EMC Radio MIL-STD-810 F/G Standards - Hermon...Seminar AGENDA MIL-STD-810 introduction 09:00...

EMC

Radio

Telecom

Environmental

Product Safety

International Approvals

MIL-STD-810 F/G Standards

Presented by Mr. Vladimir Kogan, Group Manager Environmental

and Michael Mirin, Environmental Test Engineer.

28-June-11

jpg. Files

Seminar AGENDA

MIL-STD-810 introduction 09:00 – 09:30, Vladimir Kogan

MIL 810 overview – What it is

MIL 810 tests :Mechanical, Climatic, Special

MIL 810 F vs. MIL 810G

Explosive Atmosphere 09:30 – 10:30, Vladimir Kogan

Scope, Purpose and Test Process

Break 10:30 – 10:45

Mechanical testing 10:45-11:30, Michael Mirin


Altitude and Decompression test , 11:30 – 12:50, Vladimir KoganLow, High Temperatures and Humidity testing


Lunch break, 13:00-14:00

Explosive & Mechanical presentation/demonstration 14:00 -15:00

Explosive & Mechanical presentation/demonstration 15:00 -16:00

Q & A 16:00

MIL-STD-810 F/G Standards Seminar

WELCOME!

MIL-STD-810 F/G Introduction

Scope of the standard

This standard contains materiel acquisition program planning and engineering direction

for considering the influences that environmental stresses have on materiel throughout all

phases of its service life. It is important to note that this document does not impose

design or test specifications.

“MIL-STD-810G, DEPARTMENT OF DEFENSE TEST METHOD STANDARD:

ENVIRONMENTAL ENGINEERING CONSIDERATIONS AND LABORATORY TESTS

(31 OCT 2008) – USA”


Broad range of environmental conditions that include:

• Low pressure for ALTITUDE testing;

• Exposure to HIGH AND LOW TEMPERATURES plus TEMPERATURE SHOCK (both operating

and in storage);

• RAIN (including wind blown and freezing rain);

• HUMIDITY,

• FUNGUS,

• SALT FOG for rust testing;

• SAND AND DUST exposure;

• EXPLOSIVE ATMOSPHERE;

• LEAKAGE;

• ACCELERATION;

• SHOCK and transport shock (i.E., Triangle/sine/square wave shocks);

• GUNFIRE VIBRATION;

• RANDOM VIBRATION.



History and rationale


This standard is approved for use by all Departments and Agencies of the Department of

Defense (DoD). Although prepared specifically for DoD applications, this standard

may be tailored for commercial applications as well.

• MIL 810G includes significant changes vs. 810F

• One new additional Part

• 5 New Test Methods


The MIL- STD includes 3 parts


Part 1:

ENVIRONMENTAL ENGINEERING

PROGRAM GUIDELINES

Part 2:

LABORATORY TEST METHODS

Part 3:

WORLD CLIMATIC REGIONS –GUIDANCE

Describes management,

engineering, and technical

roles in the environmental

design and test tailoring

process.

It focuses on the process of

tailoring materiel design and

test criteria to the specific

environmental conditions a

materiel item is likely to

encounter during its service

life


Task 401 - Environmental Engineering

Management Plan (EEMP)

Task 402 - Life Cycle Environmental Profile

(LCEP)

Task 403 - Operational Environment

Documentation (OED)

Task 404 - Environmental Issues/Criteria List

(EICL)

Task 405 - Detailed Environmental Test Plans

(DETP)

Task 406 - Environmental Test Reports (ETR)

Part One Environmental engineering program guide

MIL-STD-810 F/G Introduction: Roles

MIL-STD-810 F/G Life Cycle (Transportation)

MIL-STD-810 F/G Life Cycle (Operational)


Part 1:


PROGRAM GUIDELINES

Part 2:


Part 3:


Contains environmental

laboratory test methods to

be applied according to the

general and specific test

tailoring guidelines

described in Part One.

MIL-STD-810; 1962

Test methods

The MIL-STD-810 test series contains environmental laboratory test methods that are applied using specific test tailoring

guidelines described within the standard.

MIL-STD-810 F/G : Part two Test methods “F”

MIL-STD-810 F/G: Part two Test methods “G”

MIL-STD-810 F/G: Part two Test methods comparison: 1962 vs. “G”


Part 1:


PROGRAM GUIDELINES

Part 2:


Part 3:


Contains a compendium of climatic

data and guidance assembled from

several sources.

Part Three provides planning guidance

for realistic consideration of climatic

conditions in the research,

development, test, and evaluation

(RDTE) of materiel and materials used

throughout their life cycles in various

climatic regions throughout the world.

