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ROBUST PROJECT Department of Aerospace engineering* - Politecnico di Milano WP5 - Computational Mechanics - B5 – Round Robin Concrete barrier MAIN REPORT Volume 1 of 1

(*)via La Masa, 34 Milan-ITALY tel: +39 02 23998316 - fax: +39 02 23998334 Oct 2005 Doc. No.: ROBUST-05-012 - Rev. 0

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Department of Aerospace engineering - Politecnico di Milano Doc. No.: ROBUST-05-012 - Rev. 0 WP5 - Computational Mechanics - B5 – Round Robin Concrete barrier

MAIN REPORT MAIN REPORT

Report title:

WP5 - Computational Mechanics - B5 – Round Robin Concrete barrier Doc. No.: ROBUST-05-012 - Rev. 0 Reporter(s):

Mario Mongiardini Abstract: The Robust Project aims to improve scientific and technical knowledge on the main issues still open in the new European standards on road restraint system EN 1317 [1-2]. The knowledge acquired will form the basis of updated standards for EN1317 and lead to more advanced road restraint systems and improve road-users safety. This report is part of the deliverables from Work Package 5 (WP5) - Computational Mechanics. KEYWORDS: Road restraint system, crash testing, Finite Element simulation

Rev. Date Prepared by Checked by Approved by Others

0 11/10/2005 Mario Mongiardini

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MAIN REPORT CONTENTS

ROBUST PROJECT........................................................i

1 INTRODUCTION ..........................................................1

2 SUMMARY AND CONCLUSIONS...............................2 Summary ...........................................................................................................................................2 2.1 Conclusions..........................................................................................................................3

3 SIMULATIONS RESULTS: CASE 1 ............................4 3.1 General ................................................................................................................................4 3.2 Additional data .....................................................................................................................4 3.3 Input data .............................................................................................................................4

3.3.1 Test items ............................................................................................................. 4 3.3.2 Test procedure...................................................................................................... 5 3.3.3 Barrier model ........................................................................................................ 5 3.3.4 Vehicle model ....................................................................................................... 6 3.3.5 Analysis data ........................................................................................................ 7

3.4 Analysis results ....................................................................................................................7 3.4.1 Barrier ................................................................................................................... 7 3.4.2 Vehicle .................................................................................................................. 7 3.4.3 General description of vehicle trajectory .............................................................. 8 3.4.4 Assessment of the impact severity ....................................................................... 8 3.4.5 Impact sequences and vehicle damage ............................................................... 9

4 SIMULATIONS RESULTS: CASE 2 ..........................17 4.1 General ..............................................................................................................................17 4.2 Additional data ...................................................................................................................17 4.3 Input data ...........................................................................................................................17

4.3.1 Test items ........................................................................................................... 17 4.3.2 Test procedure.................................................................................................... 17 4.3.3 Barrier model ...................................................................................................... 18 4.3.4 Vehicle model ..................................................................................................... 18 4.3.5 Analysis data ...................................................................................................... 19

4.4 Analysis results ..................................................................................................................19 4.4.1 Barrier ................................................................................................................. 19 4.4.2 Vehicle ................................................................................................................ 20

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MAIN REPORT

4.4.3 General description of vehicle trajectory ............................................................ 20 4.4.4 General description of dummy behaviour........................................................... 20 4.4.5 Assessment of the impact severity ..................................................................... 21 4.4.6 Impact sequences and vehicle damage ............................................................. 22 4.4.7 Dummy behaviour (impact sequences) .............................................................. 29

REFERENCES.................................................................32

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Department of Aerospace engineering Politecnico di Milano Doc. No.: ROBUST-05-012 - Rev. 0 WP5 - Computational Mechanics - B5 – Round Robin Concrete barrier

MAIN REPORT 1 INTRODUCTION The Robust Project aims to improve scientific and technical knowledge on the main issues still open in the new European standards on road restraint system EN 1317 [1-2]. The knowledge acquired will form the basis of updated standards for EN1317 and lead to more advanced road restraint systems and improve road-users safety. This report is part of the deliverables from Work Package 5 - Computational Mechanics. The objective of WP5 is:

• Evaluation and enhancement of the use of computational mechanics to complement experimental activity

• Criteria and procedures for the validation of computational mechanics results through comparison with test results

• Reconstruction of real life accidents • Identification of the activity needed for further enhancement of the use of

computational mechanics. This report documents the simulation performed on the RoundRobin barrier.



