WP5 - Computational Mechanics B1 (ESP-N2) Barrier Steel N2 MAIN REPORT Volume 2 of 2

Transcription

1 ROBUST PROJECT TRL Limited WP5 - Computational Mechanics B1 (ESP-N2) Barrier Steel N2 Volume 2 of 2 November 2005 Doc. No.: ROBUST 5-014b Rev. 1.

2 (Logo here) Main Report Report title: WP5 - Computational Mechanics Client: TRL Limited TRL Project no.: ROBUST EC/HA / Doc. no.: Document no: ROBUST-5-014b - Rev. 1 Reporter(s): M McGrath, G Williams (S Sumon) Abstract: The Robust Project aims to improve scientific and technical knowledge on the main issues still open in the new European standards on the road restraint system EN1317. The knowledge acquired will form the basis of updated standards for EN 1317 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. This report documents the simulations performed on the B1 (ESP-N2) barrier. The simulations were performed by TRL Limited. Keywords: Restricted Internal Free distribution Ref. allowed Rev. no. Date Prepared by Checked by Approved by Reason for revision M McGrath G Williams no-en

3 ROBUST project Page i CONTENTS 1 INTRODUCTION SUMMARY AND CONCLUSIONS Summary Conclusions SIMULATION OF BARRIER B1 CASE General Additional data Input data Test item Test procedure Analysis data Analysis results SIMULATION OF BARRIER B1 CASE General Additional data Input data Test item Test procedure Analysis data Analysis results REFERENCES...23

4 ROBUST project Page 1 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 systems EN The knowledge acquired will form the basis of updated standards for EN1317 and lead to more advanced road restraint systems and improved 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 simulations performed on the B1 (ESP-N2) barrier. The simulations were performed by TRL Limited as part of the ROBUST project and were run with version 970 revision 5434a of LS_DY. The data was output at 1.0E-5 from the THF and NODOUT files. PLEASE NOTE: This report should be read in conjunction with B1 (ESP-N2) Barrier Steel N2 Volume 1 of 2. This report documents the results from the same model, run under version 970 revision of LS-DY. The data was output at 1.0E-5 from the THF files and 1.0E- 3 from the RBDOUT file.

5 ROBUST project Page 2 2 SUMMARY AND CONCLUSIONS 2.1 Summary The following simulations have been performed with the B1 barrier: Barrier Test Name id. Chapter B1 case 1 Post fixed 200mm below ground level. The ends of profile are fixed. B1 case 2 Post fixed 200mm below ground level. The ends of profile are fixed. TB11 TB11 GM_R2_Vehicle- ESP-N2_barrier (R2 Vehicle Model) Generic_Vehicle- ESP-N2_barrier (TRL Generic Vehicle Model) Chapter 3 Chapter 4 The main results are summarised in Table 2-1 below. Table 2-1 Results from simulations with the B1 barrier Case ASI [-] THIV [km/h] PHD [g] Working Width [mm] Exit speed [km/h] Exit angle [deg] Trajectory Detailed description OK Chapter OK Chapter4 2.2 Conclusions

6 ROBUST project Page 3 3 SIMULATION OF BARRIER B1 CASE General This chapter gives a brief description of the results obtained from a simulation of a small car (GM_R2) hitting the B1 barrier with a velocity of 100 km/h and at an angle of 20 degrees. The B1 barrier is an ESP-N2 barrier, which consists of sigma posts and N2 steel profile. The characteristics specific to this simulation are: The sigma posts are fixed 200 mm below ground level All posts are modelled as non-linear The ends of the w-profile are fixed No friction between barrier and vehicle Friction between the ground and tyres was set to Additional data The following data and files supplement the result presentation of the simulation as presented in this chapter. Excel worksheet file: Rawdata file: Animations: GM_R2_Vehicle-ESP-N2_barrier_A.xls GM_R2_Vehicle-ESP-N2_barrier_Rawdata_A.zip - front view GM_R2_Vehicle-ESP-N2_barrier_Front_view_A.mpg * - side view GM_R2_Vehicle-ESP-N2_barrier_Side_view_A.mpg * - top view GM_R2_Vehicle-ESP-N2_barrier_Top_view_A.mpg * - perspective GM_R2_Vehicle-ESP-N2_barrier_Perspective_view_A.mpg * *AVI format of the animation is available on request (approximately 130MB each) 3.3 Input data Test item Test item: Vehicle: ESP-N2 GeoMetro GM_R2

7 ROBUST project Page Test procedure 1) Test type TB11 Impact speed: Impact angle: Impact point Spinning wheels: Inertial vehicle test mass: 100 km/h 20 degrees About 26 metres from the beginning of the VRS Yes 855 kg 2) VRS model Barrier type: Number of posts: Spacing: Total length: Element formulation/type: Connection/Joints: Foundation: End anchoring: Soil (type and formulation): Roadway: ESP N2 37 (including 2 x 3 posts at the end slopes) 2 m 76 m Shell elements used for all sections Bolt connections are modelled using spotwelds with failure (between the posts and profile). Modelled W-profile is fixed at the ends Plot of FE-Model Table 3.2 Material Data Table 3.3 Modelled as rigid walls 3) Vehicle model The model of the GeoMetro, version GM_R2 was used in the simulations. The version of the GM_R2 that was used in the model run has not been identified. The mass of the vehicle was calculated by removing the barrier from the model Analysis data Timestep: Precision: Friction barrier/vehicle (static coefficient): 0 Friction barrier/vehicle (dynamic coefficient) E-6 Single Friction wheel/ground (static coefficient) 0.7

