MIL-STD-810G – Part 27 – (Rail Impact) Method 526

MIL-STD-810G covers Rail Impact in Method 526.  Method 526 is new to 810G and the purpose of this test method is to replicate the railroad car impact conditions that occur during the life of transport of systems, subsystems and units, and the tiedown arrangements during the specified logistic conditions.  Method 526 is short at 7 pages.

Method 526 is also not intended for testing small, individually packaged material that would normally be shipped when mounted on a pallet or as part of a larger shipment.  It is intended for testing items such as tanks, trucks, etc., that are transported by rail.

The rail impact test is intended to test materiel that will be transported by rail; to determine the effect of railroad car impacts that may occur during rail shipment, to verify the structural integrity of the materiel, to evaluate the adequacy of the tiedown system and the tiedown procedures, and to assess transportability1 by the Military Surface Deployment and Distribution Command Transportation Engineering Agency (SDDCTEA). All items are to be tested at their maximum gross weight (fully loaded) rating unless otherwise specified in the transportability requirements for the materiel. 

Subjecting materiel to a lab shock test or performing an analytical simulation does not eliminate the requirement to conduct a rail impact test.

Method 526 is not intended for railcar crash conditions. 

Effects of Rail Impact

Rail impact shock has the potential for producing adverse effects on the physical and functional integrity of transported materiel. The following are examples of problems that could occur when materiel is exposed to the rail impact environment.

1. Loosening of tiedown straps.


2. Failure of attachments, creating a safety hazard.


3. Shifting of materiel on the railcar.


4. Failure of materiel.


5. Structural failure.


6. Fuel spills.

Testing

Tests are performed with rail cars. 

Loaded cars are preferred for use as the buffer or struck cars. However, empty cars may also be used. In either case, the total weight of the buffer cars is to be at least 113,400kg (250,000 lb). The first buffer car must be a standard draft gear car. The remaining buffer cars should have standard draft gear, if possible.  Draft gear is the shock absorber which is part of the coupler.

The test railcar is equipped with chain tiedowns and end-of-car cushioned draft gear, unless other railcar types are approved by Director, SDDCTEA. SDDCTEA is the designated DoD agent for land transportation. Some materiel may require other types of railcars for testing to be representative of the intended shipping methods.

A locomotive and at least 200 feet of dry, level track is used to get the rail cars up to the required speed as below.  At the desired speed, the test load car is released so it rolls freely into the buffer cars with the couplings open.  An alternative method of testing is to use an inclined track of sufficient length and gradient to achieve the test speeds.

The test item secured to the test railcar should be at gross weight with the fuel tanks at least 3/4 full.

Subject the test item to four impacts, the first three of which are in the same direction and at speeds of 4, 6, and 8 mph respectively. Perform the fourth impact at 8 mph (+0.5, -0.0 mph) impacting the opposite end of the test car from the first three impacts. If it is not possible to turn the test car because of track layout, this may be accomplished by running the test item car to the opposite end of the buffer cars and impacting as above.

Analysis

1. The test item fails this test if the test item, or any item that is attached to it, or that is included as an integral part of the test item, breaks free, loosens, or shows any sign of permanent deformation beyond specification tolerances.


2. The test item and its subassemblies must be operationally effective after the test.


3. f tiedown securement items break or displace substantially, photograph and document the problem areas for evaluation of the procedures and materials used. The test director and SDDCTEA jointly decide if any failed securement items require reconfiguring and, if so, whether a complete retest is required.


4. Additional considerations:
   (1) Loosening of tiedown straps.
   (2) Failure of attachments, creating a safety hazard.
   (3) Shifting of materiel on the railcar.
   (4) Failure of materiel.
   (5) Structural failure.
   (6) Fuel spills.

MIL-STD-810G – Part 27 – (Rail Impact) Method 526

MIL-STD-810G – Part 27 – (Rail Impact) Method 526

MIL-STD-810G covers Rail Impact in Method 526.  Method 526 is new to 810G and the purpose of this test method is to replicate the railroad car impact conditions that occur during the life of transport of systems, subsystems and units, and the tiedown arrangements during the specified logistic conditions.  Method 526 is short at 7 pages.

Method 526 is also not intended for testing small, individually packaged material that would normally be shipped when mounted on a pallet or as part of a larger shipment.  It is intended for testing items such as tanks, trucks, etc., that are transported by rail.