MAIN REPORT 2 SUMMARY AND CONCLUSIONS

Summary The simulations were run using the Non-Linear Finite Element code LS-Dyna [3-4]. The following simulations were performed for the RoundRobin barrier (see Table 3.1):

Barrier Vehicle Test ChapterMain

characteristics Name id. Main Characteristics Name id.

Case 1: • Barrier bottom & endings fixed to the ground • Car-barrier friction imposed.

RuondRobin.dyn Geo-Metro (Ver.2): • Small car (900 kg) • FE model with spinning wheels • Road-tyre friction =0.8

GM_R2.dyn TB11 3

Case 2: • Barrier bottom & endings fixed to the ground • Car-barrier friction imposed.

RuondRobin.dyn Geo-Metro (Ver.4): • Small car (900 kg) • FE model with spinning wheels • Improved FE model (Steering system & Suspensions) • Road-tyre friction =0.6

GM_R4.dyn TB11 4



MAIN REPORT The main results are summarised in Table 2.1 below. Case ASI

[-] THIV

[km/h] PHD [g]

Workingwidth [mm]

Exit speed[km/h]

Exit angle[deg]

Trajectory Detailed description

1 1.86 31.7 17 0 0 2.5 Pretty good Chapter 3 2 1.78 26.6 17.2 0 0 0 Good Chapter 4

Table 2.1 Results from simulation of RoundRobin barrier

2.1 Conclusions NA



MAIN REPORT 3 SIMULATIONS RESULTS: CASE 1

3.1 General This chapter gives a brief description of the results obtained from the simulation of a TB11 test (small car of 900 kg) hitting the RoundRobin barrier, with an initial velocity of 100 km/h and an angle of 20 degrees. The RoundRobin barrier is a rigid barrier made of concrete. The simulation reported in this chapter is characterized by the following:

• The barrier is rigidly fixed to the ground. • The barrier is modelled using an elastic material. • Friction between barrier and vehicle was imposed • Friction between road and tires is 0.8 (road pavement modelled using a rigidwall).

3.2 Additional data The Severity Indexes evaluated in this chapter have been obtained from the following data and files:

• Rawdata files: Rawdata_C1.zip • Excel worksheet file: Accelerations&YawRate_C1.xls • TRAP files: Trap-files_C1.zip

The following animations of the simulation are available:

• front view: Front_view_C1.avi • rear view: Rear_view_C1.avi • side view. Side_view_C1.avi • top view: Top_view_C1.avi • perspective: Perspective_view_C1.avi

3.3 Input data

3.3.1 Test items Barrier RoundRobin Vehicle GeoMetro (version GM_R2)Drawings See Table 3.1



MAIN REPORT

RoundRobin barrier

800

mm

15000 mm

400

mm

Table 3.1

3.3.2 Test procedure Test type: TB11 TB11 test Impact speed : 100 km/h Impact angle: 20 degrees Impact point: ≈ 4.5 meters from the beginning of the barrier Spinning wheels: Yes Inertial vehicle test mass: 860 kg

3.3.3 Barrier model Barrier type: RoundRobin (concrete barrier) Total length: ≈ 15 m (see the plot of the barrier model in Table 3.2) Element type: Solid elements with an external cover of shell elements (for

contact accuracy) Foundation: Lower solid elements of the barrier fixed End anchoring: Barrier ending elements fixed Soil (type and formulation):

