Downloaded from https://www.everyspec.com MIL-STD-1312B 40.3 Load cycle. ‘Thesmallest segment of the load-time function which is repeated periodically. 40.4 Maximum load. The load having the higheat algebraic value in the load cycle, tensile load being considered positive and compressive load being considered negative. fLo.5 Minimum load. The load having the lowest algebraic value in the load cycle, tensile load being considered positive and compressive load being considered negative. ,,. 40.6 Mean load. The algebraic average of the maximum and minimum loada in the load cycle. 40.7 Load amplitude. tie half of the algebraic difference between the maximum and minimum loads in the load cycle.
40.8 Set loads. ‘Themaximum and minimum loads (or the mean load and the load amplitude) that relate tn the settings and adjustment of the controls of a fatigue-testing machine, according to an existing set of guidelines. These guidelines may have been furnished by the manufacturer of the machine or they may have been developed by the user. ! 0 ,,, ! 40.9 Indicated loads. The maximum and minimum loads (or the mean load and the load amplitude) that relate to the readings obtained from the indicating or recording equipment associated with the fatigue testing machine, according to an existing calibration.
This calibrationmay have been furnished by the manufacturer of the machine, or may have been developed by the user. In the case of fatigue-testing machines having no provision for load readout, the indicated loads shall be determined by introducing an appropriate sized dynamometer into the load chain. I 40.10 ~namome ter. An elastic calibration device for use in verifying the indicated loads applied by a fatigue testing machine.
It shall consist of an instrumented member having mass, stiffneas, and end displacements such that the inertial I I effects of the apecim.enand its attachment to the test machine, for which the verification of loads is desired, are duplicated as nearly as is reasonable. The instrumentation shall permit an accurate determination of the magnitude of the average strain, in a region of uniform transverse cross section, when the dynamometer is subjected to a tensf.leor compressive force along its longitudinal axia. 40.11 Dynamometer range. The range of loads for which the dynamometer may be used for verification purposes.
A dynamometer for use in tension and in compression will have two dynamometer ranges, one in tenaion and one in compression. 9