AUTOMATED SENSORY MONITORING SYSTEM PROTOTYPE FOR CONTINUOUS MONITORING OF MATERIAL AND STRUCTURE STATE

The goal of this article is to solve problems of automated monitoring systems of industrial and aviation constructions. Based on the latest research results, the most cost-effective solutions are covered, and a practical solution is offered. This article is part of the scientific project “Development of an integrated sensor system for material and structure monitoring”. The article describes the problem and suggests a practical solution for an integrated sensor system for material and structure monitoring prototype.

Airline and Aircraft Reliability

Development of the inspection programme of fatigue-prone aircraft construction under limitation of airline fatigue failure rate. The highest economical effectiveness of airline under limitation of fatigue failure rate and failure probability is discussed. For computing is used exponential regression, Monte Carlo method, Log Normal distribution, Markov chains and semi-Markov process theory. The minimax approach is offered for processing the results of full-scale fatigue approval test of an airframe. Fatigue crack parameters and numerical examples are given and explained.

Inspection Program Development for an Aircraft Fleet and an Airline on the Basis of the Acceptance Fatigue Test Result

An inspection interval planning is considered in order to limit the probability of any fatigue failure (FFP) in a fleet of N aircraft (AC) and to provide an economical effectiveness of airline (AL) under the limitation of fatigue failure rate (FFR). A solution of these two problems is based on the processing of the result of acceptance fatigue test of a new type of aircraft. During this test an estimate of the parameter ϴ, of a fatigue crack growth trajectory has been obtained. If the result of this acceptance test is too bad then this new type of aircraft will not be used in service. A redesign of this project should be done. If the result the acceptance test is pretty good then the reliability of the aircraft fleet and the airline will be provided without inspections. For this strategy there is a maximum of FFP (a maximum of FFR) as a function of an unknown parameter ᶿ. This maximum can be limited by the use of the offered here procedure of the choice of the inspection number. The economic effectiveness of the AL operation is considered using the theory of Markov process with rewords

Investigation on fracture of epoxy-filled composites by acoustic emission

Acoustic emission (AE) technique is widely used to monitor failure processes in composite materials includ-ing development of cracks and plastic deformations within the polymer matrix, fracture and debonding of inclusions, etc. In this study, the AE technique was applied investigating failure character of epoxy polymers with different content of nanofiller – fine polyethersulfone (PES) powder. Variation of material properties of the epoxy with 0, 5%, 7.5%, 10%, and 12.5% concentration (by weight) of the PES was assessed experimentally. Correlation between the PES content and the modulus of elasticity was found negligible. The same was characteristic for the tensile strength. Whereas, such a correlation was found significant for the fracture toughness that increased 1.5 times concerning the pure epoxy reference. Analysis of the cumulative AE counts indicated existence of three different stages of the damage accumulation process, which were unidentified using the load and the deformation diagrams. In the PES-modified composites, the damage ac-cumulation process was evidenced at the 10–20% of the ultimate load; whereas, in the pure epoxy, such a process was fairly slow until the 85% of the loading