SRS Tool is a professional Shock Response Spectrum (SRS) analysis application built for structural dynamics engineers working with OROS NVGate data acquisition systems. It reads shock recordings directly from NVGate measurement folders, computes SRS using the Smallwood (1981) recursive digital filter, and pushes results back into NVGate as live TCP result channels — all from a single application.
Figure 1 — SRS Tool main window. Time signal with auto-detected shock zone (top right, yellow markers) and log-log SRS plot (bottom right). Three-channel triaxial measurement loaded: channels x, y, z.
NVGate injection: injects all SRS curves into NVGate on log-log display, autoscaled
Preprocessing: DC offset removal, noise floor suppression
Dark theme: optimised for lab-room screen visibility
Quick Start
⚡ Five steps from measurement folder to qualification verdict
Main tab → Select signal folder… → navigate to the NVGate Measurement folder
Channels appear automatically — shock zone is auto-detected (yellow markers on signal plot)
Set Q = 10, range 1–10 000 Hz, resolution 1/12 oct → click Compute SRS
Pass / Fail tab → limit curve is pre-set to MIL-STD-810H Mid-field → click ▶ Run Pass / Fail
Read the per-channel verdict, export CSV / PNG, or click Inject into NVGate
Installation
Note: NVGate does not need to be running to load signals or compute SRS. It is only required for Inject into NVGate.
Main Tab
Figure 2 — Main tab controls. From top: NVGate connection indicator, Signal folder, channel checkboxes with Reload, Calculation parameters, Output type selectors, Compute and Inject buttons.
Signal
Click Select signal folder… to open a folder browser (default root: C:\OROS\NVGate data\Projects). Select the Measurement folder — channels are listed and the signal is plotted immediately.
Channels
One checkbox per recorded channel, showing label, sampling rate, duration and unit:
☑ x (25 600 Hz 13.86 s m/s²)
☑ y (25 600 Hz 13.86 s m/s²)
☑ z (25 600 Hz 13.86 s m/s²)
Channel labels (x, y, z…) come from the Name field set by the operator in NVGate at recording time.
Uncheck a channel to exclude it. ↺ Reload channels re-reads files from disk after a new recording.
Calculation parameters
Parameter
Description
Recommended default
Frequency range
f_min to f_max of the SRS output
1 Hz → 10 000 Hz
Q / Damping
Q factor or damping ratio ζ (linked: Q = 1/2ζ)
Q = 10 (ζ = 5 %)
Resolution
Octave subdivision: 1/3, 1/6, 1/12, 1/24 oct
1/12 octave
Q = 10 (ζ = 5%) is the universal standard for aerospace shock SRS — MIL-STD-810H, ECSS-E-ST-10-03C, NASA-STD-7003A all specify this value. f_max is auto-clamped to Nyquist (f_s / 2).
Output
Type
Acc — Acceleration SRS. Always available. Vel — Pseudo-velocity SRS. Disp — Pseudo-displacement SRS. (Vel and Disp require an acceleration input.)
Curve
Maximax — max(positive, |negative|). The standard curve required by most norms. Positive — max tensile response. Negative — max compressive response.
Signal and SRS plots
Figure 3 — Time signal plot. Three channels (x/y/z) overlaid. Yellow dashed lines mark the auto-detected shock zone. Drag horizontally anywhere on the plot to redefine the zone manually.
Figure 4 — SRS log-log plot. Channels x (blue), y (orange), z (green). Each curve is the Maximax acceleration SRS over the detected shock zone. Q = 10, 1/12 octave, 1–10 000 Hz.
Injecting results into NVGate
Click Inject into NVGate (or the duplicate button in the Advanced tab) to send all computed curves via the NVDrive TCP protocol as NVD REAL SPECTRUM channels:
All SRS curves → separate TCP result channels
X and Y axes: log scale (set automatically)
Y axis: autoscaled
All curves displayed in window SRS_Results of Layout1
NVGate channel naming convention:
SRS Acc Shock AbsMax: x
SRS Acc Shock AbsMax: y
SRS Acc Shock AbsMax: z
The shock zone is auto-detected every time a signal loads — you normally do not need to touch these settings. Use manual override only to fine-tune the boundary.
Auto-detection
The detection algorithm:
Compute a smoothed envelope: rolling mean of |signal| over a 3 ms window
Trigger threshold = Threshold % × peak envelope
Zone = first to last sample above threshold
Expand by Padding ms on each side, clamped to signal bounds
Parameter
Effect
Default
Threshold (% of peak)
Lower → wider zone; higher → core impact only
5 %
Padding (ms)
Symmetric margin added on both sides of detected zone
20 ms
Padding example: shock detected at 8.055 s – 9.978 s with 20 ms padding → zone becomes 8.035 s – 9.998 s, ensuring ring-down is fully captured.
