Formulation and numerical implementation of constitutive equations of irreversible deformations in the framework of the nonlinear 6-parameter shell theory - Project - Bridge of Knowledge

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Formulation and numerical implementation of constitutive equations of irreversible deformations in the framework of the nonlinear 6-parameter shell theory

Celem projektu jest formułowanie równań konstytutywnych i ich implementacja numeryczna w formalizmie metody elementów skończonych (MES) opisujących odkształcenia trwałe: • powłok o funkcjonalnie zmiennych własnościach materiału (ang. functionally graded materials, FGM), • powłok kompozytowych, w ramach nieliniowej sześcioparametrowej teorii powłok. Charakterystycznymi cechami rozpatrywanej teorii powłok są brak symetrii membranowych i zgięciowych miar naprężeń i odkształceń zgodnych z występowaniem tzw. szóstego stopnia swobody prostopadłego do powierzchni odniesienia powłoki nazywanego owinięciem. Obecność szóstego stopnia swobody pozwala w naturalny sposób na analizę złożonych wielopłatowych struktur powłokowych bez stosowania specjalnych zabiegów, jak ma to miejsce np. w przypadku teorii trój- i pięcioparametrowych. Cel zamierzamy osiągnąć rozwiązując następujące zadania badawcze: 1. sformułowanie 4-węzłowych hybrydowo-mieszanych elementów powłokowych, 2. sformułowanie kryteriów wytężenia powłok kompozytowych uwzględniających brak symetrii miar naprężeń i odkształceń oraz analizy zniszczenia typu FPF i LPF, 3. sformułowanie równań konstytutywnych powłok sprężysto-plastycznych wykonanych z materiału FGM ujmujących długość charakterystyczną materiału. Wymienione wyżej równania i elementy skończone zostaną zaimplementowane w autorskich programach MES, pisanych w języku Fortran. Oryginalność zaproponowanego planu badawczego w porównaniu z rozwiązaniami znanymi już z literatury przedmiotu wynika z braku symetrii miar naprężeń i odkształceń. Prace przewidziane do wykonania w ramach projektu są rozwinięciem oryginalnej polskiej szkoły mechaniki powłok skupionej wokół pracowników Politechniki Gdańskiej (profesor J. Chróścielewski, Wydział Inżynierii Lądowej i Środowiska oraz Instytutu Maszyn Przepływowych PAN w Gdańsku (profesor W. Pietraszkiewicz). Realizacja planowanych zadań ma w konsekwencji przyczynić się do zdobycia stopni doktorskich, zaawansowania dwóch rozpraw habilitacyjnych i tytułu naukowego profesora kierownika projektu.

Details

Financial Program Name:
OPUS
Organization:
Narodowe Centrum Nauki (NCN) (National Science Centre)
Agreement:
UMO-2015/17/B/ST8/02190 z dnia 2016-01-26
Realisation period:
2016-01-26 - 2018-07-25
Project manager:
prof. dr hab. inż. Wojciech Witkowski
Realised in:
Katedra Wytrzymałości Materiałów
Project's value:
229 580.00 PLN
Request type:
National Research Programmes
Domestic:
Domestic project
Verified by:
Gdańsk University of Technology

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Year 2019

Year 2018

  • A study on transverse shear correction for laminated sandwich panels
    Publication

    - Year 2018

    The paper presents a study on an application of the First Order Shear Deformation Theory in a linear static analysis of elastic sandwich panels. A special attention has been given to the issue of the transverse shear correction. Two benchmark examples of sandwich plate problems with known reference solutions have been selected for a comparative analysis performed with own Finite Element codes. Interesting results allowed for drawing...

  • Direct shear stress vs strain relation for fiber reinforced composites
    Publication

    The majority of fiber reinforced composites exhibit strong non-linear behavior in in-plane shear state. The effect is attributed to the micro-cracks appearing in the matrix and can be modeled on the micro and macro level. In this work the author proposes constitutive laws describing the non-linear in-plane shear response, which can be alternative for the relations commonly considered in the literature. The proposed equations are...

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  • Elastoplastic nonlinear FEM analysis of FGM shells of Cosserat type

    The paper is a continuation of [1] where the formulation of the elastic constitutive law for functionally graded materials (FGM) on the grounds of nonlinear 6-parameter shell theory with the 6th parameter (the drilling degree of freedom) was presented. Here the formulation is extended to the elasto-plastic range. The material law is based on Cosserat plasticity and employs the well-known Tamura-Tomota-Ozawa (TTO) [2] mixture...

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  • Estimation of Failure Initiation in Laminated Composites by means of Nonlinear Six-Field Shell Theory and FEM
    Publication

    - Year 2018

    The monography deals with the problem of failure initiation in thin laminated composites. Known techniques of laminate structures modelling are briefly characterised. Eventually, shell based approach is chosen for the purpose of the description of the composite structures behaviour, as it predicts their deformation and states of stress effectively in a global sense. The nonlinear six parameter shell theory (6p theory) with asymmetric...

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  • FEM simulation of laminate failure in the three point bending
    Publication

    - Year 2018

    The paper presents a FEM simulation of failure of laminate subjected to the three point bending. The numeri-cal model is based on the equivalent single layer approach with 6-paramater non-linear shell theory kinematics. It is implemented in the non-commercial FEM code. The failure initiation is detected with the use of Tsai-Wu criterion. After the failure onset the progressive failure process is modelled through the appropriate...

  • Mixed 4-node shell element with assumed strain and stress in 6-parameter theory

    We propose a mixed hybrid 4-node shell elements based on Hu-Washizu principle. Apart from displacements both strains and stress fields are treated as independent fields. The element is derived in the framework of a general nonlinear 6-field shell theory with drilling rotation which is dedicated to the analysis of multifold irregular shells with intersections. The novelty of the presented results stems from the fact that the measures...

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  • Nonlinear FEM analysis of irregular shells composed of fiber metal laminates

    The paper deals with the analysis of failure initiation in shells made of Fiber Metal Laminates (FML). The elas-tic material law for orthotropic lamina is stated accounting for asymmetric in-plane stress and strain measures. The asymmetry results from the employed general nonlinear 6-field shell theory where the generalized dis-placements involve the translation and the proper rotation field. The novelty of the presented results...

  • Progressive failure analysis of laminates in the framework of 6-field nonlinear shell theory
    Publication

    The paper presents the model of progressive failure analysis of laminates incorporated into the 6-field non-linear shell theory with non-symmetrical strain measures of Cosserat type. Such a theory is specially recommended in the analysis of shells with intersections due to its specific kinematics including the so-called drilling rotation. As a consequence of asymmetry of strain measures, modified laminates failure criteria must...

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Year 2017

  • FEM analysis of composite materials failure in nonlinear six field shell theory
    Publication

    - Year 2017

    The monography deals with the problem of failure initiation in thin laminated composites. Known techniques of laminate structures modelling are briefly characterised. Eventually, shell based approach is chosen for the purpose of the description of the composite structures behaviour, as it predicts their deformation and states of stress effectively in a global sense. The nonlinear six parameter shell theory (6p theory) with asymmetric...

    Full text available to download

  • Mixed 4-node shell element with assumed strain and stress in 6-parameter theory

    We propose a mixed hybrid 4-node shell elements based on Hu-Washizu principle. Apart from displacements both strains and stress fields are treated as independent fields. The element is derived in the framework of a general nonlinear 6-field shell theory with drilling rotation which is dedicated to the analysis of multifold irregular shells with intersections. The novelty of the presented results stems from the fact that the measures...

    Full text to download in external service

Year 2016

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