Time Frame
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Transcript of Time Frame
1 NCHRP_22_24 January 22 2007
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Time Frame
• CM/E finalised the vehicle and test object modelling documents (Parts 2&3) – These documents should be revised at regular
intervals
• Validation procedures still require research– Further analysis of the Round Robin data in
ROBUST is a necessary input – Difficult to predict the delivery of a draft
procedure – possibly 2007
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Validation.
• If we want to use CM for the certification of a system which are the requirements for a “validated” model?
• Validation should be based on a comparison between test and simulation using:– Severity indices.– Barrier performance:
• Deformation.• Failures.
– Vehicle trajectories.– Vehicle time histories (acceleration yaw ratio …)– …..
• Validation methods MUST be able to validate also tests repetition.
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Validation
• The problem is how to define an objective procedure to compare time histories.
• Direct comparison between avcceleration has been already demonstrated to be not applicable. Is not possible to find an objective way to compare such different curves.
• Other approaches:– Statistical approach (Chalmers software).– Velocity.
• Chalmers software:– Statistical comparison between a master and a signal to
be tested.– The comparison is based on 8 statistical indices.
4 NCHRP_22_24 January 22 2007
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CFC 60
• 3 over 8. We could relax the limits. But with no statistical meaning.
5 NCHRP_22_24 January 22 2007
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Filtered at 12.5 hz
• Always 3 over 80 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
-10
-5
0
5
10
15
20
25
30simulationtest
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Different experimental test
• Worse condition. Different requirements in the second phase?
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Only the first phase.Always the same problem.
• Minimum peak fails even if is less important.
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First phase.
• Only way to pass all the tests.• First part of the impact and relaxation of
limits.
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Two experimental tests
• 4 over 8!
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Other possibility
• Window obtained from test where simulation must be contained.
• Not easy to justify a window (delta time, delta g, filtering)
-0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4-10
-5
0
5
10
15
20
25
30upper boundtest lower boundsimulation
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Other possibilty 3.Final consideration
• Compare two velocity time histories (experimental and numerical).
• If the difference between these two time histories become greather than X(t)% your model is validated until this time.
• After this time your model is not validated.• We are applying this approach also to the deformable barrier and
to other impacts
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Validation.
• Comparison based on local velocity components.– Reference frame is not inertial.– Accelerations evaluated on a reference system “mounted” on
the vehicle.– To proper evaluation of velocity relative mechanics should be
used.
• Comparison based on global velocity components.• Planar motion.
• Need of yaw rotation (not filtered).• Evaluation of global components of velocity
(interpretation less immediate)
13 NCHRP_22_24 January 22 2007
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Vehicle rotation
Vy GlobalVy Local
x
yx
y
X
Y
αx
y
α
X X
αx
y
X
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Round Robin.
• Rigida barrier h=800 mm.• Tb11
– 900 kg– 20°
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Round Robin 1.
-0.2 0 0.2 0.4 0.6 0.8-2
0
2
4
6
8
10
12Vy global Unfiltered
AutostradeHut Cidaut Lier TRL
-0.2 0 0.2 0.4 0.6 0.816
18
20
22
24
26
28Vx global Unfiltered
AutostradeHut Cidaut Lier TRL
-0.2 0 0.2 0.4 0.6 0.8-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2Vz global Unfiltered
AutostradeHut Cidaut Lier TRL
Same new vehicle. Only exp. results
16 NCHRP_22_24 January 22 2007
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Round Robin 2
• Different not new vehicles
-0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6-2
0
2
4
6
8
10
12Vy global Unfiltered
-0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6-3
-2
-1
0
1
2
3
4Vz global Unfiltered
-0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.614
16
18
20
22
24
26
28Vx global Unfiltered
17 NCHRP_22_24 January 22 2007
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Robust 4.3
– Two more tests on RR1
-0.2 0 0.2 0.4 0.6 0.8 1 1.2-2
0
2
4
6
8
10Vy global Unfiltered
-0.2 0 0.2 0.4 0.6 0.8 1 1.219
20
21
22
23
24
25
26
27
28Vx global Unfiltered
-0.2 0 0.2 0.4 0.6 0.8 1 1.2-1.5
-1
-0.5
0
0.5
1Vz global Unfiltered
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All the tests.