Manual override
Type Start and End (seconds, 3-decimal precision) — the yellow markers on the signal plot update immediately.
Dragging on the signal plot synchronises the spinboxes in return.
Residual SRS
Check Also compute residual SRS to run a second computation on the signal after the shock zone end. This captures the free-vibration decay required by MIL-STD-810H Method 517 and ECSS-E-ST-10-03C for fragility assessment. Residual curves appear on the SRS plot labelled "(residual)".
Advanced Preprocessing
Option
Effect
Typical use
Remove DC offset (N ms)
Subtracts the mean of the first N ms from the whole signal
Sensor bias, thermal drift
Noise floor (N ms)
Zeroes the first N ms
Pre-trigger noise before impact
Multi-axis Combination
Enabled automatically when ≥ 2 acceleration channels are loaded. Check one or both options before computing:
Option
Formula
Display
SRSS — Square Root Sum of Squares
√(SRS_x² + SRS_y² + SRS_z²)
White dashed curve, Maximax only
Worst-case Envelope
max(SRS_x, SRS_y, SRS_z) at each frequency
Orange dash-dot curve, all types
Pass / Fail Tab
Figure 6 — Pass/Fail controls. Grouped limit curve library (30+ curves), user CSV option, scale factor, channel selector, Run button, and export buttons.
The Pass/Fail tab compares computed SRS against any normative or user-defined limit curve.
Built-in limit curve library
30+ normative curves are pre-programmed — select a standard from the grouped drop-down and run immediately. No other standalone SRS tool provides this library out of the box.
Standard
Curves included
MIL-STD-810H — Method 517
Near-field (< 0.3 m), Mid-field ★ (0.5–1.5 m), Far-field (> 1.5 m), Gunfire, Tall vehicles
ECSS-E-ST-10-03C
Protoflight, Proto+, Acceptance, Qualification, Protoqualification (equipment & system level)
NASA-STD-7003A
Payload near/far-field, structure-borne near/far
DEF-STAN 00-35
Land vehicle, Ship (deck), Airborne external/internal
MIL-S-901D
High-impact shock Grade A / Grade B
IEST-RP-DTE032
Light / medium / heavy equipment
RTCA DO-160G
Avionics Cat. A / B / C
★ MIL-STD-810H Mid-field is the default — the most common qualification specification.
User-defined CSV
Select ← User-defined (CSV), load a two-column file (Hz, g). Interpolation is log-log linear between breakpoints. Example:
10, 5 100, 50 2000, 50 10000, 50
Scale factor (dB)
Scales the limit curve before comparison: L_scaled(f) = L_nominal(f) × 10^(dB/20)
dB
Multiplier
Typical use
+6
×2.00
Conservative / tighter requirement
+3
×1.41
Standard qualification margin check
0
×1.00
Nominal — no change
−6
×0.50
Relaxed limit
Pass/Fail results
Figure 7 — Pass/Fail chart. Three channels (x/y/z) vs MIL-STD-810H Mid-field limit (red dashed). All channels are well within spec: the margin subplot (bottom) shows 30–60 dB positive margin throughout the full frequency range.
Top panel — SRS vs Limit
Each channel plotted in a distinct colour. Limit curve: red dashed. Red fill = exceedance (SRS > limit). Orange fill = caution zone (0 ≤ margin < 3 dB).
Bottom panel — Margin (dB)
Margin M(f) = 20 × log₁₀( Limit(f) / SRS(f) )
Colour
Condition
Meaning
Green
M ≥ 3 dB
Well within specification
Orange
0 ≤ M < 3 dB
Caution — low margin
Red
M < 0 dB
FAIL — exceedance
Interactive cursor
Hover anywhere on either panel to see a floating readout snapped to the nearest frequency band, showing frequency, SRS value, limit value, margin in dB, and PASS/FAIL status. The readout border turns green, orange or red accordingly.
Verdict text
The result box below the chart shows global verdict, per-channel minimum margin, and the 10 worst exceedance frequencies. Example output:
PASS — Maximax SRS
Limit: MIL-STD-810H Meth.517 — Mid-field (0.5–1.5 m)
Per-channel result:
PASS x min +42.1 dB @ 500 Hz
PASS y min +38.7 dB @ 342 Hz
PASS z min +45.3 dB @ 1000 Hz
Worst margin (all channels): +38.7 dB @ 342.0 Hz
No exceedance detected over the computed frequency range.
Export
Button
Output
Content
Export CSV…
.csv
Per-channel SRS · Worst SRS · Limit · Per-channel margin · Worst margin · Status. Header block includes curve name and scale factor for traceability.
Export graph PNG…
.png / .pdf
Both panels at 150 dpi.
