LEVEL CONTROLLER FOR IRREGULAR WAVE OF FATIGUE TESTING MACHINE

摘要

PURPOSE:To take a continuous test using an irregular wave in a short time by placing a random load on a testing machine by a random function generator and making corrections by an amplitude controller through a D/A converter so that the maximum value of stress generated in a test material is held constant. CONSTITUTION:The amplitude controller 3 as a multiplier is connected between the random function generator 1 and testing machine 2 and a signal processor 4 which inputs part of the load output of the testing machine 2 is connected; and the D/A converter 5 which converts a digital signal which is the output signal of this signal processor 4 into an analog signal, and the amplitude controller 3 is controlled with the output of the D/A converter 5. Namely, the load output of the testing machine 2 is sampled by the signal processor 4 with the random wave for a certain time section to calculates the arithmetic mean value of respective maximum values and the value K is converted into an analog value by the D/A converter 5 so as to have the same value as a similar value at the start. Then, the amplitude controller 3 corrects it to vary the level of the input signal to the testing machine 2 at constant intervals of time.