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vibration-test for RESS
1. quantification the load of different vibration profiles
with a test specimen
2. proposal for a test-profil
RESS-4-19
04.07.2011Seite 2
• vibration signal of a car on proving ground (example)
• random vibration ISO12405 vertical
• 8g-Sweep UN38.3
• 2g-Sweep proposal
approx. 15 Hz
approx. 30 Hz
approx. 75 Hz
evaluated profils for vibration test
test specimen
strain gage
load direction
04.07.2011Seite 3
sweep-signal
The vibration shall be a sinusoidal waveform with a logarithmic sweep between 7 Hz and 200 Hz and back to 7 Hz traversed in 15 minutes. This cycle shall be repeated 12 times for a total of 3 hours for each of three mutually perpendicular mounting positions of the RESS.
UN38.3 8g-sweep
from 7 Hz to a peak acceleration of 1 gn is maintained until 18 Hz is reached. The amplitude is then maintained at 0.8 mm (1.6 mm total excursion) and the frequency increased until a peak acceleration of 8 gn occurs (approximately 50 Hz). A peak acceleration of 8 gn is then maintained until the frequency is increased to 200 Hz.
Proposal 2g-sweep
from 7 Hz to a peak acceleration of 1 gn is maintained until 18 Hz is reached. The amplitude is then maintained at 0.8 mm (1.6 mm total excursion) and the frequency increased until a peak acceleration of 2 gn occurs (approximately 25 Hz). A peak acceleration of 2 gn is then maintained until the frequency is increased to 200 Hz.
04.07.2011Seite 4
power spectral density (PSD)of test-profils
vibrationsignal from proving-ground (example)random vibration ISO12405 vertical8g-sweep UN38.32g-sweep proposal
04.07.2011Seite 5
-1
-0,8
-0,6
-0,4
-0,2
0
0,2
0,4
0,6
0,8
1
Messstelle 15 Hz Messstelle 30 Hz Messstelle 75 Hz
abso
lute
r M
axim
alw
ert
[mV
/V]
load of test speciment
max. strain on test specimen
vibrationsignal from proving-ground (example)random vibration ISO12405 vertical8g-sweep UN38.32g-sweep proposal
max.
str
ain
[m
V/V
]
measuring point 15Hz measuring point 30Hz measuring point 75Hz
04.07.2011Seite 6
0
1
10
100
1.000
10.000
100.000
1.000.000
Messstelle 15 Hz Messstelle 30 Hz Messstelle 75 Hz
rel.
Bel
astu
ng
ske
nn
zah
l
auf Zielprüfdauer extrapoliert
fatigue damage on test specimen, relative to vibrationsignal from proving-ground
vibrationsignal from proving-ground (example)random vibration ISO12405 vertical8g-sweep UN38.32g-sweep proposal
load of test speciment
extrapolated to target
rela
tive f
ati
gu
e
dam
ag
e
measuring point 15Hz measuring point 30Hz measuring point 75Hz
04.07.2011Seite 7
0,00001
0,0001
0,001
0,01
0,1
1 10 100
Frequenz [Hz]
Les
itu
ng
sdic
hte
[g
²/H
z]range of measured accelerations (vertical) on car body, approx. 50 different cars
• micro compact car
• luxury sedan
• roadster
• SUV
• …
measured accelerations,power spectral density
PS
D [g
²/H
z]
04.07.2011Seite 8
measured accelerationsfrequency spectrum FFT
0 20 40 60 80 100 120 140 160 180 200Frequenz [Hz]
0
0.5
1
1.5
2
Bes
chle
uni g
ung
[m/s
²]
S-Klasse (Ihinger Hof)E-Klasse (Porsche)CLK (Porsche)M-Klasse (Porsche)SLK (Porsche)SLS (Porsche)Smart (Porsche)
0 20 40 60 80 100 120 140 160 180 200Frequenz [Hz]
0
0.5
1
1.5
2
Bes
chle
uni g
ung
[m/s
²]
Fahrersitzkonsole vorn links Z-Richtung
Integralträger vorn links Z-RichtungKla
re 10.0
6.2
0 11 Por-Spy
der1
0_201011
29_166_V01_Stu
PeakM
ax_
por_
90 (1.
Kurv
e)
car body - frequency spectrum
frequency [Hz]
accele
rati
on
y [
g]
micro compact car
0 5 10 15 20 25 30Frequenz [Hz]
0
0.5
1
1.5
2
Bes
chle
uni g
ung
[m/s
²]
S-Klasse (Ihinger Hof)E-Klasse (Porsche)CLK (Porsche)M-Klasse (Porsche)SLK (Porsche)SLS (Porsche)Smart (Porsche)
0 5 10 15 20 25 30Frequenz [Hz]
0
0.5
1
1.5
2
Bes
chle
uni g
ung
[m/s
²]
Fahrersitzkonsole vorn links Z-Richtung
Integralträger vorn links Z-Richtung
Kla
re 10.0
6.2
011 P
or -
Spy
der1
0_20101 1
29_166_V
01_S
tuP
eakM
ax_
por_
90 (1.
Kurv
e)
frequency [Hz]
accele
rati
on
y [
g]
car body - frequency spectrum
micro compact car
•no significant response upwards 50 Hz•highest peaks for micro compact car
04.07.2011Seite 9
0
1
2
3
4
5
6
7
8
9
10
11
12
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75frequency [Hz]
acceleration [m/s^2]
acceleration – frequency curve
• maximum acceleration 10m/s^2 (1g), maximum frequency 50 Hz• sinusoidal waveform with a logarithmic sweep
RESS vibration test proposal
frequency[Hz]
acceleration[g]
acceleration
[m/s2]5 - 18 1 10
18 - 30 0,5 530 – 50 0,2 2
04.07.2011Seite 10
At the request of the manufacturer, a higher acceleration level as well as a higher maximum frequency can be conducted. In the case of a higher maximum frequency, the lowest frequency can be greater than 5 Hz, but shall not exceed 10% of the highest frequency.
At the request of the manufacturer a test profile determined by the vehicle-manufacturer, verified to the vehicle application and agreed by the Technical Service can be used as a substitute of the frequency – acceleration correlation of the proposal.
RESS vibration test proposal
