Date of Award

Fall 1996

Document Type

Thesis - Open Access

Degree Name

Master of Science in Aerospace Engineering


Graduate Studies

Committee Chair

David Kim

Committee Member

Eric v. K. Hill

Committee Member

James G. Ladesic


Backpropagation neural networks have been used to predict strain resulting from the maneuver in-flight loads in the empennage structure of a Cessna 172P. The purpose of this research was to develop a methodology for the prediction of strain in the tail section of a general aviation aircraft and to determine the minimum set of sensors necessary to adequately train the neural networks. Linear accelerometer, angular accelerometer, rate gyro, and strain gage signals were collected in flight using DAQBook portable data acquisition system for dutch-roll, roll, sideslip left, sideslip right, stabilized g turn left, stabilized g turn right, and push-pull maneuvers at airspeeds of 65 KIAS, 80 KIAS, and 95 KIAS. The sensor signals were filtered and used to train the neural networks. Modular Neural Networks were used to predict the strains. The horizontal tail neural network was trained with CGNz and x-, y-, and z-axis angular accelerometer signals and predicted 93% of all strains to within 50 :, of the measured value. The vertical tail neural network predicted 100% of all strains to within 50 :, of the measured value.