Abstract
This special issue contains selected papers first presented in a short format at the 5th International
Conference ECCOMAS MSF 2019-Multiscale Computations for Solids and Fluids, organized in Dalmatian capital Split, Croatia, June 30-July 2, 2021.
Key Words
fluid mechanics; multiscale computations; solid mechanics
Address
Adnan Ibrahimbegovic: Universite de Technologie Compiegne – Sorbonne Universite, Laboratoire Roberval de Mecanique,
Centre de Recherche Royallieu, Compiegne, France; Institut Universitaire de France (IUF); Academy of Sciences and Arts BiH
Abstract
With glass becoming a structural material there is a whole new approach for loading and ensuring the safety of construction. Due to its brittle nature, it is necessary to predict all possible problems so that structural integrity would not be endangered. In this paper, different approaches to modelling the glass elements are presented with references to the advantages, disadvantages, and application of each of them. The intention is clear, there is a need to improve and simplify the design guidelines. Given the increasing use of glass in construction it is not practical to produce experimental tests each time when the verification is needed. Today, architecture is bringing us different types of structures and every project presents a new challenge for engineers. A practical and simple approach is crucial for progress and efficiency. In this paper, different approaches to modelling glass are presented with an emphasis on soft body impact.
Key Words
glass structures; impact load; pendulum test
Address
Gabrijela Grozdanic, Mirela Galic and Pavao Marovic: Department of Civil Engineering, Faculty of Civil Engineering, Architecture and Geodesy, University of Split, Matice hrvatske 15, HR-21000 Split, Croatia
Abstract
The aim of this paper is to conduct a hydrodynamic analysis of fluid flow over different weir types using the analytical solution, the physical model taken from another article, and numerical simulations through the Smoothed particle hydrodynamic method (SPH) using the compiled DualSPHysics source code. The paper covers the field of real fluid dynamics that includes a description of different proposed types of weirs in various flow regimes and the optimal solution for the most efficiency structure shape. A detailed presentation of the method, the structure and it's characteristics are included. Apart from the single stepped weir, two other weir types are proposed: a Divided type and a Downstream slopped type. All of them are modeled using the SPH method.
Key Words
hydraulic structures; single stepped weir; smoothed particle hydrodynamics; weir
Address
Haris Kalajdzisalihovic, Zoran Milasinovic: Faculty of Civil Engineering, University of Sarajevo, Patriotske lige 30, Sarajevo, Bosnia and Herzegovina
Alen Harapin: Faculty of Civil Engineering, Architecture and Geodesy, University of Split, Matice Hrvatske 15, Split, Croatia
Abstract
Fiber-reinforced concrete (FRC) is a composite material where small fibers made from steel or polypropylene or similar material are embedded into concrete matrix. In a material model each constituent should be adequately described, especially the interface between the matrix and fibers that is determined with the 'bond-slip' law.
'Bond-slip' law describes relation between the force in a fiber and its displacement. Bond-slip relation is usually
obtained from tension laboratory experiments where a fiber is pulled out from a matrix (concrete) block. However,
theoretically bond-slip relation could be determined from bending experiments since in bending the fibers in FRC get
pulled-out from the concrete matrix. We have performed specially designed laboratory experiments of three-point
beam bending with an intention of using experimental data for determination of material parameters. In addition, we
have formulated simple layered model for description of the behavior of beams in the three-point bending test. It is not
possible to use this 'forward' beam model for extraction of material parameters so an inverse model has been devised.
This model is a basis for formulation of an inverse model that could be used for parameter extraction from laboratory
tests. The key assumption in the developed inverse solution procedure is that some values in the formulation are known
and comprised in the experimental data. The procedure includes measured data and its derivative, the formulation is nonlinear and solution is obtained from an iterative procedure. The proposed method is numerically validated in the example at the end of the paper and it is demonstrated that material parameters could be successfully recovered from measured data.
Key Words
experimental data inversed model; FBM; FRC; layered model; three-point beam bending
Address
Ivica Kozar, Natalija Bede, Anton Bogdanic and Silvija Mrakovcic: Faculty of Civil Engineering, University of Rijeka, R. Matejcic 3, Rijeka, Croatia
Abstract
In this work, we present the development of a 3D lattice-type model at microscale based upon the Voronoi-cell representation of material microstructure. This model can capture the coupling between mechanic and electric fields with non-linear constitutive behavior for both. More precisely, for electric part we consider the ferroelectric constitutive behavior with the possibility of domain switching polarization, which can be handled in the same fashion as deformation theory of plasticity. For mechanics part, we introduce the constitutive model of plasticity with the Armstrong-Frederick kinematic hardening. This model is used to simulate a complete coupling of the chosen electric and mechanics behavior with a multiscale approach implemented within the same computational architecture.
Key Words
finite element method; lattice model; multi-scale model; piezoelectricity; Voronoi-cell microstructure representation
Address
Pablo Moreno-Navarro: Department of Continuum Mechanics & Theory of Structures, UPV-Universitat Polit'ecnica de Val'encia, Valencia, Spain
Adnan Ibrahimbegovic: UTC-Universit'e de Technologie de Compi'egne-Alliance Sorbonne Universit'e, Lab. Roberval, Chaire de M'ecanique UTC & IUF Membre Senior, Compi'egne, France
Dragan Damjanovic: EPFL-Ecole Polytechnique Federale de Lausanne, Group for Ferroelectrics and Functional Oxides, Lausanne, Switzerland
Abstract
An in situ experiment imaged via X-ray computed tomography was performed on a continuous glass fiber mat reinforced epoxy resin composite. The investigated dogbone specimen was subjected to uniaxial cyclic tension. The reconstructed scans (i.e., gray level volumes) were registered via Digital Volume Correlation. The calculated maximum principal strain fields and correlation residual maps exhibited strain localization areas within the material bulk, thus indicating damage inception and growth toward the specimen surface. Strained bands and areas of elevated correlation residuals were mainly concentrated in the narrowest gauge section of the investigated specimen,
as well as on the specimen ligament edges. Gray level residuals were laid over the corresponding mesostructure to
highlight and characterize damage development within the material bulk.
Key Words
correlation residuals; damage; digital volume correlation; fiber reinforced polymer; X-ray computed tomography
Address
Ana Vrgoc, Zvonimir Tomicevic: Laboratory of Experimental Mechanics, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lucica 5, 10002, Zagreb, Croatia
Benjamin Smaniotto, Francois Hild: Universite Paris-Saclay, ENS Paris-Saclay, CNRS, LMT–Laboratoire de Mecanique et Technologie, 91190 Gif-sur-Yvette, France