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EQUIPMENT
Document f'.Jo.DQANlEL/2000lOOl-version-l
datedJ[Jan 2007, ''Guidelines on
Sh~--k Standards and Sheck Testing of Naval ElectronitlElectric~t EquipmeJ1tR is
fOiWarded here.vith for record and necessary action.
2.
IHQ-MoO(N} fl1aV refer these Guidelines for inclusion of Shock Standard
r~uirementsf
formulatIng
ElectronjcjEiectrteal equipment.
\'lihile
Technkaf
SpedfkationslSOTRs
of
Navat
r
~
(Devinder Singh)
Captain, IN
Director
for Pnndpai Director
IHQ-MoO(N)/DEE/f)\/JE/DJiD/Qs.f
OQA(wP)
POQAN
OQAN
'\I
!
I
I
I
I
}I
JDQAN(El)
i
f
JfXlAN{WEA)
j
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With Enclosure
P'Qfjl\liffl,,/20{)O/OB.1.-Ver
I
Dat2d,- (Jon 2007.
Guidelines on Shock Standards
and
Shock Testin9
'"aval Electronic/Electrical
of
Equipment
-~-----------------------------------------------------
Directorate of Quality Assurance (Naval)
Director General of Quality Assurance
livest Block V/ RK Puram
Ne"0J Dell1i-
110066
GUIDELINES ON SHOCK STANDARDS/SHOCK TESTING
OF NAVALElECTRONICfElECTRICAlS
i.
Introduction.
Ship/Submarine
EOUIPMENT
An undervvater explosion wH! impart to the huH of the
a force, which causes rapid local movement of both the hull
to it. Shock may also be caused by an
structure as well as equipmentat'"\Eched
explosion of a shell on board the platform. Such an explosion onboard or outside
the ship's hull results in a shock wave. The shock waVE travEls faster through the
denser water medium "than in air. This shock wave jmposes a large acCeleration
on the structure
and units/subunits
in the immediate
environment,
which is
followed by a smaller deceleration as the structural stiffness of the hull arrests
the initial movement propagated
by the shock wave. As regards shock standards
and shock testing of Engineering equipments, separate guidelines may be issued
by NHQ/Dr"lE.
2.
Factors affectinQ severity of shock wave. The magnitude of severity
of shock wave depends on: -
(a)
Mass of equipment/structure.
(b)
Installed position relative to the explosion as: -
(c)
(d)
3.
(0
Below water line/above water line.
(Ii)
Ship - side mounted or otherwise.
(Iii)
Fore/mid ship/AFT portion of ship.
Type of mounting
CO
Bulk head mounted.
(ii)
Deck mounted.
(m)
Deck-head mounted.
The type of hull structure.
Generally, in case of external explosions the severest shock is experienced
by light items rigidly attached to vessels bottom or side (below the water line)
and closest to the explosion.
4.
Shock Testing. The
follov-J!ng standards
are norma!!y consulted tor
specifying' the shock tests: Ca)
BR 3021 (1) - Shock tvlanuai (metric)
(b)
BR 3021 (2) - Shock Manua! (FOr' Shock fvlountings)
( c.1
J5S 55555
(d)
DEf 133 (Defence Specification)
: 2QOO --
Shock testing of Naval equipment.
- Ciimatic Shock and Vibration
Testing Of Service Equipment
5.
Shock.
leveis.
While testing
the equipment
for shock standards, the
severities of shock levels are specified in BR 3021 (1). As per above SR, the
following shock grades have been speeified:(a) NSS Grade I (for equipment
fitted below Water line)- 120g, 8 m see
(Vertical) and 70g, 8 m sec (lateral)
(b) NSS Grade II (For equipment
fitted above Water line) - 50g, 11m see
(Vertical) and 229, 11 m see (lateral)
6.
The Graphsof NSSI, and NSS2 Grade
curves are placed
at Appendices
"A" and "8" for ready reference.
7.
Test Procedure. jSS 55555
testing. 'Procedure
ground
two types of
procedures
for Shock
l' pertains to shipborne equipment, while 'Procedure
and airborne
shipbome equipment
4.24.1
specifies
equipment.
However,
also, jf the equipment
2' is for
the JSS permits 'Procedure 2' for
specification states so. Further Table
of JSS 55555 indicates the peak acceleration
in m/s2 and pulse duration
in
millisec for testing in vertical direction and Table 4.24.2 gives the multiplication
factor for testing
in transverse/longitudinal
direction. During conduct of testing
three shock inputs or two shock inputs in each of 6 faces along each of the three
mutually perpendicular
axis (Le. total of 18 shocks or 12 shocks for "procedure
1" or "procedure
2" respectively) shall be applied.
8.
Practice.
