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
Vibration
20,000lb vector, 2 inch displacement
Vibration
12,000lb vector, 2 inch displacement
Vibration
17,000lb vector, 1.5 inch displacement
Vibration
6000lb vector, 1 inch displacement
Vibration
6000lb vector, 1 inch displacement
Thermotron
Vibration
5 Hammer Repetitive Shock
Elite
Package Vibration
AVCO FF367-1
Mechanical Shock
AVCO A105
TIRA TIRA Unholz Dicke MB Corp Model C-60 Ling
Schaevitz G-6-A
Range
Capabilities
5-2500Hz
3 axis slip plate; 5 ft. x 5 ft. slip table
5-2500Hz
3 axis slip plate; 30 in. x 30in . slip table
5 – 2500 Hz
3 axis slip plate; 36 in. x 36 in. slip table
5 – 3000 Hz
3 axis slip plate; 30 in. x 30in . slip table
5 – 2000 Hz
3 axis slip plate; call for size limitations
5-20,000 Hz
HALT Thermal Shock with vibration
2 – 4 Hz
Cam operated bounce test for transportation
300g’s/20ms
Inquire
Sine or saw-tooth
Mechanical Shock
30,000g’s/0.02ms
Inquire
Sine or saw-tooth
Acceleration
Limited by 3 ft. arm; Call for size
Vibration and Shock
Vibration and Shock
Heating Elements HALT Test Vibration Impactors
Vibration and Shock HALT/HASS Chamber
HALT -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 Ultimate Strength
Proportional Limit
Stress
Stress
Yield Strength
Endurance Limit
Strain
Cycles
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
Vibration More 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
1. 2. 3.
Which Shock Pulse should I Apply? How Many? Which Level? What is the vibration spectrum of interest? How long should I test for? Follow the Contract Specifications Create Your Test Based on Existing Specifications as Guidance 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
Commercial Products
IEC 68-2-27; -29; -31
Commercial Aviation
FORD, GM SAE J1455
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 A(Gs) A(Gs)
Time (msec)
Time (msec)
Reference Specification MIL-STD-810F Ground Equipment ISO 16750-3
Amplitude Pulse and Duration Shape 75g-6ms Saw-tooth 50g-6ms Half-Sine
Quantity 3 pulses x 3 axes x 2 Dir (18 total) 10 pulses x 3 axes x 2 Dir (60 total)
General Motors GMW 3172 General Motors GMW 3172
25g-15ms 100g-11ms
Half-Sine Half-Sine
132 pulses x 3 axes x 2 Dir (792 total) 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) RTCA DO-160D (Crash Safety)
6g-11ms 20g-11ms
Saw-tooth Saw-tooth
1 pulse x 3 axes x 2 Dir (6 total) 1 pulse x 3 axes x 2 Dir (6 total)
Typical Classical Shock Tests for Electronic SystemsIEC 68-2-27 Gs
Time
Wave
Components
Equipment General handling and transport.
15
11
ST, HS, TR
30
18
ST, HS, TR
30
11
ST, HS, TR
Land based items or items transported by road, rail or air in secured shock resistant packages Installed or tranported in a secured position on normal road or rail vehicles or in transport aircraft
Items in secured packages transported by wheeled vehicles, aircraft, merchant ships or light marine craft.
Items in secured packages transported by full cross country vehicles. Items mounted in ST, HS, TR equipment tranported by or installed in full cross country vehicles or aircraft
100
6
500
1
HS
1500
0.5
HS
Structural integrity semiconductors, microcircuits. Structural integrity semiconductors, microcircuits.
tests on integrated circuits, tests on integrated circuits,
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.
Elite Capability for Classical Shock
Large Avco (Assume 150lb load and fixture)
Small Avco (Assume 50lb load and fixture)
Short Pulse 3msec- 300Gs Long Pulse 30msec-20Gs
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
Axis1(g's) Axis2(g's) Axis3(g's)
Classical Shock Tests Engine 3.sif -
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15 10 5 0 -5 -10 -15 -20 15 10 5 0 -5 -10 -15 10 5 0 -5 -10 -15
Engine 3.sif -
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Engine 3.sif -
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0
20
40
60 Time(secs)
80
100
Classical Shock Tests TmpEdit_0004.sif -
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15 10
Axis3(g's)
5 0 -5 -10 -15 -20 0
5
10 Time(secs)
15
20
Shock Response Spectrum
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
3.
Follow the Contract Specifications Create Your Test Based on Existing Specifications as Guidance Make Field Measurements
4.
Call us with your application needs.
1. 2.
Thank you for this opportunity to serve you.
