mechanical shock and vibration testing
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Shock and Vibration Testing
Agenda
Shock Testing Comparison and Selection of Methods
Comparison of Specs Rationale for Selection of Testing
Vibration Testing Comparison and Selection of Methods
Comparison of Specs Rationale for Selection of Testing.
Vibration and Shock
Vibration and Shock Machine Type Range Range Capabilities
TIRA Vibration 20,000lb vector, 2 inch displacement 5-2500Hz
3 axis slip plate; 5 ft. x 5 ft. slip table
TIRA Vibration 12,000lb vector, 2 inch displacement 5-2500Hz
3 axis slip plate; 30 in. x 30in . slip table
Unholz Dicke Vibration 17,000lb vector, 1.5 inch displacement
5 – 2500 Hz
3 axis slip plate; 36 in. x 36 in. slip table
MB Corp Model C-60 Vibration
6000lb vector, 1 inch displacement
5 – 3000 Hz
3 axis slip plate; 30 in. x 30in . slip table
Ling Vibration 6000lb vector, 1 inch displacement
5 – 2000 Hz
3 axis slip plate; call for size limitations
Thermotron Vibration 5 Hammer Repetitive Shock 5-20,000 Hz
HALT Thermal Shock with vibration
Elite Package Vibration 2 – 4 Hz
Cam operated bounce test for transportation
AVCO FF367-1 Mechanical Shock 300g’s/20ms Inquire Sine or saw-tooth
AVCO A105 Mechanical Shock 30,000g’s/0.02ms Inquire Sine or saw-tooth
Schaevitz G-6-A Acceleration
Limited by 3 ft. arm; Call for size
Vibration and Shock
Vibration and Shock
HALT Test Vibration Impactors
Heating Elements
Vibration and Shock
HALT/HASS ChamberHALT -Highly Accelerated Life Testing
•Combined six-axis vibration and temperature extremes.•Intentionally but systematically produces test item failures for the purpose of rapidly identifying mechanical, electrical, design and functional weak points.•Design weaknesses can be analyzed, corrected, and the product design optimized.
HASS -Highly Accelerated Stress Screening •Overstress test to identify marginal or defective products before shipment. •HASS test levels are identified during HALT and are established to compress test time without damaging the product or reducing its life.
Vibration and Shock
Elite HALT/HASS Chamber Capabilities -100C to +200C (-148F to +302F) Greater than +70C per minute product temperature change
rates (heating or cooling) 30” x 30” Vibration Table, 480lbs total weight capacity for test
item & fixture Workspace Dimensions 42”W x 42”D x 40”H Vibration Frequency Range: 2Hz-10kHz; Vibration Level: Up
to 50Grms Two (2) 3”x8” access ports, Three (3) 20”x20” viewing
windows
Vibration and Shock
Vibration Testing
Sine, Random, SOR,
Field Data Replication
•Record actual vibration levels
•Import data to vibration controller
•Operate vibration table according to recorded profile and acceleration magnitude
• Run test item for endurance
•Mechanical Shock
•SRS
Vibration and Shock
Drop Shock
Sawtooth, Half-Sine
Classical Shock Test Machines
Vibration and Shock
High G Mechanical Shock
Vibration and Shock
High G Constant Acceleration
Vibration and Shock
Str
ess
Cycles
Endurance Limit
Strain
Str
ess
Yield Strength
Ultimate Strength
Proportional Limit
Fatigue Crack Growth
Vibration and Shock
Sine Vibration From rotating or oscillating machinery; electric motors, wheels, engines, gears, springs.Useful for evaluating dynamic characteristics of structures, i.e resonance
Random VibrationMore accurately represents the true environment. Excites all frequencies
Most damage occurs at fundamental frequency of electronics PCB.
Vibration and Shock
Shock High stresses causing fracture or permanent deformation High accelerations which can cause relays to chatter,
potentiometers to slip, bolts to loosen. High displacement which can cause impact between
adjacent circuit boards Usually not considered a fatigue failure if shock quantity
less than 1,000 cycles.
