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INTRODUCTION OF INSTABILITY AND PLASTICITY PHENOMENA INTO A COMPUTER AIDED DESIGN PROJECT FOR METALLIC STRUCTURES

Objective

THE DESIGN METHODS FOR STEEL STRUCTURES ARE USUALLY RESTRICTED TO THE METHODS OF STANDARD LINEAR ELASTIC ANALYSIS. THIS PROJECT AIMS AT INTRODUCING INSTABILITY AND PLASTICITY IN THE DESIGN AND ANALYSIS OF STEEL STRUCTURES.
FINELG is a nonlinear finite element method (FEM) which has been developed for simulation of geometrically and materially nonlinear actual structural behaviour. It may be used in civil engineering, mechanical pieces, or on both linear and nonlinear subjects.
The operating environment is as follows :
Hardware: VAX, IBM, FPS;\Operating language: Fortran 77
Workstations (UNIX system manager)
PC

An experimental program has been developed into an advanced tool for structural analysis. To simplify the preparation of the data file access to a databank is available for the geometrical properties of the beam cross sections; for this same type of beam elements, users can choose between different residual stress schemes introduced within the nonlinear finite element program FINELG; and inital geometric imperfections can be introduced either directly as coordinates of the imperfect structures, or as increments of the coordinates of the perfect structure. Increments are either given in the data file, or read in other files.

The main finited elements available for a discrediting are plane or spatial truss, taking account of the behaviour of hauger, a cable or hinged imperfect beam; plane or spatical beams with any arbitrary cross section, taking account of elastoplastic steel of concrete constitutive law, residual stesses, eccentric and semirigid connection, thermic loads etc; thin or thick shell; nonlinear spring between 2 nodes; nonlinear supports or linear constraints.
AT THE LIEGE UNIVERSITY, A NON-LINEAR FINITE ELEMENT PROGRAMME, SO-CALLED FINELG HAS BEEN DEVELOPED. INITIALLY, THIS PROGRAMME HAS BEEN WRITTEN BY SOME RESEARCHERS DURING THEIR PH.D. THESES. THE BRITE PROJECT WAS ESPECIALLY AIMED AT MAKING THIS PROGRAMME AVAILABLE FOR INDUSTRIAL PURPOSES - MAINLY FOR USE BY SMES - BY IMPLEMENTING THE COMPUTATION CAPABILITIES AND TENDERING IT AS A "USERS FRIENDLY" PROGRAMME.

THE FINELG PROGRAMME IS ABLE TO PREDICT THE ACTUAL BEHAVIOUR OF STRUCTURES WITH ACCOUNT TAKEN OF PLASTICITY, INSTABILITY PHENOMENA, RESIDUAL STRESSES, AND INITIAL GEOMETRICAL IMPERFECTIONS. THE NUMERICAL SIMULATION CONDUCTED BY MEANS OF FINELG RESULTS IN SOME ADVANTAGES:
- THE COLLAPSE LOAD OF THE STRUCTURES CAN BE PREDICTED ACCURATELY;- THE BEHAVIOUR AND THE SAFETY MARGIN CAN BE STUDIED AND KNOWN IN AN EXTENSIVE WAY;
- THE WAY IS OPEN TO VALUABLE PARAMETRIC STUDIES;
- THE ELABORATION OF DESIGN RULES FOR ENGINEERS;
- THE POSSIBLITY TO SUBSTITUTE NUMERICAL SIMULATIONS FOR DIFFICULT SCALE EXPERIMENTS.

PARALLEL TO THE PROGRAMMING WORK CARRIED OUT BY THE UNIVERSITY'S STAFF, THE COMPUTER PROGRAMME WILL BE USED BY INDUSTRIAL PARTNERS FOR PARAMETRIC STUDIES OF TYPICAL COMPLEX STRUCTURES, WHICH WERE TILL NOW DESIGNED ON THE BASIS OF EMPIRICAL METHODS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSITE DE LIEGE*ULG
Address
Place Du 20 Aout 7
4000 Liege
Belgium

Participants (3)

Arbed SA
Luxembourg
Address

2930 Luxembourg
Ateliers de Braine-Le-Comte et Thiriau Réunis
Belgium
Address

7090 Braine-le-comte
Bureau d'Etudes R. Greisch
Belgium
Address
66,Rue De Beyne
4020 Jupille