The rail impact test is intended to test materiel that will be transported by rail; to determine the effect of railroad car impacts that may occur during rail shipment, to verify the structural integrity of the materiel, to evaluate the adequacy of the tiedown system and the tiedown procedures, and to assess transportability1 by the Military Surface Deployment and Distribution Command Transportation Engineering Agency (SDDCTEA). All items are to be tested at their maximum gross weight (fully loaded) rating unless otherwise specified in the transportability requirements for the materiel. 

Subjecting materiel to a lab shock test or performing an analytical simulation does not eliminate the requirement to conduct a rail impact test.

Method 526 is not intended for railcar crash conditions. 

Effects of Rail Impact

Rail impact shock has the potential for producing adverse effects on the physical and functional integrity of transported materiel. The following are examples of problems that could occur when materiel is exposed to the rail impact environment.

1. Loosening of tiedown straps.


2. Failure of attachments, creating a safety hazard.


3. Shifting of materiel on the railcar.


4. Failure of materiel.


5. Structural failure.


6. Fuel spills.

Testing

Tests are performed with rail cars. 

Loaded cars are preferred for use as the buffer or struck cars. However, empty cars may also be used. In either case, the total weight of the buffer cars is to be at least 113,400kg (250,000 lb). The first buffer car must be a standard draft gear car. The remaining buffer cars should have standard draft gear, if possible.  Draft gear is the shock absorber which is part of the coupler.

The test railcar is equipped with chain tiedowns and end-of-car cushioned draft gear, unless other railcar types are approved by Director, SDDCTEA. SDDCTEA is the designated DoD agent for land transportation. Some materiel may require other types of railcars for testing to be representative of the intended shipping methods.

A locomotive and at least 200 feet of dry, level track is used to get the rail cars up to the required speed as below.  At the desired speed, the test load car is released so it rolls freely into the buffer cars with the couplings open.  An alternative method of testing is to use an inclined track of sufficient length and gradient to achieve the test speeds.

The test item secured to the test railcar should be at gross weight with the fuel tanks at least 3/4 full.

Subject the test item to four impacts, the first three of which are in the same direction and at speeds of 4, 6, and 8 mph respectively. Perform the fourth impact at 8 mph (+0.5, -0.0 mph) impacting the opposite end of the test car from the first three impacts. If it is not possible to turn the test car because of track layout, this may be accomplished by running the test item car to the opposite end of the buffer cars and impacting as above.

Analysis

1. The test item fails this test if the test item, or any item that is attached to it, or that is included as an integral part of the test item, breaks free, loosens, or shows any sign of permanent deformation beyond specification tolerances.


2. The test item and its subassemblies must be operationally effective after the test.


3. f tiedown securement items break or displace substantially, photograph and document the problem areas for evaluation of the procedures and materials used. The test director and SDDCTEA jointly decide if any failed securement items require reconfiguring and, if so, whether a complete retest is required.


4. Additional considerations:
   (1) Loosening of tiedown straps.
   (2) Failure of attachments, creating a safety hazard.
   (3) Shifting of materiel on the railcar.
   (4) Failure of materiel.
   (5) Structural failure.
   (6) Fuel spills.

MIL-STD-810G – Part 27 – (Rail Impact) Method 526

MIL-STD-810G – Part 27 – (Rail Impact) Method 526

MIL-STD-810G covers Rail Impact in Method 526.  Method 526 is new to 810G and the purpose of this test method is to replicate the railroad car impact conditions that occur during the life of transport of systems, subsystems and units, and the tiedown arrangements during the specified logistic conditions.  Method 526 is short at 7 pages.

Method 526 is also not intended for testing small, individually packaged material that would normally be shipped when mounted on a pallet or as part of a larger shipment.  It is intended for testing items such as tanks, trucks, etc., that are transported by rail.

The rail impact test is intended to test materiel that will be transported by rail; to determine the effect of railroad car impacts that may occur during rail shipment, to verify the structural integrity of the materiel, to evaluate the adequacy of the tiedown system and the tiedown procedures, and to assess transportability1 by the Military Surface Deployment and Distribution Command Transportation Engineering Agency (SDDCTEA). All items are to be tested at their maximum gross weight (fully loaded) rating unless otherwise specified in the transportability requirements for the materiel. 

Subjecting materiel to a lab shock test or performing an analytical simulation does not eliminate the requirement to conduct a rail impact test.

Method 526 is not intended for railcar crash conditions. 

Effects of Rail Impact

Rail impact shock has the potential for producing adverse effects on the physical and functional integrity of transported materiel. The following are examples of problems that could occur when materiel is exposed to the rail impact environment.

