Shock Control Test Advanced Tutorial

Complete Step-by-Step Guide for Running a Shock Control Test

Spectral Dynamics Panther Control System
Modern Vibration Test Control System

Section 1: INTRODUCTION & SAFETY OVERVIEW

⚠ CRITICAL SAFETY WARNING: Shock testing produces extremely high instantaneous accelerations (50-10,000+ g) and forces. A single misplaced bolt or improperly mounted accelerometer can result in equipment destruction, flying debris, and serious personnel injury. This tutorial emphasizes safety at every step.

About This Tutorial

This comprehensive tutorial provides detailed, step-by-step procedures for conducting classical shock vibration tests using the Spectral Dynamics Panther Shock Control system. Every procedure, parameter, and safety consideration is explained in detail to ensure successful, safe testing.

Panther Shock Control represents over 50 years of Spectral Dynamics innovation in transient waveform control. From the first digital vibration controller in 1969 to today's state-of-the-art Panther system, Spectral Dynamics has continuously advanced the technology that protects your test articles and delivers accurate, repeatable shock test results.

What is Shock Testing?

Shock testing subjects a Device Under Test (DUT) to a transient acceleration event - typically a single pulse or series of pulses lasting milliseconds. Unlike continuous vibration (sine or random), shock events are discrete, high-amplitude, short-duration accelerations that simulate handling drops, transportation impacts, or operational shocks.

Shock testing answers critical questions:

Will the product survive a drop from packaging height?
Can electronics withstand handling during installation?
Will aerospace components survive pyrotechnic separation events?
Does packaging provide adequate protection?
What is the damage threshold and safety margin?
Where are structural weak points?

Critical Safety Considerations for Shock Testing

⚠ DANGER: Shock testing is the most hazardous form of vibration testing. Peak accelerations can reach 1000+ g with forces exceeding 100,000 lbf instantaneously. Component or fixture failure can launch debris at high velocity.

Unique Hazards of Shock Testing:

Extremely high peak accelerations (50-10,000+ g possible)
Instantaneous forces with no warning or ramp-up
Violent motion - fixture or DUT can become projectile
No time to react once shock pulse initiated
Cumulative damage - each shock weakens structure
Resonance amplification can multiply input by 10× or more

MANDATORY Safety Requirements:

ALL personnel trained in shock testing before operating
Safety barriers or shields REQUIRED for >100g tests
Minimum 10-foot clear zone around shaker
Safety glasses MANDATORY
Emergency stop button accessible and tested
Never leave shock test unattended
Inspect ALL mounting hardware before EVERY shock
Use stud-mounted accelerometers for >50g shocks
Verify force limits calculated correctly
Start at reduced amplitude (25-50%) for initial characterization

Panther Superior Safety Capability: Panther Shock Control uses ultra-high-speed acquisition up to 262,144 samples/second with 24-bit resolution - capturing complete shock pulse detail with <4 microsecond time resolution. This is 10-50× faster than competitive systems. Panther performs comprehensive pre-test validation BEFORE executing each shock, calculating expected peak force and verifying safety limits.

Section 2: PRE-TEST SAFETY INSPECTION

⚠ MANDATORY: This inspection checklist must be completed before EVERY shock test. A single overlooked item can result in equipment destruction or injury.

Step 2.1: Shaker System Physical Inspection

Foundation and Mounting Verification:

☐ All foundation bolts present and torqued
☐ No cracks in foundation
☐ Armature moves freely through full stroke
☐ No binding or roughness detected
☐ Head expander (if used) properly mounted
☐ All fasteners present with lock washers

Step 2.2: Fixture Inspection:

☐ ALL mounting holes occupied with proper fasteners
☐ Grade 8 bolts recommended for shock
☐ Torque verified with calibrated wrench
☐ No cracks or damage visible
☐ Fixture weight documented

Step 2.3: DUT Mounting

⚠ CRITICAL: DUT mounting failure is the most common cause of shock test failures.

☐ DUT positioned correctly per test procedure
☐ ALL mounting fasteners present and torqued
☐ DUT cannot rock or shift when tested manually
☐ No overhang beyond fixture support
☐ DUT weight documented

Step 2.4: Accelerometer Installation

⚠ CRITICAL: Use stud mount for ALL shocks >50g. Adhesive mounting unreliable for high-g shock.

Accelerometer mounting is THE most critical measurement consideration. High-g shocks create enormous forces on the sensor. A 100g shock on a 20-gram sensor creates 44 pounds of force on that tiny sensor.

