This is part of a series of blog posts concerning the MIL-STD 810 Vibration Section. This blog was written with reference to MIL-STD-810G w/Change 1 dated 15 April 2014. DES has the experience and expertise to help you determine what profiles are appropriate for your product and to run your MIL-STD-810 vibration test. For more information, please check out our Vibration Testing services page and the other blog posts in this series,
Procedure I (General Vibration), Category 9 of Method 514.7 Vibration testing details the vibration profile of cargo carried in helicopters. This vibration profile is unique because it superimposes strong narrowband peaks of sinusoidal vibration caused by rotating components such as the main or tail rotors, over low-level wideband random vibration caused by aerodynamic flow. This vibration profile is generally referred to as Sine on Random Vibration Testing. Figure 1 outlines the typical vibration profile and the variables which are determined based upon the type of helicopter as well as the location on the helicopter where your product will be used or stored. Tables 1 and 2 define the equations and properties used to determine the variables used in the Figure 1 plot.
Default test duration is 4 hours in each of 3 orthogonal axes for a total test time of 12 hours. This test duration represents a 2500-hour operational life. The levels in Figure 1, Tables 1 and 2 are intended to envelope worst-case environments, and have been aggressively compressed in time from 2500 hours to 4 hours.
Figure 1. Figure 514.7C-9 from MIL-STD-810G w/ Change 1 – Helicopter Vibration Profile (Sine over Random)
Table 1. Table 514.7C-IXa from MIL-STD-810G w/ Change 1 – Typical Helicopter Vibration parameters
Table 2. Table 514.7C-IXb from MIL-STD-810G w/ Change 1 – Helicopter Vibration Exposure and Variables