Improving the performance parameters of metal cylindrical grid shell structures

In this article, to improve the performance of metal cylindrical mesh shells used as roofs for modern construction projects, the sub-aperture diaphragms and the corresponding nodal connections are proposed in the context of the problem of the increased vulnerability of individual sections from actual loads. Finite element models are designed taking into account minimization of production and assembly costs, special features of load perception and structural geometry changes in an acceptable range of overall parameters. The effect of sustaining elements located in the direction of the arc of the circle on the percentage of depletion of the bearing capacity and the maximum value of the deflection of circular mesh surfaces with square and rectangular cells are investigated. An economical design solution of IFI type unit is used to increase the bearing capacity and reduce the deformation of rectangular cylindrical multi-element grids. A joint connection which improves operational characteristics of a structure taking into account the features of the geometric formation and spatial design of the structures has been developed. The force factors and deformation parameters of the basic circuits of a cylindrical mesh surface are checked with conventional and developed joint connections. Increased rigidity and stability of the structure due to the introduction of the diaphragms and the use of units with sustaining elements have been achieved.Keywords: joint connection, grid shell, cylindrical surface, roof diaphragm

Generation a solution to the equations of elasticity theory for a layered strip basing on the principle of compressed mappings

A systematic presentation of the modified classical semi-inverse SaintVenant method as an iterative one is given on the example of generating a solution to the differential equations of elasticity theory for a long layered strip. The firstorder differential equations of the plane problem are reduced to the dimensionless form and replaced by integral equations with respect to the transverse coordinate, just as it is done in the Picard method of simple iterations. In this case, a small parameter appears in the integral equations before the integral sign as a multiplying factor, which is used to ensure convergence of solutions in accordance with the Banach’s principle of compressed mappings. The equations and elasticity relations are converted to a form that enables to calculate the unknowns consecutively, so that the unknowns being calculated in one equation are the inputs for the next equation, and etc. Fulfillment of the boundary conditions at the long edges leads to ordinary differential equations for slowly and rapidly changing singular components of the solution with sixteen effective stiffness coefficients that are defined by integrals from the given ones as a stepped function of Young's moduli for each layer. Integrating of these ordinary differential equations makes it possible to obtain the formulas for all the required unknowns of the problem, including transverse stresses that are not defined in the classical theory of the beam and solutions of the edge effect type, and to fulfill all the boundary conditions for the elasticity theory problem. The solution of three boundary value problems of the strip elasticity theory is provided such as for a two-layer strip with layers of the same thickness and different thicknesses, and a strip with an arbitrary number of layers. Formulas for all unknowns of the problem are obtained

generatrix SLOPE ANGlE INFLUENCE ON THE mode of deformation of OPEN HELICOIDAL SHELLS CALCULATED BY ANALYTICAL SMALL PARAMETER METHOD WITH THREE TERMS OF SERIES

There is the analysis of generatrix slope angle influence on the mode of deformation of thin elastic open helicoidal shells which was calculated by the method of small parameter wit

On application and analysis of helicoidal shells in architecture and civil engineering

There is the review article of application and calculation of helicoidal shells in architecture and civil engineering. Helicoidal shells are used as ramps, winding staircases, screws, elements of bore machines and so on. Different numerical methods are widely used nowadays, but analytic methods need research. There is also information about author's computer programs written in MathCad for analysis of shallow right and open helicoids. The method of Rekach was corrected by the author and led to numerical results. Analytical method of S.N. Krivoshapko was simplified by author due to the application of Bernoulli numbers in the process of integration of equations. The author suggests using mentioned programs for rough analyses of helicoids instead of expensive program complexes based on numerical methods

ON PROBLEM OF STRENGTH ANALYSIS OF THIN LINEAR HELICOIDAL SHELLS

The review of the known methods of strength analysis of five types of linear thin heli- coidal shells is presented. The recommendations for future investigations are give

UMBRELLA TYPE SURFACE FOR A SPORTS CENTER

The practical examples of umbrella-type shells and domes, methods of their genesis are given in the article, the prospects for future application are considered. Two innovational umbrella type surfaces of six equal elements, proposed for adaptation by Strength of materials department of PFUR, their application illustrated by the sports center roof