Select mounting location with flat surface
Tap hole to proper thread size (10-32 or 1/4-28 typical)
Install mounting stud with anti-seize compound
Torque stud: 20-30 in-lbs for 10-32
Thread accelerometer onto stud
Torque accelerometer per manufacturer spec (10-30 in-lbs typical)
Install safety wire for >200g shocks
Verify sensor oriented correctly
Route cable with strain relief

Step 2.5: Clearance Verification

Shock pulses create significant displacement. Calculate expected displacement and verify adequate clearance.

Formula (Half-Sine): Displacement = (Amplitude × Duration²) × 386.4 / (π² × 4)

Example: 100g, 11ms
Displacement = (100 × 0.011²) × 386.4 / 39.48 = 0.118 inches

Require 2× safety factor: 0.24 inches minimum clearance

☐ Calculate expected displacement
☐ Apply 2× safety factor
☐ Verify clearance in shock direction
☐ Minimum clearance: Greater of 2× calculated OR 2 inches
☐ Check lateral clearance (1 inch minimum)

Section 3: SYSTEM STARTUP & HARDWARE VERIFICATION

⚠ CRITICAL: Never power on amplifier before Panther system is ready. Incorrect sequence can cause DC offset damage to shaker.

Step 3.1: Power-On Sequence

MANDATORY SEQUENCE - Follow exactly:

Verify amplifier is OFF
Power on Panther hardware modules
Wait 30 seconds for initialization
Launch Panther Shock Control software
Verify "Hardware Connected" status (green indicator)
Create new test or open existing (.csk file)
Enable IEPE power for accelerometer channels (if external)
Wait 5 seconds for sensor stabilization
Verify DC level 10-12V (proper IEPE operation)
Power on amplifier (last step)
Wait for amplifier warm-up (1-2 minutes)
Verify amplifier green "Ready" status

NOTE: Shock does not have an online mode to perform this process. Use online mode in Analyzer if needed.

Step 3.2: Channel Signal Verification

Using GTX, add time history plot for each channel
Observe baseline signal (<0.01g expected)
Gently tap fixture near each sensor
Confirm signal spike for each channel
Verifies sensor mounted, connected, responding

Section 4: CHANNEL CONFIGURATION

Step 4.1: Understanding Channel Types

Control Channel (One Only):

Primary measurement for shock pulse
System drives to match target on this channel
Mounted on shaker head or fixture near DUT
Most representative of desired input
Classical shock uses single control channel

Measurement Channels (Monitor Only):

Record response at other locations
NOT used for control - recording only
Up to 31 additional channels possible

Step 4.2: Enable Channels

Navigate: Setup → Channels

Change Type to "Control for Channel 1
Enter descriptive name: "Control_Shaker_Head_Z"
Enable additional measurement channels as needed
Name clearly: "DUT_Mount_Point_Z", etc.

Step 4.3: Enter Accelerometer Sensitivities

⚠ CRITICAL: Incorrect sensitivity causes incorrect shock amplitude. 10% error = 10% amplitude error.

Accelerometer sensitivity is output voltage per unit acceleration (mV/g).

Example: 10 mV/g sensor at 100g outputs 1000 mV = 1.0 Volt

Typical ranges:

Low-g: (0-100g): 50-100 mV/g
Medium-g: (0-500g): 5-20 mV/g
High-g: (0-10,000g): 0.5-5 mV/g

Obtain calibration certificate for EACH sensor
Note sensitivity value (mV/g)
For each enabled channel:
1. Enter sensitivity in "Sensitivity" field
2. Double-check entry (typos common)
3. Typical values: 0.5 to 100 mV/g7.
Document sensor serial numbers
Match sensor to channel

Step 4.4: Configure IEPE Power

IEPE sensors require constant current power (4 mA) through signal cable.

Configuration:

Check "IEPE Power" for each sensor channel
Set "Coupling" to AC (required for IEPE)
Wait 5 seconds for stabilization
Verify DC level 10-12V

Step 4.5: Set Voltage Range

Calculate required range:
Peak Voltage = Peak Acceleration (g) × Sensitivity (mV/g) / 1000

Example: 500g shock, 5 mV/g sensor
Peak Voltage = 500 × 5 / 1000 = 2.5V
Select ±5V range (next higher with headroom)

Recommendation:

Development: Use "Auto" range
Production: Calculate and set fixed range with 2× margin

Panther Superior Capability: Panther's 24-bit ADCs provide >110 dB dynamic range on every range. Even on ±12V range, Panther resolves <20 microvolts. Competitive 16-bit systems (96 dB) lose resolution on wide ranges.

Section 5: PULSE PARAMETERS & COMPENSATION

Step 5.1: Selecting Test Type

Under Panther main menu, Select Test → "Classical Shock"

Classical shock defines pulse by shape, amplitude, and duration. System creates ideal mathematical pulse and compensates for hardware response.

