ISO 19453-3:2018

INTERNATIONAL ISO
STANDARD 19453-3
First edition
2018-03
Road vehicles — Environmental
conditions and testing for electrical
and electronic equipment for
drive system of electric propulsion
vehicles —
Part 3:
Mechanical loads
Véhicules routiers — Spécifications d'environnement et essais
de l'équipement électrique et électronique pour les véhicules à
propulsion électrique —
Partie 3: Contraintes mécaniques
Reference number
©
ISO 2018
© ISO 2018
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Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Tests and requirements . 2
4.1 Vibration . 2
4.1.1 General. 2
4.1.2 Tests . 4
4.2 Mechanical shock .11
4.2.1 Shock I — Test for devices on rigid points on the body and on the frame .11
4.2.2 Shock II — Test for devices in or on the gearbox.11
4.3 Free fall .12
4.3.1 Purpose .12
4.3.2 Test .12
4.3.3 Requirements .13
4.4 Surface strength/scratch and abrasion resistance .13
4.5 Gravel bombardment .13
5 Code letters for mechanical loads .13
6 Documentation .13
Annex A (informative) Guidelines for the development of test profiles for vibration tests .14
Annex B (informative) Recommended mechanical requirements for equipment depending
on the mounting location .39
Bibliography .40
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
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on the ISO list of patent declarations received (see www .iso .org/ patents).
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constitute an endorsement.
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expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/ iso/ foreword .html
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 32,
Electrical and electronic components and general system aspects.
A list of all parts in the ISO 19453 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 19453-3:2018(E)
Road vehicles — Environmental conditions and testing for
electrical and electronic equipment for drive system of
electric propulsion vehicles —
Part 3:
Mechanical loads
1 Scope
This document specifies requirements for the electric propulsion systems and components with
maximum working voltages according to voltage class B. It does not apply to high voltage battery packs
(e.g. for traction) and systems or components inside. It describes the potential environmental stresses
and specifies tests and requirements recommended for different stress levels on/in the vehicle.
This document describes mechanical loads.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 16750-1, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 1: General
ISO 19453-1, Road vehicles — Environmental conditions and testing for electrical and electronic equipment
for drive system of electric propulsion vehicles — Part 1: General
ISO 19453-4:2018, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment for drive system of electric propulsion vehicles — Part 4: Climatic loads
IEC 60068-2-14, Environmental testing — Part 2-14: Tests — Test N: Change of temperature
IEC 60068-2-27, Environmental testing — Part 2-27: Tests — Test Ea and guidance: Shock
IEC 60068-2-31, Environmental testing — Part 2-31: Tests — Test Ec: Rough handling shocks, primarily for
equipment-type specimens
IEC 60068-2-64, Environmental testing — Part 2-64: Tests — Test Fh: Vibration, broadband random and
guidance
IEC 60068-2-80, Environmental testing — Part 2-80: Tests — Test Fi: Vibration — Mixed mode
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16750-1 and ISO 19453-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
4 Tests and requirements
4.1 Vibration
4.1.1 General
The vibration test methods specified consider various levels of vibration severities applicable to on-
board electrical and electronic equipment. The customer and the supplier should choose the test
method, environmental temperature and vibration parameters depending on the specific mounting
location.
The following basic idea of environmental test methods is expressed in MIL -STD -810G: 2008, Foreword.
When applied properly, the environmental management and engineering processes described in
this document can be of enormous value in generating confidence in the environmental worthiness
and overall durability. However, it is important to recognize that limitations inherent in laboratory
testing make it imperative to use proper caution and engineering judgment when extrapolating these
laboratory results to results that can be obtained under actual service conditions. In many cases, real
world environmental stresses (singularly or in combination) cannot be duplicated practically or reliably
in test laboratories. Therefore, users of this document should not assume that a system or component
that passes laboratory tests of this document would also pass field/fleet verification trials.
The specified values are the best estimation one can get up to the moment when results from
measurements in the vehicle are received, but they do not replace a vehicle measurement.
The specified values apply to direct mounting in defined mounting locations. The use of a bracket for
mounting can result in higher or lower loads. Vibration tests shall be carried out according to actual
vehicle conditions.