1. Loosening of tiedown straps.


2. Failure of attachments, creating a safety hazard.


3. Shifting of materiel on the railcar.


4. Failure of materiel.


5. Structural failure.


6. Fuel spills.

Testing

Tests are performed with rail cars. 

Loaded cars are preferred for use as the buffer or struck cars. However, empty cars may also be used. In either case, the total weight of the buffer cars is to be at least 113,400kg (250,000 lb). The first buffer car must be a standard draft gear car. The remaining buffer cars should have standard draft gear, if possible.  Draft gear is the shock absorber which is part of the coupler.

The test railcar is equipped with chain tiedowns and end-of-car cushioned draft gear, unless other railcar types are approved by Director, SDDCTEA. SDDCTEA is the designated DoD agent for land transportation. Some materiel may require other types of railcars for testing to be representative of the intended shipping methods.

A locomotive and at least 200 feet of dry, level track is used to get the rail cars up to the required speed as below.  At the desired speed, the test load car is released so it rolls freely into the buffer cars with the couplings open.  An alternative method of testing is to use an inclined track of sufficient length and gradient to achieve the test speeds.

The test item secured to the test railcar should be at gross weight with the fuel tanks at least 3/4 full.

Subject the test item to four impacts, the first three of which are in the same direction and at speeds of 4, 6, and 8 mph respectively. Perform the fourth impact at 8 mph (+0.5, -0.0 mph) impacting the opposite end of the test car from the first three impacts. If it is not possible to turn the test car because of track layout, this may be accomplished by running the test item car to the opposite end of the buffer cars and impacting as above.

Analysis

1. The test item fails this test if the test item, or any item that is attached to it, or that is included as an integral part of the test item, breaks free, loosens, or shows any sign of permanent deformation beyond specification tolerances.


2. The test item and its subassemblies must be operationally effective after the test.


3. f tiedown securement items break or displace substantially, photograph and document the problem areas for evaluation of the procedures and materials used. The test director and SDDCTEA jointly decide if any failed securement items require reconfiguring and, if so, whether a complete retest is required.


4. Additional considerations:
   (1) Loosening of tiedown straps.
   (2) Failure of attachments, creating a safety hazard.
   (3) Shifting of materiel on the railcar.
   (4) Failure of materiel.
   (5) Structural failure.
   (6) Fuel spills.

MIL-STD-810G – Part 27 – (Rail Impact) Method 526

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MIL-STD-810G – Part 27 – (Rail Impact) Method 526

MIL-STD-810G covers Rail Impact in Method 526.  Method 526 is new to 810G and the purpose of this test method is to replicate the railroad car impact conditions that occur during the life of transport of systems, subsystems and units, and the tiedown arrangements during the specified logistic conditions.  Method 526 is short at 7 pages.

Method 526 is also not intended for testing small, individually packaged material that would normally be shipped when mounted on a pallet or as part of a larger shipment.  It is intended for testing items such as tanks, trucks, etc., that are transported by rail.

The rail impact test is intended to test materiel that will be transported by rail; to determine the effect of railroad car impacts that may occur during rail shipment, to verify the structural integrity of the materiel, to evaluate the adequacy of the tiedown system and the tiedown procedures, and to assess transportability1 by the Military Surface Deployment and Distribution Command Transportation Engineering Agency (SDDCTEA). All items are to be tested at their maximum gross weight (fully loaded) rating unless otherwise specified in the transportability requirements for the materiel. 

Subjecting materiel to a lab shock test or performing an analytical simulation does not eliminate the requirement to conduct a rail impact test.

Method 526 is not intended for railcar crash conditions. 

Effects of Rail Impact

Rail impact shock has the potential for producing adverse effects on the physical and functional integrity of transported materiel. The following are examples of problems that could occur when materiel is exposed to the rail impact environment.

1. Loosening of tiedown straps.


2. Failure of attachments, creating a safety hazard.


3. Shifting of materiel on the railcar.


4. Failure of materiel.


5. Structural failure.


6. Fuel spills.

Testing

Tests are performed with rail cars. 

Loaded cars are preferred for use as the buffer or struck cars. However, empty cars may also be used. In either case, the total weight of the buffer cars is to be at least 113,400kg (250,000 lb). The first buffer car must be a standard draft gear car. The remaining buffer cars should have standard draft gear, if possible.  Draft gear is the shock absorber which is part of the coupler.

The test railcar is equipped with chain tiedowns and end-of-car cushioned draft gear, unless other railcar types are approved by Director, SDDCTEA. SDDCTEA is the designated DoD agent for land transportation. Some materiel may require other types of railcars for testing to be representative of the intended shipping methods.