NA

Roadway: Modelled as a rigidwall Plot of FE-model: See Table 3.2 Material data: See Table 3.3



MAIN REPORT

RoundRobin barrier FE model:

• The barrier is fixed at the ground level N° of nodes: 8154 N° of elements: 7200

Table 3.2

Parts Density

[kg/m^3] Elastic module [Mpa]

Poisson’s ratio

Yield stress [Mpa]

Ultimate stress [Mpa]

Failure strain

ALL 1400 15000 0.2 NA NA NA Table 3.3

3.3.4 Vehicle model GeoMetro (version GM_R2). This Finite Element vehicle model (Figure 1) is characterized by spinning wheels and front & rear suspensions. The steering system has not been modelled. For documentation see Ref. 5-6.

Z

Y

X



MAIN REPORT

Figure 1

3.3.5 Analysis data Timestep: Max: 1.18 E-6

min: 1.25 E-6 Mass scaling option NO Code version / Precision: Ls–Dyna 960 /

Single static coefficient 0.1 Friction barrier/vehicle: dynamic coefficient 0.05 static coefficient 0.8 Friction wheel/ground: dynamic coefficient NA

Friction other: NA Respect to the CoG (see Figure 1):

Longitudinal 111 mm Lateral 32 mm

Accelerometer location (mounting block):

Vertical 138 mm Sampling rate: 100 kHz

3.4 Analysis results

3.4.1 Barrier Maximum global dynamic deflection: 0 mm Working width: 0 mm Maximum global permanent deflection: 0 mm Length of contact: ≈ 2.9 m Major parts fractured or detached: No Description of damage to test items: NA Ground anchorages meets design levels: NA Plots of test item: See below (Table 3.4-3.7)

3.4.2 Vehicle Exit speed: 81 km/h Exit angle: 2.5 degrees Rebound distance: NA Vehicle breaches barrier: No Vehicle passes over the barrier: No Vehicle within CEN .box.: Yes Vehicle rolls over after impact: No



MAIN REPORT Damage to test vehicle: See below (Table 3.9)

3.4.3 General description of vehicle trajectory The vehicle hits the barrier with an initial angle of 20° and exits with an angle of about 1.5 degrees. The vehicle does not pass over the barrier and does not roll-over. Hence the trajectory can be considered good. The initial speed is 102.5 km/h, while the exit speed is 78 km/h. Vehicle damage TAD: NA Vehicle damage VDI: NA Vehicle cockpit def. index VCDI: NA Major parts of vehicle detached: No Plots of the vehicle: See below (Table 3.9)

3.4.4 Assessment of the impact severity Post-processing procedure: Data from nodout database (node 700002) pre-filtered with a SAE60 filter and subsequently post-processed in TRAP with a second SAE180 filter. Acceleration severity index (ASI): 1.86 Acceleration graphs: NA THIV: 31.7 km/h Time of flight: NA Post-impact head deceleration (PHD): 17 g’s Flail space: 300 mm in y-direction



MAIN REPORT

3.4.5 Impact sequences and vehicle damage

Front view t=0 sec t=0.08 sec

t=0.16 sec t=0.24 sec

t=0.32 sec t=0.40 sec



MAIN REPORT

Table 3.4

Rear view t=0 sec t=0.08 sec

t=0.16 sec t=0.24 sec

t=0.32 sec t=0.40 sec



MAIN REPORT

Table 3.5



MAIN REPORT

Top view t=0 sec t=0.08 sec

t=0.16 sec t=0.24 sec

t=0.32 sec t=0.40 sec



MAIN REPORT

Table 3.6



MAIN REPORT

Side view t=0 sec t=0.08 sec

t=0.16 sec t=0.24 sec

t=0.32 sec t=0.40 sec

Table 3.7



MAIN REPORT

Isometric view t=0 sec t=0.08 sec

t=0.16 sec t=0.24 sec

t=0.32 sec t=0.40 sec

Table 3.8



MAIN REPORT

Vehicle damage Top Bottom

Right Left

Right Iso Left Iso

Table 3.9



MAIN REPORT 4 SIMULATIONS RESULTS: CASE 2

4.1 General This chapter gives a brief description of the results obtained from the simulation of a TB11 test (small car of 900 kg) hitting the RoundRobin barrier, with an initial velocity of 100 km/h and an angle of 20 degrees. The RoundRobin barrier is a rigid barrier made of concrete. The simulation reported in this chapter is characterized by the following:

