Applicability of Fuzzy Logic to the Definition of the Buckling Length of Steel Plane Frames

Abstract

This paper presents a fuzzy-logic-based approach to the definition of buckling length evoked by the uncertainty of joint stiffness and boundary conditions for the member support. The example demonstrates a lucid and specific application of fuzzy sets in modelling uncertainties in design. To carry out analysis, the extension principle in the form of α-cuts was used. Buckling lengths were analysed utilizing stability solution according to the second-order theory. The beam finite element method with the shape functions of sin and sinh was utilized in the analysis taking into account valuable information on the uncertainties of input data.

Straipsnis pateikia siūlomą skaičiuojamojo ilgio nustatymo metodą, grįstą formaliąja logika, sukeltą esant nepastoviam jungčių standumui ir elemento atramų ribinėms sąlygoms. Pateiktas pavyzdys demonstruoja aiškų ir specifinį formaliosios aibės pritaikomumą modeliuojant nepastovumą projektavimo metu. Skaičiuojamasis ilgis buvo analizuojamas panaudojant stabilumo sprendinius taikant antros eilės teoriją. Sijos baigtinių elementų metodas su sinuso ir hiperbolinio sinuso formos funkcijomis buvo pritaikytas analizėje. Ivedamų duomenų nepastovumas taip pat buvo įvertintas analizėje.

Keywords:

• steel
• concrete
• structure
• design
• reliability
• random
• fuzzy logic
• imperfection

Reikšminiai žodžiai:

• plienas
• betonas
• konstrukcija
• projektavimas
• patikimumas
• atsitiktinis
• formalioji logika
• trūkumas

Additional information

Notes on contributors

Zdeněk Kala

Zdeněk KALAProf. PhD at the Department of Structural Mechanics, Faculty of Civil Engineering of Brno University of Technology, the Czech Republic. The author and co-author of 1 book, 3 textbooks and more than 180 scientific papers (120 published abroad). Research interests; structural safety and reliability, problems of structure stability, FEM - nonlinear behaviour of hot-rolled members, frames and thin-walled structures, Monte Carlo type reliability methods, elastic-plastic analysis and optimisation of structures, including material and geometrical nonlinearities, numerical methods in structural mechanics, reliability methods fuzzy sets theory.

Abayomi Omishore

Abayomi OMISHOREScientific worker at the Department of Structural Mechanics, Faculty of Civil Engineering of Brno University of Technology, the Czech Republic. The author and co-author of more than 40 scientific papers. Research interests: elasticplastic analysis and optimisation of structures, including material and geometrical nonlinearities, numerical methods in structural mechanics, reliability methods, safety and reliability of steel structures fuzzy sets theory.

Libor Puklický

Libor PUKLICKÝ PhD student at the Department of Structural Mechanics, Faculty of Civil Engineering of Brno University of Technology, the Czech Republic. The author and co-author of more than 20 scientific papers. Research interests: elastic-plastic analysis and optimisation of structures, including material and geometrical nonlinearities, numerical methods in structural mechanics, reliability methods structural design of bridges, safety and reliability of concrete structures, steel structures, composite structures.