It is intended that this and related

documents will help achieve the

objective of developing materiel that will

perform adequately under the

environmental conditions likely to be

found throughout its life cycle in the

areas of intended use.

MIL-STD-810 F/G: Part three

Areas of occurrence of climatic design types.


Distribution of absolute minimum temperatures


Distribution of absolute maximum temperatures

Explosive Atmosphere


Explosive Atmosphere test: Purpose

The explosive atmosphere test is performed to:

1. Demonstrate the ability of materiel to operate in fuel-air explosive atmospheres

without causing ignition

2. Demonstrate that an explosive or burning reaction occurring within encased

materiel will be contained, and will not propagate outside the test item.

Application

This method applies to all materiel designed for use in the vicinity of

fuel-air explosive atmospheres associated with aircraft, automotive,

and marine fuels at or above sea level.


Explosive Atmosphere: Limitations

1. Conservative testIf the test item does not ignite the test fuel-air mixture, there is a low probability that the

materiel will ignite prevailing fuel vapor mixtures in service. Conversely, the ignition of the

test fuel-air mixture by the test item does not mean the materiel will always ignite fuel vapors

that occur in actual use.

2. Altitudes above 16 kmThese procedures are not appropriate for test altitudes above approximately 16 km where

the lack of oxygen inhibits ignition.

3. High surface temperatures.

This method is not intended to demonstrate ignition due to high surface temperatures.

Effects of explosive atmosphere environments

Low levels of electrical energy discharge or electrical arcing by devices as simple as

pocket transistor radios can ignite mixtures of fuel vapor and air.

Fuel vapors in confined spaces can be ignited by a low energy discharge such as a

spark from a short-circuited flashlight cell, switch contacts, electrostatic discharge,

etc.

Explosive Atmosphere: Effects

Sequence among other methods

Considering the approach to conserve test item life by applying what are perceived to

be the least damaging environments first, generally apply the explosive atmosphere

test late in the test sequence.

Vibration, shock, and temperature stresses may distort seals and reduce their

effectiveness, thus making ignition of flammable atmospheres more likely.

Recommend the test item first undergo the above tests (on the same item) to better

approximate the actual operational environment.

Explosive Atmosphere: Sequence

Selecting Procedure Variations.

Before conducting this test, complete the tailoring process by selecting specific

procedure variations (special test conditions/techniques for this procedure) based on

requirements documents, Life Cycle Environmental Profile (LCEP), and information

provided with these procedures.

Fuel

Unless otherwise specified, use n-hexane as the test fuel, either reagent grade or 95 percent n-

hexane with 5 percent other hexane isomers. This fuel is used because its ignition properties in

flammable atmospheres are equal to or more sensitive than the similar properties of 100/130-

octane aviation gasoline, JP-4 and JP-8 jet engine fuel. Optimum mixtures of n-hexane and air will

ignite from temperatures as low as 223°C, while optimum JP-4 fuel-air mixtures require a minimum

temperature of 230°C for auto-ignition, and 100/130 octane aviation gasoline and air requires

441°C for hot-spot ignition. Minimum spark energy inputs for ignition of optimum fuel vapor and air

mixtures are essentially the same for n-hexane and for 100/130-octane aviation gasoline. Much

higher spark energy input is required to ignite JP-4 or JP-8 fuel-air mixtures. Use of fuels other

than n-hexane is not recommended.

Explosive Atmosphere: Procedure Variations

Temperature

Heat the fuel-air mixture to the highest ambient air temperature at which the materiel is

required to operate during deployment and provide the greatest probability of ignition.

Altitude simulation

The energy required to ignite a fuel-air mixture increases as pressure decreases. Ignition energy

does not drop significantly for test altitudes below sea level. Therefore, unless otherwise

specified, perform all tests with at least two explosive atmosphere steps, one at the

highest anticipated operating altitude of the materiel (not to exceed 12,200 m (40,000 ft.) where

the possibility of an explosion begins to dissipate), and one between 78 and 107 kPa which is

representative of most ground ambient pressures.

Because of the lack of oxygen at approximately 16 km, do not perform this test at or above this

altitude.


Fuel-vapor mixture

Use a homogeneous fuel-air mixture in the correct fuel-air ratios for the explosive atmosphere test.

Fuel weight calculated to total 3.8 percent by volume of the test atmosphere represents 1.8

stoichiometric equivalents of n-hexane in air, giving a mixture needing only minimum energy for ignition.

Required information to determine fuel weight:

Chamber air temperature during the test.

Fuel temperature.

Specific gravity of n-hexane

Test altitude: ambient ground or as otherwise identified.

