Shock and Vibration Testing

Transcription

1 Shock and Vibration Testing

2 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.

3 Vibration and Shock

4 Vibration and Shock Machine Type Range Range Capabilities TIRA TIRA Unholz Dicke Vibration Vibration Vibration MB Corp Model C-60 Vibration Ling Thermotron Elite AVCO FF367-1 AVCO A105 Schaevitz G-6-A Vibration Vibration Package Vibration 20,000lb vector, 2 inch displacement 12,000lb vector, 2 inch displacement 17,000lb vector, 1.5 inch displacement 6000lb vector, 1 inch displacement 6000lb vector, 1 inch displacement 5 Hammer Repetitive Shock Hz Hz Hz Hz Hz 5-20,000 Hz 2 4 Hz 3 axis slip plate; 5 ft. x 5 ft. slip table 3 axis slip plate; 30 in. x 30in. slip table 3 axis slip plate; 36 in. x 36 in. slip table 3 axis slip plate; 30 in. x 30in. slip table 3 axis slip plate; call for size limitations HALT Thermal Shock with vibration Cam operated bounce test for transportation Mechanical Shock 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

5 Vibration and Shock

6 Vibration and Shock Heating Elements HALT Test Vibration Impactors

7 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.

8 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

9 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

10 Vibration and Shock Drop Shock Sawtooth, Half-Sine

11 Classical Shock Test Machines

12 Vibration and Shock High G Mechanical Shock

13 Vibration and Shock High G Constant Acceleration

14 Vibration and Shock Ultimate Strength Stress Yield Strength Proportional Limit Stress Endurance Limit Strain Cycles

15 Fatigue Crack Growth

16 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.

17 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.

18 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 Specifications 2. Create Your Test Based on Existing Specifications as Guidance 3. Make Field Measurements

19 1- Follow Contract Requirements

20 Contract Requirements MIL-PRF-15305

21 Contract Requirements MIL-PRF MIL-STD-202G Method 213

22 2- Use Existing Specifications for Guidance Military, Regulatory, and OEM Specs Industry Standard Test Methods with Recommended Levels Create Your Own Specification

23 Shock Test Specs & Methods Automotive FORD, GM SAE J1455 Commercial Products IEC ; -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

24 Handling and Free Fall Drop Tests Drop Surfaces Concrete Steel Wood Sand Package or Device

25 Typical Classical Shock Tests for Electronic Systems A(Gs) A(Gs) Time (msec) Time (msec) Reference Specification Amplitude 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 g-6ms Half-Sine 10 pulses x 3 axes x 2 Dir (60 total) General Motors GMW g-15ms Half-Sine 132 pulses x 3 axes x 2 Dir (792 total) General Motors GMW g-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)

26 Typical Classical Shock Tests for Electronic Systems- IEC Gs Time Wave Components Equipment ST, HS, TR ST, HS, TR General handling and transport. 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 ST, HS, TR Items in secured packages transported by wheeled vehicles, aircraft, merchant ships or light marine craft. 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 ST, HS, TR HS HS 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 Structural integrity tests on semiconductors, integrated circuits, microcircuits. Structural integrity tests on semiconductors, integrated circuits, microcircuits.

27 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

28 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

29 Axis1(g's) Axis2(g's) Axis3(g's) Classical Shock Tests Engine 3.sif - AccelTH@Axis3.RN_2 Engine 3.sif - AccelTH@Axis2.RN_2 Engine 3.sif - AccelTH@Axis1.RN_ Time(secs)

30 Axis3(g's) Classical Shock Tests 15 TmpEdit_0004.sif - AccelTH@Axis3.RN_ Time(secs)

31 Shock Response Spectrum

32 Shock Response Spectrum Input Pulse Measured Response

33 Shock Response Spectrum

34 Shock Response Spectrum

35 Shock Response Spectrum

36 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

37 Pyrotechnic Shock

38 Pyrotechnic Shock

39 Pyrotechnic Shock

40 Ballistic Shock

41 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

42 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.

43 Thank you for this opportunity to serve you.