Structural Integrity – Yesterday – Today – Tomorrow
Early airplanes were designed using purely static conditions and mainly tested only with simple wing tests. But despite the significant advances in design, manufacturing and testing capabilities, structural failures may still occur. Thus new concepts are required to ensure safe operations over the lifetime of an airframe. In 1952 Juerg Branger developed a concept for a fatigue simulator at the Federal Swiss Aircraft Factory (F+W). The Pilatus P3 trainer became the first airplane to be tested in Emmen, Switzerland to demonstrate the safety of the airframe over a lifetime of 2500 FH. This first test demonstrated the importance of full scale fatigue tests to ensure the structural integrity of the airframe. Due to the intense usage of the fighters deployed by the Swiss Air Force, further full scale fatigue tests were undertaken on the Venom, the Mirage III, and the F/A-18. As the complexity of the materials used in modern aircraft design increases, more and more analysis is being taken over by highly sophisticated software and test procedures. Structural integrity is still an important means to ensure safe operations in aviation for all types of airplanes.