Navigate: Setup → Classical Profile → Pulse Parameters tab

Step 5.2: Select Pulse Shape

Half-Sine Pulse (MOST COMMON):

Smooth sinusoidal rise and fall
Simulates dropped impacts, cushioned collisions
Gentlest on equipment
MIL-STD-810 Method 516 standard
Recommended for first-time characterization

Terminal Peak Sawtooth (TPS):

Linear rise to peak, instantaneous fall
Most severe classical pulse
Navy shipboard standard (MIL-S-901)
Use with extreme caution
NOT recommended for initial characterization

Amplitude Entry:

Locate "Pulse Amplitude" field. Enter target peak acceleration in g. For initial test, enter 25-50% of final target.

Step 5.3: Set Pulse Duration

Duration is time width in milliseconds (ms).

Typical Effects:

• Frequency content: Shorter = higher frequencies
• Displacement: Longer = more displacement
• Energy: Amplitude × Duration

Dominant frequency ≈ 1 / (2 × Duration)
Example: 11ms → 45 Hz dominant

Common values: 3, 6, 11, 15, 18 ms
MIL-STD-810: Typically 11ms

Duration Entry: Locate "Pulse Duration" field, enter in milliseconds.

Understanding Pulse Compensation

Real shaker systems don't respond perfectly to input signals. Compensation adjusts the drive waveform to account for shaker, amplifier, and fixture dynamics, producing accurate pulses at the control point despite hardware imperfections.

Compensation adds pre-pulse and post-pulse components that:

Cancel fixture oscillation after main pulse
Pre-condition fixture before main pulse
Minimize residual vibration
Achieve specification compliance

Step 5.4: Select Compensation Type

Compensation Type Options:

Pre & Post Pulses (Recommended): Lowest compensation amplitudes, longer total duration, best for most applications
Pre-pulse Only: Use if no excitation prior to main pulse allowed, measures residual effects accurately
Post-pulse Only: Accurate measurement of residual resonance, less common

Select "Pre & Post Pulses" for standard testing.

Step 5.5: Select Optimization Method

Single Sided: Displacement limited to one direction, conservative approach
Double Sided (Recommended): Displacement both directions, best utilization of shaker stroke

Step 5.6: Select Method

Displacement (Recommended): Best for utilizing shaker displacement, compensation produces balanced positive/negative displacement
Symmetric Accel: Equal amplitude and duration before/after main pulse
Non-Symmetric Accel: Post-pulse twice pre-pulse amplitude, shorter duration

Step 5.7: Compensation Amplitude

Pre-Comp / Post-Comp Amplitude: Percentage of main pulse (5-100%)

Typical Settings:

Pre-Comp: 30-50%
Post-Comp: 30-50%

Higher percentages provide better compensation but require more displacement. Start with 40% for both, adjust if needed.

Step 5.8: SRS Parameters

Shock Response Spectrum (SRS) parameters define post-test analysis:

SRS Definition:

Absolute Acceleration (most common)
Relative Displacement (less common)

SRS Spacing:

1/3 Octave (standard for most specifications)
1/6 or 1/12 Octave (higher resolution)

SRS Damping:

5% (Q=10) most common
Range: 0.1% to 99%
Higher damping = lower SRS values

For MIL-STD-810: Use Absolute Acceleration, 1/3 Octave, 5% damping

Configuration:

Select "Absolute Accel" for SRS Definition
Select "1/3 Octave" for SRS Spacing
Enter 5% for SRS Damping
These settings match most specifications

Section 6: PULSE TOLERANCE SETUP

Navigate: Setup → Classical Profile → Pulse Tolerance tab

Understanding Pulse Tolerance

Pulse tolerance defines acceptable deviation from ideal pulse shape. During testing, Panther compares actual pulse to target and determines pass/fail based on these criteria.

Tolerance applies to:

Pre-pulse amplitude
Main pulse amplitude
Post-pulse amplitude
Pulse duration
Overall pulse shape

Step 6.1: Select Tolerance Type

MIL-STD-810 (Recommended for Compliance): Predefined tolerances per military standard, use for MIL-STD testing
Custom: User-defined tolerances, use for non-military specifications or tighter control

Step 6.2: MIL-STD-810 Tolerances (If Selected)

MIL-STD-810 Method 516 specifies:

Main Pulse Tolerance:

+10% / -10% amplitude
±20% duration

Pre-Pulse and Post-Pulse:

±25% of pre/post amplitude limits

These cannot be changed when MIL-STD-810 selected.

