Modeling the Strength Properties of Power Bulkheads in the Frame Structures

Abstract

The work deals with modeling methods of frame structures, used in rocket technology. To estimate their inertia, stiffness and strength properties it is necessary to create its calculation model. Currently, a finite element method is generally used. Various finite elements and combinations thereof may constitute such models. It is obvious that parameters of design under consideration, resulting from calculation, depend on the selected calculation model. To simulate the properties of a longitudinal set of elements (stringers and longerons), as well as braces a girder (beam) idealization is offered, because their transverse dimensions are substantially smaller than the longitudinal ones. The elements of a transverse power set (frames) is a plated arch-shaped construction of variable sections with holes. Weld tubes of different diameters reinforce the holes in plates. There are cutouts in the vertical plates to mount the stringers. It is impossible to take completely into consideration the mentioned features in the frame idealization of bulkheads. Therefore, it seems more appropriate to use plate-frames for modeling the bulkheads. . The paper discusses two possible models of the bulkhead to show their stiffness properties, namely frame and plate. Describes strengths and shortcomings of represented bulkhead design schemes. Based on the test calculations shows which errors may be possible in calculating the strength properties of the bulkhead under consideration when using a frame model. Gives recommendations on the proper use of potential bulkhead models to estimate a general and local strength of the bulkhead structure. The SADAS software package developed at the Department SM8 in BMSTU was used to create the bulkhead models under study, perform their test calculations and analyze calculation results.