Impact of pulse dynamic loading direction and surface curvature on the stress-strain state of a three-layered spherical shell

Abstract

On two size types of the semispherical three-layered structures, impact of the surface curvature and impact of the pulse dynamic loading on the stress-strain state (SSS) of these structures has been investigated. The layered hemispheres have been analyzed with the clamped footing and diameters (D1=0.30 m, D2=0.60 m), which had similar bearing layers’ thickness (h1=h3=0.010 m), polymeric filler with h2=0.020 m thickness, reinforced with the 5 discrete stiffening rings rigidly bound to the bearing layers.
 Values of normal stresses and vertical displacements of the structures’ bearing layers and distribution of these indicators along the spatial coordinate have been determined. Distribution of displacements’ and stresses’ magnitudes along the spatial coordinate α was determined by the software complex Nastran through the direct transient dynamic process algorithm within the time interval 0 ≤ t ≤ 10T. The time interval step duration was 0.25*10-6 s and the total number of steps was 200. The detailed and accurate calculation results have determined the choice of the solid finite element type.
 Value of the Gaussian curvature of the layered shell structures impacts their stress-strain state. Increase of the surface curvature of spherical structures under the impact of the dynamic pulse load increases the displacement and stress of their bearing layers.
 In addition to the vertical displacements and normal stresses of the bearing layers of the analyzed semispherical three-layered structures, their first natural frequency (f1) was also calculated.