Step 6.3: Custom Tolerances (If Selected)

If "Custom" selected, configure individual tolerances:

Parameter	Typical Value	Range
+Main Pulse %	+10%	5-100%
-Main Pulse %	-10%	5-100%
Pre/Post Pulse %	±25%	5-100%

Step 6.4: Tolerance Philosophy

Tolerance Selection Guidelines:

Tight Tolerances (±5-10%):

Development testing
Characterization work
Requires excellent control
More iterations may be needed

Standard Tolerances (±10-15%):

Production testing
Qualification testing
Good balance of control and efficiency

Loose Tolerances (±20-30%):

Screening tests
Go/no-go testing
Faster execution

Recommendation: Start with ±10% for most applications. Tighten to ±5% for critical development work. Loosen to ±15-20% only if control difficulties arise.

Section 7: SCHEDULE CONFIGURATION

Navigate: Setup → Schedule

Understanding Test Schedules

A schedule defines the sequence of shocks to be executed:

Amplitude levels
Number of pulses at each level
Pulse polarity (positive or negative)
Delays between pulses
Delays between groups

Schedules enable automated testing with level progression and allow systematic documentation of test execution.

Step 7.1: Create Schedule Table

Schedule table has the following columns:

Level (dB): Amplitude in dB relative to reference (0 dB = full amplitude, -6 dB = 50%)
Number of Pulses: How many shocks to execute at this level
Polarity: Positive or Negative pulse direction
Pulse Delay (s): Time between individual pulses (seconds)
NLAF: Non-Linear Adjustment Factor (typically 1.0)
Pause: Pause before next level (requires operator action)

Step 7.2: Example Schedule for 100g Characterization

Level (dB)	# Pulses	Polarity	Pulse Delay	Purpose
-12	3	Positive	5 sec	Equalization (25g)
-6	3	Positive	10 sec	Verification (50g)
-3	3	Positive	10 sec	75g intermediate
0	3	Positive	10 sec	Full level (100g)

Step 7.3: dB Level Conversion

dB levels are relative to full reference amplitude:

0 dB = 100% of reference
-3 dB ≈ 71% of reference
-6 dB = 50% of reference
-12 dB = 25% of reference
-20 dB = 10% of reference

Formula: Amplitude = Reference × 10^(dB/20)

Examples (100g reference):

-12 dB: 100g × 10^(-12/20) = 100g × 0.251 = 25.1g
-6 dB: 100g × 10^(-6/20) = 100g × 0.501 = 50.1g
0 dB: 100g × 10^(0/20) = 100g × 1.0 = 100g

Step 7.4: Adding Schedule Rows

Click "On" button to enable row
Enter Level in dB
Enter Number of Pulses (1-1000)
Select Polarity (Positive or Negative)
Enter Pulse Delay in seconds (0-1000)
Leave NLAF at 1.0 unless non-linearity observed
Check "Pause" if operator verification needed before next level
Repeat to add more rows

Step 7.5: Non-Linear Adjustment Factor (NLAF)

NLAF compensates for shaker non-linearity between equalization level and test level.

When to Use:

Large step from equalization to test level (>12 dB)
Observed consistent under/over-shoot at test level
Long-stroke shakers (airbag testing)

How it Works:

After equalization at low level, first pulse at test level may be low due to gain change. NLAF scales compensation by observed ratio.

Example:
Equalize at -12 dB, jump to 0 dB
First pulse measures 90g instead of 100g (10% low)
Set NLAF = 1.1 for next test
System applies 10% gain correction

Typical Values: 0.8 to 1.2
Leave at 1.0 unless non-linearity confirmed

Step 7.6: Schedule Execution Parameters

Equalization Level: -12 dB typical, can use -20 dB for extra safety
Level Increment: Step size for automatic progression (1-20 dB), use 3-6 dB typical
Pause Between Levels: Requires operator click to continue, good for inspection between levels

Section 8: SAFETY LIMITS CONFIGURATION

⚠ CRITICAL: Safety limits are your last line of defense. This section is MANDATORY. Improper configuration has destroyed shakers and injured personnel.

Navigate: Setup → Limits

Step 8.1: Configure Safety Limits Tab

Safety limits protect against over-testing and equipment damage. Panther monitors multiple parameters continuously and takes action if limits exceeded.

Alarm vs Abort

Alarm: Warning displayed, test continues, operator notified
Abort: Test stops immediately, output disabled, requires operator intervention

Step 8.2: gRMS Limits

gRMS (RMS acceleration) provides overall energy monitoring.

Typical Settings:

Alarm: +3 dB above expected level
Abort: +6 dB above expected level

These limits catch unexpected high-energy events.

