As a MIL-STD-810 certified lab, we realize the importance of vibration compliance testing. Meeting the MIL-STD-810 standard requirements can be difficult. We understand the challenges and guide companies through the process.
Keystone provides the peace of mind that all of your needs will be met. When products do not meet the requirements, we assist with finding solutions. We are in constant communication throughout the entire test process. Thus, our proven process helps avoid product launch delays.
The Importance of MIL-STD 810 Vibration Compliance Testing
Vibration testing is performed for two purposes. First, this MIL-STD 810 compliance testing is used to develop material to function in and withstand vibration exposures of a life cycle. Including synergistic effects of other environmental factors, material duty cycle, and maintenance. Second, MIL-STD-810 test method 514 is used to verify that material will withstand the vibration exposures of a life cycle.
How Vibration Method 514 Testing Affects the Product
Vibrations result in dynamic deflections of and within material. These deflections and associated velocities contribute to structural fatigue and mechanical wear of structures, assemblies and parts. In addition, dynamic deflections may result in the impacting of elements and/or disruption of functions. Some typical symptoms of these test conditions are listed below, however, the list is not intended to be all inclusive.
- Chafed wiring.
- Loose Fasteners/Components.
- Intermittent electrical contacts.
- Electrical shorts.
- Deformed seals.
- Failed components.
- Optical or mechanical misalignment.
- Cracked and/or broken structures.
- Migration of particles and failed components lodged in circuitry or mechanisms.
Information on the MIL-810 Standard Testing
Identify the environments of the materials life cycle when selecting which method works best for the material. Test the material for each category to which it will be exposed during an environmental life cycle.
Some other considerations when selecting an MIL-810 test method are as follows. Analytical estimates of fatigue damage potential should be made on the assumption of well-understood models of the material. Another method for reducing test duration is through a combination of random test profiles.
This is by either employing the fatigue damage spectrum or via statistical methods. However, a combination of vibration tests should not be performed with dissimilar spectra or spectra with dissimilar bandwidths.
All material, one way or another, will experience vibration. Vibration may be during manufacturing, transportation or operational use. The procedures of this military standard test address most of the situations within an item’s life cycle. This includes during which vibration is most likely to occur.
Selecting the military testing lab procedure most appropriate for the material to be tested will be mentioned in the text below. Note that the LCEP may reveal more vibrational scenarios that are not specifically addressed within these procedures. The tailoring process is necessary to capture those LCEP variations.
Fidelity of the laboratory test environment – As noted in the paragraphs above, laboratory test methods are limited in their abilities to simulate synergistic or antagonistic stress combinations. An assessment of the test item should be used to determine the environmental deficiencies in the test environment.
Conservatism with measured data – This document encourages the use of material-specific measured data as the basis of vibration analysis. Due to limitations within data and accessibility, the numbers do not include all extreme conditions but still must be factored within the testing method.
Conservatism with default or enveloped data – Use caution when conducting MIL-810 vibration tests with default or enveloped vibration data if nonlinear behavior is expected or observed at full test level. The test options and proposed path forward should be sent to the appropriate test authority for concurrence prior to proceeding.
How Each of the Four MIL-STD-810 Test Procedures Differ
Procedure I – General Vibration – This procedure is designed for material to be transported as secured cargo or deployed for use on a vehicle. For this procedure, the test item is secured to the vibration exciter and vibration is applied to the test item. Procedure I uses standard laboratory vibration exciters, slip tables, and fixtures.
Procedure II – Loose Cargo Transportation – Use this Procedure for material to be carried in/on trucks, trailers, tracked vehicles and not tied down to the carrying vehicle. The test severity is not tailorable and represents loose cargo transport in military vehicles through rough terrain. This procedure requires use of a package tester that imparts a peak-topeak, circular synchronous motion.
Procedure III – Large Assembly transportation – This procedure is intended to replicate the vibration and shock environment incurred by large assemblies of thermal material installed or transported by wheeled or tracked vehicles.
Generally, measured vibration data is not used to define this MIL-STD 810 test. However, measured data is often acquired during this test to verify that the vibration and shock criteria for material subassemblies are realistic. The test facility for this procedure is a test surface that replicates vehicular transportation. The item is loaded on a vehicle and secured or mounted to represent the life cycle event
Procedure IV – Assembled Aircraft Store Captive Carriage and Free Flight – Procedure IV is used to apply fixed wing aircraft carriage and free flight portions of the environmental life cycles of all aircraft stores. This procedure is also used to free flight phases of ground or sea-launched missiles. Lastly, this 810-test procedure uses a standard laboratory vibration shaker driving the test item directly or through a fixture. The test item is supported by a test frame independent of the vibration exciters.
What is the Test Item Configuration?
The test item is configured for each test as it will be in the corresponding life cycle phase. In cases representing transportation, all packing, shoring, and padding are duplicated in the vibration test lab. Other configuration modifications of the shipment are also considered. The transportation configuration may be different for different modes of transportation.
For loose cargo the procedure presented is a general representation based on experience as well as measurement, and is not tailorable. The most realistic alternative for truck, trailer, or other ground transportation requires the transportation vehicle and a full cargo load. This is the best vibration testing option.
In this test, the cargo is free to bounce, scuff and collide with other cargo, and the sides of the vehicle. The loose cargo environment includes conditions experienced by cargo transported in a vehicle traversing irregular surfaces. This test replicates the repetitive impact environment incurred by cargo transported under these conditions.
This procedure assumes no relative motion between the vehicle cargo deck, or cargo compartment and the cargo. This applies directly to material that is tied down or secured. The tethers should ensure that no relative motion is allowed considering vibration, shock, and acceleration loads.
Sometimes restraints are not used or they allow limited relative motions. When this occurs, allowances should be provided in the test setup, and in the vibration excitation system, to account for this. Procedure III is an alternative for ground transportation.
Keystone Compliance Provides Vibration Lab Testing Services
Keystone Compliance is one of the best test method 514, vibration testing labs in the country. We employ expert test engineers and properly equip our laboratory in order to provide MIL-STD-810 vibration test certifications.
Keystone has a full lab of test equipment which permits us to provide short lead times on scheduling. Our team strives to give our customers more time and energy on product development instead of testing.
Request a quote and learn why so many manufacturers rely on Keystone Compliance to meet their MIL-STD 810 lab compliance testing needs.