Embed Size (px)
Citation preview
© Fraunhofer LBF
NUMERICAL SIMULATION OF THE BIAXIAL WHEEL TEST
ZWARP Users Conference 2017 08.11.2017 Riccardo Möller Fraunhofer LBF, Darmstadt
© Fraunhofer LBF
Seite 2 Seite 2
CONTACT
Dipl.-Ing. Riccardo Möller
Group manager Numerical System Analysis
Department Assemblies and Systems Division Structural Durability Fraunhofer Institute for Structural Durability and System Reliability LBF Bartningstr. 47, 64289 Darmstadt Phone: +49 6151 705-408 Mobil: +49 172-6935445 [email protected]
www.lbf.fraunhofer.de
© Fraunhofer LBF
Seite 3 Seite 3
CONTENT
Introduction
Multibody simulation model (MBS model)
Simulation process
Results
Conclusions
Summary
© Fraunhofer LBF
Seite 4 Seite 4
Introduction
Multibody simulation model (MBS model)
Simulation process
Results
Conclusions
Summary
CONTENT
© Fraunhofer LBF
Seite 5 Seite 5
INTRODUCTION
Situation:
Physical tests on biaxial wheel test bench
Experiences in numerical simulation for various test bench application cases
Motivation: Improvements of the ZWARP
Accumulation of experiences
Identification of parameters which influence the results
Tasks:
Numerical model of LBF ZWARP
Including capable tire simulation model
Validation physical test vs. numerical test
© Fraunhofer LBF
Seite 6 Seite 6
Introduction
Multibody simulation model (MBS model)
Simulation process
Results
Conclusions
Summary
CONTENT
© Fraunhofer LBF
Seite 7 Seite 7
MBS MODEL OVERVIEW
Multibody simulation tool: MSC.ADAMS
Rigid parts, kinematic joints
Link for loading wheel assembly modelled with different level of detail
Rotating drum
Wheel assembly
Dampers (longitudinal and lateral)
Actuators (vertical and lateral, drum rotational movement)
Source of data:
CAD, measurements
© Fraunhofer LBF
Seite 8 Seite 8
MBS MODEL KINEMATIC LINK
CAD Rigid
CAD/Beam Modal structure
CAD/FEA Modal structure
Kinematic link level of detail
Rigid formulation CAD
Flexible formulation
CAD Beam modal structure
CAD FEA modal structure
Flexible formulation:
Additional results: strain on link
Approximation of inertia/stiffness
Modelling effort
© Fraunhofer LBF
Seite 9 Seite 9
MBS MODEL EXCITATION CONCEPT
Wheel assembly
Drum: revolution speed
Vertical / Lateral actuation: force / motion (input)
© Fraunhofer LBF
Seite 10 Seite 10
MBS MODEL EXCITATION CONCEPT
Drum Vertical Lateral
Wheel assembly
Drum: revolution speed
Vertical / Lateral actuation: force / motion (input)
© Fraunhofer LBF
Seite 11 Seite 11
MBS MODEL EXCITATION CONCEPT
Drum Vertical Lateral
Wheel assembly
Drum: revolution speed
Vertical / Lateral actuation: force / motion (input)
© Fraunhofer LBF
Seite 12 Seite 12
MBS MODEL EXCITATION CONCEPT
Drum Vertical Lateral
Wheel assembly
Drum: revolution speed
Vertical / Lateral actuation: force / motion (input)
© Fraunhofer LBF
Seite 13 Seite 13
MBS MODEL SENSOR APPLICATION FOR VALIDATION
© Fraunhofer LBF
Seite 14 Seite 14
MBS MODEL TIRE MODEL | INTERFACE TO MBS TOOL GENERAL
Rim
Tire
Road
Force Torque
Kinematical Rigid Body State
Force Torque
Kinematical Rigid Body State
Mechanical interface
MBD solver supplies Rim (Road) kinematical state
Position
Orientation
Velocity
Angular velocity
MBD solver expects accumulated force and torque acting on rim center
Tire DOFs are hidden from MBD solver
Only accumulated entities are returned in standardized (STI) interface
Source: Fraunhofer ITWM
© Fraunhofer LBF
Seite 15 Seite 15
MBS MODEL TIRE MODEL | STRUCTURAL MBD TIRE MODELS
Typ
ical
nu
mb
er
of
sim
ula
tio
ns Ty
pica
l com
pu
tatio
nal e
ffort
100
101
102
103 100
101
102
103
104
105
DOFs
Empirical
Frequency-based
Rigid ring
Emperical contact
Flexible belt
Brush-type contact
FEA
Handling
NVH
Active safety
Ride/Comfort
Durability
Crash
REPs
CDTire/
Realtime
CDTire/3D
CDTire
CDTire/MF++
CDTire/NVH
CDTire/Thermal
Source: Fraunhofer ITWM
© Fraunhofer LBF
Seite 16 Seite 16
MBS MODEL TIRE MODEL | CDTIRE
Complete 3 D shell based model
FD shell discretization
Materialized belt + materialized sidewall
Functional layer modeling (accessible in pre-processing)
Brush type contact
Inflation pressure
Acts as a normal force to inner shell
Can change during simulation
Belt/Sidewall/Rim Contact
Belt Sidewall
Rim Source: Fraunhofer ITWM
© Fraunhofer LBF
Seite 17 Seite 17
MBS MODEL TIRE MODEL | CDTIRE/3D
Functional layer modeling
Tread (brush type)
Cap ply
Belt 1
Belt 2
Carcass
Inner liner + matrix
Anisotropic material
Orthotropic layers
Kirchhoff-Love bending
Discrete cords
Condensed into one shell
In pre-processing
Using a 3-dimensional meta-model
2
1
9
3
8
9
8
1
2
3
Source: Fraunhofer ITWM
© Fraunhofer LBF
