In this chapter, the hysteresis behavior of fiber-reinforced ceramic-matrix composites (CMCs) is investigated. Based on the interface slip state inside of CMCs, the hysteresis loops can be divided into four different cases. The relationship between the internal damage and the hysteresis loops of CMCs is established. Using the experimental hysteresis loops, the fiber/matrix interface frictional coefficient can be obtained. The mechanical hysteresis loops and the fiber/matrix interface frictional coefficient of SiC/CAS and C/SiC composites are predicted using the present models. When the fiber/matrix interface frictional coefficient decreases under cyclic fatigue loading, the fatigue hysteresis loops, fatigue hysteresis dissipated energy, fiber/matrix interface debonding, and slip all change. The fatigue hysteresis dissipated energy first increases and then decreases with decreasing interface frictional coefficient.
Part of the book: Hysteresis of Composites
This chapter outlines the results of risk analysis and economic analysis of commercial aero engines during aircraft operation. Risk analysis is the procedure for identifying risk factors and assessing their significance, in essence, analysis of the likelihood that certain undesirable events may occur and as such adversely affect operation. Risk analysis includes risk assessment and methods to reduce risks or reduce adverse effects associated with it. Furthermore, economical analysis is a scientific way of understanding the essence of economic phenomena and processes, which in turn are based on dividing them into their constituent parts. In doing so, the variety of relationships and dependencies aimed at improving the associated work through the development and implementation of optimal solutions is studied. The purpose of the economic analysis is to give management of the actual state, and for persons who are not directly working with it, but are interested in its financial condition, the information necessary for an impartial judgment.
Part of the book: Safety and Risk Assessment of Civil Aircraft during Operation