Robust: Road Upgrade of Standards GRD1-2002-70021 Testing - PowerPoint PPT Presentation

Robust: “Road Upgrade of Standards” GRD1-2002-70021 Testing procedures and severity indices evaluation. Marco Anghileri Dipartim ento di I ngegneria Aerospaziale Politecnico di Milano I taly

Scope of the activities. Scope of the activities. • To harmonise the measurement practice in the European laboratories and remove possible discrepancies from different transducer and test set-up. Robust. GRD1-2002-70021 • Part of the consideration already presented by Lier. 2 • Fields: – Experimental – Analytical 2 /77 Bruxelles 30/05/2006

Contribution. Contribution. 1. Statistical analysis of already performed tests. 2. Severity indices definition. Robust. GRD1-2002-70021 3. Data acquisition and severity indices evaluation. 3 4. Instrumentation mounting. 3 /77 Bruxelles 30/05/2006

Statistical analysis of already Statistical analysis of already performed tests. performed tests. • Analysis of existing data obtained form European laboratories to investigate possible correlation betw een severity Robust. GRD1-2002-70021 indices. 4 • Analysis of existing data obtained form European laboratories to investigate differences betw een tests houses 4 /77 Bruxelles 30/05/2006

Data base. Data base. • From European laboratories a set of 174 data of TB11 full scale crash tests have been obtained containing the follow ing information: – year of test – vehicle make – vehicle test mass Robust. GRD1-2002-70021 – data sample rate – actual speed and angle – barrier dynamic deflection 5 – ASI – THIV/PHD • Data w ere received from 7 Laboratories. Of 174 TB11 tests, 111 w ere successful and 63 unsuccessful. Some tests have been received w ithout PHD data. 5 /77 Bruxelles 30/05/2006

THIV-ASI THIV-ASI Correlation THIV- ASI (All data except singular points) 50.00 45.00 y = 25.033x 0.4983 R 2 = 0.7451 40.00 35.00 30.00 THIV/ASI-Re IV H 25.00 T Pow er (THIV/ASI-Re) 20.00 Robust. GRD1-2002-70021 15.00 10.00 5.00 0.00 6 0 0.5 1 1.5 2 2.5 ASI • This graph show s a fair correlation betw een ASI and THIV indices. Correlation factor of 0.7451 = 0.4989 ฀ THIV 25.033 ASI 6 /77 Bruxelles 30/05/2006

Thiv-Asi different labs. Thiv-Asi different labs. Lab Corr. function ALL y = 25.0 ASI^0.4983 Correlation THIV/ASI 70.00 1 y = 26.9 ASI^0.4305 60.00 50.00 Lab1 2 y = 24.0 ASI^0.3305 Lab 2 Robust. GRD1-2002-70021 40.00 THIV Lab 3 30.00 Lab 4 Lab 5 20.00 3 y = 24.8 ASI^0.545 10.00 7 0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 4 y = 25.1 ASI^0.5596 ASI 5 y = 23.6 ASI^0.4899 7 /77 Bruxelles 30/05/2006

THIV-PHD PHD-ASI THIV-PHD PHD-ASI THIV-PHD correlation 50.00 45.00 40.00 35.00 THIV [km/h] 30.00 25.00 20.00 15.00 • no correlation 10.00 Robust. GRD1-2002-70021 5.00 0.00 betw een PHD 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 PHD [g] and THIV or ASI 8 PHD-ASI correlation 3 2.5 2 ASI 1.5 1 0.5 0 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 8 /77 Bruxelles 30/05/2006 PHD [g]

ASI-DD THIV-DD PHD-DD ASI-DD THIV-DD PHD-DD ASI-dynamic deflection PHD - Dynamic deflection 2.00 35.00 30.00 1.60 25.00 1.20 20.00 ASI-DD PHD-DD PHD ASI Espo. (PHD-DD) Espo. (ASI-DD) 15.00 0.80 10.00 0.40 y = 1.4448e 0.683x- Robust. GRD1-2002-70021 5.00 0.6093x- y = 16.719e R 2 0.5653 = 2 0.2336 = R 0.00 0.00 0.00 0.50 1.00 1.50 2.00 0.00 0.50 1.00 1.50 2.00 Dynamic deflexion Dynamic deflexion 9 • PHD: no THIV - Dyn. deflexion correlation. 45.00 40.00 35.00 • THIV-DD ASI_DD: 30.00 25.00 THIV-DD w eak correlations THIV Espo. (THIV-DD) 20.00 0.3764x- 15.00 y = 30.631e 2 0.5591 = R 10.00 5.00 0.00 0.00 0.50 1.00 1.50 2.00 9 /77 Bruxelles 30/05/2006 Dynamic deflexion

Different Labs Different Labs Lab Corr. Function ASI-dynamic deflection All y = 1.4448e-0.683x 3.00 2.50 1 y = 1.2829e-0.5836x Lab 1 2.00 Lab 2 2 y = 1.4973e-0.6099x ASi 1.50 Lab 3 Lab 4 1.00 3 y = 1.3841e-0.6902x Lab 5 0.50 4 y = 1.6442e-0.9867x Robust. GRD1-2002-70021 0.00 0.00 0.50 1.00 1.50 2.00 5 y = 1.4716e-0.8779x Dynamic deflection [m] THIV-dynamic deflection Lab Corr. Function 10 70.00 All y = 30.631e-0.3764x 60.00 50.00 Lab 1 1 y = 32.827e-0.5464x THIV [km/h] Lab 2 40.00 Lab 3 2 y = 32.141e-0.4018x 30.00 Lab 4 Lab 5 20.00 3 y = 27.476e-0.2846x 10.00 4 y = 29.923e-0.4634x 0.00 0.00 0.50 1.00 1.50 2.00 10 /77 Bruxelles 30/05/2006 5 y = 27.801e-0.3747x Dynamic deflection [m]

