Numerical analysis of flexural buckling resistance of non-uniform compression members

Abstract

This paper presents parametric linear-elastic analysis of flexural buckling of idealised non-uniform member and nonlinear analysis of flexural buckling with equivalent imperfections, using software package Abaqus. The analysis includes hinged and cantileverstepped members, where the stiffness ratio of the upper and lower segments and the ratio of the values of axial forces at the top and at the change in the cross-section are varied. The aim of this paper is to define graphic and table models for determining effective lengths coefficients of non-uniform members' segments based on a relevant and reliable database that was obtained using the Finite element method. In addition, the reliability of the method for calculating the flexural stability of the compressed columns according to EC3 was evaluated in which the critical load value was determined in the previous step using the Elastic buckling analysis of idealised elements.

Rad prikazuje parametarsku linearno-elastičnu analizu fleksionog izvijanja idealizovanog neuniformnog elementa i nelineranu analizu fleksionog izvijanja sa ekvivalentnim geometrijskim imperfekcijama, urađenu u programu Abaqus. Analizom su obuhvaćeni zglobno oslonjeni i konzolni elementi sa stepenastom promenom poprečnog preseka, kod kojih je variran odnos krutosti gornjeg i donjeg segmenta i odnos vrednosti aksijalnih sila na vrhu i na mestu promene preseka. Rezultat rada je definisanje grafičkih i tabelarnih modela za određivanje koeficijenata dužine izvijanja segmenta neuniformnih elemenata na osnovu relevantne i pouzdane baze podataka koja je dobijena primenom Metode konačnih elemenata. Kao dodatak, ocenjena je pouzdanost metode proračuna fleksione stabilnosti pritisnutih stubova prema EC3 u kojoj je vrednost kritične sile izvijanja određena u prethodnom koraku primenom Elastične analize izvijanja idealizovanog elementa.