Onooino
Some
of
the Electrical/Electronics
have been tested in the past as per values/parameters
equipment
non-conforming
may
to the
above standards. Therefore, there is a need to Specify in future and finaHse the
applicable
of shock' seventies oepending \Joon the factors mentlonel
standards
- hr>' Ie>
a t P-dra 2 d'j""
'- ,-+
\..u,r' itn,g "ft..u"
. p\...
9_
Modaiitii"'!Sof Shock Caic[dation~. The shock values
to
be
encountE-teG
".
hI' ca,CulateG'.'ar tne o2S1gr:
"
Its 52f\flCe
user neeo m De
b Y t-h
.
'-l'"uunng
L e equIpment
stan€
itself, keenino
in mind the oiatform
where
::::
1
_
I
it
is to be fitted, ' as well as !ts
location on the platform.
10.
Actuai difficulties may be experienced in conduct of shock test where the
equipment
is bulky/iarge
in size. In such cases, instead of testing the equipment,
realistic shock calculations can be submitted by the designer, which could be
accepted after due analysis.
11.
Shock Mounts/lsolatOi"Se
equipment,
The intensity of shock transmitted to the
when they are directly mounted on the target plates, is higher than
when instaUed on shock mountings, which reduce shock values transmitted
the cabinets/equipments
to
and subunits there-in. Therefore, shock· mounts playa
very important ro~e for safety of the equipment during their service life.
Therefore, .the utmost care is to be taken for selection of shock mounts.
12.
In view of the above, equipment intended for use with shock mounts (also
called isolators)
shail be tested with its isolators to ascertain the value or shock
that the equipment would be capable to safely withstand. In case appropriate
shock mounts
irreversible
are not used during
shock test or actual fitment,
severe and
damage can be caused to structural integration of equipment[ even
though the correctly
calculated severities of shOCK are applied while testing.
."
cannot
be disrnantied to functional
calculations
$ub-assernbiies
the fviathernatlca!
51-
may be obtained from the designer of the equipment and submjtted
for analvsis/aoorGva!
of the aonmprlate
, . l'
•..{
authorities. In such cases the shock test
may be waived off and results of [\1athemat!cal Calculation (usuaHv FEfvl analysis}
accepted in Heu.
14.
Test Conditions -Severities of shock levels and number of shocks.
The test severities/shock
levels and number of shocks to be applied in
each axis and direction are to be decided as per Tables 4.24.1 and 4.24.2 of 355
555551 considering the factors mentioned
at Para Z above as well as those, if
any, stipulated in NSQR/SOTR. While determining ·the test conditions, the aspect
of "Yellow banding" also needs to be addressed.
15.
YeUov.l BandinQ. Shock testing does not induce any residual fatigue or
impair duration of service life of equipment!
if the design is appropriate and
selection of Shock mounts is as per BR 3021 (2). Therefore, yeliow banding of
Electronic/Electrical equipment after their shock test (with shock mounting) is not
required in case the equipment has been able to withstand the shock values
transmitted
it through
to
the Shock mounting. It is only in case of a failure of the
Shock mounts (due to wrong selection of isolators or their improper installation)
or in the case an equipment has been damaged consequential to applied shock,
that the shock tested equipment would need to be yellow banded. Further a
damage to electronic equipment (Structure, components etc) needs to be
differentiated from its malfunction caused due to disturbance in its parameter
setting . by
controls/adjustments.
In
case of
mechanical/electromechanical
equipments such as pumps, motors, shafts etc, a permanent misalignment or
displacement
(not easily correctable) may take piace necessitating yellow
banding as per para 3.9.3 of Sub-section 5.24 of JSS 55555. In such cases,
it is
opined that the equipment would withstand the pre-reqUisite grades and the
possibilities
the
of mechanical misalignment
selection
of
damaqesfmalfunctlons
isolators
have
manifesting itself is remote, as long as
been
appropriate.
Further
any
observed durinq shock tests need to be suitably recorded
in the Test Reports issued by the testing Laboratory vvh!ch may' [)2 for 2,g.<CQAE
having a proper Test Laboratory!
prJmarlly
meant for conducting
Envjronmenta\
Tests as per JSS 55555 and other Defence specifications as a part of Type
Testing on Defence equipment/components.
The equipment are tested free of
cost, if ordered against Defence requirements or othervvise against payment by
firms. Further firms have to provide the necessary Test Jigs for mounting the
equipment.
