Analysis of mechanical properties of spatial truss structures sections

The paper presents the results of computational study of sections of spatial truss structures. They can form large supporting structures on spacecraft to place onboard equipment. The calculations were carried out by the finite element method in FEMAP with Nastran. The chosen section, the object of study, is a set of straight rods rigidly connected at the nodes in such a way that the cross section of the truss structure is a triangle. Calculation models, procedures for calculation and results analysis are presented. The purpose of the calculation is to determine how the relative position of the rods in the structural scheme affects the mechanical properties of the structure. The main criterion for strength estimating was the magnitude of the stresses derived by load. Stiffness was determined by the value of the first natural frequency. The sequential addition of rods and varying their connection allow modifying the structural schemes of truss structures. Next, the mechanical properties of the structure which effected by made modifications were evaluated again. Thus, six structural schemes of sections of the truss structure, obtained from the results of the study, have been developed. At the same time, the mass of the section, its shape and dimensions, the material and shape of the rods section as well as the initial and boundary conditions, remained unchanged. Based on the results of the analysis, someone can notice that each structure has unique mechanical characteristics. Thus, the paper gives recommendations for choosing a specific structural scheme of the section, depending on the required operating conditions and acceptable manufacturing technology. So, the criteria for choosing one of the above various sections of a truss structure or the principle of its building can be the complexity of manufacturing, maximum stiffness and strength, or minimum displacement. Structural schemes of sections with the highest strength and capability have been selected for use as part of spatial truss rods of spacecraft.