ANALYSIS OF THE CAPABILITIES OF THE LOGOS SOFTWARE PACKAGE FOR CALCULATING THE SEISMIC IMPACT ON A STRUCTURE

Abstract

The possibilities of the LOGOS software package for calculating seismic vibrations of buried structures, considering the contact interaction with the ground and the gravity field, are investigated and expanded. To reduce computational costs, the LOGOS software package includes a method for modeling non-reflective boundary conditions that was developed earlier and implemented in the “Dynamics-2” software package, which allows reducing the size of the computational domain. The results of numerical simulation in the LOGOS of shear wave propagation in an elastic bounded subdomain of a continuous medium are presented, demonstrating the effectiveness of non-reflecting boundary conditions for a three-dimensional formulation. The dynamic relaxation technique used in the dynamic strength module of the LOGOS software package for calculating the initial static stresses from the action of the gravity field with the subsequent solution of the non-stationary problem is investigated. Numerical estimates of the expected accuracy of the dynamic solution are obtained, depending on the specified accuracy of the static calculation. Thus, the relative error in the change in kinetic energy when using the dynamic relaxation algorithm 10–4 gives a relative error of 10–3 in velocities and 10–2 in stresses, reducing the specified calculation error by 2 orders of magnitude reduces the relative error in calculating velocities by 3 times, stresses – by 5 times. The calculation of the initial stress-strain state of the building-ground system from the action of the gravity field is compared using the dynamic relaxation procedure and using the stationing procedure implemented in the “Dynamics-2” software package. In all problems in the three-dimensional formulation, 8-node hexahedra with one-point integration are used, in the two-dimensional formulation – equivalent 4-node finite elements, for the integration of the defining system of equations, an explicit “cross” scheme is used. Between the subdomains, variants of contact with gluing and contact with friction are implemented. The capabilities of LOGOS for conducting multiprocessor calculations allowed us to make estimates of the convergence of the problem under consideration based on a series of computational experiments.