The paper presents the author’s non-linear FEM solution of an initially stressless deformed flat frame element, in which the nodes are situated along the axis of the bar initially straight. It has been assumed that each node may sustain arbitrary displacements and rotation. The solution takes into account the effect of shear, the geometrical non-linearity with large displacements (Green-Lagrange’s strain tensor) and moderate rotations (i.e. such ones which allow a linear-elastic behaviour of the material) and alternative small rotations when the second Piola-Kirchhoff stress tensor is applied. This solution is based on [1], concerning beams without any initial bow imperfections. The convergence of the obtained results at different numbers of nodes and Gauss points in the element was tested basing on the example of circular arcs with a central angle of 120°÷180°. The analysis concerned elements with two, three, five, seven, nine and eleven nodes, for the same number of points of numerical integration and also with one more or less. Moreover, the effect of distributing the load on the convergence of the results was analyzed.

JO - Archives of Civil Engineering L1 - http://www.journals.pan.pl/Content/83891/mainfile.pdf L2 - http://www.journals.pan.pl/Content/83891 IS - No 3 EP - 400 KW - initially deformed fl at frame element KW - geometrical non-linearity KW - large displacements KW - large and small rotations ER - A1 - Zamorowski, J. PB - WARSAW UNIVERSITY OF TECHNOLOGY FACULTY OF CIVIL ENGINEERING COMMITTEE FOR CIVIL ENGINEERING POLISH ACADEMY OF SCIENCES JF - Archives of Civil Engineering SP - 381 T1 - An Initially Deformed Flat Frame Finite Element UR - http://www.journals.pan.pl/dlibra/docmetadata?id=83891