MIL-STD-810 Archives - Delserro Engineering Solutions

MIL-STD-810 Pyroshock Testing

MIL-STD 810 Method 517 Pyroshock Testing is performed to evaluate whether products can withstand the shock effects caused by the detonation of a pyrotechnic device, typically found in missiles or rockets. A pyroshock test can also be used to determine an item’s fragility level experimentally. This allows for the application of shock mitigation techniques to protect its structural and functional integrity. The latest revision of this test standard is Method 517.3 from MIL-STD-810H.

DES is a leader in MIL-STD-810 Pyroshock testing, having performed hundreds of tests using our state-of-the-art Mechanical Impulse Pyroshock Simulator (MIPS).

Understanding Pyroshock

A pyroshock creates a stress wave that propagates through the structure into components that are mounted to the structure. A Pyroshock has the following characteristics:

Frequency range from 100 Hz up to 10,000 Hz and beyond
High accelerations from 300 G’s up to 200,000 G’s with low structural velocity and displacement response
Short-time durations less than 20 milliseconds

Common Failures caused by Pyroshock Impulses?

Destruction of the structural integrity of micro-electronic chips
Electrical relay chatter causing operational faults
Circuit board malfunction and/or damage
Electronic connector failure or momentary disconnects
Cracks and fractures in crystals, ceramics, epoxies, or glass envelopes

Pyroshock definitions are from MIL-STD-810H, Method 517.3

Near-field Pyroshock. The stress wave propagation effects govern the response. Near-field pyroshock tests require frequency control up to and above 10,000 Hz for amplitudes greater than 10,000G’s. A pyrotechnically excited simulation is mostly used, although in some cases a mechanically excited simulation technique may be used.
Mid-field Pyroshock. The pyroshock response is governed by a combination of material stress wave propagation and structural resonance response effects. Mid-field pyroshock tests require frequency control from 3,000 Hz to 10,000 Hz for amplitudes less than 10,000G’s. A mechanically excited simulation technique other than shaker shock is typically used.
Far-field Pyroshock. The pyroshock response is governed by a combination of material stress wave propagation and structural resonance response effects. Far-field pyroshock tests require frequency control no higher than 3,000 Hz for amplitudes less than 1,000G’s. An electro dynamic shaker or a mechanically excited simulation technique is typically used.

Method 517.3 Pyroshock has Five Testing Procedures:

Procedure I – Near-field with an Actual Configuration. For Procedure I, the pyroshock is replicated using the actual material and the associated pyrotechnic shock test device configuration.
Procedure II – Near-field with a Simulated Configuration. Procedure II replicates the pyroshock using the actual material, but the associated pyrotechnic shock test device is isolated from the test item. For example, by being mounted on the back of a flat steel plate.
Procedure III – Mid-field with a Mechanical Test Device. For Procedure III, replication of the pyroshock is performed using a mechanical device that simulates the pyroshock peak acceleration amplitudes and frequencies. A mechanical device such as DES’s MIPS is used. An electrodynamic shaker is not capable because of frequency range, peak acceleration and weight limitations.
Procedure IV – Far-field with a Mechanical Test Device. Procedure IV also replicates the pyroshock with a mechanical device such as DES’s MIPS. An electrodynamic shaker is not capable of performing Procedure IV pyroshocks because of limitations.
Procedure V – Far-field with an Electrodynamic Shaker. The pyroshock is replicated using an electrodynamic shaker to simulate the low frequency structural resonant response.

How MIL-STD-810 Pyroshock Testing is Performed at DES?

The pyroshock test criteria, including the required Shock Response Spectrum (SRS), are provided to DES. A specialized fixture is then fabricated to attach to our shock test equipment. The test setup is experimentally determined using a mass model to achieve the required SRS. Once the SRS is replicated with the mass model, the actual test item is tested on the shock apparatus. The shock pulse is captured using high-speed data acquisition and specialized shock accelerometers, with SRS plots calculated and analyzed using our specialized software.

The testing is performed along 3 orthogonal axes. In most cases, the required SRS is achieved in both positive and negative directions during a single strike. Upon test completion, DES promptly delivers a detailed report that includes pyroshock plots, test observations, results, and color photographs of the setup and any failures.