Step 8.3: Loop Check Parameters

Type: Normal (recommended) or Rigorous
Max Noise: Maximum ambient noise in mV RMS, typical: 10-50 mV
Max Drive: Maximum drive voltage during loop check, typical: 2-5V

Step 8.4: Alarm/Abort Error Criteria

Max Average Error: Average deviation across entire pulse

Typical: 10% alarm, 20% abort

Max Peak Error: Maximum instantaneous deviation

Typical: 15% alarm, 30% abort

Peak errors naturally higher at pulse boundaries.

Step 8.5: Shaker Limits Tab (MANDATORY)

⚠ MANDATORY: Force limit configuration is REQUIRED. Exceeding shaker force rating causes catastrophic failure.
Understanding Force Limits

Shock generates peak forces that can be 100× higher than continuous vibration.

Force Calculation:

Force (lbf) = Total Moving Mass (lb) × Peak Acceleration (g)

Total Moving Mass Includes:

Shaker armature
Head expander (if present)
Slip Table
Drive Bar
Mechanical Support
Test Object

Step 8.6: Force Limit Configuration Procedure

Click "Shaker Limits" tab
Obtain shaker rated force from specification
Apply safety factor: 75-80% for shock
Enter safe force limit in "Max Force (lbf)" field
Select "Prevent Test Start" in Max Force Check dropdown
This provides absolute protection
Enter all Test Equipment masses
System calculates Total Mass automatically
System calculates Max Safe Acceleration
Verify Max Safe ≥ Test Amplitude
If Max Safe < Test Amplitude: CANNOT RUN
Must reduce mass, level, or use larger shaker
Document all measurements

Step 8.7: Displacement Limits

Enter shaker maximum displacement in:

+Displacement (in) - positive direction
-Displacement (in) - negative direction

Typical values: 0.5 to 4.0 inches depending on shaker size

System warns if calculated pulse displacement exceeds limits.

Step 8.8: Velocity and Acceleration Limits

Max Velocity: Shaker maximum velocity (in/sec), prevents over-velocity
Max Acceleration: Absolute acceleration limit (g), typically 2× test level
Max Voltage: Amplifier input limit (V), typically ±10-12V

Check "Symmetric Limits" to make negative limits equal positive.

Panther Superior Capability: Panther performs pre-test validation BEFORE each shock. System calculates expected force, displacement, velocity, and voltage, then verifies against limits. If any would be exceeded, Panther prevents execution and displays specific warning - protecting equipment before damage occurs.

Section 9: SYSTEM IDENTIFICATION & LOOP CHECK

Understanding System Identification

System ID characterizes the complete shock test system - shaker, amplifier, fixture, and DUT response. This measures the transfer function H(f) between drive output and control response.

The transfer function accounts for:

Shaker frequency response
Amplifier gain and phase
Fixture dynamics
Mounting characteristics
Sensor response

With H(f), Panther creates pre-compensated drive waveforms producing accurate pulses despite hardware characteristics.

System ID Process

Low-level characterization pulses (-12 to -20 dB)
Measure drive and response simultaneously
Calculate transfer function H(f) frequency-by-frequency
Create pre-compensated drive waveform
Output test pulse and measure response
Compare actual vs target
Update H(f) if needed (iterative convergence)
Proceed when tolerance met

Step 9.1: System ID Execution

System ID executes automatically when test starts. Monitor progress in test control panel and log window.

Typical Sequence:

"Starting Loop Check" - Verifies connections
"Loop Check Complete" - System ready
"Starting System ID" - Initial characterization
"Measuring Transfer Function" - H(f) calculation
"System ID Complete" - Ready for pulses
"Starting Equalization" - Low-level verification
"Equalization Pulse 1 of N" - Iterative refinement
"Equalization Complete" - System converged
"Ready for Pulse Outputs" - Full-level testing ready

Total time: 2-5 minutes typical

Step 9.2: Monitoring System ID

Watch log window for progress messages
Green "OK" messages indicate success
Yellow "Warning" messages may appear (usually OK)
Red "Error" messages require attention
Observe GTX for pulse shapes if open
System ID pulses visible as small amplitude events
Coherence must be >0.90 for good H(f)
Low coherence indicates noise or loose connection

Step 9.3: System ID Parameters

Navigate: Setup → System Identification

Equalization Level: -12 dB typical, use -20 dB for extra safety, lower = more iterations
Number of Averages: 4-8 typical, more = better H(f) but slower
Coherence Threshold: 0.90 typical, minimum coherence for valid H(f)
Feedback Gain: 0.25-0.50 typical, controls adaptation speed

Step 9.4: Troubleshooting System ID

Problem	Solution
Low coherence	Check connections, reduce noise, increase drive level
No convergence	Reduce feedback gain to 0.25, lower equalization level
Oscillation	Lower feedback gain, check for resonances in fixture
Timeout error	System needs more time, increase iteration limit or averages

Panther Superior Capability: Panther uses proprietary adaptive equalization algorithms with transfer function updating and coherence smoothing to compensate for non-linearities and time-varying dynamics. The system iteratively converges to accurate pulse reproduction faster than competitive systems, minimizing test time and cumulative damage to DUT.

