Computational Analysis of Axial Compressor Stages Characteristics

Published data on flat grid purges allow to evaluate the efficiency of blade devices with different kinematic scheme of stages and design parameters. The corresponding computer program ODOS-GP04 and examples of numerical analysis of the efficiency of flat grids and spatial blade devices of axial stages with different combinations of design parameters was provided. Further development of the ODOS-GP04 program is described below, which makes it possible to perform an estimated calculation of the gas-dynamic characteristics of the stages designed using this program. Analysis of the calculated characteristics of a number of typical stages allows to draw a conclusion about the influence of the main design parameters. This article is primarily addressed to people who are developing their knowledge of the gas dynamics of axial compressors. Some results of calculations do not correspond to the published experimental data. The authors expect that this may attract the attention of specialists working in the field of gas dynamics of axial compressors.

Analysis of the Efficiency of Elementary Grids of Axial Compressors Based on the Data of Flat Grid Purges

Published data on flat grid purges allow to evaluate the efficiency of blade devices with different kinematic scheme of stages and design parameters. The authors present the main provisions of the calculation program algorithm and some results of numerical analysis of the efficiency of flat grids of axial stages with different combinations of design parameters. The content of the article and the computer program are addressed to people who are improving their knowledge of gas dynamics of axial compressors. Some of the results may be of interest to specialists working professionally in this field.

A New Design Conception for Large Span Deployable Flat Grid Structures

The deployable flat grids, consisting of only hinged pantographic units, usually have low structural stiffness, and the bending moment constitutes a great part of internal forces. This results in structural inefficiency, especially for large span grids. Diagonals (web struts) and lower chords are added herein to enhance the structural stiffness. The newly added web struts must be compatible with the deployable geometry. Cables or foldable bars can be used as lower chords. The statical determinacy characteristics are analysed for the newly proposed grid system. On the basis of this concept, several flat grids are firstly developed for potential applications. And a joint conception also developed. The structural performances are investigated for a series of deployable flat grids. Steel quantities and deflections are compared for four different grids. The results indicate that the newly proposed conception has fairly high economic scale, structural efficiency and promising potential application field.

Elastoplastic Analysis of Flat Grids Using Mathematical Programming

This paper presents a method of analysing elastoplastic grids using a mathematical programming based formulation. The elastoplastic analysis is cast as a linear complementarity problem which can be efficiently solved by means of a scheme proposed by Kaneko. A computer program based on this scheme has been developed and can be used to analyse skeletal structures including grillages. The program's application is illustrated in this paper by performing the historical elastoplastic analysis of one of the grids tested at the University of Surrey.

Reduction Method of Analysis for Dense Flat Grids

The analysis of dense flat grids on computer poses problems of computer storage and time and this may lead to an unacceptable cost for the analysis. The purpose of this paper is to present an approximate method of analysing dense flat grids using the concept of structural factoring. This concept provides a method for reducing a dense flat grid to a grid of lower density, thereby reducing the degrees of freedom of the structure. A relationship is established between the forces and displacements in the dense flat grid, and those in the reduced one. The resultant saving in computer resources is considerable with the loss of accuracy lying within a range acceptable for design purposes.

Plastic design of regular orthotropic grids with two adjacent edges fixed, free, or hinged

Lower-bound solutions to the problem of collapse of regular rectangular, orthotropic grids with two adjacent edges clamped and the other two either free or simply supported and carrying a uniform concentration of normal nodal forces are developed. The virtual-work method of plastic analysis is used to derive generalized formulae for grids composed of cantilevered and propped-cantilevered beams. The uniqueness of the work-method solutions are confirmed by use of the techniques of discrete field mechanics. The present study is restricted to flat grids with uniform members possessing no torsional resistance. An example is provided to illustrate the applications of the proposed solutions.