Why Choose DES for MIL-STD-810 Pyroshock Testing

When it comes to MIL-STD-810 Pyroshock Testing, selecting the right laboratory is crucial for repeatable results. DES stands out because:

DES has performed hundreds of Pyroshock tests for defense and space manufacturers
Our lab is A2LA accredited to MIL-STD-810, Method 517 Pyroshock Testing
We utilize state-of-the-art Mechanical Impulse Pyroshock Simulator (MIPS) capable of performing MIL-STD-810 Pyroshock testing
Our high speed data acquisition captures the shock pulse and has specialized accelerometers rated for pyroshock testing

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MIL-STD-810 High Temperature Testing

MIL-STD 810, Method 501 High Temperature Testing is used to evaluate the effects of high temperature conditions on performance, materials, and integrity. Method 501 is applicable for temperature testing products that are deployed in areas where temperatures (ambient or induced) are higher than standard ambient. Note, the latest revision of this method is 501.7 from MIL-STD-810H.

Method 501 is limited to evaluating the effects of relatively short-term (months, as opposed to years), even distributions of heat throughout the test item. This method is not typically practical for evaluating materials where solar radiation produces thermal gradients or photochemical effects. Method 505 is used to test the effects of solar radiation. It is also not practical to evaluate degradation that occurs from continuous long-term exposure to high temperatures where synergetic effects may be involved.

The following are typical failures that could occur from products used in high temperature environments.

Parts bind from the differential expansion of dissimilar materials.
Lubricants become less viscous; joints lose lubrication by the outward flow of lubricants.
Materials change in dimension.
Packing, gaskets, seals, bearings, and shafts become distorted, bind, and fail causing mechanical failures.
Gaskets display permanent sets.
Closure and sealing strips deteriorate.
Fixed-resistance resistors change in values.
Electronic circuit stability varies with differences in temperature gradients and differential expansion of dissimilar materials.
Transformers and electromechanical components overheat.
Operating/release margins of relays and magnetic or thermally activated devices alter.
Shortened operating lifetimes.
High pressures are created within sealed cases (batteries, etc.).
Discoloration, cracking, or crazing of organic materials.
Out-gassing of composite materials or coatings.
Failure of adhesives.

MIL-STD-810 Method 501 Tests: High Temperature Procedures

Procedure I – Storage. Procedure I is for testing products that are stored at high temperatures. After the high temperature storage test is completed, an operational test at ambient conditions is performed. Procedure I can be either a cyclic temperature test or a constant temperature test.
Procedure II – Operation. Procedure II is used to investigate how high temperatures could affect the performance of items while they are operating. Temperature Procedure II can be performed as either a cyclic temperature test or a constant temperature test.
Procedure III – Tactical-Standby to Operational. This temperature procedure evaluates the material’s performance at normal operating temperatures after being presoaked at high non-operational temperatures. An example of Procedure III is a product that is stored in an enclosed environment that develops high internal temperatures before being removed and then operated in a relatively short period of time.

What is the procedure for MIL-STD-810 High Temperature Testing?

First, identify the high temperature levels, test conditions, and applicable procedures. DES can help determine the appropriate temperature ramp rates and durations of the tests based on the equipment’s intended use and the operating environmental conditions. Consider the following climatic temperatures from Table 501.7-I. (MIL-STD-810H):

Design Type	Location	Ambient Air ^oC (^oF)	Induced² ^oC (^oF)
Basic Hot (A2)	Many parts of the world, extending outward from the hot dry category of southwestern United States, northwestern Mexico, central and western Australia, Saharan Africa, South America, Southern Spain, and southwest and south central Asia.	30 – 43 (86 – 11)	30 – 63 (86 – 145)
Hot Dry (A1)	Southwest and south central Asia, southwestern United States, Saharan Africa, central and western Australia, and northwestern Mexico.	32 – 49 (90 – 120)	33 – 71 (91 – 160)

Table 501.7-I from MIL-STD-810H

Next, determine whether a constant temperature test or a cyclic temperature test is appropriate. Constant temperature testing is used only for items situated near heat-producing equipment or when it is necessary to verify the operation of an item at a specified constant temperature. The duration for constant temperature test temperature is at least two hours following test specimen stabilization.

For cyclic exposure, there are two 24-hour cyclic profiles contained in Tables 501.7-II and 501.7-III. The number of cycles for the Procedure I storage test is a minimum of seven to coincide with the one percent frequency of occurrence of the hours of extreme temperatures during the most severe month in an average year at the most severe location. The minimum number of cycles for the Procedure II operational testing is three. This number is normally sufficient for the test item to reach its maximum response temperature.

You can trust the DES MIL-STD-810 High Temperature Testing lab

Advantages with DES :

DES is A2LA accredited to MIL-STD-810, Method 501 High Temperature Testing
DES has extensive experience running MIL-STD-810 Method 501.7 high temperature Tests
DES has multiple temperature chambers capable of performing MIL-STD-810 high temperature compliance testing

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