Carry out the vibration with the DUT suitably mounted on a vibration table. The mounting method(s)
used shall be noted in the test report. Carry out the frequency variation by logarithmic sweeping of
0,5 octave/min for the sinusoidal vibration part of sine-on-random tests. The scope of the recommended
vibration tests is to avoid malfunctions and breakage mainly due to fatigue in the field. Testing for wear
has special requirements and is not covered in this document.
Loads outside the designated test frequency ranges shall be considered separately.
NOTE Deviations from the load on the DUT can occur, should vibration testing be carried out according
to this document on a heavy and bulky DUT, as mounting rigidity and dynamic reaction on the vibrator table
excitation are different compared to the situation in the vehicle. Such deviations can be minimized by applying
the average control method (see A.3).
The application of the weighted average control method in accordance with IEC 60068-2-64 may be
agreed upon.
During the vibration test, subject the DUT to the temperature cycle in accordance with IEC 60068-2-
14, with electric operation according to Figure 1. Alternatively, a test at constant temperature may be
agreed on.
Operate the DUT electrically as indicated in Figure 1 at T (short functional test after the DUT
min
completely reached T ). This functional test shall be as short as possible ― only long enough to check
min
the proper performance of the DUT. This minimizes self-heating of the DUT. A long period of electric
operation is started at room temperature (RT) in order to allow possible condensation of humidity
on the DUT. A permanent operation starting at T would prevent this due to the electric power
min
dissipation.
Additional drying of test chamber air is not permitted.
In the vehicle, vibration stress can occur together with extremely low or high temperatures; for this
reason, this interaction between mechanical and temperature stress is simulated in the test, too. A
2 © ISO 2018 – All rights reserved

failure mechanism occurs, for example, when a plastic part of a system/component mellows due to the
high temperature and cannot withstand the acceleration under this condition.
In case of doubt, a separate measurement shall be performed to determine what soak time at max. or
min. ambient temperature is necessary to warrant that this desired temperature is also reached in the
core of the DUT. The core temperature shall be maintained for at least one hour during the vibration
test; therefore the temperature cycle shall be adjusted accordingly.
Measures regarding the functional performance are allowed to avoid overheating of the DUT during
high-temperature operation with self-heating effects.
The complete profile of temperature cycle duration of T and that of T shall be more than 1 h. The
min max
supplier and the customer shall agree on a complete profile of temperature cycle.
Key
T temperature, in °C
t time, in h
T minimum operating temperature as defined in ISO 19453-4
min
T maximum operating temperature as defined in ISO 19453-4
max
RT room temperature as defined in ISO 19453-1
t , t , t , t , t , t time parameter (as defined in Table 1)
1 2 3 4 5 6
a
Operating mode 4.2 as defined in ISO 19453-1.
b
Operating mode 2.1 as defined in ISO 19453-1.
c
One cycle.
Figure 1 — Temperature profile for the vibration test
If operating mode 4.2 is not technically feasible, operating mode 3.2 may be used. For electric motors,
active operation in operating mode 3.2 or 4.2 can be performed in order to avoid unrealistic failure
mechanisms, e.g. wear in the bearings due to the vibration input.
Table 1 — Temperature versus time for the vibration test
Parameter Duration Temperature
h
t As agreed From RT to T
1 min
t > 1 Stabilized time at T
2 min
t As agreed From T to RT
3 min
t As agreed From RT to T
4 max
t > 1 Stabilized time at T
5 max
t As agreed From T to RT
6 max
NOTE  T and T are defined in ISO 19453-4:2018, Table 1. (codes A to X). In the vehicle environment, some equipment
min max
can experience different conditions regarding temperature, temperature gradients and duration: in all these cases, code Z
is used.
4.1.2 Tests
4.1.2.1 Test I — Passenger car, powertrain (combustion engine, gearbox)
4.1.2.1.1 Purpose
This test checks the DUT on the powertrain for malfunctions and/or breakage caused by vibration.
The vibrations on the powertrain can be split up into three kinds:
— sinusoidal vibration that results from the unbalanced mass forces in the cylinders;
— random vibration due to all other vibration schemes of an engine, e.g. closing of valves; and
— random vibration due to the influence of rough-road conditions.