Section 10: SHOCK TEST EXECUTION

⚠ CRITICAL: Once shock initiated, pulse executes in milliseconds. No time to react. Final safety check is MANDATORY before pressing Start.

Step 10.1: Pre-Execution Final Safety Check

☐ All Section 2 inspection items completed
☐ All channels configured and verified
☐ Test parameters entered correctly
☐ Schedule created and verified
☐ Safety limits configured and force calculation verified
☐ Test area cleared, minimum 10 feet
☐ Safety glasses on all personnel
☐ Emergency stop accessible
☐ Visual inspection: nothing loose, no debris
☐ Ready to proceed

Step 10.2: Start Test Sequence

Click "Start" button in Test tab in ribbon panel
System performs automatic pre-test checks
Log window displays status messages
"Test Started" - Initialization begun
"Measuring Ambient Noise" - Baseline measurement
Ambient noise displayed for each channel
"Starting Loop Check" - Connection verification
"Loop Check Complete" or "Loop Okay"
"Starting System ID" - Transfer function measurement
Low-level characterization pulses output
"System ID Complete" - H(f) calculated
"Starting Equalization" - Low-level convergence
Equalization pulses executed at -12 dB or configured level
"Equalization Complete" - System ready
"Ready for Pulse Outputs" button becomes active

Step 10.3: Pulse Output Execution

When "Ready for Pulse Outputs" button active:

Click "Output" button to execute schedule
Or operate in Manual Mode for individual pulses

Automatic Mode (Recommended):

System executes complete schedule automatically
Progresses through levels as configured
Pauses if "Pause Between Levels" checked
Continues until all pulses completed

Manual Mode:

Check "Manual Mode" in Test Control
Operator controls each parameter
Set Level, Number of Pulses, Pulse Delay, Units and Polarity manually
Click "Output" for each group
Provides maximum control but slower

Step 10.4: Monitoring During Execution

Maintain visual contact with shaker/fixture
Watch for any unusual motion or vibration
Listen for abnormal sounds
Monitor log window for warnings
Observe real-time plots if GTX is open
Green "Pass" or Red "Fail" displayed after each pulse
Pass: Pulse within tolerance
Fail: Pulse exceeded tolerance (investigate)
Hand on emergency stop throughout test
NEVER leave test unattended

Step 10.5: Post-Pulse Inspection

⚠ MANDATORY: Inspect after EVERY shock pulse, especially during characterization.

Pause test after each pulse (use schedule pause feature)

Visually inspect:

DUT condition (no visible damage)
Mounting hardware (no loosening)
Fixture (no cracks or deformation)
Accelerometer mounting (still secure)
Cables (no damage or disconnection)
Gently test mounting by hand (should be rigid)
If any concerns: STOP and investigate
Document observations
Continue only if setup verified safe

Step 10.6: Emergency Procedures

Emergency Stop Activated: Press red emergency stop button if ANY abnormality observed, output stops immediately, do NOT restart until cause identified
Alarm Triggered: Warning displayed, test may continue or pause depending on settings, investigate cause, verify setup
Abort Triggered: Test stops automatically, output disabled, red "Abort" message displayed, identify problem before restarting
Equipment Damage: STOP immediately, secure test area, photograph damage, document conditions, notify supervisor
Personnel Injury: STOP immediately, render first aid if qualified, call for medical help, secure area, document incident

Step 10.7: Test Completion

All schedule pulses executed
"Test Complete" message displayed
System returns to idle state
Final data saved automatically
Perform final post-test inspection (Section 12)
Proceed to data review

Section 11: POST-TEST PROCEDURES & DATA REVIEW

Step 11.1: Immediate Post-Test Actions

Leave shaker powered on for 2-3 minutes (cool-down)
Do NOT immediately power off amplifier
Allow electronics to stabilize before shutdown
Save test data if not auto-saved
Click File → Save or Save As
Use descriptive filename with date: "DUT_100g_11ms_20250127.csk"
Verify data saved successfully