Calculation Reference
Shock Response Spectrum
The SRS is the peak response of a bank of Single Degree Of Freedom (SDOF) oscillators, each with a different natural frequency f_n, driven by a common base acceleration x(t):
z(t) + 2ζωₙz'(t) + ωₙ²z(t) = −x(t)
Curve
Definition
Standard?
Positive SRS
maxt[ ωₙ² z(t) ]
Supplementary
Negative SRS
maxt[ −ωₙ²z(t) ]
Supplementary
Maximax SRS
max(Positive, Negative)
Required by most norms
Smallwood Recursive Filter
The Smallwood (1981) filter avoids step-by-step numerical integration, giving an exact discrete-time equivalent with coefficients computed once per frequency:
All N natural frequencies are processed in a single forward pass through the signal using NumPy broadcasting — typically 50–100× faster than a frequency-by-frequency loop.
Frequency axis
Log-spaced at 1/n octave: f_k = f_min × 2^(k/n)
Resolution
Bands 1–10 000 Hz
1/3 octave
40
1/6 octave
80
1/12 octave (default)
160
1/24 octave
320
Q factor and damping
Q = 1/(2ζ) ↔ ζ = 1/(2Q)
Q
ζ
Use
10
5 %
Aerospace standard — MIL-STD-810, ECSS, NASA
50
1 %
Lightly damped structures
5
10 %
Rubber-mounted, heavily damped
Primary and Residual SRS
Zone
Signal segment
Required by
Primary
[t_start → t_end] — the shock transient
All norms
Residual
[t_end → end] — free vibration decay
MIL-STD-810H §517, ECSS §8.4.3
Pseudo-velocity and pseudo-displacement
Quantity
Formula
Unit (SA in m/s²)
Pseudo-velocity
SV(fn) = SA(fn) / (2π·fn)
m/s
Pseudo-displacement
SD(fn) = SA(fn) / (2π·fn)²
m
Multi-axis combination
Method
Formula
Applied to
Use case
SRSS
√(SA_x² + SA_y² + SA_z²)
Maximax only
Euclidean resultant, triaxial sensor
Worst-case Envelope
max(SA_x, SA_y, SA_z) at each f
All types
Space programmes (ECSS App. H)
Supported Input Units
Unit
Physical quantity
Vel/Disp SRS available
m/s², g
Acceleration
✔ Yes
m/s, mm/s
Velocity
✘ No
m, mm, µm
Displacement
✘ No
N, kN
Force
✘ No
V, mV
Voltage
✘ No
Pa, N/m²
Pressure
✘ No
rad/s, RPM
Angular velocity
✘ No
Glossary
Term
Definition
SRS
Shock Response Spectrum. Peak SDOF response as a function of natural frequency.
Maximax
Negative|). The absolute peak response — required by most norms.
SDOF
Single Degree Of Freedom. A mass–spring–damper system with one resonant frequency.
Q factor
Quality factor. Q = 1/(2ζ). Q = 10 is the universal aerospace standard.
Symmetric time margin added around the auto-detected shock zone.
Pyroshock
Shock from explosive devices: separation bolts, pyrocutters, pin pullers.
.orm
NVGate JSON channel metadata: sampling rate, unit, name.
.ors
NVGate binary signal: float32 little-endian samples, SI units.
NVDrive
OROS TCP protocol for programmatic communication with NVGate.
Appendix SRS Limit Curves — Normative Reference
This page documents all predefined SRS limit curves available in the SRS Tool.
Each curve is identified by a confidence level tag shown next to its name in the interface.
Confidence level indicators
Tag
Meaning
What to expect
[normative]
Curve taken directly from the published standard as an SRS specification.
Breakpoints are faithful to the document. Use for compliance testing.
[approximate]
Standard defines a time-domain waveform (half-sine, sawtooth…), not an SRS.
The SRS envelope is computed from the pulse shape. For exact results, import the waveform and run compute_srs() on it.
[indicative]
Levels depend on mounting position, equipment mass or mission profile, or the exact document version was not available.
Use as a first-pass estimate only. Always verify with the applicable programme document.
All curves use Q = 10 (damping ζ = 5 %) and acceleration units (g).
Between breakpoints, interpolation is log-log linear (constant dB/octave slope).
Summary table
Standard
Sector
Tag
Application
Peak level
Freq. range
NASA GEVS 2500 g
Space
normative
Hardware on primary structure
2 500 g
20–10 000 Hz
NASA GEVS 1000 g
Space
normative
Hardware on panel or bracket
1 000 g
20–10 000 Hz
NASA GEVS 3750 g (Qual.)