NOTE If the DUT needs to be tested for a specific resonance effect, then a resonance dwell test in accordance
with 8.3.2 of IEC 60068-2-6:2007 can also be applied.
4.1.2.1.2 Test
4.1.2.1.2.1 General
Vibration of powertrain is the sine-on-random vibration induced by crankshaft rotation and engine
combustion. A separate test condition covers random vibration from road surface. The test duration
shall be at least as long as one temperature cycle necessary to ensure thermal stability in the DUT.
NOTE 1 The test duration is based on A.4.1.2 and A.4.1.3. The test duration and vibration load level can be
adjusted accordingly based on the Basquin’s equation given in A.6.
NOTE 2 When agreed between the supplier and the customer, the test duration can be adjusted based on
Basquin’s model by taking into account the slope k of the S-N curve specific to this component (see also A.6). For
the component which is freely placed or is not anticipated to be installed in a certain position and orientation
(e.g. inverter), the maximum profile out of all three axes can be applied to all three axes.
NOTE 3 As the driveshaft of an electric motor is always parallel to the ground floor, it is reasonable to have a
direction-specific profile, separating vertical excitations from horizontal ones.
The definition of the coordinate system is shown in Table A.3.
4 © ISO 2018 – All rights reserved

4.1.2.1.2.2 Sine-on-random vibration
This test shall be performed as a mixed mode vibration test in accordance with IEC 60068-2-80.
a) Sinusoidal vibration part
A sweep rate of 0,5 octave/min or less shall be used.
The test duration is 33 h for each axis of the DUT.
The profiles in Table 2 and Figure 2 show the sinusoidal vibration part of the sine-on-random profile.
Key
Y acceleration amplitude, in m/s
f frequency, in Hz
1 curve for X axis
2 curve for Y axis
3 curve for Z axis
Figure 2 — Acceleration versus frequency
Table 2 — Values for maximum acceleration versus frequency
X axis Y axis Z axis
Acceleration Acceleration Acceleration
Frequency Frequency Frequency
amplitude amplitude amplitude
2 2 2
Hz m/s Hz m/s Hz m/s
100 10 100 15 100 15
200 25 180 50 200 30
440 25 240 50 440 30
— — 260 30 — —
— — 440 30 — —
b) Random vibration part
Perform the test in accordance with IEC 60068-2-64.
The test duration is 33 h for each axis of the DUT.
The RMS acceleration value shall be 68,7 m/s . For the random part of the sine-on-random profile, the
vibration loads are equivalent for all three primary axes. Therefore, only one profile for all three axes
shall be used.
The power spectral density (PSD) versus frequency is illustrated in Figure 3 and Table 3.
NOTE The PSD values (random vibration) are reduced in the frequency range of the sinusoidal vibration
test of 100 to 500 Hz as well as in the low-frequency range of 10 to 100 Hz as the rough-road influence has been
eliminated (see A.4.1.1).
Key
2 2
Y PSD, in (m/s ) /Hz
f frequency, in Hz
Figure 3 — PSD of acceleration versus frequency
Table 3 — Values for PSD and frequency
Frequency PSD
2 2
Hz (m/s ) /Hz
10 0,1
300 0,1
500 3
2 000 3
4.1.2.1.2.3 Random vibration
As the excitation from the combustion engine and gearbox at high engine speeds usually does not occur
simultaneously with rough-road excitation, a separate test with a broadband random profile has been
created.
In the lowest frequency range from 10 Hz to 100 Hz, the influence of rough-road conditions is taken into
account. The main failures to be identified by this test are malfunctions and/or breakage due to fatigue.
This rough-road profile shall be applied to the very same DUT that has been submitted to the sine-on-
random test described above. After the mixed mode vibration test, a random vibration test is performed
in accordance with IEC 60068-2-64.
6 © ISO 2018 – All rights reserved

The test duration is 10 h for each axis of the DUT.
The RMS acceleration value for all three primary axes shall be 21,4 m/s .
The PSD versus frequency is illustrated in Figure 4 and Table 4.
