Doncheva, Elisaveta
Preferred name
Doncheva, Elisaveta
Official Name
Doncheva, Elisaveta
Main Affiliation
Email
elisaveta.doncheva@mf.edu.mk
34 results
Now showing 1 - 10 of 34
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Item type:Publication, Mechanical properties of parts fabricated with additive manufacturing: A review of mechanical properties of fused filament fabrication parts(Scientific Technical Union of Mechanical Engineering, 2022); ; ; Hadzieva, Bojana - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Mathematical model of dynamic vibration absorber-response prediction and reduction(Faculty of Engineering Hunedoara, 2016-02); This paper is dealing with procedures for mathematical modeling of DVA. Usually the problems of optimization are converted to equivalent single degree of freedom (SDOF) structure at particular mode in order to optimize the damper. There are three main parameters in a DVA system: DVA mass, DVA stiffness coefficient and DVA damping ratio. Consequently, the objective is to find the optimum value of these parameters. This paper is investigating also the effect of relative speed of primary structure and its influence on response. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Review of current welding technology and literature review of weld repair without post-weld heat treatment for X10CrMoVNb9-1 steel in dissimilar metal welds(Elsevier BV, 2025); ; ; Petreski, Martin - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A review of fused deposition modeling process: parameter optimization, materials, and design(ICAMTAFDM 2022: International Conference on Additive Manufacturing Technologies, Applications and Fused Deposition Modelling, 2022-07-21); ; ; Hadjieva, BojanaIn the past decade, additive manufacturing technology or 3D printing has been promoted as an efficient method for fabricating hybrid composite materials and structures with superior mechanical properties and complex shape and geometry. Fused deposition modeling (FDM) process is commonly used additive manufacturing technique for production of polymer products. Therefore, many studies and experiments are focused on investigating the possibilities for improving the obtained results on product properties as a key factor for expanding the spectrum of their application. This article provides an extensive review on recent research advances in FDM and reports on studies that cover the effects of process parameters, material, and design of the product properties. The paper conclusions provide a clear up-to date information for optimum efficiency and enhancement of the mechanical properties of 3D printed samples and recommends further research work and investigations. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Experimental investigation on mechanical properties of FFF parts using different materials(Elsevier BV, 2022); ; Hadjieva, BojanaFused filament fabrication (FFF) is one of the additive manufacturing processes that provides parts with finest mechanical properties. Different materials offer different mechanical properties of the part. In this research we investigated parts fabricated with polylactic acid (PLA), polycarbonate (PC) and polyethylene terephthalate glycol, PETG. Samples are designed according to the ASTM standards and fabricated under the same process parameters. The mean effect on the tensile strength and flexural strength have been studied. From the study it can be concluded that there is a difference in the results as expected. But we cannot say that there is one material with superior properties, simply different materials are suitable for different applications. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Sustainability and environmental life cycle analysis of welding processes(Emerald, 2024); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Design for Sustainability: A Review(SCIENTIFIC TECHNICAL UNION OF MECHANICAL ENGINEERING INDUSTRY-4.0, 2023-11-08); ustainability is topic of great concern since the last decade and still today does not lose of its popularity. Reason for that is that the contemporary way of living is causing great damages to the environment. Designers have been talking about changing the ways in which the products are designed in order to have sustainable product. But, for achieving sustainability many aspects need to be addressed, such as: cultural, social, economical and technological. Nowadays, we believe that these aspects are on higher level and we can talk about sustainable design. Every product development process starts with the design phase and this is why we believe that it is most important for making improvements of the products. In this paper we have the premise that good and appropriate design can have positive influence on the sustainability. In order to check the validity of the premise we are reviewing paper dealing with sustainability, eco design, and engineering materials. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Mechanical properties of parts fabricated with additive manufacturing: A review of mechanical properties of fused filament fabrication parts(2022); ; ; Hadjieva, BojanaAdditive Manufacturing (AM) Technologies are in constant development since their emergence in the late 80s. However, standardization is still in its infancy, owing to the numerous changing variables in each process. One of the most common are the material extrusion process, in which thermoplastic is extruded, also known as fused filament fabrication (FFF). The popularity of this process is due to the relatively simple method as well as the relatively good mechanical properties of the fabricated parts. There are numerous research studies evaluating mechanical properties because the FFF process allows for the investigation of many variables and the production of many parts with a wide range of characteristics. But how good are those characteristics in reality, and how good do we need them to be? It all depends on the application for which those parts are required. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A REVIEW STUDY ON HYDROGEN EMBRITTLEMENT OF STEEL(Society for Structural Integrity and Life and IMS Institute, 2024); A common and intricate phenomenon known as hydrogen embrittlement of steel is the deterioration of the mechanical properties of metal in relation to stress corrosion cracking. This phenomenon has been extensively studied, with numer-ous works proposed over the last two decades, but there is still a lack of unified solutions and a solid understanding of the phenomenon. The purpose of this paper is to provide a review of the literature and publications on hydrogen embrittlement in steel. It focuses on recent developments and methods that have contributed to a better understand-ing of the relationship between steel structure, properties, and performance, with a particular emphasis on hydrogen diffusion, characterisation, mechanisms, and prevention of hydrogen embrittlement in structural steel. Furthermore, the paper discusses recent advances in experimental and multi-scale modelling and proposes future studies to address challenges related to hydrogen embrittlement in steels. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Weldability of austenitic heat-resisting steels(Serbian Welding Society, 2024); ; ; Krstevska, AleksandraAustenitic heat-resisting steels are used in a wide range of industries. Their use is motivated not only by their excellent mechanical properties but also due to their excellent resistance to corrosion and the ability to withstand high temperatures. These steels are prone to defects and challenges during welding because of their high content of Cr, Ni, Al, and other alloying elements. The main problem is the high heat energy input, which causes differences in structure between the welded joint and the surrounding area. The relatively high heat input and cooling in the heat-affected zone (HAZ) causes carbide formation and, as a result, coarse grain formation, which is undesirable for obtaining favourable mechanical properties. This study investigates the weldability of two heatresistant austenitic steels (EN X12CrNi23-13 and EN X8CrNi25-21) using the gas tungsten arc welding (GTAW) technique. Both materials are separately analyzed, and the results are discussed in terms of potential welding techniques and technological plan improvements to achieve highquality welds without pre-heating or any other additional post-welding heat treatment, which is important for the industry because it can reduce production time and cost.