A locomotive and at least 200 feet of dry, level track is used to get the rail cars up to the required speed as below.  At the desired speed, the test load car is released so it rolls freely into the buffer cars with the couplings open.  An alternative method of testing is to use an inclined track of sufficient length and gradient to achieve the test speeds.

The test item secured to the test railcar should be at gross weight with the fuel tanks at least 3/4 full.

Subject the test item to four impacts, the first three of which are in the same direction and at speeds of 4, 6, and 8 mph respectively. Perform the fourth impact at 8 mph (+0.5, -0.0 mph) impacting the opposite end of the test car from the first three impacts. If it is not possible to turn the test car because of track layout, this may be accomplished by running the test item car to the opposite end of the buffer cars and impacting as above.

Analysis

1. The test item fails this test if the test item, or any item that is attached to it, or that is included as an integral part of the test item, breaks free, loosens, or shows any sign of permanent deformation beyond specification tolerances.


2. The test item and its subassemblies must be operationally effective after the test.


3. f tiedown securement items break or displace substantially, photograph and document the problem areas for evaluation of the procedures and materials used. The test director and SDDCTEA jointly decide if any failed securement items require reconfiguring and, if so, whether a complete retest is required.


4. Additional considerations:
   (1) Loosening of tiedown straps.
   (2) Failure of attachments, creating a safety hazard.
   (3) Shifting of materiel on the railcar.
   (4) Failure of materiel.
   (5) Structural failure.
   (6) Fuel spills.

MIL-STD-810G – Part 27 – (Rail Impact) Method 526

MIL-STD-810G – Part 26 – (Freeze/Thaw) Method 524

MIL-STD-810G covers Freeze/Thaw in Method 524.  Method 524 is new to 810G and was adopted from NATO STANAG 4370, AECTP 300, Method 315. The purpose of the test is to determine the ability of material to withstand the effects of moisture phase changes between liquid and solid (freezing) and the effects of moisture induced by transfer from a cold-to-warm or warm-to-cold environment.  It is a short 6 pages. This test is applicable to materiel that will experience one or more excursions through the freeze point while wet or in the presence of moisture (free water or vapor).

This test is not intended to evaluate the effects of low temperature, thermal shock, rain, or icing. These may be determined using Methods 502.5, 503.5, 506.5, and 521.3, respectively.

Effects of the Environment

This test induces physical changes in or on the materiel that is not stationary. Examples of problems that could occur during this test are as follows:

1. Distortion or binding of moving parts.


2. Failure of bonding materials.


3. Failure of seals.


4. Failure of materials due to freezing/re-freezing of absorbed, adjacent, or free water.


5. Changes in characteristics of electrical components.


6. Electrical flashover/reduced insulation resistance.


7. Fogging of optical systems during freeze-thaw transitions.


8. Inability to function correctly due to ice adhesion and interference or blockage of moving parts.

Test Procedures

Method 524 provides three test procedures:

Procedure I, Diurnal Cycling Effects – To simulate the effects of diurnal cycling on materiel exposed to temperatures varying slightly above and below the freeze point that is typical of daytime warming and freezing at night when deposits of ice or condensation, or high relative humidity exist.  Test for 20 cycles.

Procedure II, Fogging – For materiel transported directly from a cold to a warm environment such as from an unheated aircraft, missile or rocket, to a warm ground area, or from a cold environment to a warm enclosure, and resulting in free water or fogging.  Test for 3 cycles.

Procedure III, Rapid Temperature Change – For materiel that is to be moved from a warm environment to a cold environment (freeze) and then back to the warm environment, inducing condensation (free water).  Test for 3 cycles.

Because this is a freezing cycle test, the required temperature range is narrow with cycle ranges between +5 deg C and-10 deg C.  Use moisture from local, clean sources and apply as water vapor or free water spray.

 

 

 

MIL-STD-810G – Part 26 – (Freeze/Thaw) Method 524

MIL-STD-810G – Part 25 – (Vibro-Acoustic/Temperature) Method 523.3

MIL-STD-810G covers Vibro-Acoustic/Temperature in Method 523.3.  Method 523.3 is performed to determine the synergistic effects of vibration, acoustic noise, and temperature on externally carried aircraft stores such as bombs, missiles and sensor pods during captive carry flight.  It is 16 pages plus one 9-page Annex.

This method would apply to rugged embedded computer systems as installed in externally mounted sensor pods.