Key
2 2
Y PSD, in (m/s ) /Hz
f frequency, in Hz
Figure 4 — PSD of acceleration versus frequency
Table 4 — Values for PSD versus frequency
Frequency PSD
2 2
Hz (m/s ) /Hz
10 3
100 3
300 0,05
2 000 0,05
4.1.2.1.3 Requirements
Malfunctions and/or breakage shall not occur.
Functional status class A as defined in ISO 19453-1 is required during operating mode 3.2 and/or 4.2 as
defined in ISO 19453-1, and functional status C is required during periods with other operating modes.
4.1.2.2 Test II — Passenger car, sprung masses (vehicle body)
4.1.2.2.1 Purpose
This test checks the DUT on the vehicle body for malfunctions and/or breakage caused by vibration.
4.1.2.2.2 Test
4.1.2.2.2.1 General
Vibration of the vehicle body is the random vibration induced by rough-road driving. The main failure
to be identified by this test is breakage due to fatigue.
NOTE 1 The test duration is based on A.5.1.2 and A.5.1.3. According to Annex A, 20 h of test duration per axis
are equivalent to 6 000 h (240 000 km at 40 km/h average speed) lifetime requirement of the vehicle.
NOTE 2 When the test conditions cannot be realized as the test system is not capable of exciting a heavy DUT
with the given profile, the load and duration can be adjusted according to the Basquin model (see A.6).
The definition of the coordinate system is shown in Table A.2.
4.1.2.2.2.2 Random vibration
Perform the test in accordance with IEC 60068-2-64 (random vibration).
The test duration is 20 h for each axis of the DUT.
The RMS acceleration value for all three primary axes shall be 13,3 m/s .
The PSD versus frequency is illustrated in Figure 5 and Table 5.
Key
2 2
Y PSD, in (m/s ) /Hz
f frequency, in Hz
Figure 5 — PSD of acceleration versus frequency
8 © ISO 2018 – All rights reserved

Table 5 — Values for PSD and frequency
Frequency PSD
2 2
Hz (m/s ) /Hz
10 17
100 0,33
500 0,000 6
1 000 0,000 6
4.1.2.2.3 Requirements
Malfunctions and/or breakage shall not occur.
Functional status class A as defined in ISO 19453-1 is required during operating mode 3.2 and/or 4.2 as
defined in ISO 19453-1, and functional status C is required during periods with other operating modes.
4.1.2.3 Test III — Electric vehicle, (directly equipped with) electric motor
4.1.2.3.1 Purpose
This test checks the DUT for malfunctions and/or breakage caused by vibration.
4.1.2.3.2 Test
4.1.2.3.2.1 General
Vibration of electric motors is the random vibration induced by rough-road driving. The main failure to
be identified by this test is breakage due to fatigue.
NOTE 1 The test duration is based on A.5.1.2 and A.5.1.3. According to Annex A, 20 h of test duration per axis
are equivalent to 6 000 h (240 000 km at 40 km/h average speed) lifetime requirement of the vehicle.
NOTE 2 When the test conditions cannot be realized as the test system is not capable of exciting a heavy DUT
with the given profile, the load and duration can be adjusted according to the Basquin model (see A.6).
NOTE 3 As the driveshaft of an electric motor is always parallel to the ground floor, it is reasonable to have a
direction-specific profile, separating vertical excitations from horizontal ones.
The definition of the coordinate system is shown in Table A.4.
4.1.2.3.2.2 Random vibration
Perform the test in accordance with IEC 60068-2-64 (random vibration).
The test duration is 20 h for each axis of the DUT.
The RMS acceleration values for all three primary axes shall be:
— X:  35,1 m/s ,
— Y:  20,5 m/s ,
— Z:  36,2 m/s .
The PSD versus frequency is illustrated in Figure 6 and Table 6.
For the component which is freely placed or is not anticipated to be installed in a certain position and
posture (e.g. inverter), the maximum profile out of all primary three axes shall be applied to all primary
three axes.
Key
2 2
Y PSD, in (m/s ) /Hz
f frequency, in Hz
1 curve for X axis
2 curve for Y axis
3 curve for Z axis
Figure 6 — PSD of acceleration versus frequency
Table 6 — Values for PSD and frequency
Frequency PSD
2 2
Hz (m/s ) /Hz
X axis Y axis Z axis
10 55 11 55
40 28 11 28
120 0,02 0,02 0,06
1 000 0,02 0,02 0,06
4.1.2.3.3 Requirements
Malfunction and/or breakage shall not occur.