Net volume of the test chamber (L)


Explosive Atmosphere Fuel Calculation

Calculation of the volume of liquid n-hexane fuel for each test altitude:

Explosive Atmosphere: Test Facility

Explosive atmosphere set up data sheet

Chamber volume 160 L

Chamber dimension Ø 45 cm, depth 70 cm

Chamber temperature ambient to +80°C

Chamber altitude up to 20 km (65.617 ft) (55 mBar)

Preparation for test

Before starting the test, review pretest information in the test plan to determine test details:

procedures, test item configuration, test temperature and test altitude.

Install the test item in the test chamber in such a manner that it may be operated and controlled

from the exterior of the chamber via sealed cable ports.

Unless permanently sealed (not to be opened for maintenance or other purposes), remove or

loosen the external covers of the test item to facilitate the penetration of the explosive mixture. Test

items requiring connection between two or more units may, because of size limitations, have to be

tested independently. In this case, extend any interconnections through the cable ports.

Operate the test item to determine correct operation.

In all instances, operate the test item in a manner representative of service use.

Explosive Atmosphere: Test procedure

Operation in explosive atmosphere

Step 1. With the test item installed, seal the chamber and stabilize the test item and chamber inner walls

to within 10°C below the high operating temperature of the test item.

Step 2. Adjust the chamber air pressure to simulate the highest operating altitude of the test item (not to

exceed12,200m) plus 2000 meters to allow for introducing, vaporizing, and mixing the fuel with the air.

Step 3. Slowly introduce the required volume of n-hexane into the test chamber.

Step 4. Circulate the test atmosphere and continue to reduce the simulated chamber altitude for at least

three minutes to allow for complete vaporization of fuel and the development of a homogeneous mixture.

Step 5. At a pressure equivalent to 1000m above the test altitude, verify the potential explosiveness of

the fuelair vapor by attempting to ignite a sample of the mixture taken from the test chamber using a

spark-gap device with sufficient energy to ignite a 3.82-percent hexane mixture. If ignition does not occur, purge the

chamber of the fuel vapor and repeat Steps 1-4.


Operation in explosive atmosphere

Step 6. Operate the test item and continue operation from this step until completion of Step 7. Make and

break electrical contacts as frequently and reasonably possible.

Step 7. To ensure adequate mixing of the fuel and air, slowly decrease the simulated chamber altitude at

a rate no faster than 100 meters per minute by bleeding air into the chamber.

Step 8. Stop decreasing the altitude at 1000m below the test altitude, perform one last operational check

and switch off power to the test item.

Step 9. Verify the potential explosiveness of the air-vapor mixture as in Step 5 above. If ignition does not

occur, purge the chamber of the fuel vapor, and repeat the test from Step 1.

Step 10. Adjust the simulated chamber altitude to the equivalent of 2000 m above site pressure.

Step 11. Repeat Steps 3-7. At site pressure, perform one last operational check and switch-off power to

the test item.

Step 12. Verify the potential explosiveness of the air-vapor mixture as in Step 5, above. If ignition does not

occur, purge the chamber of the fuel vapor, and repeat the test from Step 10.

Step 13. Document the test results.


Operation in Explosive Atmosphere

0 Test Altitude


Explosive Atmosphere test algorithm (only MIL-STD-810 F/G)

Explosive Atmosphere: test results example

Explosion tests

in the sampling tube

Temperature and pressure at test altitudes 30kft to site level

Mechanical tests

Mechanical tests: Vibration

What is vibration:

According to WWW Webster on-line, as of 1997, Main Entry:

vi·bra·tionPronunciation: vI-’brA-sh&n. Function: noun.

Date: 1655

1. a periodic motion of the particles of an elastic body or medium in alternately opposite directions from

the position of equilibrium when that equilibrium has been disturbed (as when a stretched cord produces

musical tones or particles of air transmit sounds to the ear)

b : the action of vibrating : the state of being vibrated or in vibratory motion: as

(1) : OSCILLATION (2) : a quivering or trembling motion : QUIVER

2. an instance of vibration

3. vacillation in opinion or action : WAVERING

4. a characteristic emanation, aura, or spirit that infuses or vitalizes someone or something and that can

be instinctively sensed or experienced, often used in plural.

b : a distinctive, usually emotional atmosphere capable of being sensed, usually used in plural

- vi·bra ·tion ·al /-shn&l, -sh& -n&l / adjective

vi·bra·tion·less /-sh&n-l&s/ adjective


Purpose of Vibration:

Vibration tests are performed to:

1. Develop materiel to function in and withstand the vibration exposures of a life cycle including

synergistic effects of other environmental factors, materiel duty cycle, and maintenance.

