MIL-STD 810, Method 516, Shock Testing Procedure V – Crash Hazard Shock

This is another part of a series of blog posts concerning the MIL-STD 810 Shock Section, Method 516.  This blog was written with reference to MIL-STD-810G w/Change 1 dated 15 April 2014.  DES has the experience and expertise to run your MIL-STD-810 test.  For more information, please check out our DES shock testing services page and our other MIL-STD-810 shock testing blog articles:

MIL-STD 810, Method 516, Shock Testing Overview

MIL-STD 810, Method 516, Shock Testing Procedure I – Functional Shock

MIL-STD 810, Method 516, Shock Testing Procedure II – Transportation Shock

MIL-STD 810, Method 516, Shock Testing Procedure III – Fragility

MIL-STD 810, Method 516, Shock Testing Procedure IV – Transit Drop

Crash hazard shocks apply to materiel mounted in air or ground vehicles.  Shock testing according to Procedure V of MIL-STD 810, Method 516 is intended to test the strength of products during a crash situation to verify that parts do not break apart, eject and become a safety hazard.  Failures of this nature could cause dangerous projectiles that could impact occupants or create significant damage to the vehicle.

This article will focus on the shock test condition when measured field data is not available and the testing will use classical shock impulses.  The terminal peak sawtooth is the default classical shock pulse to be used for this condition.  Figure 516.7-10 from MIL-STD-810 shows its shape and tolerance limits.  Table 516.7-IV contains the terminal peak sawtooth default test parameters for Procedure V – Crash Hazard Shock.  In limited cases a half sine shock impulse is specified.  Its shape and tolerance limits are shown in Figure 516.7-12.

Continue Reading MIL-STD 810, Method 516, Shock Testing Procedure V – Crash Hazard Shock

MIL-STD 810, Method 516, Shock Testing Procedure IV – Transit Drop

This is another part of a series of blog posts concerning the MIL-STD 810 Shock Section, Method 516.  This blog was written with reference to MIL-STD-810G w/Change 1 dated 15 April 2014.  DES has the experience and expertise to run your MIL-STD-810 test.  For more information, please check out our DES shock testing services page and our other MIL-STD-810 shock testing blog articles:

MIL-STD 810, Method 516, Shock Testing Overview

MIL-STD 810, Method 516, Shock Testing Procedure I – Functional Shock

MIL-STD 810, Method 516, Shock Testing Procedure II – Transportation Shock

MIL-STD 810, Method 516, Shock Testing Procedure III – Fragility

Method 516, Procedure IV is for testing products that could be accidently dropped such as when they are removed from a shelve or dropped when handling.  The test item is physically dropped onto a hard surface to produce the shock.  Products can be tested inside their transit case or unpackaged.  Typically, they would be tested in the configuration that is normally used for transportation, handling, or a combat situation.

Continue Reading MIL-STD 810, Method 516, Shock Testing Procedure IV – Transit Drop

MIL-STD 810, Method 516, Shock Testing Procedure III – Fragility

This is another part of a series of blog posts concerning the MIL-STD 810 Shock Section, Method 516.  This blog was written with reference to MIL-STD-810G w/Change 1 dated 15 April 2014.  DES has the experience and expertise to run your MIL-STD-810 test.  For more information, please check out our DES shock testing services page and our other MIL-STD-810 shock testing blog articles:

Procedure III is used to determine what shock conditions will cause a product to stop operating, degrade or fail.  The shock magnitudes are systematically increased until a problem occurs.  This procedure can be also performed using environmental temperature conditioning.

This article will assume that the fragility shocks expected to be encountered by the product are not complex transients.  Therefore, the trapezoidal classical shock pulse, as defined in Figure 516.7-11 and Table 516.7-V from MIL-STD-810, Method 516 would be used for Fragility testing.