Functional status class A as defined in ISO 19453-1 is required during operating mode 3.2 and/or
4.2 as defined in ISO 19453-1, and functional status class C is required during periods with other
operating modes.
10 © ISO 2018 – All rights reserved

4.2 Mechanical shock
4.2.1 Shock I — Test for devices on rigid points on the body and on the frame
4.2.1.1 Purpose
This test checks the DUT for malfunctions and/or breakage caused by a shock to the body and frame.
The load occurs when driving over a curb stone at high speed, etc. The failure mode is a mechanical
damage (e.g. a detached capacitor inside the housing of the DUT, such as on-board power electronics
components, due to the occurring high accelerations).
4.2.1.2 Test
Perform the test in accordance with IEC 60068-2-27 using the following test parameters:
— operating mode of the DUT:  3.2 as defined in ISO 19453-1;
— pulse shape:  half-sinusoidal;
— acceleration:  500 m/s ;
— duration:  6 ms;
— number of shocks:  10 per test direction.
The acceleration due to the shock in the test shall be applied in the same direction as the acceleration of
the shock which occurs in the vehicle. If the direction of the effect is not known, the DUT shall be tested
in all six spatial directions.
4.2.1.3 Requirements
Malfunction and/or breakage shall not occur.
The functional status shall be class A as defined in ISO 19453-1.
4.2.2 Shock II — Test for devices in or on the gearbox
4.2.2.1 Purpose
This test checks the DUT for malfunctions and/or breakage caused by a shock of gear shifting.
This test is applicable to DUT intended for mounting in or on the gearbox.
The loads occur during pneumatic powered gear-shifting operations. The failure mode is a mechanical
damage (e.g. a detached capacitor inside the housing of an electronic control module due to the high
accelerations caused by pneumatically powered gear-shifting operations).
4.2.2.2 Test
Perform the test in accordance with IEC 60068-2-27 using the following test parameters:
— operating mode of the DUT:  3.2 as defined in ISO 19453-1;
— pulse shape:  half-sinusoidal;
— typical maximum acceleration:  to be agreed between the customer and the supplier;
— typical duration:  < 1 ms;
— temperature:  to be agreed between the customer and the supplier;
— number of shocks:  to be agreed between the customer and the supplier.
The actual shock stresses depend both on the installation position of the gearbox and on the design
features of the gearbox: in individual cases, it shall be ascertained by means of suitable measurements
(recommended sampling frequency: 25 kHz or more). A test shall be arranged between the supplier and
the customer.
The acceleration due to the shock in the test shall be applied in the same direction as the acceleration of
the shock which occurs in the vehicle. If the direction of the effect is not known, the DUT shall be tested
in all six spatial directions.
4.2.2.3 Requirements
Malfunction and/or breakage shall not occur.
The functional status shall be class A as defined in ISO 19453-1.
4.3 Free fall
4.3.1 Purpose
This test checks the DUT for malfunctions and/or breakage caused by free fall.
A system/component can drop down to the floor during handling (e.g. at the manufacturing line of the
vehicle manufacturer). If a system/component is visibly damaged after a fall, it is replaced, but if it is not
visibly damaged, it is installed in the vehicle and shall work correctly. The failure mode is a mechanical
damage (e.g. a detached capacitor inside the housing of the DUT, such as on-board power electronics
components, due to the occurring high accelerations when the DUT hits the ground).
4.3.2 Test
Parts that are obviously damaged by the fall shall not be checked (e.g. headlights). Parts that can
withstand falling without visible damage shall be checked as follows:
Perform the test sequence in accordance with IEC 60068-2-31 using the following test parameters:
— number of DUTs:  3;
— falls per DUT:  2;
— drop height:  selected from Table 7;
— impact surface:  concrete ground or steel plate;
— orientation of the DUTs:  first fall of each DUT on a different dimensional axis; second fall with the
given DUT on the same dimensional axis, but on the opposite side of the housing;
— operating mode of the DUTs:  1.1 as defined in ISO 19453-1;
— temperature:  to be agreed between the customer and the supplier.