The facilities available at CQAE (WE) Bangalore)
Test on equipments
I
II
~
are as follows: -
rl P" 11h_msand
item
'<0.5
11
ms
and
ms
ms
0.75
MxO.75
and
IO.7M
Maximum
(b)
Half
sine
curve
Md.O
M
(H)
Md.5
NSSII800
Kg
200
!i JSS
55555
(a)
III,Iiii p-lilcabtA
Shock Specification
NSS
NSSII(c)sine
1Pulse
500
300
durations
Kg
Kg
]SS of
of
Equipment
up
to
120
98 of
IAmplitude
Test
Parameters
up
120
98fv1(H)
dimensions
(c)
Pulse
durations
(a)
Shock
Amplitude
(b) to
Half
curve
under
test
Shock
I
Verti~al
for conduct of Shock
If _
Shock Test Facilities
infrastructure
no.
i;
payioad
---TP-;y-l~ad'\Remarks--·-·----··
i Size
i
L-~--+------_· ....
1,........._.
i 1.
(Test
i!
machine!
i (Drop
i
!I (Free
.
at NSTL.
for undertakIng actual shock testlfig of eqUIpment: -
;-51--- \ Test FaCmty!
available
I
-
---+-----.-~---~-_+------_----- - -----~--------.-'
Up to 600 Kg : Im:><lm
i
:
test !
:
fair i•
i
i machine)
600 kg - 90 g
90 kg - 6009
.
I
;.
I Test machine Up to 1000 j 1.5mxl.5m
2.
Max acceieration-600g
'j
!.
I (Drop test/free I kg
!,
I
Min weight - 200 kg
I fa!! mar-hine')
i
L
I
- .
J
13 .
I
j
)
I
,
;
.
.V
.•
20no
II 25.,1
r· .•••••.
,' .••••
5,,-1
5m
I'.
Th~ p!~"o"m
,.'-
'~\..\'
VU"" __
!"s fin;;;.,tPrl
in
U.
I PtatfOr~
! kg
:
NSTL Shock tank of size
I (FSP-I
1
I
15m,,12mdOm
explosives are used in the
small)
I
I
•
J
I
I
I
j
j
i
I.
!I
II
I
I
Floating ShOCk! Upto
.
'.
15000 ( 8d:.z2m
tank
to
and
create
the
required shock fevers .
The platform is floated in
I
Platform (FSP-
I kg
!
NSTLShock tank of size
II Large)
I
I
.!
15mx12mxl0m
I
open
I
explosives are used in the
!
tank
)
I
I
I
I
II
1
or
water
to
create
in
and
the
required shock levels.
I
I
I
i
\I Shock tubes are fabricated to accommodate any size of
j
Shock tubes
5.
I
I
L_.-L
jequiPment. Very. high levels of shock pulses are
i charmelised in the shock tubes and applied on the test
I
._ I equipment.
---------------------.-.----------.
-'
18.
Test facility at Dl'1DE~Se~tmderabad
Df<1Dt nas an Impact-testing
19.
Shock Test Reoorts.
Amplitude
macfi!f!e (K-20or'1) for subjectiPQ equlpmem
The test reports should dearly state the following;-
of shocK pulse duration.
Graphical representation
[ D)
of shOCk pulse, If feasible and on
availability of required instruments
20.
(c)
The details or shock testing machine used.
(d)
Damages/malfunction
(e)
Recommendation on yellow banding.
observed.
Analvsis of Shock Test Results.
ana lysed along with their design documents
well as Mathematical
The test reports are required to be
like selection of Shock mounts as
Calculation (FEJlti analysis) of acceptable residual Shock
levels. OEMs may approach Naval Headquarters, or through them NSTL1
Vishakhapatnam for .any guidance on above. These may be also suitably
incorporated
in SOTRs; so that
equipment
manufacturers approach the
appropriate authority for any clarification, waivers etc.
21.
Authority for Waiver or reduction of severity levels.
manufacturers
Equipment
need to approach Naval authorities for any waiver of shock test or
reduction in their severity level for technical/administrative
reasons, though the
primary reason could be a fear of failure of the equipment, due to the shock
testing. It is recommended that all test conditions need to be incorporated in the
RFP/lndent
stage .and any subsequent requests for reduction of shock level or
waiver of shock test must be forwarded by OEM to either the order placing
Authority or the concerned Professional Directorate of NHQ. NHQ may seek
additional
purview.
data,
if
required,' from DQA(N)fDQA(WP)
for equipment
under their
BR 30:1 Vol I
.'
(
Ch:!p I
r ,)
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. UWJJI
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6 1 8~
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100
MASS Of ITfM IN TONNES
Fig 1.9 NSSI Grade Olives
4.11,
1.15
llR 3Q21 Vol I
Q.llp 1
;...::,
f.
/
"
,-
loll
1
II
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2
I
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•
•
7
1
6
z
1000
..on
10
..,.
.~
Q
:(
5
tlo
c
Z
-<
\0 ~
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to'1
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2
~ L OlsrlACEMENT
~
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i·1
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I.g.
10
0.'
11
a
3
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,;
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0.1
1.0
IJ
100
r
l~
Fig 1.10 NSS2 Grade Curves
r
l
IIi
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,tot
.,
AmJ! I 4.70
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