2. Verify that materiel will function in and withstand the vibration exposures of a life cycle.

Consumers expect and demand products of high quality and reliability. To fulfill these requirements we

must consider vibration, since at some time in its life the product will be subjected to vibration. Poor

mechanical design will result in mechanical failure and customer dissatisfaction which will add cost and

reduce credibility.


Mechanical tests: Reasons for Vibration Testing

Some reasons for Vibration Testing

- Reduce product development time

- Ensure new products are fit for purpose

- Reduce in-plant rework due to QA rejection

- Reduce damage in transit and subsequent rejection by the customer

- Reduce marginal or non-performance rejection under Warranty

- Reduce legal costs and damage claims due to incorrect operation of the product

- Maintain a good reputation for the company and its products

- Maintain profit margins

In a highly competitive world marketplace Vibration Testing makes good sense.

Mechanical tests: Sequence among other methods

The accumulated effects of vibration-induced stress may affect materiel performance under other

environmental conditions such as temperature, altitude, humidity, leakage, or electromagnetic

interference (EMI/EMC). When evaluating the cumulative environmental effects of vibration and other

environments, expose a single test item to all environmental conditions, with vibration testing

generally performed first.

If another environment (e.g., temperature cycling) is projected to produce damage that would make the

materiel more susceptible to vibration, perform tests for that environment before vibration tests. For

example, thermal cycles might initiate a fatigue crack that would grow under vibration.

Effects of vibration environment

Vibration results in dynamic deflections of and within materiel. These dynamic deflections and associated

velocities and accelerations may cause or contribute to structural fatigue and mechanical wear of

structures, assemblies, and parts. In addition, dynamic deflections may result in impacting of elements

and/or disruption of function. Some typical symptoms of vibration-induced problems follow.

1. Chafed wiring.

2. Loose fasteners/components.

3. Intermittent electrical contacts.

4. Electrical shorts.

5. Deformed seals.

6. Failed components.

7. Optical or mechanical misalignment.

8. Cracked and/or broken structures.

9. Migration of particles and failed components.

10. Particles and failed components lodged in circuitry or mechanisms.

11. Excessive electrical noise.

12. Fretting corrosion in bearings.

Mechanical tests: Vibration Effects

Mechanical tests: Vibration environment categories

Mechanical tests: Type of Vibration - Sine

Sine Vibration

One of the most common vibration tests is a swept sine test. These tests, as they imply, are a test where

the signal driven into the vibrator is a sine wave and the frequency of the sine wave will change with time

i.e. it will sweep. The level or amplitude of the signal measured on the vibration table can be either

Acceleration, Velocity or Displacement. However, the sensor measuring the vibration is normally an

Accelerometer which produces an output proportional to Acceleration. The controller, however, can

convert the signal from the accelerometer to Velocity (by integration) or Displacement (by double

integration).


The units used for sinusoidal vibration testing are:

Frequency Hz or radians/second

Displacement mm or inches peak - peak or peak

Velocity m/s or in/sec peak

Acceleration m/s² or gn peak

Metric Units Imperial Units SI Units

D = mm peak - peak D = in peak - peak D = mm peak - peak

V = mm/s peak V = in/s peak V = mm/s peak

A = gn peak A = gn peak A = m/s² peak

F = Hz F = Hz F = Hz

G = 9806.65 mm/s² G = 386.0885827 in/s² G = 1000 mm/s²

= 3.141592654 = 3.141592654 = 3.141592654


There must be hundreds, if not thousands, of swept sine test specifications, but whatever the test, it

should define the following:

1. The upper and lower frequency of the test,

2. The level to be maintained at the appropriate frequency,

3. The rate at which the frequency will sweep and whether it is logarithmic or linear.

4. The duration of the test or the number of sweeps.

In addition to the option that we have discussed (Sweep Sine), in which sine runs at certain velocity

(sweep rate), there is also an option, where sine will “stand” a certain time in one frequency. This

vibration is called Sine Dwell.

There is also possibility to combine several frequencies in a single experiment, each frequency will be a

certain time.

Because sweep sine "running" at certain frequencies and any moment he is located at certain frequency,

main use is for research - testing the product behavior, search for resonance frequencies (Resonance

Search), and the goals like this.

But there are also cases that sweep sine are used to complete an endurance and resistance tests of the

product.

As we said before, there is also sine dwell. He is used if we want to put load on certain frequencies,

which were found problematic or suspected as those.

Mechanical tests: Type of Vibration - Random

If we observe a structure which has several beams of different length and we excite the structure with a

swept sine test, each beam will vibrate vigorously when excited by its unique resonant frequency.