Step 11.2: Final Physical Inspection

☐ DUT condition - any damage, cracks, or failures?
☐ Mounting hardware - any loosening?
☐ Fixture condition - cracks or deformation?
☐ Accelerometers - still properly mounted?
☐ Cables - any damage or stress?
☐ Shaker - any abnormal sounds or feel?
☐ Document all observations
☐ Photograph any damage or concerns

Step 11.3: Data Review - Time History

Review recorded shock pulses:

Open GraphTool via Panther (View → GraphTool) if not currently running
Load test data file (.sdd)
Display time history for control channel
Verify pulse characteristics:
1. • Correct amplitude
2. • Correct duration
3. • Correct shape
4. • Clean baseline before/after pulse
5. • No excessive oscillation
Compare to target pulse (overlay if available)
Check measurement channels
Look for unexpected response or resonance

Step 11.4: Pulse Verification Criteria

Parameter	Typical Tolerance	Check
Peak Amplitude	±10%	Measure peak, compare to target
Pulse Duration	±20%	Measure at 10% amplitude points
Pre-pulse	<25% of main	Measure amplitude before main pulse
Post-pulse	<25% of main	Measure amplitude after main pulse
Baseline	<5% of peak	Check signal before and after pulse

Step 11.5: System Shutdown Sequence

Save all data close Panther Shock Control software
Wait for software to fully close
Power off amplifier
Wait 1 minute for amplifier discharge
Power off Panther hardware modules
Disconnect any non-permanent cables
Clean work area
Complete test log documentation

Step 11.6: Test Documentation Recommendations

Test date and time
Operator name
DUT identification and serial number
Test specification and procedure reference
Shaker and fixture identification
Accelerometer serial numbers and sensitivities
Test parameters (amplitude, duration, pulse shape)
Number of shocks executed
Pass/fail status for each pulse
Any anomalies or observations
Data file names and locations
Photographs of setup

Section 12: DATA ANALYSIS & INTERPRETATION

Step 12.1: Time History Analysis

Time history plots show acceleration vs time for each pulse.

Key Analysis Points:

Peak amplitude accuracy
Pulse shape fidelity
Duration compliance
Pre/post pulse levels
Baseline stability
Unexpected resonances

Use GraphTool cursors to measure specific values:

Right-click on plot
Select "Add Cursor"
Drag to desired location
Read values in cursor window

Step 12.2: Shock Response Spectrum (SRS)

SRS represents shock severity across frequency range. Shows peak response of single-degree-of-freedom systems at various natural frequencies.

SRS Analysis:

In GraphTool, select pulse data
Click "Calculate SRS" or Analysis → SRS
SRS curve displays frequency vs peak acceleration
Compare to specification limits if applicable

SRS Interpretation:

Higher SRS = more severe shock at that frequency
SRS peaks indicate dominant frequencies in pulse
Use for comparing different shock pulses
Essential for aerospace and defense testing

Step 12.3: Multi-Channel Comparison

Compare control channel to measurement channels:

Overlay multiple channel time histories
Observe amplitude differences
Note phase relationships
Identify amplification (DUT response > input)
Typical fixture/DUT amplification: 2-5×
Amplification indicates resonance excitation

Critical: If DUT response significantly exceeds input, reduce test level or modify mounting to avoid resonance.

Step 12.4: Transfer Function Analysis

Transfer function shows how DUT responds vs input across frequency range.

Calculation:
TF(f) = DUT Response(f) / Control Input(f)

Values >1.0 indicate amplification
Values <1.0 indicate attenuation

Use to identify:

DUT resonant frequencies (TF peaks)
Critical modes needing damping
Frequency ranges of concern
Mounting effectiveness

Step 12.5: Data Export (if applicable)

Select Data Convert in GTX (if available)
Select SDD as source.
Select export format:
1. • ASCII (.txt, .dat) - universal compatibility
2. • UFF (.uff) - universal file format for FEA
3. • MATLAB (.mat) - MATLAB processing
Choose channels to export
Choose functions and records
Specify output filename
Click Export

Section 13: TROUBLESHOOTING GUIDE

Common Problems and Solutions

Problem	Cause	Solution
Pulse amplitude low	Insufficient compensation, low drive	Increase drive, re-run System ID, check amplifier gain
Pulse amplitude high	Excessive compensation	Reduce NLAF if used, re-run equalization
Pulse shape distorted	Fixture resonance, inadequate compensation	Modify fixture, increase compensation amplitude, use longer duration
Excessive oscillation after pulse	Under-damped fixture, insufficient post-compensation	Increase post-comp amplitude, add damping, modify fixture design
No convergence during equalization	Low coherence, fixture instability	Reduce feedback gain to 0.25, increase averages, check mounting
Pulse duration incorrect	Timing error, pulse definition issue	Verify duration entry, check sample rate, re-define pulse parameters
Control signal loss abort	Loose cable, sensor disconnected	Check all connections, verify IEPE power, inspect cable for damage
Force limit exceeded	Mass too high for amplitude	Reduce test amplitude, reduce fixture mass, or use larger shaker
Displacement limit exceeded	Duration too long for amplitude	Reduce amplitude, reduce duration, or use longer-stroke shaker
Inconsistent pulse-to-pulse	Thermal drift, mounting loosening	Allow warm-up time, check mounting torque, verify fixture stability