Space
normative
Qualification unit (dedicated test article)
3 750 g
20–10 000 Hz
Ariane 5 Equipment Bay
Space
indicative
Satellite equipment bay, component level
2 000 g
100–10 000 Hz
Ariane 6
Space
indicative
All payload positions, component level
1 600 g
100–10 000 Hz
VEGA-C
Space
indicative
Small satellite missions, component level
1 200 g
100–10 000 Hz
ECSS-E-ST-10-03C Protoqual.
Space
indicative
European space programmes, proto-qualification
2 000 g
20–10 000 Hz
MIL-STD-810H M517 Near-field
Military / Pyro
normative
Equipment < 0.5 m from pyrotechnic source
10 000 g
100–10 000 Hz
MIL-STD-810H M517 Mid-field
Military / Pyro
normative
Equipment 0.5–1.5 m from pyrotechnic source
1 000 g
100–10 000 Hz
MIL-STD-810H M517 Far-field
Military / Pyro
normative
Equipment > 1.5 m from pyrotechnic source
100 g
100–10 000 Hz
MIL-STD-810H M516 Functional 40 g
Military / Mech
approximate
Functional shock — must operate before and after
80 g (2×A)
5–2 000 Hz
MIL-STD-810H M516 Crash 40 g
Military / Mech
approximate
Crash hazard — must not endanger personnel
60 g
5–2 000 Hz
MIL-STD-810H M516 Bench 15 g
Military / Mech
approximate
Bench handling — drops during maintenance
30 g
5–2 000 Hz
MIL-S-901D Grade A
Military / Naval
indicative
US Navy lightweight shipboard equipment (< 136 kg)
2 000 g
20–10 000 Hz
MIL-S-901D Grade B
Military / Naval
indicative
US Navy medium-weight equipment (136–2 268 kg)
1 000 g
20–10 000 Hz
DO-160G Cat. B 6 g
Aviation
approximate
Airborne equipment — operational flight shock
12 g
5–2 000 Hz
DO-160G Cat. C 15 g
Aviation
approximate
Avionics — bench handling during maintenance
30 g
5–2 000 Hz
DO-160G Cat. D 20 g
Aviation
approximate
Airborne equipment — crash / emergency landing
40 g
5–2 000 Hz
DEF STAN 00-35 Cat. M
European Defence
indicative
UK defence — general military ground equipment
1 000 g
10–10 000 Hz
DEF STAN 00-35 Cat. P
European Defence
indicative
UK defence — aircraft store / weapon release
2 000 g
100–10 000 Hz
GAM EG-13 Choc sévère
European Defence (DGA)
indicative
French military — pyrotechnic devices, ejection seats
2 000 g
20–10 000 Hz
GAM EG-13 Choc modéré
European Defence (DGA)
indicative
French military — vehicle impacts, transport drops
500 g
10–5 000 Hz
STANAG 4370 AECTP-201 M417
NATO
indicative
NATO — pyroshock, severity level 3
2 000 g
100–10 000 Hz
STANAG 4370 AECTP-201 M403
NATO
approximate
NATO — mechanical shock, severity level 3
50 g
5–2 000 Hz
IEC 60068-2-27 15 g / 11 ms
Industrial
approximate
General industrial / commercial equipment qualification
Railway — equipment mounted on vehicle body (interior)
6 g
2–2 000 Hz
IEC 61373 Cat.1 Class A
Railway
approximate
Railway — bogie-mounted equipment (running gear)
15 g
2–2 000 Hz
IEC 61373 Cat.2 Under-body
Railway
approximate
Railway — under-body / axle-box mounted equipment
50 g
2–2 000 Hz
Confidence level indicators
Tag
Meaning
What to expect
[normative]
Curve taken directly from the published standard as an SRS specification.
Breakpoints are faithful to the document. Use for compliance testing.
[approximate]
Standard defines a time-domain waveform (half-sine, sawtooth…), not an SRS.
The SRS envelope is computed from the pulse shape. For exact results, import the waveform and run compute_srs() on it.
[indicative]
Levels depend on mounting position, equipment mass or mission profile, or the exact document version was not available.
Use as a first-pass estimate only. Always verify with the applicable programme document.
All curves use Q = 10 (damping ζ = 5 %) and acceleration units (g).
Between breakpoints, interpolation is log-log linear (constant dB/octave slope).
Space / Launcher
NASA GEVS — Protoflight, 2500 g (GSFC-STD-7000B)
Field
Value
Tag
[normative]
Reference
NASA GSFC-STD-7000B Rev B (2013)
Application
Hardware mounted on primary structure
Description: Protoflight SRS for hardware mounted on primary structure. The curve rises at +9 dB/oct from 20 Hz, reaching a flat plateau of 2 500 g above 100 Hz. Breakpoints are faithful to the published standard.
