841. General position polynomialsVesna Iršič, Sandi Klavžar, Gregor Rus, James Tuite, 2024, original scientific article Abstract: A subset of vertices of a graph $G$ is a general position set if no triple of vertices from the set lie on a common shortest path in $G$. In this paper we introduce the general position polynomial as $\sum_{i \geq 0} a_i x^i$, where $a_i$ is the number of distinct general position sets of $G$ with cardinality $i$. The polynomial is considered for several well-known classes of graphs and graph operations. It is shown that the polynomial is not unimodal in general, not even on trees. On the other hand, several classes of graphs, including Kneser graphs $K(n,2)$, with unimodal general position polynomials are presented.
Keywords: general position set, general position number, general position polynomial, unimodality, trees, Cartesian product of graphs, Kneser graphs
Published in DiRROS: 28.02.2024; Views: 231; Downloads: 134
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842. 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: 200; Downloads: 115
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843. 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: 259; Downloads: 0
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847. 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: 234; Downloads: 73
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