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One of the most urgent questions in aviation engine development is how to reduce the mass of composition details, while meeting the demands for strength and reliability. The production of complex, critical aircraft engine details is constrained by the limited capabilities of traditional fabrication methods. However, complex-shaped parts can now be created using emerging additive technologies that will avoid many of the traditional manufacturing methods’ limitations and reduce material and time costs. In addition, using additive technologies facilitates the manufacturing of details such as cellular and lattice structures, the production of which is impossible with traditional methods. The use of cellular structures is one way to reduce the weight of parts. Lattice structures are used to provide rigidity and strength in industries where parts are exposed to compression, bending and impact loads. The cell structures can withstand significant deformation without fracture and have a high resistance to fatigue. Since the weight of such structures is much less than the original prototypes, using them creates new opportunities for future aircraft applications. This article discusses the issue of creating lightweight structures for compressor components containing different cellular structures and their manufacturing using additive technology methods. We have examined several simple models of cellular structures and studied their geometrical, mass and stiffness characteristics. Analysis of the stress states of the cellular structures was conducted on the samples, with testing intended for three-point bending and cantilever beams. The influence of the geometrical parameters of the cells on the mass and strength characteristics of the structures was determined. The method for determining the density and elastic modulus of the equivalent homogenous material using these parameters in the calculations was complex. A few models containing the cellular region were proposed and the designs of several fan blades containing the cellular region were discussed. Samples to determine the strength of the developed structural elements were made from titanium alloy powder using Powder Bed Fusion (PBF). Continuous model samples and samples with different cellular structures were manufactured to test.

The possibility of reducing the weight, simplifying the design, reducing the time and cost of development, production and operation are important advantages in the implementation of additive technologies (AT). The use of AT can significantly improve fuel efficiency, environmental and other characteristics of aircraft engines. The possibility of using AT in the production of various parts and components of engines is being currently investigated at CIAM. Examples of these developments, advantages of the use of AT and problems arising in the implementation of these technologies are presented in this article. Models of turbine blades with a highly efficient cooling system, in particular, with penetration cooling were designed and manufactured using optimization methods and taking into account the capabilities of AT. The possibilities of using AT for the manufacture of elements of molds for precision casting of gas turbine engine (GTE) blades of heat-resistant alloys and ceramic rods are shown. Elements of a two-zone front module of the low-emission combustion chamber of an advanced GTE are designed and manufactured using the AT method. Research of prospective branched tree channels of heat exchangers with mutually porous bodies that can be made only by AT methods and the use of which will make it possible to increase the efficiency of heat exchange in the case of lower weight, than that of the structures made by traditional technologies, is being carried out. The AT was used to manufacture complex elements of a ramjet engine. Fire tests of printed sections of the combustion chamber were carried out successfully. Cellular structures to be used in gas turbine engine parts with the aim of reducing their weight were developed. A hollow blade model with cellular-type core was made using AT. Tests of the designed cellular prototypes were carried out. The possibilities of reducing the mass of structural elements using cellular structures obtained by AT methods are shown. Research of hollow disks of turbines and other engine components produced with the aid of AT are carried out. Despite the fact that experimental studies of structural elements obtained by additive technologies have not been completed yet, these works show the prospects for the use of AT in the development of a wide range of engine parts and components.

Lifetime of disks and other aviation engine parts critical for safe operation is currently probabilistically predicted using mainly two methods. One method to predict lifetime is to confirm lifetime to low-cycle fatigue (LCF) cracking of a part without initial defects. The other method to predict lifetime is to confirm lifetime for safe propagation of a crack from initial defects available in a part. Combination of the above stated methods along with usage of margins on cyclic durability that ensure the required nonfracture probability presents another more conservative approach. Confirmation of lifetime to LCF cracking of a part without initial defects is usually performed based on results of cyclic tests of parts. The safe life determination algorithms were developed in Central Institute of Aviation Motors (CIAM) that take into account a difference in test outcome (“failure”–“no failure”). The developed software makes possible to consider the admissible failure probability, use the actual cyclic durability spread characteristics of the parts involving both lognormal and Weibull durability distributions. This paper discusses the examples of application of the elaborated methods and software. To confirm lifetime for safe propagation of a crack from defects available in a part, a program of statistical determination of durability of powder alloy disks with random fields of ceramic inclusions was developed in CIAM. This program allows performing the partition of disks into typical elements, the generation of realizations of initial defects for each typical disk element and calculation of life realizations corresponding to them, the statistical processing of the obtained data made with usage of asymptotic theory of extreme values, and the determination of technical risk functions for a disk as a whole. While developing the software, the problems of crack initiation and its stable propagation from ceramic inclusions were sequentially decided. Example of the calculation made according to the developed program is given in this paper. The probabilistically-justified approaches to determine the safe life shall be supplemented with the methods of economical and ecological risk analysis. In this case these approaches may become a good support for arranging the engine service to Reliability Centered Maintenance.