1. Mechanisms of defect formation in Ti-6Al-4V product during re-melting of layers in selective laser meltingSnehashis Pal, Matjaž Finšgar, Radovan Hudak, Viktoria Rajtukova, Tomaž Brajlih, Nenad Gubeljak, Igor Drstvenšek, 2023, izvirni znanstveni članek Opis: Knowledge of defect formation mechanisms in the manufacturing process helps improve product quality. In this study, defect formation due to re-melting of each layer in selective laser melting of Ti-6Al-4V demonstrated the physical behavior in the manufacture of metallic parts. The re-melting strategy was based on scanning with low energy density (ED) and increased ED with various combinations of laser processing parameters. The increased EDs and their parameters, namely laser power, scanning speed, and hatch distance, were selected based on the previous research experience by the authors. The concept of selecting a low ED followed by a high ED was to reduce the spattering of the powder material during the process. The low ED caused partial sintering of the powder, while the high ED caused the melting of the material, resulting in different metallurgical properties of the manufactured parts. Densities, pore properties, porosity in the initial layers, surface morphologies, and microstructures in the defective areas of the samples were studied to determine the effects of re-melting. Advantages and disadvantages were found with respect to the range of applications of the products
Ključne besede: re-melting, pore properties, defect, surface morphology, Ti-6Al-4V, selective laser melting
Objavljeno v DKUM: 14.03.2025; Ogledov: 0; Prenosov: 2
 Celotno besedilo (16,16 MB) |
2. Influence of crosslinker on the properties of terpene-based poly(high internal phase emulsion)sRumeysa Beyaz, Stanko Kramer, Burcu Kekevi, Emine Hilal Mert, Irena Pulko, Peter Krajnc, 2024, izvirni znanstveni članek Ključne besede: terpene, alpha-myrcene, polyHIPE, pore morphology, mechanical properties
Objavljeno v DKUM: 03.02.2025; Ogledov: 0; Prenosov: 5
Celotno besedilo (1,37 MB) |
3. Experimental testing of single APM spheresMatej Vesenjak, Lovre Krstulović-Opara, 2010, objavljeni znanstveni prispevek na konferenci Opis: 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.
Ključne besede: advanced pore morphology, foam, composite APM foam structures
Objavljeno v DKUM: 26.07.2017; Ogledov: 1428; Prenosov: 379
Celotno besedilo (1,61 MB)
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4. Computer Modelling of Porous Composite Structures with Advanced Pore MorphologyAljaž Kovačič, 2016, doktorska disertacija Opis: 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.
Ključne besede: Metal foams, advanced pore morphology, composite materials, mechanical properties, contact modelling, discrete particle methods, computer simulations
Objavljeno v DKUM: 11.03.2016; Ogledov: 2635; Prenosov: 248
Celotno besedilo (44,29 MB) |
