File:D. Dębski, M. Dębski, K. Gołoś, J. Kaźmierski, Fatigue Analysis Tools of Aerostructures.jpg

The following monograph is the result of a significant participation of the authors in the implementation of various research programs such as the research program for the PZL I-22 Iryda combat jet trainer aircraft, several national and two European scientific and research programs, a cooperation with Polish and foreign aviation companies and the authors' own work and research. It was mainly carried out at the Institute of Aviation and the Warsaw University of Technology at the Faculty of Automotive and Construction Machinery Engineering. Chapter 1 of this study contains a review, comparison and analysis of the methods for assessing fatigue of bearing structures of an aircraft. Some examples of fatigue tests of the PZL I-22 Iryda were used for that purpose. As for now, it has probably been the largest research and construction program carried out in Poland in the field of aviation technology. This allowed the authors to take a critical look at the basics of the analytical methods to assess fatigue of a structure. The result was a formulation of a number of new hypotheses on the fatigue of materials and structures. These issues are explored in Chapter 2. The quest for full and balanced use of the fatigue of the bearing structure (not only of aircraft structures) was an impulse for the development of the Idea of Continuous Fatigue Estimation of Airframe Structures. This issue is addressed in Chapter 3 of this study. The admission of a construction for use with a controlled development of fatigue damage (Fail Safe or Damage Tolerance philosophy) requires a detection and observation, in the course of its operation, of the critical areas of the bearing structure of the construction. Chapter 4 shows examples of critical areas of an airplane structure from the point of view of fatigue. One of the essential elements of the implementation of the Idea of Continuous Fatigue Estimation of Airframe Structures is the need for continuous monitoring of fatigue loads of the structure under normal operating conditions. Therefore, some measuring systems have been developed and implemented, both in terms of software and hardware, and of the analysis of the signal. This issue is discussed in Chapter 5. Chapter 6 presents an innovative (patented) solution for combining components of a supporting structure, using the so-called composite joints. This solution increases the fatigue strength and reduces the weight of the structure, as shown in the fatigue test for a fuselage truss of a DEKO 9 Magic aerobatic aircraft. Chapters 7 and 8 contain a critical analysis of the issue of cumulative fatigue damage. In this study we used published and unpublished authors' own works, and an extensive and multi-layered monograph entitled 'Selected problems of fatigue of aircraft structures' (“Wybrane zagadnienia wytrzymałości zmęczeniowej konstrukcji lotniczych”), which was issued in Polish as a part 36 of the Scientific Library of the Institute of Aviation in 2014.