• The barrier is rigidly fixed to the ground. • The barrier is modelled using an elastic material. • Friction between barrier and vehicle was imposed. • Friction between road and tires is 0.6 (road pavement modelled using a rigidwall).

4.2 Additional data The Severity Indexes evaluated in this chapter have been obtained from the following data and files:

• Rawdata files: Rawdata_C2.zip • Excel worksheet file: Accelerations&YawRate_C2.xls • TRAP files: Trap-files_C2.zip

The following animations of the simulation are available:

• front view: Front_view_C2.avi • rear view: Rear_view_C2.avi • side view. Side_view_C1.avi • top view: Top_view_C2.avi • perspective: Perspective_view_C2.avi

4.3 Input data

4.3.1 Test items Barrier RoundRobin Vehicle GeoMetro (version GM_R4)Drawings See Table 3.1

4.3.2 Test procedure Test type: TB11



MAIN REPORT TB11 test Impact speed : 100 km/h Impact angle: 20 degrees Impact point: ≈ 4.5 meters from the beginning of the barrier Spinning wheels: Yes Inertial vehicle test mass: 928 kg

4.3.3 Barrier model Same as case C1: Barrier type: RoundRobin (concrete barrier) Total length: ≈ 15 m (see the plot of the barrier model in Table 3.2) Element type: Solid elements and with an external cover of shell elements

(for contact accuracy) Foundation: Lower solid elements of the barrier fixed End anchoring: Barrier ending elements fixed Soil (type and formulation):

NA

Roadway: Modelled as a rigidwall Plot of FE-model: See Table 3.2 Material data: See Table 3.3

4.3.4 Vehicle model GeoMetro (version GM_R4). The GeoMetro version 4 is basically the same as the version 3 with the addition of a rigid dummy and front passenger seats. For the characteristics of the GeoMetro version 3, see paragraph 3.3.4 The dummy used is the rigid GEBOD (Figure 2) made by ellipsoids, which is internally generated by the Ls-Dyna solver (*COMPONENT_GEBOD_MALE). It is a 35th percentile male dummy. The dummy is placed on the driver seat and is constrained by a seatbelt.



MAIN REPORT

Figure 2

4.3.5 Analysis data Timestep: Max: 0.9 E-7

min: 1.63 E-8 Mass scaling option NO Code version / Precision: Ls–Dyna 970 /

Single static coefficient 0.1 Friction barrier/vehicle: dynamic coefficient 0.05 static coefficient 0.6 Friction wheel/ground: dynamic coefficient NA

Friction other: NA Respect to the CoG (see Figure 1):

Longitudinal 111 mm Lateral 32 mm

Accelerometer location (mounting block):

Vertical 138 mm Sampling rate: 100 kHz

4.4 Analysis results

4.4.1 Barrier Maximum global dynamic deflection: 0 mm Working width: 0 mm



MAIN REPORT Maximum global permanent deflection: 0 mm Length of contact: (See paragraph 4.4.3)

> 6m

Major parts fractured or detached: No Description of damage to test items: NA Ground anchorages meets design levels: NA Plots of test item: See below (Table 4.1-4.4)

4.4.2 Vehicle Exit speed: 88 km/h Exit angle: (See paragraph 4.4.3)

≈ 0 degrees

Rebound distance: NA Vehicle breaches barrier: No Vehicle passes over the barrier: No Vehicle within CEN .box.: Yes Vehicle rolls over after impact: No Damage to test vehicle: See below (Table 4.5)