Seite 18 Seite 18
MBS MODEL TIRE MODEL | ADVANTAGES
Complete materialized model of sidewall and belt
Physical modelling of all functional layers of a modern tire
Separation of geometry and material properties
Physical correct inflation pressure dependency no pressure dependency in parameters
Possibility to adapt wheel and tire configurations (rim width, tire size,…) without re-parameterization
Wider application range
Constructional approach for parameter identification
Source: Fraunhofer ITWM
© Fraunhofer LBF
Seite 19 Seite 19
MBS MODEL TIRE/RIM MODEL
Typical model approach
Fx,Mx
Fz,Mz
Rim rigid body
Contact forces between tire and rim are summed
Resulting forces and torques are applied directly in the wheel center sufficient to represent to loading of the tire/rim assembly to the hub but no information about loading of rim itself
Additional required information (non-standard)
Each tire/rim contact force/torque: function of time sufficient to define the loading of the rim
Assumption: local deflection of the rim does not influence the dynamic loading
Fy,My
Picture of tire: Fraunhofer ITWM
© Fraunhofer LBF
Seite 20 Seite 20
Introduction
Multibody simulation model (MBS model)
Simulation process
Results
Conclusions
Summary
CONTENT
© Fraunhofer LBF
Seite 21 Seite 21
SIMULATION PROCESS STEP 1: MBS-SIMULATION
Frame Tire
CDTire
Excitation
measurement
comparison in validation phase
simulation
x y
z
Fxi (t), Fyi (t), Fzi (t), Mxi (t), Myi (t), Mzi (t)
i tire-rim contact nodes
Input for Step 2
CDTire
© Fraunhofer LBF
Seite 22 Seite 22
SIMULATION PROCESS STEP 2: SIMULATION OF STRAIN ON THE WHEEL
CAD
FEA | Contact nodes including load distribution to surrounding mesh
Fxi (t), Fyi (t), Fzi (t), Mxi (t), Myi (t), Mzi (t)
i tire-rim contact nodes
FEA Input File Generator Matlab-Script
Output from Step 1
ABAQUS
- FEA solver input deck
- Time-depending quasi-static loads
Post-processing local strain
© Fraunhofer LBF
Seite 23 Seite 23
Introduction
Multibody simulation model (MBS model)
Simulation process
Results
Conclusions
Summary
CONTENT
© Fraunhofer LBF
Seite 24 Seite 24
RESULTS VALIDATION LOAD CASES
Excitation signal:
Drum speed:
Synthetic signals: 10, 20 and 93 km/h
Eurocycle: 93 km/h
Actuator forces
Synthetic test cycle
Pure vertical load
Vertical and horizontal load
Measured forces from physical test low pass filtered and applied to numerical model
© Fraunhofer LBF
Seite 25 Seite 25
RESULTS ZWARP
Good correlation between test and simulation (FEA)
Differences, if high and lateral load add each other
Different load offsets on different load levels between BEAM and FEA simulation
Strain on spindle:
© Fraunhofer LBF
Seite 26 Seite 26
RESULTS ZWARP
Strain on link:
Results for strain gauge 04 on kinematic link
Good correlation between test and simulation
Differences increases with increasing vertical load
© Fraunhofer LBF
Seite 27 Seite 27
RESULTS WHEEL
Strain on Wheel – Strain Gauge 09
Strain on Wheel – Strain Gauge 10
Several strain gauges are applied on the rim
Signal characteristic and range for all strain gauges pretty good
Amplitudes for some strain gauges fits well (e.g. 09)
Results not yet sufficient for all strain gauges (e.g. 10)
Possible reason might be transfer of position/ orientation in regions with high strain gradient from physical test to FEA-mesh
© Fraunhofer LBF
Seite 28 Seite 28
Introduction
Multibody simulation model (MBS model)
Simulation process
Results
Conclusions
Summary
CONTENT
© Fraunhofer LBF
Seite 29 Seite 29
CONCLUSIONS
Advantages of a simulation model
Change of parameters
Generation of additional results
Possible application cases at Fraunhofer LBF?
Improvement of test benches: Identification of the influence of
drum (inner/outer)
wheel dimensions in relation to diameter of drum
boundary conditions (wheel, wheel-hub-assembly)
General understanding of our test benches ( numerical models)
Test parameter (initial estimation of CV / CH , camber angle)
Improvement of load profiles
© Fraunhofer LBF
Seite 30 Seite 30
Introduction
Multibody simulation model (MBS model)
Simulation process
Results
Conclusions
Summary
CONTENT
© Fraunhofer LBF
Seite 31 Seite 31
SUMMARY
MBS model of biaxial test bench created
Complex tire model CDTire (Fraunhofer ITWM) included
Process to estimate local strains on the rim in combination with tire simulation model established
First validation of model using simplified load cases performed
Simulation model will support the development of biaxial test benches and may be used to generate additional information
© Fraunhofer LBF
Seite 32 Seite 32
Thank you for your attention!