The DUTs shall be visually examined after the falls.
12 © ISO 2018 – All rights reserved

Table 7 — Value for drop height
Code Drop height
mm
A 250
B 100
C 25
Z As agreed
NOTE  Further information on a suitable drop height depending on the
mass of the DUT can be found in IEC 60068-2-31:2008, 5.2.3.
4.3.3 Requirements
Hidden damage is not permitted. Minor damage of the housing is permitted as long as this does not
affect the performance of the DUT. Proper performance shall be proven following the test.
The functional status shall be class C as defined in ISO 19453-1.
4.4 Surface strength/scratch and abrasion resistance
The supplier and the customer shall agree on tests and requirements (e.g. marking and labelling on
control elements and keys shall remain visible).
4.5 Gravel bombardment
This test checks the resistance against gravel bombardment (in exposed mounting locations, e.g.
front end).
5 Code letters for mechanical loads
For code letters for mechanical loads, see Table 8. Recommended mechanical requirements for the DUT
depending on the mounting location are given in Annex B (Table B.1).
Table 8 — Coding in relation to tests and requirements
Requirement according to
Section 4.1.2.1 4.1.2.2 4.1.2.3 4.2.1 4.2.2 4.3
Code letter Test I Test II Test III Shock I Shock II Free fall
A yes — — — — yes
B yes — — — yes yes
C — yes — — — yes
D — yes — yes — yes
E — — yes — — yes
F — — yes — yes yes
Z As agreed
6 Documentation
For documentation, the designations outlined in ISO 19453-1 shall be used.
Annex A
(informative)
Guidelines for the development of test profiles for vibration tests
A.1 Scope
The aim of these guidelines is to make sure that the user of this document is able to develop test profiles
from vibration measurements in a reproducible way thus avoiding errors.
A.2 General
The process of creating test profiles is clarified using the recommended documentation and is described
in Tables A.1 to A.5.
Table A.1 — Test profile definition
Item Description
Nominal speed n : nominal speed with maximum power output of the engine
nominal
Maximum speed n : maximum safe engine speed
max
Table A.2 — Vehicle axes
Item Description
X’: driving direction
Vehicle axes Y’: perpendicular to driving direction and vertical axis
Z’: vertical axis
Table A.3 — Powertrain axes
Item Description
X: crankshaft direction
Powertrain axes Y: perpendicular to crankshaft and piston direction
Z: piston direction
Table A.4 — e-motor axes
Item Description
X : driving direction (as the driveshaft of an electric motor is always parallel to the
EM
ground floor)
e-motor axes
Y : perpendicular to driving direction and vertical axis
EM
Z : vertical axis
EM
Table A.5 lists some basic definitions used to assess a vehicle measurement in order to create a test
profile. The coordinate systems for the vehicle and powertrain are shown in Tables A.2 and A.3 and are
taken from DIN 70003, which also gives other valuable information regarding procedures for a vehicle
measurement of vibrational loads.
14 © ISO 2018 – All rights reserved

Table A.5 — Development of test profiles for vibration tests
Recommended documentation/
Item Documentation Comments
parameters
Technical data (e.g. power, max.
Description of the
−1
min , nominal speed, displacement,
vehicle
kind of engine, number of cylinders)
Full load
Powertrain
There is some indication that higher
Dynamometer and/or road
mounted
values can occur at trailing throttle
condition.
Boundary
conditions Proving ground/test track description —
Body Road surfaces (e.g. Belgian block,
—
mounted washboard, hip hop, etc.)
Driving speed —
Sampling frequency ≥ 2,5 times of f f = frequency limit for evaluation
max max
Block length b ≥ 2 k —
Resolution LSB < 0,1 % of max. value LSB = least significant bit
Anti-aliasing filter at f with
max
Filtering techniques
> 48 db/octave, high pass filter —
and methods
( f < f ) to avoid offset
filter min.
If the engine revolution increases too
Engine speed Engine speed increase rate, e.g.
fast, there is a possibility that exist-
−1
increase 3 000 min /min
ing resonances are not detected.
