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Abstract: The remarkable development of timber construction technologies in recent decades has led to an increase in the number of timber buildings worldwide, including multi-storey buildings. The design of timber buildings, especially those of greater height, is relatively demanding and, even in the context of architectural expression, has certain constraints due to the specific structural and physical properties of this material. Thus, it is important for designers to have an overview of existing timber structural systems and their specificities to be able to make the right design decisions during the design process. Unfortunately, there is a lack of scientific literature that systematically addresses the essential features of contemporary timber structural systems. Within the aims of this paper to provide the systematic review of contemporary structural systems, both the scientific and professional literature are comprehensively reviewed. This paper presents a systematic classification and description of the following structural systems of timber buildings: all-timber and hybrid timber structural systems with an additional description of constituent structural elements, while examples of completed multi-storey timber buildings are also given for each structural system. The findings provide a broader view of the knowledge of contemporary solutions of timber structural systems and their application, thus representing a novelty in the field of timber construction review.
Keywords: timber structural systems, hybrid timber structural system, timber-concrete composite, timber-steel composite, timber-timber composite, timber structural elements, timber buildings, multi-storey timber buildings
Published in DKUM: 09.02.2024; Views: 258; Downloads: 30
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Abstract: Advanced pore morphology (APM) foam, consisting of sphere-like metallic foam elements, proves to have advantageous mechanical properties and unique application adjustability. Since the APM foam manufacturing procedure has been developed recently, the mechanical characterization of these materials is still very limited. Therefore, the purpose of this research was to determine the behaviour of APM spheres and its composites when subjected to quasi-staticand dynamic compressive loading. The results of the performed research have shown valuable mechanical properties of the composite APM foam structures, offering new possibilities for their use in general engineering applications.
Keywords: advanced pore morphology, foam, composite APM foam structures
Published in DKUM: 26.07.2017; Views: 1421; Downloads: 373
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Abstract: In this paper we present the production of NiTi/Ni-TiO2 composite nanoparticles via the synthesis method called ultrasonic spray pyrolysis (USP). The precursor solution for the synthesis of spherical NiTi particles was prepared from an orthodontic wire with a chemical composition of Ni (amount fraction x = 51.46 %) and Ti (x = 48.54 %). TEM microscopy, in combination with EDX analyses, was used for a detailed characterization of the obtained NiTi nanoparticles. The results showed the nanoparticle sizes ranging from 60 nm to 600 nm, depending on the parameters of the production procedure. This showed the versatility of the new USP synthesis procedure, proving its usefulness for different materials and applications.
Keywords: ultrasonic spray pyrolysis, NiTi/Ni-TiO2 composite nanoparticles, characterization, Transmission electron microscope (TEM), TEM microscopy
Published in DKUM: 23.03.2017; Views: 1604; Downloads: 130
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Abstract: Advanced pore morphology (APM) structures are composite metal foams, which are assembled from a large number of small spherical elements with cellular structure, and are bonded into a composite with polymeric adhesive. The result of such composition is a wide spectrum of achievable mechanical behaviour in APM structures. To explore their full potential, efficient computational models are needed, which allow for simple parameter variation. Unfortunately, the current computer models do not allow for efficient simulations of porous composite structures with advanced pore morphology, as they employ complex discretisation approaches. A new approach to simulation is presented in this work, based on the discrete particle method (DPM), where every element of APM structure is discretised with a single node. This enables more efficient simulations of APM structures, while still allowing for simple variation of structural parameters. The DPM method was augmented with constitutive models of normal and tangential contact behaviour of APM elements and bonds between them, which were formulated based on an extensive experimental study of APM structure's geometry and mechanical behaviour. Consequently, the models enable simulations of large APM structure's behaviour by modelling the contact behaviour of individual elements. The implementation of new models was verified on a set of analytically solvable examples, and the accuracy of the models was validated with very good correspondence between computational and experimental results. Moreover, the models were validated on a wide set of examples, also taking into account the various strain rates and the absence of the bonds. The applicability of new models was demonstrated in a comprehensive parametrical study, where the influential structural parameters and properties were identified for low and high strain rate deformations. The study also demonstrated the possibility of customising the mechanical behaviour with property gradation, and with introduction of regular, as well as geometrically complex APM element assemblies. The possibility of coupled discrete particle method and finite element method simulations was also addressed. The newly developed models represent a breakthrough in the field of computational investigation of APM structures, and provide for simpler and more efficient investigations of APM structures in the future.
Keywords: Metal foams, advanced pore morphology, composite materials, mechanical properties, contact modelling, discrete particle methods, computer simulations
Published in DKUM: 11.03.2016; Views: 2629; Downloads: 241
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Abstract: We prove that any nontrivial connected strong product graph can be uniquely reconstructed from each of its one vertex deleted subgraphs.
Keywords: matematika, teorija grafov, problem rekonstrukcije, šibka rekonstrukcija, krepki produkt grafov, mathematics, graph theory, reconstruction problem, strong product, composite graphs
Published in DKUM: 10.07.2015; Views: 29077; Downloads: 416
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