However, if we excite the same structure with a broad band random signal, we will observe that all the

beams are vibrating vigorously which would tend to indicate that all of the frequencies are present at the

same time. Well they are, and they aren’t. This may seem irrational. However if you consider that over a

short period of time that several frequencies are present, but the quantity and phase of those frequencies

is varying randomly it may make more sense. Time is the key to understanding random. In theory, you

must consider an infinite period of time in order to produce a true spectrum analysis of a random signal.

If the signal is truly random, it will never repeat.

The equipment used to analyze random signals years ago employed electronic bandpass filters to

separate and quantify each frequency. All modern spectrum analyzers now use a mathematical process

known as an FFT (Fast Fourier Transform).

Mechanical tests: Random

As a further explanation of random the following may help. The diagram below shows how sine waves of

different frequencies can be summed to form a complex waveform.

10Hz

20Hz

50Hz

Sum

90Hz

0.1 sec




Figure and Break points for curves Composite two-wheeled trailer vibration exposure.


Mechanical tests: Shock

In field simulation tests were examined three general types of mechanical motion and force:

1. Continuous and periodic (like sine vibration)

2. Continuous, but not periodic (like random vibration)

and the last type

3. Not continuous and not periodic

The nearest thing for this is a mechanical shock.


A mechanical or physical shock is a sudden acceleration or deceleration caused, for

example, by impact, drop, kick, earthquake, or explosion. Shock is a transient physical

excitation.

Purpose of Shock test:

Shock tests are performed to:

1. provide a degree of confidence that materiel can physically and functionally withstand the relatively

infrequent, non-repetitive shocks encountered in handling, transportation, and service environments. This

may include an assessment of the overall materiel system integrity for safety purposes in any one or all of

the handling, transportation, and service environments;

2. determine the materiel's fragility level, in order that packaging may be designed to protect the

materiel's physical and functional integrity; and

3. test the strength of devices that attach materiel to platforms that can crash.


Effects of shock.

Mechanical shock has the potential for producing adverse effects on the physical and functional integrity

of all materiel. In general, the level is affected by both the magnitude and the duration of the shock

environment. Durations of shock that correspond with natural frequency periods of the materiel and/or

periods of major frequency components in input shock environment waveforms that correspond with

natural frequency periods of the materiel will magnify the adverse effects on the materiel's overall

physical and functional integrity.


Sequence among other methods.

Sequencing among other methods will depend upon the type of testing, i.e., developmental, qualification,

endurance, etc., and the general availability of test items for test. Normally, schedule shock tests early in

the test sequence, but after any vibration tests.

(1) If the shock environment is deemed particularly severe, and the chances of materiel survival without

major structural or operational failure are small, the shock test should be first in the test sequence. This

provides the opportunity to redesign the materiel to meet the shock requirement before testing to the

more benign environments.

(2) If the shock environment is deemed severe, but the chance of the materiel survival without structural

or functional failure is good, perform the shock test after vibration and thermal tests, allowing the

stressing of the test item prior to shock testing to uncover combined vibration, and temperature failures.

(3) There are often advantages to applying shock tests before climatic tests, provided this sequence

represents realistic service conditions. Test experience has shown that climate-sensitive defects often

show up more clearly after the application of shock environments.

However, internal or external thermal stresses may permanently weaken materiel resistance to vibration

and shock that may go undetected if shock tests are applied before climatic tests.

Mechanical tests: Shock types

Classical shock pulses (mechanical shock machine). Unless the procedure requires the use of a

classical shock pulse, the use of such a pulse is not acceptable unless it can be demonstrated that

measured data is within the tolerances of the classical shock pulses. Only two classical shock pulses are

defined for testing in the method – the terminal peak sawtooth pulse, and the trapezoidal pulse.

Mechanical tests: Shock types - sawtooth pulse

Mechanical tests: Shock types - trapezoidal pulse

Mechanical tests: Test facility - LDS V875 Shaker specification

LDS V875 Electrodynamic Shaker System vibration force (kN) 35.6

System max shock force (kN) 105

Max acceleration sine peak (gn) 110

System velocity sine peak (m/s) 1.8

Displacement pk-pk (mm) 50.6

Payload, max (kg) 600

Mechanical tests: Test facility – “Closed loop”

Mechanical tests: Test facility – Fixture requirements and design



Date post:	25-May-2020
Category:	Documents
Upload:	others
View:	8 times
Download:	0 times

EMC Radio MIL-STD-810 F/G Standards - Hermon...Seminar AGENDA MIL-STD-810 introduction 09:00...

Documents