Design and Implementation of a Microprocessor Flight Damage Monitor

摘要

In order to design a constrained layer damping treatment for aircraft components, the Air Force Flight Dynamics Laboratory at Wright-Patterson Air Force Base, Ohio requires a knowledge of vibration and temperature variations which a component encounters during its life. This report discusses the design and implementation of a microprocessor based system to acquire vibration and temperature information, and computes the cumulative damage factor versus frequency and temperature in real time. The cumulative damage factor is computed for one of eight user selectable frequency ranges and for a temperature range of -50 to +225 degrees Fahrenheit and is stored in a non-volatile memory. The designed systems uses an LSI11 microcomputer systems consisting of an LSI-11 processor, an analog-to-digital converter, a real-time clock, PROM, a non-volatile memory, and a serial interface. The software developed for this system controls the data acquisition, the computation of a fast Fourier transform (FFT), the power spectrum of vibration data, and the subsequent computation of the cumulative damage factor. The data acquisition and FFT modules were coded in assembly language, and the other modulus were coded in FORTRAN. The output of the system consists of a table containing the cumulative damage as a function of frequency and temperature. A bench model system was constructed and tested, and a proposal for a flight-worthy system is made. (Author)