In this study, polyethersulfone (PES) and polyvinylidene fluoride (PVDF) microfiltration membranes containing polyvinylpyrrolidone (PVP) with and without support layers of 130 and 150 μm thickness are manufactured using the phase inversion method and then experimentally characterised. For the characterisation of membranes, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and pore size analysis are performed, the contact angle and water content of membranes are measured and the tensile test is applied to membranes without support layers. Using the results obtained from the tensile tests, the mechanical properties of the halloysite nanotube (HNT) and nano-silicon dioxide (nano SiO2) reinforced nanocomposite membranes are approximately determined by the Mori–Tanaka homogenisation method without applying any further mechanical tests. Then, plain polymeric and PES and PVDF based nanocomposite membranes are modelled using the finite element method to determine the effect of the geometry of the membrane on the mechanical behaviour for fifteen different geometries. The modelled membranes compared in terms of three different criteria: equivalent stress (von Mises), displacement, and in-plane principal strain. Based on the data obtained from the characterisation part of the study and the numerical analysis, the membrane with the best performance is determined. The most appropriate shape and material for a membrane for water treatment is specified as a 1% HNT doped PVDF based elliptical membrane.

This study focuses on the mechanical behavior and design of membrane filters that are used in water and wastewater treatment. The aim of this study is, after characterizing the mechanical behavior of the membrane materials, to find a better shape in terms of mechanical parameters. As the first step, uniaxial tensile testing is applied to the produced polymeric membranes with certain contents of poly(ether imide), poly(vinylpyrrolidone), and N-methyl-2-pyrrolidone to get an understanding of the mechanical behavior of the membrane materials. The material data obtained from this experimental process are used as input to software where a finite element model of the membrane is built. Each geometry has the same boundary conditions and the same area, and the same pressure is applied to each geometry. Using these numerical models, the selected geometries are analyzed in terms of displacement, equivalent stress, and equivalent strain. The results are discussed based on these parameters.

To investigate the effect of polyvinylpyrrolidone (PVP) addition and consequently porosity, two different sets of membranes are manufactured, since PVP is a widely used poring agent which has an impact on the mechanical properties of the membrane material. The first set (PAN 1) includes polyacrylonitrile (PAN) and the necessary solvent while the second set (PAN 2) is made of PAN and PVP. These membranes are put through several characterisation processes including tensile testing. The obtained data are used to model the static behaviour of the membranes with different geometries but similar loading and boundary conditions that represent their operating conditions. This modelling process is undertaken by using the finite element method. The main idea is to investigate how geometry affects the load-carrying capacity of the membranes. Alongside membrane modelling, their materials are modelled with representative elements with hexagonal and rectangular pore arrays (RE) to understand the impact of porosity on the mechanical properties. Exploring the results, the best geometry is found as the elliptic membrane with the aspect ratio 4 and the better RE as the hexagonal array which can predict the elastic properties with an approximate error of 12%.

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This study investigated the failure of the roof, with steel truss construction, of a factory building in Tekirdag in the northwestern part of Turkey. The failure occurred under hefty weather conditions including lightning strikes, heavy rain, and fierce winds. In order to interpret the reason for the failure, the effects of different combinations of factors on the design and dimensioning of the roof were studied. Finite element analysis, using the commercial software Abaqus (Dassault Systèmes, Vélizy-Villacoublay, France), was performed several times under different assumptions and considering different factors with the aim of determining the dominant factors that were responsible for the failure. Each loading condition gives out a characteristic form of failure. The scenario with the most similar form of failure to the real collapse is considered as the most likely scenario of failure. In addition, the factors included in this scenario are expected to be the responsible factors for the partial collapse of the steel truss structure.