Publications by authors named "Jernej Klemenc"

Magnesium alloys, particularly AZ31, are promising materials for the modern automotive industry, offering significant weight savings and environmental benefits. This research focuses on the challenges associated with accurate modelling of multiaxial cyclic plasticity at small strains of AZ31 under low-cycle fatigue conditions. Current modelling approaches, including crystal plasticity and phenomenological plasticity, have been extensively explored.

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Due to their advantages-longer internal force delay compared to bulk materials, resistance to harsh conditions, damping of a wide frequency spectrum, insensitivity to ambient temperature, high reliability and low cost-granular materials are seen as an opportunity for the development of high-performance, lightweight vibration-damping elements (particle dampers). The performance of particle dampers is affected by numerous parameters, such as the base material, the size of the granules, the flowability, the initial prestress, etc. In this work, a series of experiments were performed on specimens with different combinations of influencing parameters.

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Article Synopsis
  • This article discusses the modeling of high-strength steel SZBS800's response to strain rates using a combination of standard tensile tests and a unique method involving shooting a ball into specimens.
  • The authors employed the Cowper-Symonds viscoplastic model to factor in strain-rate effects and estimated its parameters through a systematic procedure involving rough estimates and fine-tuning techniques.
  • Optimal parameter values were determined using explicit dynamic simulations and a genetic algorithm, effectively capturing the material's response, although the optimal candidates spanned a wide range for some parameters.
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Granular materials promise opportunities for the development of high-performance, lightweight vibration-damping elements that provide a high level of safety and comfort. Presented here is an investigation of the vibration-damping properties of prestressed granular material. The material studied is thermoplastic polyurethane (TPU) in Shore 90A and 75A hardness grades.

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In recent years, elastocaloric cooling has shown great potential as an alternative to vapor-compression refrigeration. However, there is still no existing elastocaloric device that offers fatigue-resistant operation and yet high cooling/heat-pumping performance. Here, we introduce a new design of an elastocaloric regenerator based on compression-loaded Ni-Ti tubes, referred to as a shell-and-tube-like elastocaloric regenerator.

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In real engineering applications, machine parts are rarely completely homogeneous; in most cases, there are at least some minor notch effects or even more extensive inhomogeneities, which cause critical local stress concentrations from which fatigue fractures develop. In the present research, a shift of the Coffin-Manson - material curve in a structure with random porosity subjected to dynamic LCF loads was studied. This allows the rest of the fatigue life prediction process to remain the same as if it were a homogeneous material.

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When wood is used as a structural material, the fact that it is a highly inhomogeneous material, which significantly affects its static and fatigue properties, presents a major challenge to engineers. In this paper, a novel approach to modelling the fatigue-life properties of wood is presented. In the model, the common inverse-power-law relationship between the structural amplitude loads and the corresponding number of load cycles to failure is augmented with the influence of the wood's mass density, the loading direction and the processing lot.

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The problem of characterizing the structural residual life is one of the most challenging issues of the damage tolerance concept currently applied in modern aviation. Considering the complexity of the internal architecture of composite structures widely applied for aircraft components nowadays, as well as the additional complexity related to the appearance of barely visible impact damage, prediction of the structural residual life is a demanding task. In this paper, the authors proposed a method based on detection of structural damage after low-velocity impact loading and its classification with respect to types of acting stress on constituents of composite structures using the developed processing algorithm based on segmentation of 3D X-ray computed tomograms using the package, real-oriented dual-tree wavelet transform and supporting image processing procedures.

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Magnesium is one of the lightest metals for structural components. It has been used for producing various lightweight cast components, but the application of magnesium sheet plates is less widespread. There are two reasons for this: (i) its poor formability at ambient temperatures; and (ii) insufficient data on its durability, especially for dynamic loading.

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