8 ROBUST project Page 5 Friction wheel/ground (dynamic coefficient) Accelerometer location (mounting block) from COG (mm) Sampling rate Friction other: 111 longitudinally / 27 laterally / 140 vertically 1.0E-5 for THF and NODOUT data Table 3-1 Model description. VRS for roads Vehicle restraint system Computer model, VRS for roads Model description Nodes Shell elements / Brick elements Spot welds Materials / Other The VRS was modelled using shell elements for all sections. The bolt connections were modelled using spot-welds (between the posts and profile). There is no friction between the car and the VRS. The road was modelled in the FE-model. The posts were extended below the road. Table 3-2 Material characteristic Steel and plastic sections. Vehicle restraint system Part E-Module [MPa] Density [kg/m3] Yield Stress [MPa] Ultimate Stress Failure Strain [-] Comments [MPa] Sigma Posts Non-linear W-profile Non-linear Brackets Non-linear Strain Rate Stress vs. strain values STRAIN -- STRESS MPa MPa

9 ROBUST project Page Analysis results 1) VRS Maximum global dynamic deflection: Working width: Maximum global permanent deflection: Length of contact: Major parts fractured or detached: Description of damage to test items: Ground anchorage s meets design levels: 636 mm 774 mm Unable to calculate because the barrier was still moving at the end of the run at 500 ms. Approx 6 m No 3 posts detached from profile Plot of test items: Table 3.4 Table 3.7 2) Vehicle Image of the vehicle at the time when the exit angle and speed were calculated at 500ms Exit speed: km/h Exit angle: 8.9 degrees Rebound distance: Vehicle breaches barrier: No Vehicle passes over the barrier: No Vehicle within CEN box : See General Statement (Section 3.4, 5) Vehicle rolls over after impact: No Damage to test vehicle: Table 3.8

10 ROBUST project Page 7 3) General description of vehicle trajectory: The vehicle hits the VRS at a velocity of 100 km/h and at an angle of 20 degrees. The vehicle leaves the VRS at an angle of 8.90 degrees. The trajectory is good in the simulation. Vehicle damage TAD: Vehicle damage VDI: Vehicle cockpit def. index VCDI: Major parts of vehicle detached: No Plots of the vehicle: Table 3.8 4) Assessment of the impact severity Post-processing procedure Accelerometer data used in Diadem Acceleration severity index, ASI: 0.86 Acceleration graphs: No THIV: km/h Time of flight: Post-impact head deceleration, PHD: g Flail space: 0.6 x 0.3 m 5) General statement Based on the above it can be concluded that the crash protection system fulfils the requirements of the CEN standard

11 ROBUST project Page 8 Table 3-3 Vehicle - Front view. Time 0.00 Time 0.12 Time 0.16 Time 0.24 Time 0.35 Time 0.45

12 ROBUST project Page 9 Table 3-4 Vehicle Side view. Time 0.00 Time 0.12 Time 0.16 Time 0.24 Time 0.35 Time 0.45

13 ROBUST project Page 10 Table 3-5 Vehicle - Top view Time 0.00 Time 0.12 Time 0.16 Time 0.24 Time 0.35 Time 0.45

14 ROBUST project Page 11 Table 3-6 Vehicle Iso View Time 0.00 Time 0.12 Time 0.16 Time 0.24 Time 0.35 Time 0.45

15 ROBUST project Page 12 Top view Table 3-7 Vehicle damage. Bottom view Side view Side view View View

16 ROBUST project Page 13 4 SIMULATION OF BARRIER B1 CASE General This gives a brief description of the results obtained from a simulation of a small generic vehicle (940 kg) hitting the B1 barrier with a velocity of 100 km/h and at an angle of 20 degrees. The B1 barrier is an ESP-N2 barrier which consists of sigma posts and N2 steel profile. The characteristics specific to this simulation are: The sigma posts are fixed 200 mm below ground level All posts are modelled as non-linear The ends of the w-profile are fixed There is no friction between the barrier and the vehicle Friction between the ground and the tyres was set to Additional data The following data and files supplement the result presentation of the simulation as presented in this chapter. Excel worksheet file: Rawdata file: Animations: Generic_Vehicle-ESP-N2_barrier_A.xls Generic_Vehicle-ESP-N2_barrier_Rawdata_A.zip - front view Generic_Vehicle-ESP-N2_barrier_Front_view_A.mpg * - side view Generic_Vehicle-ESP-N2_barrier_Side_view_A.mpg * - top view Generic_Vehicle-ESP-N2_barrier_Top_view_A.mpg * - perspective Generic_Vehicle-ESP-N2_barrier_Perspective_view_A.mpg * *AVI format of the animation is available on request (approximately 130MB each) 4.3 Input data Test item Test item: Vehicle: ESP-N2 Generic Model Test procedure 4) Test type TB11