Frequency (Hz)
Level (g)
20
224
100
2 500
10 000
2 500
NASA GEVS — Protoflight, 1 000 g (GSFC-STD-7000B)
Field
Value
Tag
[normative]
Reference
NASA GSFC-STD-7000B Rev B (2013)
Application
Hardware mounted on a panel or bracket
Description: Lower protoflight level for panel- or bracket-mounted hardware. Same +9 dB/oct slope, plateau at 1 000 g. Choose between 2 500 g and 1 000 g based on the mounting position specified in the programme's MTP/ATP.
Frequency (Hz)
Level (g)
20
89
100
1 000
10 000
1 000
NASA GEVS — Qualification, 3 750 g (GSFC-STD-7000B)
Field
Value
Tag
[normative]
Reference
NASA GSFC-STD-7000B Rev B (2013)
Application
Qualification test (1.5 × protoflight 2 500 g level)
Description: Qualification SRS = 1.5 × protoflight 2 500 g level, per GSFC-STD-7000B. Applied when a dedicated qualification unit is available (as opposed to protoflight testing, which tests the flight unit at a lower margin).
Description: Representative SRS at the equipment bay for Ariane 5 missions. Covers separation events (SYLDA, VEB, fairing jettison, etc.). Actual levels depend on satellite integration position — contact Arianespace for flight-specific requirements.
Frequency (Hz)
Level (g)
100
100
2 000
2 000
10 000
2 000
Ariane 6 — Component Level
Field
Value
Tag
[indicative]
Reference
Ariane 6 User's Manual Issue 1 Rev 0 (2020)
Application
Component level, all payload positions
Description: Component-level SRS for Ariane 6 missions. Slightly lower than Ariane 5 thanks to the improved fairing and dispenser design. Contact Arianespace for actual flight requirements.
Frequency (Hz)
Level (g)
100
80
2 000
1 600
10 000
1 600
VEGA-C — Component Level
Field
Value
Tag
[indicative]
Reference
VEGA-C User's Manual Issue 0 Rev 1 (2022)
Application
Small satellite missions, component level
Description: Component-level SRS for VEGA-C missions. Contact Avio / ESA for actual flight requirements.
Description: Representative proto-qualification SRS for European space programmes. ECSS-E-ST-10-03C defines the methodology and test flow, not a universal level. Actual levels must come from the programme's System Verification Plan (SVP).
Frequency (Hz)
Level (g)
20
50
100
500
2 000
2 000
10 000
2 000
Military / Pyroshock — MIL-STD-810H Method 517
Method 517 (Pyroshock) is one of the few military standards that defines SRS limits directly — all three curves below are therefore [normative].
MIL-STD-810H Meth.517 — Near-field (< 0.5 m)
Field
Value
Tag
[normative]
Reference
MIL-STD-810H, Method 517.2, Table 517.2-IV
Application
Equipment < 0.5 m from the pyrotechnic source
Description: Pyroshock near-field SRS. Rises at +9 dB/oct from 100 Hz, reaching a flat plateau of 10 000 g above 3 000 Hz. This is the most severe of the three field classifications.
Frequency (Hz)
Level (g)
100
61
3 000
10 000
10 000
10 000
MIL-STD-810H Meth.517 — Mid-field (0.5–1.5 m)
Field
Value
Tag
[normative]
Reference
MIL-STD-810H, Method 517.2, Table 517.2-IV
Application
Equipment 0.5–1.5 m from the pyrotechnic source
Description: Pyroshock mid-field SRS. Same +9 dB/oct slope, plateau at 1 000 g above 3 000 Hz. 10× lower than near-field (20 dB).
Frequency (Hz)
Level (g)
100
6
3 000
1 000
10 000
1 000
MIL-STD-810H Meth.517 — Far-field (> 1.5 m)
Field
Value
Tag
[normative]
Reference
MIL-STD-810H, Method 517.2, Table 517.2-IV
Application
Equipment > 1.5 m from the pyrotechnic source
Description: Pyroshock far-field SRS. Plateau at 100 g above 3 000 Hz. 100× lower than near-field (40 dB).
Frequency (Hz)
Level (g)
100
0.6
3 000
100
10 000
100
Military / Mechanical Shock — MIL-STD-810H Method 516
Method 516 defines time-domain waveforms (half-sine, sawtooth), not SRS limits directly. The SRS envelopes below are computed from those pulses and are therefore [approximate]. For exact compliance, import the waveform into the SRS Tool and compute the SRS directly.
MIL-STD-810H Meth.516.8 — Functional, 40 g half-sine
Field
Value
Tag
[approximate]
Reference
MIL-STD-810H, Method 516.8, Procedure I
Waveform
40 g / 11 ms half-sine
Description: Functional shock — equipment must operate normally before and after. The standard defines a 40 g, 11 ms half-sine pulse. The SRS envelope peaks near 1/(2τ) ≈ 45 Hz at 2×A = 80 g and flattens to the peak amplitude above.