Continue Reading MIL-STD 810, Method 516, Shock Testing Procedure III – Fragility

MIL-STD 810, Method 516, Shock Testing Procedure II – Transportation Shock

This is another part of a series of blog posts concerning the MIL-STD 810 Shock Section, Method 516.  This blog was written with reference to MIL-STD-810G w/Change 1 dated 15 April 2014.  DES has the experience and expertise to run your MIL-STD-810 test.  For more information, please check out our DES shock testing services page and our other MIL-STD-810 shock testing blog articles:

MIL-STD 810, Method 516, Shock Testing Overview

MIL-STD 810, Method 516, Shock Testing Procedure I – Functional Shock

Continue Reading MIL-STD 810, Method 516, Shock Testing Procedure II – Transportation Shock

MIL-STD 810, Method 516, Shock Testing Procedure I – Functional Shock

This is part two of a series of blog posts concerning the MIL-STD 810 Shock Section, Method 516.  This blog was written with reference to MIL-STD-810G w/Change 1 dated 15 April 2014.  DES has the experience and expertise to run your MIL-STD-810 test.  For more information, please check out our DES shock testing services page and our other MIL-STD-810 shock testing blog articles:

MIL-STD 810, Method 516, Shock Testing Overview

Shock testing according to Procedure I of MIL-STD 810, Method 516 is intended to test products while they are operating to see if any functional problems occur and to determine if they survive without damage.  The applied shocks usually represent those that may be encountered during operational service.  This article will focus on the shock test condition when measured field data is not available and the testing will use classical shock impulses.  The terminal peak sawtooth is the default classical shock pulse to be used for this condition.  Figure 516.7-10 from MIL-STD-810 shows its shape and tolerance limits.  Table 516.7-IV contains the terminal peak sawtooth default test parameters for Procedure I -Functional Test.  In limited cases a half sine shock impulse is specified.  Its shape and tolerance limits are shown in Figure 516.7-12.

Continue Reading MIL-STD 810, Method 516, Shock Testing Procedure I – Functional Shock

MIL-STD 810, Method 516, Shock Testing Overview

This is part one of a series of blog posts concerning the MIL-STD 810 Shock Section, Method 516.  This blog was written with reference to MIL-STD-810G w/Change 1 dated 15 April 2014.  DES has the experience and expertise to run your MIL-STD-810 test.  For more information, please check out our DES shock testing services page. 

MIL-STD-810 is a public military test standard that is designed to assist in the environmental engineering considerations for product design and testing.  For the purposes of this blog series we will focus on Method 516.7, Shock Testing.

The purpose of shock testing is to:

  1. Evaluate if a product can withstand shocks encountered in handling, transportation, and service environments
  2. Determine the product’s fragility level
  3. Test the strength of devices during a crash situation to verify that parts do not break apart, eject and become a safety hazard

Continue Reading MIL-STD 810, Method 516, Shock Testing Overview

Mixed Mode: Sine on Random Vibration Testing, RoR, SoRoR

random vibration testing

Mixed Mode Vibration Testing is less common than Sinusoidal and Random Vibration Testing.  However, it does have a special purpose for simulating specialized helicopter vibration or vibration from tracked vehicles such as tanks.

The three mixed modes of vibration testing are:

  • Sine-on-Random (SoR)
  • Random-on-Random (RoR)
  • Sine-on-Random-on-Random (SoRoR)

Some common test standards that have specifications for Mixed Mode Vibration Testing are:

  • MIL-STD-810 Department of Defense Test Method Standard for Environmental Engineering Considerations and Laboratory Tests
  • RTCA DO-160 Environmental Conditions and Test Procedures for Airborne Equipment

Continue Reading Mixed Mode: Sine on Random Vibration Testing, RoR, SoRoR

Altitude Testing: Low Pressure Vacuum Chamber

Altitude TestAltitude (Low Pressure) Testing makes use of a vacuum chamber to simulate the effects of high altitude conditions. The pressure inside the altitude chamber can be reduced to correspond to the air pressure at a specific altitude. Products can be placed inside the altitude chamber and tested to determine if they will still function after exposure to a given duration at a specified altitude.

Components sealed with internal fluid such as batteries or capacitors may fail or leak during altitude testing because an internal pressure results at rising altitudes as the external pressure is reduced.  It is also possible to power a product during the test to verify that it remains operational during the altitude test. The lower pressure at higher altitudes can reduce the cooling of components which can lead to possible failures. For this type of testing, it is necessary to have power and signal wires that can be fed into the altitude chamber without causing vacuum leaks. DES can provide a generic feed through that can be used for most testing. A custom feed through can also be fabricated if the component to be tested has specialized power or signal cables. It will be necessary to seal these cables to maintain the low pressure. Continue Reading Altitude Testing: Low Pressure Vacuum Chamber