Solution of nonlinear contact problems of deformation of nodal connections of steel structures

Abstract

All mechanisms and structures consist of parts interacting with each other, and the distribution of contact forces between these parts is unknown in advance and can only be found as a result of solving specific problems, called contact problems.Calculation of the stress-strain state under force contact conditions is important because in many cases the contact zone is a probable zone of loss of strength and a zone of structural failure.Data on the stress-strain state of such elements and units can be obtained using a modern apparatus of mathematical modeling - such as the finite element method.
 The paper presents a methodology for modeling nonlinear contact problems in calculations of nodal connections of steel structures. Modeling of contact interaction is performed by the example of a truss support node made of bent-welded profiles in the integrated software system SCAD Office. The developed method is based on the penalty function method, which is based on the concept of contact layer and contact elements with special properties.
 The contact interaction is modeled using one-way connections. The node model is calculated and investigated as geometrically nonlinear based on the method of stepwise analysis.
 The contact forces - stress and contact normal forces - in a steel truss support node have been determined. The obtained data have been analyzed and the deformed models of the nodal connection for the contact and noncontact formulations of the problem have been compared.It is possible to use the results to further investigate the contact stresses arising from the interaction of the elements of the truss support assembly.
 Taking into account the contact interaction of the elements in the calculation of the most important joints of the frame allows you to correctly assess the stress-strain state of the structures and trace the picture of the deformations of the elements, as close to the real.The research results can be used to search for contact stresses arising from the interaction of elements of the frame of civil and industrial buildings.

Strength analysis and force distribution in a tensile metal joint

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Analysis of structures with arbitrary kinematic boundary conditions by the semi-analytical finite element method

“…A wide range of building structures or machine-building equipment consists of elements that are prismatic bodies of complex shape. Modern methods that are focused on the calculation of a wide class of structures consisting of massive and thin-walled elements [3,7,14] should, along with high accuracy of the description of the stress-strain state of objects of complex shape and structure, provide a high rate of convergence to an exact solution with minimal numerical Cost. In this work, solutions of a significant number of .control problems of deformation of massive and thin-walled prismatic bodies under different boundary conditions and loads.…”

“…the object is loaded with a vertical uniformly distributed load of unit intensity. The kinematic boundary conditions are assumed to be the absence of vertical displacements in the plane3 …”