• Same rigid barrier.• Different vehicles.• 12 nominally identical.
-0.4 -0.2 0 0.2 0.4 0.6 0.8 1-2
0
2
4
6
8
10
12Vy global Unfiltered
-0.2 0 0.2 0.4 0.6 0.8 1 1.214
16
18
20
22
24
26
28Vx global Unfiltered
-0.4 -0.2 0 0.2 0.4 0.6 0.8 1-3
-2
-1
0
1
2
3
4Vz global Unfiltered
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Round Robin. Test and simulation
-0.4 -0.2 0 0.2 0.4 0.6 0.8 1-2
0
2
4
6
8
10
12Vy global Unfiltered
-0.2 0 0.2 0.4 0.6 0.8 1 1.214
16
18
20
22
24
26
28Vx global Unfiltered
-0.4 -0.2 0 0.2 0.4 0.6 0.8 1-3
-2
-1
0
1
2
3
4Vz global Unfiltered
– Not so bad.– Friction influence. (Not
understood from acceleration comparison).
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Rigid barrier results
• Components– Vy global: good agreement between tests– Vx global: scatter between tests (exit velocity is
different)– Vz global: less significative.
• Seems to work.
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Deformable barrier.
• Task 4.1 Robust.• N2 barrier (max 1500 kg 110 km/h 20°).• Different vehicles.• Gorund differences.
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Yaw angle
x
yx
y
X
Y
αx
y
α
X X
αx
y
X
Angle
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Yaw angle problems during tests
0 0.5 1 1.5 2 2.5 3-60
-40
-20
0
20
40
60Ay
0 0.5 1 1.5 2 2.5 3-100
-50
0
50
100
150
200
250Yaw rate
0 0.5 1 1.5 2 2.5 3-5
0
5
10
15
20
25
30Rotation
0 0.5 1 1.5 2 2.5 3 3.5-50
-40
-30
-20
-10
0
10
20
30
40rotation
24 NCHRP_22_24 January 22 2007
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Comparison.
-1.5 -1 -0.5 0 0.5 1 1.5 20
2
4
6
8
10
12
14Vy global Unfiltered
-1.5 -1 -0.5 0 0.5 1 1.5 2 2.55
10
15
20
25
30Vx global Unfiltered
-1.5 -1 -0.5 0 0.5 1 1.5 2 2.50
0.5
1
1.5
2
2.5Vz global Unfiltered
25 NCHRP_22_24 January 22 2007
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Comparison 1
• Dynamic deflection (ground)– Curve 1 (blue)=0.9m– Curve 3 (red)=0.7m– Difference 25%
-1.5 -1 -0.5 0 0.5 1 1.5 20
2
4
6
8
10
12
14Vy global Unfiltered
-1.5 -1 -0.5 0 0.5 1 1.5 2 2.512
14
16
18
20
22
24
26
28
30Vx global Unfiltered
-1.5 -1 -0.5 0 0.5 1 1.5 2 2.50
0.5
1
1.5
2
2.5Vz global Unfiltered
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Tests and simulation
-1.5 -1 -0.5 0 0.5 1 1.5 2 2.512
14
16
18
20
22
24
26
28
30Vx global Unfiltered
-1.5 -1 -0.5 0 0.5 1 1.5 2-2
0
2
4
6
8
10
12
14Vy global Unfiltered
-1.5 -1 -0.5 0 0.5 1 1.5 2 2.5-1
-0.5
0
0.5
1
1.5
2
2.5Vz global Unfiltered
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Conclusion
• From Round Robin encouraging results.• From deformable barrier results not
acceptable.• Problem:
– With these results (deformable) window to accept simulation is too wide.
– According to 1317 these tests are equivalent. Means that a simulation with these differences is validated?