Frequency (Hz)
Level (g)
5
80
45
80
200
40
2 000
40
MIL-STD-810H Meth.516.8 — Crash Hazard, 40 g sawtooth
Field
Value
Tag
[approximate]
Reference
MIL-STD-810H, Method 516.8, Procedure V
Waveform
40 g / 11 ms terminal sawtooth
Description: Crash hazard — equipment must not become a hazard during a crash. The terminal sawtooth waveform has a broader SRS plateau than a half-sine of the same amplitude.
Frequency (Hz)
Level (g)
5
60
100
60
500
40
2 000
40
MIL-STD-810H Meth.516.8 — Bench Handling, 15 g half-sine
Field
Value
Tag
[approximate]
Reference
MIL-STD-810H, Method 516.8, Procedure VI
Waveform
15 g / 11 ms half-sine
Description: Bench handling — simulates drops and knocks during handling and maintenance. Lower level than functional shock.
Frequency (Hz)
Level (g)
5
30
45
30
200
15
2 000
15
Military / Naval — MIL-S-901D
MIL-S-901D specifies a physical machine test (Lightweight Shock Machine or floating barge), not an SRS limit. The curves below are [indicative] envelopes representative of the machine output.
MIL-S-901D — Grade A (lightweight, < 136 kg)
Field
Value
Tag
[indicative]
Reference
MIL-S-901D (1989), Grade A
Application
US Navy — lightweight equipment (< 136 kg)
Description: High-energy naval shock test for lightweight equipment. Uses the Lightweight Shock Machine (LWSM). Representative SRS envelope of the machine output.
Frequency (Hz)
Level (g)
20
100
100
500
2 000
2 000
10 000
2 000
MIL-S-901D — Grade B (mediumweight, 136–2 268 kg)
Field
Value
Tag
[indicative]
Reference
MIL-S-901D (1989), Grade B
Application
US Navy — medium-weight equipment (136–2 268 kg)
Description: Naval shock using the floating barge platform. Lower levels than Grade A due to the larger test article mass and different test rig.
Frequency (Hz)
Level (g)
20
50
100
250
2 000
1 000
10 000
1 000
Aviation — RTCA DO-160G Section 7
DO-160G Section 7 defines time-domain shock pulses, not SRS limits. All three curves are [approximate] envelopes computed from those pulses.
DO-160G Sect.7 — Cat. B, Operational (6 g half-sine)
Field
Value
Tag
[approximate]
Reference
RTCA DO-160G, Section 7, Category B
Waveform
6 g / 11 ms half-sine
Description: Aircraft operational shock — in-service turbulence, hard landings, taxiing. The least severe DO-160G shock category.
Frequency (Hz)
Level (g)
5
12
45
12
200
6
2 000
6
DO-160G Sect.7 — Cat. C, Bench Handling (15 g half-sine)
Field
Value
Tag
[approximate]
Reference
RTCA DO-160G, Section 7, Category C
Waveform
15 g / 11 ms half-sine
Description: Bench handling shock for avionics — drops, knocks during maintenance. Matches MIL-STD-810H Procedure VI levels.
Frequency (Hz)
Level (g)
5
30
45
30
200
15
2 000
15
DO-160G Sect.7 — Cat. D, Crash (20 g)
Field
Value
Tag
[approximate]
Reference
RTCA DO-160G, Section 7, Category D
Waveform
20 g equivalent crash pulse
Description: Crash / emergency landing survivability requirement. Equipment must not create a hazard to occupants during a crash sequence.
Frequency (Hz)
Level (g)
5
40
45
40
200
20
2 000
20
European Defence
DEF STAN 00-35 Pt.3 — Category M (Mechanical)
Field
Value
Tag
[indicative]
Reference
DEF STAN 00-35 Part 3 Issue 4, Category M
Application
UK defence — general mechanical shock
Description: UK Ministry of Defence standard for general mechanical shock environments. Levels depend on the platform category. Always verify against the Test Schedule (TS) applicable to the programme.
Frequency (Hz)
Level (g)
10
25
100
250
2 000
1 000
10 000
1 000
DEF STAN 00-35 Pt.3 — Category P (Pyrotechnic)
Field
Value
Tag
[indicative]
Reference
DEF STAN 00-35 Part 3 Issue 4, Category P
Application
UK defence — aircraft store separation (pyrotechnic)
Description: Pyrotechnic shock for aircraft-delivered stores (bombs, missiles). More severe than Category M. Verify against the applicable Test Schedule.
