1791. An improved local radial basis function method for solving small-strain elasto-plasticityGašper Vuga, Boštjan Mavrič, Božidar Šarler, 2024, original scientific article Abstract: Strong-form meshless methods received much attention in recent years and are being extensively researched and applied to a wide range of problems in science and engineering. However, the solution of elasto-plastic problems has proven to be elusive because of often non-smooth constitutive relations between stress and strain. The novelty in tackling them is the introduction of virtual finite difference stencils to formulate a hybrid radial basis function generated finite difference (RBF-FD) method, which is used to solve small-strain von Mises elasto-plasticity for the first time by this original approach. The paper further contrasts the new method to two alternative legacy RBF-FD approaches, which fail when applied to this class of problems. The three approaches differ in the discretization of the divergence operator found in the balance equation that acts on the non-smooth stress field. Additionally, an innovative stabilization technique is employed to stabilize boundary conditions and is shown to be essential for any of the approaches to converge successfully. Approaches are assessed on elastic and elasto-plastic benchmarks where admissible ranges of newly introduced free parameters are studied regarding stability, accuracy, and convergence rate. Keywords: Von Mises elasto-plasticity, radial basis function, finite differences, polyharmonic splines, two dimensions, hybrid discretization Published in DiRROS: 28.02.2024; Views: 310; Downloads: 174
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1792. Raziskava vpliva procesnih parametrov na dolgoročno dimenzijsko stabilnost velikih komponent iz trde poliuretanske pene, izdelanih z ROM tehnologijo : magistrsko deloMatjaž Sekavčnik, 2023, master's thesis Keywords: trda poliuretanska pena, dimenzijska stabilnost, ROM tehnologija, tlak dolivanja izocianata, mešalno razmerje, čas vzdrževanja izdelka v orodju, magistrsko delo Published in DiRROS: 28.02.2024; Views: 418; Downloads: 0
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1796. Termoplastični kompoziti, ojačani z odpadnimi duroplastičnimi kompoziti : diplomsko deloJernej Leitinger, 2023, undergraduate thesis Keywords: kompozit, karakterizacija, ABS, termoplastična matrica, UPR, duroplastična armatura, vlaknasta ojačitev, steklena vlakna, mehanske lastnosti, termične lastnosti, diplomsko delo Published in DiRROS: 28.02.2024; Views: 420; Downloads: 157
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1800. Characterization of hFOB 1.19 cell line for studying Zn-based degradable metallic biomaterialsEva Jablonská, Lucie Mrázková, Jiří Kubásek, Dalibor Vojtěch, Irena Paulin, Tomáš Ruml, Jan Lipov, 2024, original scientific article Abstract: In vitro testing is the first important step in the development of new biomaterials. The human fetal osteoblast cell line hFOB 1.19 is a very promising cell model; however, there are vast discrepancies in cultivation protocols, especially in the cultivation temperature and the presence of the selection reagent, geneticin (G418). We intended to use hFOB 1.19 for the testing of Zn-based degradable metallic materials. However, the sensitivity of hFOB 1.19 to zinc ions has not yet been studied. Therefore, we compared the toxicity of zinc towards hFOB 1.19 under different conditions and compared it with that of the L929 mouse fibroblast cell line. We also tested the cytotoxicity of three types of Zn-based biomaterials in two types of media. The presence of G418 used as a selection reagent decreased the sensitivity of hFOB 1.19 to Zn2+. hFOB 1.19 cell line was more sensitive to Zn2+ at elevated (restrictive) temperatures. hFOB 1.19 cell line was less sensitive to Zn2+ than L929 cell line (both as ZnCl2 and extracts of alloys). Therefore, the appropriate cultivation conditions of hFOB 1.19 during biomaterial testing should be chosen with caution. Keywords: zinc degradable materials, in vitro cytotoxicity testing, hFOB 1.19 osteoblasts Published in DiRROS: 28.02.2024; Views: 358; Downloads: 125
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