Flight by Flight Fatigue Test of Aircraft Structure

conference paper

en

The most realistic method of experimental determining the mean fatigue life of an aircraft structure is a random application of loads on a flight by flight basis. This paper deal with the development of such load sequence which simulates a load history as it can occur in service. The main requirement for service simulations is deep enough information about aircraft usage, flight and ground loads. This work is based on data collected from 903 flights and approximately 585 flight hours recorded on 28 BE-1900D aircraft during typical operations. 26 flight types were proposed which are applied during fatigue test and which represent service in point of flight distance and maximum reached altitude. A computer program was written for generation of load sequence. Appropriate algorithm includes random selection of flight type, random selection of flight loads within particular altitude bands, omission of small cycles under specified limit, random selection of downwards ground loads and selection of the highest one, conversion of load factor values to the forces applied by a hydraulic actuator considering influence of aircraft weight changes during flight and determination of a load frequency for each cycle depending on its amplitude. Created load sequence is intended for a fatigue test of the wing spar specimen. This testing program is focused especially on the crack growth curves determination for fatigue cracks located in the spar web.

The most realistic method of experimental determining the mean fatigue life of an aircraft structure is a random application of loads on a flight by flight basis. This paper deal with the development of such load sequence which simulates a load history as it can occur in service. The main requirement for service simulations is deep enough information about aircraft usage, flight and ground loads. This work is based on data collected from 903 flights and approximately 585 flight hours recorded on 28 BE-1900D aircraft during typical operations. 26 flight types were proposed which are applied during fatigue test and which represent service in point of flight distance and maximum reached altitude. A computer program was written for generation of load sequence. Appropriate algorithm includes random selection of flight type, random selection of flight loads within particular altitude bands, omission of small cycles under specified limit, random selection of downwards ground loads and selection of the highest one, conversion of load factor values to the forces applied by a hydraulic actuator considering influence of aircraft weight changes during flight and determination of a load frequency for each cycle depending on its amplitude. Created load sequence is intended for a fatigue test of the wing spar specimen. This testing program is focused especially on the crack growth curves determination for fatigue cracks located in the spar web.

fatigue test, service simulation, aircraft structure

24.09.2003

Scientific Society of Mechanical Engineering

Györ

9639058203

20th Danubia-Adria Symposium on Experimental Methods in Solid Mechanics

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