SVIBOR - Project code: 2-11-054

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Project code: 2-11-054


Nonlinear numerical modelling of engineering structures


Main researcher: MIHANOVIĆ, ANTE (30725)


Assistants
Type of research: basic
Duration from: 01/01/91. to 11/01/94.
Papers on project (total): 152
Papers on project quoted in Current Contents: 9
Institution name: Građevinski fakultet, Split (83)
Department/Institute: Department for structural mechanics
Address: Matice hrvatske 15
City: 21000 - Split, Croatia
Communication
Phone: 385 (0)21 523-333, 551-475
Fax: 385 (0)21 524-162
E-mail: marovic"cigla.gradst.hr
Summary: This project develops numerical models for nonlinear modelling of engineering structures. Special attention is paid to nonlinear modelling material behaviour of concrete and steel as dominant materials, although the developed models can be expanded to other similar materials. The first group of numerical models has been developed for the materially and geometrically nonlinear plane and space structures under static loads where it is possible to simulate the composite cross-sections, the change in the cross-sectional stiffness along the line elements resulting from material nonlinaerity and the contribution of geometric nonlinearity for small and large displacements and deformations. The objective of the research and model development is directed towards the determination of failure load leading to all yield states of structures which take into account the structure nonlinearity as a whole and of each cross-section. The stability of nonlinear systems is a component part of the analyses treated by these models. The second group of nimerical models deals with materially nonlinear plane 2D structures under static and dynamic loads. In addition to the finite element method, the modelling of unbounded space is perfomed using special mapped infinite elements separately for the static and for dynamic, i.e. seismic loads. The material is considered to be composite and nonlinear like reinforced concrete, i.e. cohesive soil. The structure and the continuum are separated by special interface elements. In plane structure the formulation of the rotation degree of freedom is introduced for the analyses of rotational degree of freedom which enables the torsional analyses of cross-sections. The material model of concrete employed in these analyses is a two-parametric hypoelastic, whereas in nonlinear states smeared cracks, softening, plastification and crushing in multiaxial compression, as well as crack and softening in tension are simulated. The crack opening is treated according to the fracture mechanics. The reinforcement is modelled with special curvilinear elements and model also enables the simulation of pre and post-tensioning of cables in prestressed concrete structures. The third group of models deals with numerical simulation of surface, plates and shells, folded and space box structures under static loads. Their modelling is performed by degenerated 3D elements with six degrees of freedom per node. 3D nonlinear model for the simulation of material and geometrical nonlinearity under static loads is used for these structures. The layered model is employed for modelling cross-sections of plates and shells. The influence of shear and great axial forces is studied. The behaviour of these structures is monitored until the failure, i.e. loss of stability. The obtained results, in all presented models, are verified by simple laboratory tests.

Keywords: nonlinear numerical modelling, concrete and steel, fracture mechanics, static and dynamic loading, space frames, material and geometrical nonlinearity, plane 2D structures, continuum, interaction, thick and thin plates and shells, layered model, shear, failure.

Research goals: The objective of this project is to develop a new numericalmodels supported by computer software for the simulation ofnonlinear behaviour of specific engineering structures underdifferent loading conditions. The developed models includes: (1)material and geometrical nonlinear spatial line structuresexposed to static loading; (2) material nonlinear plane 2Dstructures under static and dynamic loading; (3) material andgeometric nonlinear shell structures under static loading. Ad. (1) The objective of this subproject is to develop a globalnonlinear model in order to simulate in appropriate way thefollowing static phenomena: (a) composite general cross-sections;(b) sigma-epsilon diagram for different materials including thestress history; (c) changing in the cross-sections stiffnesscaused by material nonlinearity; (d) influence of geometricalnonlinearity at small and large strains. Ad. (2) The aim of this subproject is to develop a nonlinearnumerical model for computations of engineering structures placedon or in unbounded continuum under static and dynamic loading.The infinity would be simulated by mapped infinite elementswithmodelling nonlinear behaviour of materials, such as reinforcedconcrete and cohesive or similar soil. The interaction betweenstructure and soil would be simulated by special interfaceelements. Ad. (3) The objective of this subproject is to develop anumerical model which will precisely simulate the behaviour ofcomplex structures, such as shells and plates (thin and thick),deep beams, plane structures, frames, beams, bars and anycombinations of the mentioned structures. Consequently, it isplanned to develop shell element with six degrees of freedom pernode. The expected contribution of the three subprojects are: (1) thedevelopment of a reliable numerical models for solvingappropriate problems; (2) possibility of applying the developedmodels in calculations of practical engineering structures; (3)the training of young researchers.

COOPERATION - PROJECTS


  1. Name of project: > TEMPUS Project ACEM - Advanced Computational Engineering Mechanics
    Name of institution: Europska zajednica
    City: Bruxelles, Belgija

COOPERATION - INSTITUTIONS


  1. Name of institution: Fakulteta za arhitekturo, gradbeništvo in geodezijo Univerza v Ljubljani
    Type of institution: University/Faculty
    Type of cooperation: Joint project
    City: 61000 - Ljubljana, Slovenija

  2. Name of institution: Institut za konstrukcije, potresno inžinirstvo in računalništvo, Univerza v Ljubljani
    Type of institution: University/Faculty
    Type of cooperation: Occasional exchange of experts
    City: 61000 - Ljubljana, Slovenija

  3. Name of institution: Department of Civil Engineering, University of Wales,Wales, United Kingdom
    Type of institution: University/Faculty
    Type of cooperation: Systematic exchange of experts
    City: Swansea, Velika Britanija

  4. Name of institution: Department of Civil Engineering, Delft University of Technology, The Netherlands
    Type of institution: University/Faculty
    Type of cooperation: Systematic exchange of information
    City: Delft, Nizozemska

  5. Name of institution: Department of Civil Engineering, Carnegie Institute of Technology, Carnegie Mellon University
    Type of institution: University/Faculty
    Type of cooperation: Systematic exchange of information
    City: Pittsburgh, U.S.A.

  6. Name of institution: Građevinski fakultet Sveučilišta u Zagrebu
    Type of institution: University/Faculty
    Type of cooperation: Joint project
    City: 10000 - Zagreb, Croatia

  7. Name of institution: Fakultet elektrotehnike, strojarstva i brodogradnje Sveučilišta u Splitu
    Type of institution: University/Faculty
    Type of cooperation: Joint project
    City: 21000 - Split, Croatia

  8. Name of institution: Fakulteta za strojništvo, Univerza v Ljubljani
    Type of institution: University/Faculty
    Type of cooperation: Systematic exchange of information
    City: 61000 - Ljubljana, Slovenija

  9. Name of institution: Department of Civil Engineering, Lulea Institute of Technology
    Type of institution: University/Faculty
    Type of cooperation: Occasional exchange of information
    City: Lulea, Švedska

OTHER ACHIEVEMENTS


  1. Name: FEROTON konstrukcije, nosači i zidovi
    Type of achievement: Prototypes
    Authors: B. Jelić, M. Zelić, A. Mihanović
Other information about the project.
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