• Displacement control : Actuating angle

• Angle control through the working range

• Driving angle range : -14° ~ +14°

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Spring system modeling

• Pre damper torsional stiffness modeling

• Rigid spring and a inertia are added at the front of pre damper spring.

• 0.07 kgf m/deg = 39.5 Nm/rad

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Spring system modeling

• Main damper torsional stiffness modeling

• Rigid spring and a inertia are added at the front of pre damper spring.

• 8.84 kgf m/deg = 4969 Nm/rad

• Backlash rangle : -2° ~ 6°

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Spring system modeling

• Two stage torsional stiffness modeling

• It is a parallel connection condition

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Pre damper

Main damper

Friction and hysteresis modeling

• Friction material and clutch model

• Frictional torque = cgeo * µ * Normal force

• cgeo : geometry information

• µ : friction coefficient

• Frictional torque = Maximum transfer torque = Clutch capacity

• Frictional torque = 1*1*83.4 = 83.4 [Nm]

• Input torque : 100 [Nm]

• Clutch torque capacity 83.4 [Nm] is work through the clutch, but other torque are dissipated with slip.

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Friction and hysteresis modeling

• Clutch Hysteresis

• There are no torque connection between the Spring-damper backlash range

• 0 value is transferred to the clutch (zero normal force), so there are no torque transferring,

• Pre damper

• No backlash, hysteresis torque = 0.425 kgf m

• Main damper

• Backlash is included, hysteresis torque = 8.5 kgf m

[Pre damper 모델] [Main damper 모델]

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Clutch system model

• Activate clutch model is validated.

• It has a same result as the given design spec.

• Unsymmetrical backlash

• Two stage spring stiffness

• Two stage hysteresis torque

• Modeling explanations are added for each part modeling.

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FFT analysis model

• Use buffer to FFT analyze

• The result is single side spectrum

Input signal

Buffer for FFT

FFT analysis and single side spectrum

Single side frequency

FFT result

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FFT analysis model

• Input signal

• y= a0 + a1*cos(2*pi*f1 + phase1) + a2*cos(2*pi/*f2 + phase2)

• a0=2, a1=3, f1=30, a2=1.5, f2=75

• at zero frequency, it is twice so divide by wo

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Vibration analysis

Driveline NVH source

• Engine torque oscillation is a torsional vibration source

• Main actuating frequency is depend on

• Engine cylinder number

• Rotating rpm

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Simple driveline system model

• Enforce condition : 6 cylinder, 700 rpm

• Enforcing frequency : 35 Hz

• Mean = 0 Nm

• Amplitude = 200 Nm

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[Torque source]

Analysis results and improvement

• Initial condition• Rotary acc. amplitude after clutch : 1030 [rad/s2]

• Modified condition• Change second inertia : 0.005 kg∙m2 => 0.01 kg ∙ m2

• Rotary acc. amplitude after clutch : 532 [rad/s2]

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Thank you