Frequency (Hz)
Level (g)
100
100
1 000
2 000
10 000
2 000
GAM EG-13 — Choc sévère (pyrotechnique)
Field
Value
Tag
[indicative]
Reference
DGA GAM EG-13 (2002), Tableau 3, Choc sévère
Application
French DGA — severe pyrotechnic shock environment
Description: French DGA (Direction Générale de l'Armement) standard for severe shock, typically from pyrotechnic devices (ejection seats, weapon release). Verify exact levels in Table 3 of the applicable programme document.
Frequency (Hz)
Level (g)
20
40
100
200
1 000
2 000
10 000
2 000
GAM EG-13 — Choc modéré (mécanique)
Field
Value
Tag
[indicative]
Reference
DGA GAM EG-13 (2002), Tableau 3, Choc modéré
Application
French DGA — moderate mechanical shock environment
Description: French DGA standard for moderate mechanical shock (vehicle impacts, transport drops). Significantly lower levels than the pyrotechnic environment.
Frequency (Hz)
Level (g)
10
20
100
100
1 000
500
5 000
500
NATO — STANAG 4370 / AECTP 201
STANAG 4370 AECTP 201 — Meth.417 Pyroshock
Field
Value
Tag
[indicative]
Reference
STANAG 4370 AECTP 201, Method 417 (Ed.3, 2009)
Application
NATO — pyroshock, severity level 3 (severe platform)
Description: NATO standardised pyroshock test method (SRS method). The curve shown is representative of severity level 3 (severe platform shock). Actual levels must be drawn from the applicable NATO programme documents.
Frequency (Hz)
Level (g)
100
50
1 000
2 000
10 000
2 000
STANAG 4370 AECTP 201 — Meth.403 Mechanical Shock
Field
Value
Tag
[approximate]
Reference
STANAG 4370 AECTP 201, Method 403 (Ed.3, 2009)
Waveform
Half-sine pulse, severity level 3
Description: NATO mechanical shock — Method 403 defines time-domain pulses (half-sine), not SRS directly. The curve shown is an SRS envelope computed from the severity level 3 half-sine waveform.
Frequency (Hz)
Level (g)
5
50
50
50
500
25
2 000
25
Industrial — IEC 60068-2-27
IEC 60068-2-27 (Test Ea) defines half-sine time-domain pulses, not SRS limits. All curves are [approximate].
IEC 60068-2-27 — Test Ea, 15 g / 11 ms half-sine
Field
Value
Tag
[approximate]
Reference
IEC 60068-2-27 Ed.3 (2008), Test Ea — 15 g / 11 ms
Application
General industrial equipment — standard shock level
Description: Standard environmental test shock (Test Ea). Widely used for industrial and commercial equipment qualification. 15 g / 11 ms half-sine is the most common combination.
Frequency (Hz)
Level (g)
5
30
45
30
200
15
2 000
15
IEC 60068-2-27 — Test Ea, 50 g / 11 ms half-sine
Field
Value
Tag
[approximate]
Reference
IEC 60068-2-27 Ed.3 (2008), Test Ea — 50 g / 11 ms (severe)
Application
Industrial equipment — severe shock level
Description: Severe industrial shock. Used for rugged equipment or harsh installation environments.
Frequency (Hz)
Level (g)
5
100
45
100
200
50
2 000
50
IEC 60068-2-27 — Test Ea, 100 g / 6 ms half-sine
Field
Value
Tag
[approximate]
Reference
IEC 60068-2-27 Ed.3 (2008), Test Ea — 100 g / 6 ms
Application
Industrial equipment — harsh shock level
Description: Harsh shock level — short duration (6 ms) shifts the SRS peak to ~83 Hz. Used for equipment exposed to impacts, sudden accelerations, or harsh transport.
Frequency (Hz)
Level (g)
5
200
83
200
500
100
2 000
100
Railway — IEC 61373
IEC 61373 defines time-domain shock pulses for railway equipment. All curves are [approximate].
IEC 61373 Cat.1 Class B — Railway, Vehicle Body
Field
Value
Tag
[approximate]
Reference
IEC 61373 Ed.2 (2010), Category 1 Class B
Application
Equipment mounted on the vehicle body (interior)
Description: Functional shock for body-mounted railway equipment. IEC 61373 defines a 3 g / 30 ms half-sine. The long duration (30 ms) places the SRS peak at only ~16 Hz — the lowest peak frequency of all curves in the library.
Frequency (Hz)
Level (g)
2
6
16
6
200
3
2 000
3
IEC 61373 Cat.1 Class A — Railway, Bogie-Mounted
Field
Value
Tag
[approximate]
Reference
IEC 61373 Ed.2 (2010), Category 1 Class A
Application
Equipment mounted on the bogie (running gear)
Description: Bogie-mounted equipment is directly exposed to rail irregularities and rail joints. Significantly higher levels than Class B (vehicle body). IEC 61373 defines a time-domain pulse, not an SRS.