Make sure that the frequency resolu-
tion is higher than the difference of
Vehicle
excitation frequency while ramping
data
engine speed. Otherwise the fast
gathering
Fourier transform (FFT) values will
Delta f = f /b
sampling
Frequency
be wrong.
resolution, Delta f
e.g. 12 500/2 048 = 6,1 Hz
Example: Delta f = 1 Hz leads to a win-
dow length of 1 s. But for a ramping
−1
engine speed with 1 000 min /min
th
during 1 s, even the 4 order will
sweep more than 1 Hz.
Cooling water temperature, oil
Description of engine conditions and
temperature
Temperature DUT conditions (esp. elastic
DUT temperature (DUT measuring
suspensioned DUT)
point and mounting area)
Table A.5 (continued)
Recommended documentation/
Item Documentation Comments
parameters
Reference for creating the
Peak-hold FFT Peak-hold sinusoidal vibration part of a
sine-on-random test
Give information: amplitude value or
Peak-hold and all
—
other spectra
RMS value shown?
Hanning for stationary signals (no
—
transient signal)
Windowing
Data
No windowing for transient signals
—
analysis
(crest factor > 6)
RMS versus
— —
speed/time
Arithmetically averaged PSD from Reference for creating random tests
the time windows with the highest or the random part of a sine-on-ran-
Signal characteris-
RMS value dom test
tic (sinusoidal/ran-
dom part of signal) Waterfall diagram —
Auto-correlation for stationary signals —
Methods and
processes used to E.g. describe all key points including
—
develop the test data reduction (averaging/enveloping)
profile
m-value = gradient of S-N curve. Its
value is 5 when the test duration is
adjusted in accordance with A.6
For powertrain mounted
Methods and Explain assumptions and models
component, the test duration is
procedures used used to correlate field stress and ser-
calculated according to the engine
to determine or vice life with test stress and duration,
speed distribution as shown in prin-
calculate the test e.g. as in MIL-STD-810G with m-value
ciple in A.4.
duration based on most critical material.
Test profile
For vehicle body mounted
develop-
components, the test duration is
ment
verified according to rough-road per-
centage in A.5.
For powertrain
Take the engine speed distribution
mounted —
into account.
components
For vehicle body
Take the mileage of bad road condi-
mounted —
tions into account.
components
Rationale for the
methods —
Processes and — —
engineering
judgement
A.3 Average control method
Generally the responses of a DUT (response level at the natural frequencies) mounted in the vehicle
and mounted on the vibration table differ because of the different mounting rigidity and the different
dynamic feedback for both cases.
To be able to reproduce the vibration tests in the laboratory, the vibration fixture shall be as stiff as
possible and therefore normally much stiffer than in the car.
16 © ISO 2018 – All rights reserved

It is also taken into account that the mounting points of the DUT move normally in phase on the
vibration fixture, whereas the mounting points in the vehicle might not move in phase at the specific
natural frequencies of the DUT. The reason is the higher stiffness of the test fixture compared to the
mounting situation in the vehicle.
Furthermore the dynamic feedback of the DUT during the vibration test (attenuation of the excitation)
is minimized by the vibration control unit.
This leads to much higher response peaks in case of resonance during the shaker test compared to the
response in the vehicle with similar excitation at least for heavy/bulky DUT.
To avoid over testing it can be necessary to apply the average control method according to IEC 60068-
2-64 Fh.
NOTE There are two different ways of carrying out average control methods (multipoint control strategies):
— weighted average control out of excitation and response of the DUT.
Recommended weighting: averaged control signal = 3 × excitation + 1 × response of the DUT.
— (“unweighted”) average control out of several control point signals on the mounting of the DUT, each
weighted with the same factor.
It shall be ensured that the DUT is not “undertested”; the stress in the laboratory shall be high enough
to cover the field conditions (e.g. by measuring the response of the DUT and spectra comparison or
fatigue calculation).
A.4 Method for determining the vibration profile and test duration on/in
powertrain
A.4.1 General
A.4.1.1 Vibration profile
In ISO 16750-3, a vibration profile for engine mounted components is defined to take into account
not only engine vibration but also road vibration, where the engine vibration occurs due to its high
speed rotation and the road vibration is due to the most severe conditions during rough-road driving.