Results of statistical analysis. Results of statistical analysis. • These results show that there is a limited correlation betw een severity indices. • Reason: from the scientific point of view , ASI, THIV and PHD are different things. • The main differences betw een these severity indices are: Robust. GRD1-2002-70021 – ASI is using three components of acceleration w hile THIV- PHD use a planar motion w here the z acceleration component is not used. 11 – THIV – PHD use a critical time that corresponds to the time w here the theoretical head impact against the conventional box representing the vehicle interior. – THIV is affected also by the yaw motion w hile ASI does not take into account this measure into account. • Test houses have similar tendencies. 11 /77 Bruxelles 30/05/2006

Severity indices definition. Severity indices definition. • EN 1317 requires, to evaluate barrier performance, to measure the follow ing severity indices: Robust. GRD1-2002-70021 ASI THIV / (PHD) 12 • Based on acceleration measured during the certification test on the vehicle CG. 12 /77 Bruxelles 30/05/2006

ASI. Acceleration Severity Index ASI. Acceleration Severity Index – “The index ASI is intended to give a measure of the severity of the vehicle motion for a person seated in the proximity of point P (CG) during an impact.” – Steps: Robust. GRD1-2002-70021 • Measure three acceleration components of vehicle CG according w ith CFC180. • Apply a 50 ms moving average on these 13 acceleration. • Evaluate Asi as: 2 ⎛ ⎞ 2 2 ⎛ ⎞ ⎛ ⎞ a a a = + + ⎜ y ⎟ ⎜ ⎟ ⎜ x ⎟ z ( ) ASI t ⎜ ⎟ ⎝ ⎠ a a ⎝ a ⎠ ⎝ ⎠ x lim y lim z lim 13 /77 Bruxelles 30/05/2006

ASI. Acceleration Severity Index. ASI. Acceleration Severity Index. = = = • Where: a 12 g a 9 g a 10 g x lim y lim z lim – “Are obtained from the human body tolerances limits.” • ASI is the maximum value of ASI(t). • “The average in equation (of ASI) is actually a low pass filter, taking into account the fact that vehicle accelerations can be transmitted to the Robust. GRD1-2002-70021 occupant body through relatively soft contacts, w hich cannot pass the highest frequencies.” • The equation (of ASI) is the simplest possible 14 interaction equation of three variables x, y and z. • The limit accelerations are interpreted as the values below w hich passenger risk is very small (light injures if any).” 14 /77 Bruxelles 30/05/2006

Moving average Moving average • Asi and Phd evaluation requires moving average techniques: – ASI 50ms – PHD 10ms (NCHRP-350 ORA 10 ms) – The original idea w as to have a w indow to Robust. GRD1-2002-70021 observe the acceleration time histories. • Questions: 15 – Is moving average a true filter? – Can moving average give w rong information? 15 /77 Bruxelles 30/05/2006

Filtering Filtering • Signal processing (analog, digital or mechanical) to: – Eliminate noise or oscillation – Amplify frequencies – Avoid problems (example: aliasing) Robust. GRD1-2002-70021 Output signal Input signal Filter 16 • Attenuation: ⎛ ⎞ Out = ⎜ ⎟ Db 20log 10 ⎝ ⎠ In 16 /77 Bruxelles 30/05/2006

Typical low -pass filter frequency Typical low -pass filter frequency response response 0 F iltro B utte rw o rth • -20 db means -5 0 Output=0.1* Input -1 0 0 -1 5 0 Ampiezza [Db] -2 0 0 Robust. GRD1-2002-70021 -2 5 0 -3 0 0 -3 5 0 -4 0 0 17 0 1 2 3 4 1 0 1 0 1 0 1 0 1 0 fre q [H z] • The moving average is a filter in the sense that it modifies the original signal. 17 /77 Bruxelles 30/05/2006

50 ms moving average – 50 ms moving average – standard standard filtering gain. filtering gain. • Gain=output/input 1 moving average over 50 ms Butterworth filter 0.9 1 0.8 0.9 0.8 0.7 Robust. GRD1-2002-70021 0.7 0.6 0.6 Gain 0.5 0.5 0.4 0.4 0.3 18 0.2 0.3 0.1 0.2 0 0 50 1 00 1 50 200 0.1 -0.1 -0.2 0 20 40 60 80 100 -0.3 freq [Hz] frequency [Hz] 18 /77 Bruxelles 30/05/2006

50 ms moving average – 50 ms moving average – standard standard filtering attenuation. filtering attenuation. • Comparison w ith a CFC shaped filter 0 100 Moving average Moving average Filter 50 -50 0 Robust. GRD1-2002-70021 -100 -50 Amplitude [Db] Amplitude [Db] -150 -100 -200 -150 19 -200 -250 -250 -300 -300 -350 0 1 2 3 4 10 10 10 10 10 -350 0 20 40 60 80 100 freq [Hz] freq [Hz] 19 /77 Bruxelles 30/05/2006