Frequency (Hz)
Level (g)
2
15
16
15
200
8
2 000
8
IEC 61373 Cat.2 — Railway, Under-Body Mounted
Field
Value
Tag
[approximate]
Reference
IEC 61373 Ed.2 (2010), Category 2
Application
Under-body mounted equipment, axle box area
Description: Most severe shock category in IEC 61373. Under-body equipment (including axle-box area) is exposed to the highest shock levels on a railway vehicle.
Frequency (Hz)
Level (g)
2
50
16
50
200
25
2 000
25
Summary table
Standard
Sector
Tag
Peak level
Freq. range
NASA GEVS 2500 g
Space
normative
2 500 g
20–10 000 Hz
NASA GEVS 1000 g
Space
normative
1 000 g
20–10 000 Hz
NASA GEVS 3750 g (Qual.)
Space
normative
3 750 g
20–10 000 Hz
Ariane 5 Equipment Bay
Space
indicative
2 000 g
100–10 000 Hz
Ariane 6
Space
indicative
1 600 g
100–10 000 Hz
VEGA-C
Space
indicative
1 200 g
100–10 000 Hz
ECSS-E-ST-10-03C Protoqual.
Space
indicative
2 000 g
20–10 000 Hz
MIL-STD-810H M517 Near-field
Military / Pyro
normative
10 000 g
100–10 000 Hz
MIL-STD-810H M517 Mid-field
Military / Pyro
normative
1 000 g
100–10 000 Hz
MIL-STD-810H M517 Far-field
Military / Pyro
normative
100 g
100–10 000 Hz
MIL-STD-810H M516 Functional 40 g
Military / Mech
approximate
80 g (2×A)
5–2 000 Hz
MIL-STD-810H M516 Crash 40 g
Military / Mech
approximate
60 g
5–2 000 Hz
MIL-STD-810H M516 Bench 15 g
Military / Mech
approximate
30 g
5–2 000 Hz
MIL-S-901D Grade A
Military / Naval
indicative
2 000 g
20–10 000 Hz
MIL-S-901D Grade B
Military / Naval
indicative
1 000 g
20–10 000 Hz
DO-160G Cat. B 6 g
Aviation
approximate
12 g
5–2 000 Hz
DO-160G Cat. C 15 g
Aviation
approximate
30 g
5–2 000 Hz
DO-160G Cat. D 20 g
Aviation
approximate
40 g
5–2 000 Hz
DEF STAN 00-35 Cat. M
European Defence
indicative
1 000 g
10–10 000 Hz
DEF STAN 00-35 Cat. P
European Defence
indicative
2 000 g
100–10 000 Hz
GAM EG-13 Choc sévère
European Defence (DGA)
indicative
2 000 g
20–10 000 Hz
GAM EG-13 Choc modéré
European Defence (DGA)
indicative
500 g
10–5 000 Hz
STANAG 4370 AECTP-201 M417
NATO
indicative
2 000 g
100–10 000 Hz
STANAG 4370 AECTP-201 M403
NATO
approximate
50 g
5–2 000 Hz
IEC 60068-2-27 15 g / 11 ms
Industrial
approximate
30 g
5–2 000 Hz
IEC 60068-2-27 50 g / 11 ms
Industrial
approximate
100 g
5–2 000 Hz
IEC 60068-2-27 100 g / 6 ms
Industrial
approximate
200 g
5–2 000 Hz
IEC 61373 Cat.1 Class B
Railway
approximate
6 g
2–2 000 Hz
IEC 61373 Cat.1 Class A
Railway
approximate
15 g
2–2 000 Hz
IEC 61373 Cat.2 Under-body
Railway
approximate
50 g
2–2 000 Hz
How the SRS Tool uses these curves
Select a curve in the Pass/Fail tab.
The tool interpolates the curve at the same frequency resolution as the measured SRS using log-log linear interpolation.
Positive margin → SRS is below the limit (PASS at that frequency)
Negative margin → SRS exceeds the limit (FAIL at that frequency)
The overall result is PASS only if the margin is positive at all frequencies.
Adding a custom curve
You can import your own limit curve via a two-column CSV file (frequency Hz, level g) using the Load CSV button in the Pass/Fail tab. The SRS Tool applies the same log-log interpolation as built-in curves.
Algorithm: D.O. Smallwood, An Improved Recursive Formula for Calculating Shock Response Spectra, Shock and Vibration Bulletin, 1981. ·
Standards referenced: MIL-STD-810H (2019) · ECSS-E-ST-10-03C (2012) · NASA-STD-7003A (2011) · DEF-STAN 00-35 Part 3 (2021).
