Downloaded from https://www.everyspec.com MIL.sTD-1312B I 80.3 Procedure. For maximumload at the verification of each test frequency following procedure: each minimum load and desired, adopt the ,.. a. Mount the dynamometer in the fatigue machine, connect the associated transducer instrumentation and allow sufficient time for stabilization of all instruments. b. Ensure that tbe strain measured by any one ,oftlie“measuring elements of the transducer attached to the dynamometer does nnt differ by more than 6 percent from the average of the strain measured by all of the elements at any load in the dynamometer range. c.
Apply the desiredminimumload staticallyand recordthe strain output of the transducer. Increa~e the “load statically t o the desired maximum and again record the transducer strain output. d. Operate the machine dynamically and adjust the mschine contro1s to the programmed load level and frequency. Record the actual minimum and maximum operating strains from tbe transducer output. e. Compute the machine error as a per&nt of cyclic amplitude and maximum load as follows: Static Comparison Dynamic Comparison Machine Dynamometer Machine Dynamometer Programmed Indicated Strain Programed Indicated Strain Load Lb ,JM@JKkL Load - Lb Min Max Min Max Min Max Min . .
Max 300 3000 18 187 300 3000 19 185 Amplitude Error: (185-19) - (187-18) ~ loo = ~ ,77 (187-18) . . Msximum Load Error: > 185-187~ 187 100 = -1.07% f. stabilized (for example, bridge output level of one element of cyclic load. After a period of restart the cyclic load, observing the output of the transducer during the first cycle. Estimate the time interval before the output stabilizes at the steady state cyclic level. .0 With the instrumentation balanced) at the maximum the transducer, stop the not less than 5 minutes, 16