Application

For captively-carried stores, this method is intended primarily to test electronics and other electro-mechanical assemblies within the store for functionality in a vibro-acoustic/temperature environment.

Limitations

This method is not intended to provide for:

1. An environmental design qualification test of a store or any of its individual components for functionality. (For such testing see Method 500.5, Altitude; Method 501.5, High Temperature; Method 502.5, Low Temperature; Method 503.5, Temperature Shock; Method 507.5, Humidity; Method 513.6, Acceleration; Method 514.6, Vibration; Method 515.6, Acoustic Noise; Method 516.6, Shock; Method 517.1, Pyroshock; and Method 520.3, Temperature, Humidity, Vibration, Altitude).


2. An environmental design qualification test of a store air frame or other structural components for structural integrity.


3. Any test to satisfy the requirements of the Life Cycle Profile except that for the combined vibration, acoustic, and temperature environments related to reliability testing.

Tailoring Guidance

Possible effects of a combination of vibration, acoustic noise, and temperature include all effects that these factors can cause separately (see Methods 514.6, 515.6, and 520.3). In addition, increased stress as a result of moisture from thermal change may produce possible effects seen in Methods 501.5, 502.5, 503.5, and 507.5. The combined vibration, acoustic noise, and temperature environments may interact to produce effects that would not occur in any single environment or a lesser combination of environments.

Not all environmental stresses contribute equally to materiel deterioration or failure. Analysis of service-use failures caused by aircraft environmental stress on the store (paragraph 6.1, reference a) has identified the following four most important causes of failure:

1. loading of the store through captive carriage,


2. temperature,


3. vibration, and


4. moisture.

Operating any materiel item produces stress that can cause failure. In the case of external aircraft stores, operation generally means providing full electrical power, that produces thermal, electromagnetic, and electrochemical stress.

Temperature

The most severe temperature shock to internal components may come from powering the materiel when it is cold. In order to induce all the stresses related to temperature in their proper proportion, use a thermal model of the store to predict the temperatures and rates of change at several internal points under service mission profiles.  Temperature is constrained by the following:

1. Ambient Temperature
   The greatest variations in ambient temperature occur near the surface of the Earth. The low temperature extreme experience by a store is, in many cases, due to low ambient temperatures immediately preceding flight.


2. Aerodynamic Heating
   During captive flight, the high convective heat transfer rate will cause the surface temperature of an external store to be near that of the boundary layer.


3. Power Dissipation
   Although the high heat transfer rate will tend to keep the surface of a store at the boundary layer recovery temperature, internal temperatures may be considerably higher due to power dissipation of electronic equipment.


4. Temperature Gradients
   The strongest temperature gradients will usually be those associated with powering the materiel when it is cold. Temperature gradients will also occur due to changes in flight speed and altitude that change the surface temperature more rapidly than internal temperatures.

Vibration

Vibration may cause mechanical fatigue failure of parts, abrasion due to relative motion, dislodging of loose particles that can cause electrical shorts, and degradation of electronic functions through microphonics and triboelectric noise.

Moisture

Moisture, in conjunction with soluble contaminants, can result in corrosion. In conjunction with electrical power it may result in shorts. Freezing of water in confined spaces may produce mechanical stress. The test cycle should provide for diffusion of water vapor and condensation.

Shock

Shock can cause failure through mechanical stress similar to that induced by vibration. Shocks that are more nearly transient vibrations (many zero crossings), such as aircraft catapult and arrested landing shock, may be included in this test. Short duration shocks such as pyrotechnic shocks associated with store or sub-munition launch, flight surface deployment, etc., are generally too difficult to reproduce at the store level. Ensure that these events that are potentially destructive to electronics are accounted for in other analyses and tests.

Altitude

Barometric pressure is generally not a stress for external stores. However, variation in pressure may enhance the penetration by moisture. Reduced pressure may increase the temperature due to reduced power dissipation and there may be increased electrical arcing.

Testing

Testing for Method 523.3 is very difficult and requires highly specialized test facilities.  The test item is subjected, simultaneously, to high energy acoustic noise up to 165dB over the range of 150 to 2500 Hz, vibration by electrodynamic or electrohydraulic exciters and temperature in the range of -40 deg C to +85 deg C with a rate of change as high as 4 deg C.  The test item is power cycled to induce electrical stress.  The test item is instrumented for acceleration, acoustic pressure, and temperature plus other measurements as required by the particular store.

Typical Arrangement of MIL-STD-810G Method 523.3 Test Apparatus

MIL-STD-810G – Part 25 – (Vibro-Acoustic/Temperature) Method 523.3