17 ROBUST project Page 14 Impact speed: Impact angle: Impact point Spinning wheels: Inertial vehicle test mass: 100 km/h 20 degrees About 26 metres from the beginning of the VRS No 940 kg 5) VRS model Barrier type: Number of posts: Spacing: Total length: Element formulation/type: Connection/Joints: Foundation: End anchoring: Soil (type and formulation): Roadway: ESP N2 37 (including 2 x 3 posts at the end slopes) 2 m 76 m Shell elements used for all sections Bolt connections are modelled using spotwelds with failure (between the posts and profile). Modelled W-profile is fixed at the ends None Plot of FE-Model Table 4.2 Material Data Table 4.3 6) Vehicle model A generic vehicle model was used in the simulations Analysis data Timestep: Precision: 2.03E-6 Single Friction barrier/vehicle (static coefficient): 0.3 Friction barrier/vehicle (dynamic coefficient) 0.1 Friction wheel/ground (static coefficient) Friction wheel/ground (dynamic coefficient) Accelerometer location (mounting block) from COG (mm) Sampling rate Friction other: 131 longitudinally / laterally / 20 vertically 1.0E-5 for THF and NODOUT data

18 ROBUST project Page 15 Table 4-1 Model description. VRS for roads Vehicle restraint system Computer model, VRS for roads Model description Nodes Shell elements / Brick elements Spot welds Materials / Other The VRS was modelled using shell elements for all sections. The bolt connections were modelled using spot-welds (between the posts and profile). Friction was modelled between the car and the VRS. The road was not modelled in the FE-model. The posts were extended below the road. Table 4-2 Material characteristic Steel and plastic sections. Vehicle restraint system Part E-Module [MPa] Density [kg/m3] Yield Stress [MPa] Ultimate Stress Failure Strain [-] Comments [MPa] Sigma Posts Non-linear W-profile Non-linear Brackets Non-linear Strain Rate Stress vs. strain values STRAIN -- STRESS MPa MPa

19 ROBUST project Page Analysis results 6) VRS Maximum global dynamic deflection: Working width: Maximum global permanent deflection: Length of contact: Major parts fractured or detached: Description of damage to test items: Ground anchorage s meets design levels: 639 mm 836 mm Unable to calculate because the barrier was still moving at the end of the run at 500 ms. Approx 7.5 m No 5 posts detached from profile Plot of test items: Table 4.4 Table 4.7 7) Vehicle Image of the vehicle at the time when the exit angle and speed were calculated Exit speed: Exit angle: Rebound distance: Vehicle breaches barrier: Vehicle passes over the barrier: km/h 2.25 degrees Vehicle within CEN box : See General Statement (Section 4.4, 10) Vehicle rolls over after impact: No No No Damage to test vehicle: Table 4.8

20 ROBUST project Page 17 8) General description of vehicle trajectory: The vehicle hits the VRS at a velocity of 100 km/h and at an angle of 20 degrees. The vehicle leaves the VRS at an angle of 2.25 degrees. Vehicle damage TAD: Vehicle damage VDI: Vehicle cockpit def. index VCDI: Major parts of vehicle detached: No Plots of the vehicle: Table 4.8 9) Assessment of the impact severity Post-processing procedure Accelerometer data used in Diadem Acceleration severity index, ASI: 0.69 Acceleration graphs: No THIV: km/h Time of flight: Post-impact head deceleration, PHD: 8.8g Flail space: 0.6 x 0.3 m 10) General statement Based on the above it can be concluded that the crash protection system fulfils the requirements of the CEN standard.

21 ROBUST project Page 18 Table 4-3 Vehicle - Front view. Time 0.00 Time 0.11 Time 0.16 Time 0.22 Time 0.35 Time 0.42

22 ROBUST project Page 19 Table 4-4 Vehicle Side view. Time 0.00 Time 0.11 Time 0.16 Time 0.22 Time 0.35 Time 0.42

23 ROBUST project Page 20 Table 4-5 Vehicle - Top view Time 0.00 Time 0.11 Time 0.16 Time 0.22 Time 0.35 Time 0.42

24 ROBUST project Page 21 Table 4-6 Vehicle Iso View Time 0.00 Time 0.11 Time 0.16 Time 0.22 Time 0.35 Time 0.42

25 ROBUST project Page 22 Top view Table 4-7 Vehicle damage. Bottom view Side view Side view View View

26 ROBUST project Page 23 5 REFERENCES Ref. 1: Ref. 2: EN : Road restraint systems Part 1: Terminology and general criteria for test methods. European Committee for Standardization, April EN : Road restraint systems Part 2: Performance classes, impact test acceptance criteria and test methods for safety barriers. European Committee for Standardization, April 1998.

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