However, the profile containing both types of excitations is too severe for components covered by this
document, and a new sequential test has been developed, which is composed of a sine-on-random test
covering engine vibration in high engine speed driving conditions and a random test covering road
vibration in low speed driving conditions (see Figure A.1).
Key
2 2
Y PSD, in (m/s ) /Hz
f frequency, in Hz
1 low speed driving on rough roads
2 high engine speed driving on flat roads
Figure A.1 — Vibration loads and vehicle speed
The vibration severity is lower than in the profiles in ISO 16750-3 due to the increased mass and inertia
of the DUT, compared to small sensors or ECUs covered by ISO 16750-3.
In ISO 16750-3, one profile is applied to all axes (X, Y and Z), enveloping measured loads in each axis.
In this document, a different profile is applied to each axis because powertrain components are usually
mounted in a certain position and orientation, and the vibration of each axis can be different.
A.4.1.2 Test duration
−1
There is a general relation between the rotational speed (min ) and the vibration level caused by engine
rotation. For fatigue testing, it is sufficient to consider the speed range with the highest acceleration
levels. According to the measurement result of an actual plug-in hybrid electric vehicle (PHEV), as
shown later, the accumulated dwell time in the engine speed range between 0,9 n and n was
nominal max
found to be 0,55 % of the overall lifetime requirement of the vehicle.
From the above result, the test duration of 33 h for each axis in sine-on-random test was calculated
by assuming a 6 000 h lifetime. This means a mileage of 240 000 km at a vehicle speed of 40 km/h on
average.
Since road vibration to powertrain mounted components attenuates through mount insulators, the
influence of vibration during flat road driving is negligible, but it is taken into account during rough-
road driving. Considering that the percentage of rough roads is approximately 10 %, the duration of the
random vibration test could be 600 h, i.e. 10 % of 6 000 h of lifetime. However, this is too long, therefore
it has been changed from 600 h to 10 h by the following procedure.
A.4.1.3 Readjusting of vibration profile with an example of test acceleration
According to the duration change from 600 h to 10 h, the vibration profile is readjusted by the following
formula which is based on the Basquin model, known as a theoretical method to accelerate fatigue tests
with equivalent damage. A general explanation of the model is provided in A.6.
W T m
1 2
=
 
W T
2 1
 
18 © ISO 2018 – All rights reserved

W
W =
T 
2 m
 
 
T
 1 
W
=
10
 
 
=×23, W
where
W is the RMS level in the original test duration from rough-road driving;
W is the RMS level in the readjusted test duration of 10 h;
T is the endurance testing time in the original test duration from rough-road driving;
T is the endurance testing time in the readjusted test duration;
m is the acceleration coefficient.
A.4.2 Verification of load in engine speed distribution
A.4.2.1 Procedure
As aforementioned, it is sufficient to consider the engine vibration load from the high speed range
between 0,9 n and n with the highest acceleration levels. This is verified by the following steps:
nominal max
a) recording of the engine speed distribution in the market driving (see A.4.2.2.1);
b) measurement of acceleration levels with an engine speed increase on the chassis dynamometer
(see A.4.2.2.2);
c) determination of the load distribution from the measured time history (cycle counting method)
(see A.4.2.2.3);
d) analysis of the number of cycles in the classed acceleration levels and engine speeds (see A.4.2.2.4);
e) verification of the dominant load from the high engine speed range (see A.4.2.2.5).
A.4.2.2 Result of the case study
A.4.2.2.1 Recording of the engine speed distribution in the market driving
When starting this study, an engine speed distribution is chosen. It has been recorded using a PHEV
with a HV battery delivering a 35 km mileage of pure electric driving which can be considered typical
of the variety of PHEV models available at the time of drafting this document. During the recording,
different types of roads have been used, such as inner-city road (39 %), countryside road (44 %) and
highway (17 %) to give a representative mixture of usages.
Due to the capability of pure electric driving, the combustion engine is completely shut off for a
significant amount of time.
Apart from that, the engine speed distribution is similar to that of ISO 16750-3:2012, A.4. The same
approach was used in determining engine speeds normalized on the nominal engine speed with the
highest power output. A probability distribution is shown in Figure A.2 and Table A.6.
...