Gumstix customer reported results from testing to the military standard MIL-STD-810 Vibration (constant acceleration).
The MIL-STD-810F 514.5 test series, approved for use by all departments and agencies of the United States Department of Defense (DoD),·emphasizes tailoring an environmental design and test limits to the conditions that it will experience throughout its service life.
July 2009: The tests performed by this Gumstix customer simulated vibration for the equivalent of 1,642,500 kilometers, which is the average distance a bus travels in 5 years making this testing an accelerated simulation of a “Diesel Engine Road Vehicle” running over an assortment of road surfaces. Essentially, an hour of simulation equates to a number of kilometres travelled.
Results
- Their Overo COM and Tobi expansion board configuration passed the 5 year, MIL-STD-810F 514.5·military test for·Vibration (constant acceleration).This extended test result was completed successfully because the customer engineers secured the Gumstix Overo and Tobi boards together with the·retaining spacers supplied by Gumstix and gluing the configuration together. This extra mechanical connection was deemed to have reduced board flexing.
- Their Overo COM and expansion board combination passed the 2-3 year, MIL-STD-810F 514.5 mark without the addition of retaining spacers, gluing or screws.
Further commentary from the customer:
- The testing done by this customer is extremely harsh.
- The customer stated that "the design and robustness of the Gumstix Overo series without the retaining spacers is extremely high and under normal circumstances are fit for purpose" and "that they "don’t believe that any units would have actually failed in the field".
- The customer tested 3 Gumstix Overo units: one announcement unit, one tracking unit and an Overo Earth/Summit combination. All three configurations complied with this MIL-STD-810F standard until approximately the 2 – 3 year mark. Under strobe light/vibration observations without spacers, the customer could see the U8 end of the Overo flexing at resonant frequencies.
The customer reported that this flexing does not happen to the Overo COM when the retaining spacers are fitted. The customer believes that this ‘flexing’ is causing small amounts of wear to the plug/sockets that eventually leads to failure at the 2-3 year mark when cycled under this accelerated simulation.
