In this paper, we present an approach to fatigue estimation of a Main Landing Gear (MLG) attachment frame due to vertical landing forces based on Operational Loads Monitoring (OLM) system records. In particular, the impact of different phases of landing and on ground operations and fatigue wear of the MLG frame is analyzed. The main functionality of the developed OLM system is the individual assessment of fatigue of the main landing gear node structure for Su-22UM3K aircraft due to standard and Touch-And-Go (T&G) landings. Furthermore, the system allows for assessment of stress cumulation in the main landing gear node structure during touchdown and allows for detection of hard landings. Determination of selected stages of flight, classification of different types of load cycles of the structure recorded by strain gauge sensors during standard full stop landings and taxiing are also implemented in the developed system. Based on those capabilities, it is possible to monitor and compare equivalents of landing fatigue wear between airplanes and landing fatigue wear across all flights of a given airplane, which can be incorporated into fleet management paradigms for the purpose of optimal maintenance of aircraft. In this article, a detailed description of the system and algorithms used for landing gear node fatigue assessment is provided, and the results obtained during the 3-year period of system operation for the fleet of six aircraft are delivered and discussed.

The energy effectiveness of the multistage gear differential in the device for speed change by carrier has been investigated with the determination of the efficiency. Considering complexity of the problem, the analytical methods of efficiency determining for two- and three-stage differential...

One approach to developing a system of continues automated monitoring of structural health is to use elastic waves excited in a given medium by a piezoelectric transducers network. Depending on their source and the geometry of the structure under consideration elastic waves can propagate over a significant distance. They are also sensitive to local structure discontinuities and deformations providing a tool for detecting local damage in large aerospace structures. This paper investigates the issue of Barely Visible Impact Damages (BVIDs) detection in composite materials. The model description and the results of impact tests verifying damage detection capabilities of the proposed signal characteristics are presented in the paper.