Prediction of the bearing capacity of composite flanges for aircraft-engine casing parts

Abstract

The introduction of lightweight composite materials (CM) to the design of aircraft gas-turbine plants is one trend in the improvement of their parameters. Above all, it is most expedient to use CM in fabricating the following casing parts: soundproofmg panels, fa~ housings, nozzle fairings, and the engine-reversing unit, which operate under comparatively light loadings. When the subassemblies in question are effectively processed, it is possible to build even more heavily loaded components from composites: power housings, force linkages, fan blades, etc. These measures make it poss~le to reduce the weight of a single engine by 100-150 kg and increase the commercial payload of the aircraft by 200-600 kg. In designing lightweight fan housings, nozzle fairings, and the reversing unit from polymeric composite materials for new aircraft, it has been established that a significant gain can he achieved in terms of weight only when traditional mechanical flange fastening assemblies are rejected and replaced by flanges also built of CM.By virtue of the fact that it is precisely the flange connections that are the most loaded components of the structures in question, the calculation of their stress-strain state (SSS) and strength assessment are decisive in confirming the serviceability of housings and failings on the whole.Flange blanks are produced by the successive facing of layers of glass-cloth-and epoxy-resin-base I~DT-69N-S prepregs and 1 lt~ unidirectional carbon-fiber prepregs on a metallic mandrel in the axial and circumferential directions. A circular subwinding with a unidirectional glass prepreg was also used in certain structural variants. After facing, the flanges are mated with the blank of the basic section of the housing or fairing, polymerized in an autoclave under a vacuum bag at a pressure of 0.5 MPa for 7 h, and allowed to cool to ambient temperature for 10 h. Degree of polymerization of the finished articles is 95-98%, and the binder content is 30-40% in the prepreg layers.In our study, we present results of SSS calculation, and estimates of the factors of safety and fatigue lives of basic typical strnctural variants of the polymerie-CM flanges shown in Fig. 1. The radius of the inner surface of the flanges was 0.88-1.01 m, the thickness of a single glass-prepreg layer 0.25 ram, and the thickness of a single carbon prepreg layer 0.125 ram. Systems of external forces acting on a housing or fairing resulted in an equivalent load distributed over the mating surface S t of the jacketed flange (see Fig. le). Free-support conditions were assigned to segment S u, which corresponds to the region of the bolted connection.The mathematical statement of the axisymmetric problem of the theory of elasticity in a variational formulation consists of a search for the minimum of the Lagrange functional, the variation of which in the absence of mass forces assumes the form Perm' State Technical University.

Prediction of the Mechanical Characteristics of Reinforced Thermoplastic Composite Materials Used in Aviation

“…The mathematical formulation of the problem corresponded to the theory of elasticity of an anisotropic body. In the variational formulation this formulation consists in finding the minimum of the Lagrange functional with additional conditions in the form of geometric Cauchy relations [9,10]. The variation of the functional in the absence of mass forces has the form:…”

“…In it, the axis OX 1 coincides with the direction of the base, OX 2 -weft, OX 3 -perpendicular to the plane of the layer. In the established local coordinate system, the components of the tensor will be determined through the technical elastic constants of the layers by formulas [9]: 1…”

Stress-Strain Analysis and Strength Prediction of Composite Outlet Guide Vane for Aircraft Jet Engine

“…Ɍɚɤɢɦ ɨɛɪɚɡɨɦ, ɷɬɚ ɡɨɧɚ ɯɚɪɚɤɬɟ-ɪɢɡɭɟɬɫɹ ɩɨɜɵɲɟɧɧɨɣ ɧɟɨɞɧɨɪɨɞɧɨɫɬɶɸ ɫɜɨɣɫɬɜ ɦɚɬɟɪɢɚɥɚ ɢ ɤɚɤ ɫɥɟɞɫɬɜɢɟ ɝɪɚɞɢɟɧɬɚɦɢ ɧɚɩɪɹɠɟɧɢɣ. ɂɫɫɥɟɞɨɜɚɧɢɹ, ɩɪɟɞɫɬɚɜɥɟɧɧɵɟ ɜ ɪɚɛɨɬɚɯ [15][16][17][18][19], ɩɨɤɚɡɵɜɚɸɬ, ɱɬɨ ɦɟɠ-ɫɥɨɟɜɵɟ ɧɨɪɦɚɥɶɧɵɟ ɢ ɤɚɫɚɬɟɥɶɧɵɟ ɧɚɩɪɹɠɟɧɢɹ ɜ ɦɟɫɬɚɯ ɩɟɪɟɝɢɛɚ ɫɥɨɟɜ ɦɨɝɭɬ ɨɤɚɡɚɬɶɫɹ ɨɩɪɟɞɟɥɹɸɳɢɦɢ ɞɥɹ ɨɰɟɧɤɢ ɡɚɩɚɫɚ ɫɬɚɬɢɱɟɫɤɨɣ ɢ ɭɫɬɚɥɨɫɬɧɨɣ ɩɪɨɱɧɨɫɬɢ ɜɫɟɣ ɤɨɧɫɬɪɭɤ-ɰɢɢ ɜɜɢɞɭ ɧɢɡɤɨɣ ɦɟɠɫɥɨɟɜɨɣ ɩɪɨɱɧɨɫɬɢ ɉɄɆ.…”

“…Ⱦɚɧɧɵɣ ɤɪɢɬɟɪɢɣ ɢɫɩɨɥɶɡɨɜɚɥɫɹ ɩɪɢ ɪɟɲɟɧɢɢ ɡɚɞɚɱ ɩɨɞɨɛɧɨɝɨ ɪɨɞɚ ɜ ɪɚɛɨɬɚɯ [16][17][18][19] ɢ ɟɝɨ ɜɵɛɨɪ ɨɛɭɫɥɨɜɥɟɧ ɨɬɫɭɬɫɬɜɢɟɦ ɞɨɫɬɨɜɟɪɧɵɯ ɞɚɧɧɵɯ ɩɨ ɩɪɨɱɧɨɫɬɢ ɦɚɬɟɪɢɚɥɚ ȼɄɍ-39 ɜ ɭɫɥɨɜɢɹɯ ɫɥɨɠɧɨɧɚɩɪɹɠɟɧɧɨɝɨ ɫɨɫɬɨɹɧɢɹ.…”