Selecting a Vibration Level or a Shock Pulse
Which Shock Pulse should I Apply? How Many? Which Level? What is the vibration spectrum of interest? How long should I test for?
1. Follow the Contract Specifications2. Create Your Test Based on Existing Specifications
as Guidance3. Make Field Measurements
1- Follow Contract Requirements
Contract Requirements MIL-PRF-15305
Contract Requirements MIL-PRF-15305
MIL-STD-202G Method 213
2- Use Existing Specifications for Guidance
Military, Regulatory, and OEM Specs Industry Standard Test Methods
with Recommended Levels
Create Your Own Specification
Shock Test Specs & Methods
Automotive FORD, GM SAE J1455
Commercial Products IEC 68-2-27; -29; -31
Commercial Aviation RTCA DO 160E Section 8
Military MIL-STD-810 Systems MIL-STD-883 Circuit Cards MIL-STD-202 Components
Handling Drop
Classical Shock (Potholes & Crashes)
Classical Shock
Bump
Free Fall
Operational and Crash Safety Shock Sustained Shock
SRS
Classical
Pyroshock
Ballistic Shock
Handling and Free Fall Drop Tests
Drop Surfaces Concrete Steel Wood Sand
Package or Device
Typical Classical Shock Tests for Electronic Systems
Reference SpecificationAmplitude
and Duration Pulse Shape Quantity
MIL-STD-810F Ground Equipment 75g-6ms Saw-tooth 3 pulses x 3 axes x 2 Dir (18 total) ISO 16750-3 50g-6ms Half-Sine 10 pulses x 3 axes x 2 Dir (60 total)
General Motors GMW 3172 25g-15ms Half-Sine 132 pulses x 3 axes x 2 Dir (792 total)General Motors GMW 3172 100g-11ms Half-Sine 3 pulses x 3 axes x 2 Dir (18 total)
Ford Motor 100g-10ms Half-Sine 6 pulses x 3 axes x 2 Dir (32 total)
RTCA DO-160D (Operational) 6g-11ms Saw-tooth 1 pulse x 3 axes x 2 Dir (6 total)RTCA DO-160D (Crash Safety) 20g-11ms Saw-tooth 1 pulse x 3 axes x 2 Dir (6 total)
A(Gs)
Time (msec)
A(Gs)
Time (msec)
Typical Classical Shock Tests for Electronic Systems- IEC 68-2-27
Gs Time Wave Components Equipment
General handling and transport.
Land based items or items transported by road, rail or air in secured shock resistant packages
30 18 ST, HS, TRInstalled or tranported in a secured position on normal road or rail vehicles or in transport aircraft
500 1 HSStructural integrity tests on semiconductors, integrated circuits, microcircuits.
1500 0.5 HSStructural integrity tests on semiconductors, integrated circuits, microcircuits.
ST, HS, TR6100
Items installed or transported in a secured position in full cross-counry vehicles. Items carried loose in normal road or rail vehicles for long periods.
Items used in industrial areas and subjected to shock from mechanical
handling equipment for example dock cranes, fork lift trucks.
Items in secured packages transported by full cross country
vehicles. Items mounted in equipment tranported by or installed
in full cross country vehicles or aircraft
Items in secured packages transported by wheeled vehicles, aircraft, merchant ships or light
marine craft.