Systematic Diagnosis Procedure

1. Document exact symptoms (save screenshots)
2. Review test log for error messages
3. Check all physical connections
4. Verify all configuration parameters
5. Repeat loop check and System ID
6. Test at lower amplitude if possible
7. Isolate variable: change one thing at a time
8. Consult Panther documentation
9. Contact technical support if needed: 800.778.8755

Section 14: PANTHER SUPERIOR CAPABILITIES SUMMARY

Panther Shock Control provides industry-leading capabilities that ensure safe, accurate shock testing. This section summarizes the technological advantages highlighted throughout this tutorial.

Ultra-High-Speed Acquisition

262,144 samples/second maximum rate
<4 microsecond time resolution
Captures complete pulse detail
10-50× faster than competitive systems
250+ samples per 1ms pulse
No transient detail missed
Competitive 50 kHz systems: only 50 samples per 1ms

24-Bit ADC Resolution

>110 dB dynamic range on all channels
Resolves <20 microvolt signals
Captures baseline noise AND high-g peaks simultaneously
No compromise between range and resolution
Auto-ranging without data artifacts
Competitive 16-bit systems: 96 dB range, forced trade-offs
Adaptive Equalization

Proprietary algorithms for accurate pulse reproduction

Transfer function updating during test
Coherence-based adaptation
Compensates for non-linearities
Handles time-varying dynamics
Minimizes iterations required
Reduces cumulative DUT damage
Patented by Spectral Dynamics

Pre-Test Validation

Calculates expected values BEFORE shock execution
Peak force prediction
Displacement calculation
Velocity estimation
Voltage requirement check
Verifies against configured limits
Prevents dangerous configurations
Protects equipment before damage occurs
Competitive systems: execute first, discover problems after

Comprehensive Safety Monitoring

Multi-layer safety architecture (6 independent layers)
Real-time monitoring at 262 kHz rate
Over-level protection on all channels
Automatic abort on limit violation
Control signal loss detection
Hardware watchdog
Emergency stop override
Pre-test force limit verification
Linear-Phase Synthesis Filters

For SRS Shock Synthesis:

Phase-accurate waveform generation
No phase distortion across frequency range
Accurate SRS matching
Complex transient reproduction
Industry-leading SRS control accuracy

Complete data traceability

Gap-Free Streaming: Real-time streaming to disk
No gaps or missed samples
Independent sample rates per channel
Complete test documentation
Long-duration recording capability
Ideal for compliance testing

Technical Specifications Summary

Specification	Check
Input Channels	8 standard (expandable to 32)
ADC Resolution	24-bit
Dynamic Range	>110 dB
Max Sample Rate	262,144 samples/second
Frequency Accuracy	±5 ppm
Output DAC	20-bit
Max Output	±12V peak
Amplitude Accuracy	±0.20% of value or ±0.03% FS

CONCLUSION

This comprehensive tutorial has provided detailed, step-by-step procedures for conducting classical shock vibration tests using Panther Shock Control. Safety has been emphasized throughout due to the extreme forces and instantaneous nature of shock testing.

Key Takeaways:

✓ Always complete pre-test inspection before EVERY shock
✓ Start at reduced amplitude (25-50%) for characterization
✓ Verify force limits BEFORE testing - calculation is MANDATORY
✓ Use stud-mounted accelerometers for >50g shocks
✓ Monitor test continuously - NEVER leave unattended
✓ Inspect after EVERY shock pulse
✓ Trust Panther's adaptive equalization and pre-test validation
✓ Document all parameters, masses, and observations

For Additional Assistance:

Technical Support: 800.778.8755 or This email address is being protected from spambots. You need JavaScript enabled to view it.

Training courses available - contact for schedule

Spectral Dynamics, Inc. is a leading worldwide supplier of systems and software for vibration testing, structural dynamics, and acoustic analysis. Spectral Dynamics' products are used for design verification, product testing and process improvement by manufacturers of all types of electronic and mechanical products.

1500 Wyatt Drive Suite 14
Santa Clara, CA 95054-1522
Tel: (800) 778-8755
sales@spectraldynamics.com
service@spectraldynamics.com