Runflat tire and it‘s impact on BiAx Testing · 2020-03-15 · Said Allouch Application...

© Fraunhofer LBF

13th Users Conference on BiAxial Fatigue Testing

November 08th, 2017

Dipl. Ing. Said Allouch Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF www.lbf.fraunhofer.de

Runflat tire and it‘s impact on BiAx Testing

© Fraunhofer LBF

Relevance of tires

With regard to vehicle dynamics the tire is the basic load transfer element

The usage of the tire in the biax testing make this technology near to the reality

development in the field of tire technology do show a clear trend towards runflat

Runflat different build up different behavior regarding the durability

© Fraunhofer LBF

Possible impacts of Tires Test

External wheel loads on the

road

Internal wheel stresses on the road/LBF flat

track

Internal wheel stresses during

testing

© Fraunhofer LBF

Differences of physical characteristics Run Flat vs. Standard Tire – vertical stiffness –

The vertical stiffness of run flat tires is 33% higher than the stiffness of standard tires

The lower the vertical stiffness of a tire, the lower the occurring vertical loads

Jeschor, M.: Ein neues Verfahren zur Bewertung von Runflat-Reifen – ein

Beitrag auf dem Weg zum reserveradlosen PKW; Diss. TU Dresden, 2005

© Fraunhofer LBF

Differences of physical characteristics Run Flat vs. Standard Tire – lateral stiffness –

The lateral stiffness of run flat tires is higher than the lateral stiffness of standard tires which cause better handling properties

This difference has also an effect on the external loads and the transmission of the loads into the wheel

Jeschor, M.: Ein neues Verfahren zur Bewertung von Runflat-Reifen – ein

Beitrag auf dem Weg zum reserveradlosen PKW; Diss. TU Dresden, 2005

© Fraunhofer LBF

Chosen tires of the investigation

Tire size 225/45 R17

Wheel size 7.0 x 17

tire abbreviation

Bridgestone Turanza BT

Bridgestone Turanza MOE BT MOE

Bridgestone Turanza RFT BT RFT

Michelin Primacy 3 ZP MP

© Fraunhofer LBF

Impact on external loads Used test vehicle

Tire size 225/45 R17

Wheel size 7.0 x 17

7x17

RoaDynET = 66,4mm

Lochkreis : 5x112

Zentrierung: 57 mm

Radbolzen M14x1,5 mit 90° Kegel

Max. Länge ab Konus Beginn 53mm

Min. Länge ab Konus Beginn 40mm

Beste Länge ab Konus 45-50mm

Bereifung: 215/50 R17

Opel Astra J 103 kW

Static load = 500 kg

© Fraunhofer LBF

Impact on external loads Measurement tracks (Dudenhofen)

Durability

Cornering

Rough road

© Fraunhofer LBF

Impact on external loads Tire positions during RLDA

A

BT BT RFT

BT MOE

MP

B

BT

MP BT

RFT

C

MP BT

MOE

BT

RFT BT

D

BT

RFT MP

BT BT

MOE

4 different wheel positions were measured with the same tire and manoever

the wheels swaped places in clockwise rotation

Air pressure of all tires: 2,7 bar

Tire temperature: comparable on each measurement

Bolting torque (wheel bolt) : 120 Nm

BT

MOE

© Fraunhofer LBF

Impact on external loads Tire positions during RLDA

A

BT BT RFT

BT MOE

MP

B

BT

MP BT

RFT

C

MP BT

MOE

BT

RFT BT

BT

MOE

D

BT

RFT MP

BT BT

MOE

© Fraunhofer LBF

Impact on external loads Results (rough road)

-200%

-150%

-100%

-50%

0%

50%

100%

150%

BT BT MOE BT RFT MP

Fh

[k

N]

80%

85%

90%

95%

100%

105%

110%

115%

120%

125%

130%

BT BT MOE BT RFT MP

Fv

[k

N]

© Fraunhofer LBF

Impact on external loads Results (cornering)

80%

85%

90%

95%

100%

105%

110%

BT BT MOE BT RFT MP

Fh

[k

N]

80%

90%

100%

110%

120%

130%

140%

BT BT MOE BT RFT MPFv

[k

N]

© Fraunhofer LBF

Impact on external loads Results (lateral forces spectra comparison)

Range pair

Late

ral f

orc

e [

kN

]

© Fraunhofer LBF

Range pair

Impact on external loads Results (vertical forces spectra comparison)

Ve

rtic

al fo

rce

[kN

]

© Fraunhofer LBF

Impact of the runflat tire on the internal stresses LBF Flat track roll rig

Fv [kN] Fh [kN]

Static load 5,0 0

Straight driving incl. rough road 13,90 +/-3,50

Cornering 9,04 6,66

© Fraunhofer LBF

0

5

10

15

20

25

under static load straight driving cornering

Am

pli

tud

e [

MP

a]

inner rim flange

0

5

10

15

20

25


Am

pli

tud

e [

MP

a]

inner spoke transition to the rim

0

10

20

30

40

50


Am

pli

tud

e [

MP

a]

inner mid of spoke

Impact of the runflat tire on the internal stresses Results I

17%

14%

18%

13%

15% 10%

© Fraunhofer LBF

0

5

10

15

20

25

30

35

40

45


Am

pli

tud

e [

MP

a]

inner spoke transition to the bolting area

0

5

10

15

20

25

30

35

40

45

50


Am

pli

tud

e [

MP

a]

bolting area

0

5

10

15

20

25

30

35

40


Am

pli

tud

e [

MP

a]

outer rim flange

Impact of the runflat tire on the internal stresses Results II

15%

17%

7%

7%

21%

© Fraunhofer LBF

Load file: LBF standard

Tire inflation pressure: 4 MPa

Measurement of 1 loop -> extrapolation to 10,000 km

Impact of the runflat tire on the internal stresses LBF ZWARP machine

© Fraunhofer LBF

Impact of the runflat tire on the internal stresses RFS results

80%

85%

90%

95%

100%

105%

110%

inner rim flange inner spoketransition to the rim

inner mid of spoke inner spoketransition to the

bolting area

bolting area outer rim flange

no

rma

lize

d

RFS

v

alu

es

RFS values comparison

BT

BT MOE

BT RFT

MP

© Fraunhofer LBF

All parts of the process chain were investigated

External loads: Runflat tires have an impact on lateral and horizontal wheel loads -> RLDA needs to be performed with RFT

Internal stresses (LBF flat track roll rig): Runflat tires cause higher internal stresses by straight … -> ESA needs to be performed with RFT

Internal stresses (LBF ZWARP): Runflat tires cause small impact on local stresses -> Test is recommended to be performed with RFT

Different RFT were investigated, they performed different, a general impact was not given

Conclusions

© Fraunhofer LBF

Contact

Fraunhofer Institute for Structural Durability and System Reliability LBF

Group Validation Wheel Related Components

Bartningstrasse 47, 64289 Darmstadt, Germany

Telefon: +49 6151 705-0, Fax: +49 6151 705-214

www.lbf.fraunhofer.de, www.zwarp.de

Said Allouch

Application specialist passenger cars

[email protected],

Runflat tire and it‘s impact on BiAx Testing · 2020-03-15 · Said Allouch Application...

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