ST, HS, TR1130
15 11 ST, HS, TR
Elite Capability for Classical Shock
Large Avco (Assume 150lb load and fixture) Short Pulse 3msec- 300Gs Long Pulse 30msec-20Gs
Small Avco (Assume 50lb load and fixture) Short Pulse 0.3msec- 1000Gs (longer pulses up to 10kGs) Long Pulse 6msec-500gs
Tira Electro-dynamic Vibration Table (Assume 150lb load and fixture) Short Pulse 0.5msec 150Gs Long Pulse 30msec 15Gs
Classical Shock Pulses
Advantages Easy to specify and understand shape, tolerance, mathematics Test machinery can generate pulses Accepted methods written into many specs
Disadvantages Not real world pulses Does not evaluate device response to shock
Classical Shock Tests
Engine 3.sif - AccelTH@Axis3.RN_2
Axis3(g's)
-20-15-10-5051015
Engine 3.sif - AccelTH@Axis2.RN_2
Axis2(g's)
-15-10-5051015
Engine 3.sif - AccelTH@Axis1.RN_2
Time(secs)0 20 40 60 80 100
Axis1(g's)
-15-10-50510
Classical Shock Tests
TmpEdit_0004.sif - AccelTH@Axis3.RN_2
Time(secs)0 5 10 15 20
Axis3(g's)
-20
-15
-10
-5
0
5
10
15
Shock Response Spectrum
-25 -20 -15 -10 -5 0 5 10 15 20-50
0
50
100
150
Time (ms)
Ac
ce
lera
tio
n (
G)
Acceleration
XAQ1
A ug 28, 2007 16:06:50
C apture 1000 mS
T rigger : 10 G (R is ing)
Pre -T r igger : 50 ms
64 C aptur ed
C hanne l: X A Q1,V SS A cc e l,C h3,C h4,Ch5,C h6,C h7,C h8,Ch9,C h10,Ch11,C h12,C h13,C h14,C h15,Ch16,C h17,C h18,C h19,C h20,C h21,C h22,C h23,C h24,C h25,C h26,C h27,C h28,C h29,Ch30,C h31,C h32
HoldOff: 0 ms
Pos t-C aptur e holdoff
Omron 38726
100 G's , 11 ms e c
half-s ine
0.1 1.0 10.0 100.0 1000.0
-71x10
-61x10
-51x10
-41x10
-31x10
-21x10
Frequency (Hz)
De
ns
ity
(G
²/H
z)
Energy Spectral Density
XAQ1
-25 -20 -15 -10 -5 0 5 10 15 20-50
0
50
100
150
Time (ms)
Ac
ce
lera
tio
n (
G)
Acceleration
XAQ1
A ug 28, 2007 16:08:50
C aptur e 1000 mS
T r igge r : 10 G (R is ing)
Pr e -T r igge r : 50 ms
80 C aptur e d
C hanne l: X A Q1,V SS A c c e l,C h3,C h4,C h5,C h6,C h7,C h8,C h9,C h10,C h11,C h12,C h13,C h14,C h15,C h16,C h17,C h18,C h19,C h20,C h21,C h22,C h23,C h24,C h25,C h26,C h27,C h28,C h29,C h30,C h31,C h32
HoldOff: 0 ms
Pos t-C aptur e holdoff
Omr on 38726
100 G's , 11 ms e c
half-s ine
0.1 1.0 10.0 100.0 1000.0
-71x10
-61x10
-51x10
-41x10
-31x10
-21x10
-11x10
Frequency (Hz)
De
ns
ity
(G
²/H
z)
Energy Spectral Density
XAQ1
Shock Response Spectrum
Input Pulse Measured Response
Shock Response Spectrum
Shock Response Spectrum
Shock Response Spectrum
Shock Response Spectrum
Preferred method for MIL-810 Describes the Peak Acceleration Response vs.
Freq Develop a simple shock pulse that will generate the
response function Some ED shakers have SRS capabilities Ringing plates
Pyrotechnic Shock
Pyrotechnic Shock
Pyrotechnic Shock
Pyrotechnic Shock
Ballistic Shock
Custom Shock Evaluation
ASTM D3332 Damage Boundary
Response to short duration pulse is a function of velocity change.
Response to long duration pulse is a function of the peak acceleration and waveform.
MIL-810 Fragility Test
Vibration and Shock Summary
1. Follow the Contract Specifications
2. Create Your Test Based on Existing Specifications as Guidance
3. Make Field Measurements
4. Call us with your application needs.
Thank you for this opportunity to serve you.
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