4.4.3 General description of vehicle trajectory The vehicle hits the barrier with an initial angle of 20°. After the impact the vehicle continues sliding along the barrier, moving parallel to it. This is due to the fact that the front right wheel is turned locked with an angle toward the barrier after the steering system collapsed as a consequence of the impact. The vehicle does not pass over the barrier and does not roll-over. Hence the trajectory can be considered good. The initial speed is 102.5 km/h, while the exit speed is 88 km/h. Vehicle damage TAD: NA Vehicle damage VDI: NA Vehicle cockpit def. index VCDI: NA Major parts of vehicle detached: No Plots of the vehicle: See below (Table 4.5)

4.4.4 General description of dummy behaviour After the impact, the dummy is pushed against the vehicle left door and the head hits the door window. The seatbelt avoids the forward motion of the dummy, whose legs stretch out as a consequence of the inertial force. For a sequence of images about the dummy behaviour, see paragraph 4.4.7



MAIN REPORT 4.4.5 Assessment of the impact severity Post-processing procedure: Data from nodout database (node 700002) pre-filtered with a SAE60 filter and subsequently post-processed in TRAP with a second SAE180 filter. Acceleration severity index (ASI): 1.78 Acceleration graphs: NA THIV: 26.6 km/h Time of flight: NA Post-impact head deceleration (PHD): 17.2 g’s Flail space: 300 mm in y-direction



MAIN REPORT

4.4.6 Impact sequences and vehicle damage

Front view t=0 sec t=0.05 sec

t=0.10 sec t=0.15 sec

t=0.20 sec t=0.25 sec



MAIN REPORT

Table 4.1



MAIN REPORT

Rear view t=0 sec t=0.05 sec

t=0.10 sec t=0.15 sec

t=0.20 sec t=0.25 sec

Table 4.2



MAIN REPORT

Top view t=0 sec t=0.05 sec

t=0.10 sec t=0.15 sec

t=0.20 sec t=0.25 sec

Table 4.3



MAIN REPORT

Side view t=0 sec t=0.05 sec

t=0.10 sec t=0.15 sec

t=0.20 sec t=0.25 sec

Table 4.4



MAIN REPORT

Isometric view t=0 sec t=0.05 sec

t=0.10 sec t=0.15 sec

t=0.20 sec t=0.25 sec

Table 4.4



MAIN REPORT

Vehicle damage Top Bottom

Right Left

Right Iso Left Iso

Table 4.5



MAIN REPORT

4.4.7 Dummy behaviour (impact sequences)

Front view t=0.06 sec t=0.12 sec

t=0.18 sec t=0.24 sec

Table 4.6



MAIN REPORT

Side view t=0.06 sec t=0.12 sec

t=0.18 sec t=0.24 sec

Table 4.7



MAIN REPORT

Top view t=0.06 sec t=0.12 sec

t=0.18 sec t=0.24 sec

Table 4.8



MAIN REPORT REFERENCES [1] EN 1317-1: Road restraint systems. Part 1: Terminology and general criteria

for test methods. European Committee for Standardization, 1998. [2] EN 1317-2: Road restraint systems. Part 2: Performance classes, impact test

acceptance criteria and test methods for safety barriers. European Committee for Standardization, 1998

[3] J. O. Hallquist, LS-DYNA Theory Manual, Livermore Software Technology Corp., Livermore, California, May 1998.

[4] J. O. Hallquist, LS-DYNA Keyword Manual Version 970, Livermore Software Technology Corp., Livermore, California, April 2003.

[5] TR-2004-0039: Evaluation of small car prepared by Politechnico di Milano, Main Report. Force Technology, April 2004, Rev.A.

[6] TR-2004-0107: Evaluation of small car vehicle model GM_R2. Force Technology Norway AS, Rev. A, December 2004.

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