Mechanical Shock and Vibration Testing

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 - [email protected]_2

Axis3(g's)

-20-15-10-5051015


Axis2(g's)

-15-10-5051015


Time(secs)0 20 40 60 80 100

Axis1(g's)

-15-10-50510

Classical Shock Tests

TmpEdit_0004.sif - [email protected]_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


Input Pulse Measured Response


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

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.

Mechanical Shock and Vibration Testing

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