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This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Sven Düzel, Robert Eberlein, Hans-Jörg Dennig; Fatigue life analysis of POM gears with transient material modeling. AIP Conf. Proc. 8 May 2024; 3158 (1): 110015. https://doi.org/10.1063/5.0204543 and may be found at https://doi.org/10.1063/5.0204543., The today’s standard calculation methods for investigating the load carrying capacity of polymer gears (such as VDI 2736) are based on the same assumptions as for steel gears. Due to strongly varying material properties of polymers regarding stiffness level, nonlinearity and rate dependency, the predicted lifetimes of polymer gears are inaccurate. In the current study a rate dependent nonlinear viscoplastic finite element (FE) modelling of polyoxymethylene (POM) allows quantifying the material influences not considered by standard assumptions for metal parts. By deploying such a nonlinear material model for POM, a POMsteel gear pairing is investigated and additionally validated on a gear test rig. Different rotational speeds but constant brake torque are investigated to analyse the influence of inertia under the dynamic conditions as well as the rate depended material properties to the fatigue lifetime. An accelerated approach for a repeated transient FE modelling of the gear meshing process makes it possible to investigate critical stress and strain states over consecutive cycles, specifically focusing on tooth root breaking. It turns out that a cyclic increase of (plastic) strains occurs in the polymer gear teeth roots. Through an extrapolation of the local maximum principal strain, the strain state of the failure causing cycles can be analysed and forms the basis for a fatigue life analysis of POM gears. In combination with a strain based failure criterion the admissible number of cycles of POM gears for various rotational speeds is predicted and validated against experimental results obtained from the gear test rig.

The Mini Labyrinth experiment is a simple neutron and gamma shielding experiment developed at STU, inspired by the ALARM-CF-AIR-LAB-001 ICSBEP benchmark experiment, originally constructed in the former Soviet Union in 1982. Compared to the original Labyrinth, which was made from concrete blocks and had dimension of several meters, the STU Mini Labyrinth is approximately ten times smaller and consists of NEUTRONSTOP shielding blocks. The purpose of this experiment is to validate the computer codes of STU and partners involved in the APVV-DS international project “Experimental and simulation shielding studies of materials used in radiation protection”. This paper gives a brief overview of the experimental workplace and brings the first experimental results and their comparison with computer simulation. The very first experiment performed in the Mini Labyrinth experimental workplace was focused on the measurement of neutron and gamma count rate inside the Mini Labyrinth using the Thermo Scientific RadEye dose meter. The experimental setup also consisted of a PuBe radioisotope neutron source and light water moderator placed in a plastic tank between the neutron source and the detector. The simulation part was carried out using the state-of-the-art MCNP6 and SCALE6 MONACO stochastic calculation tools taking into account the detailed geometry of the labyrinth and a combined neutron- gamma source of particles. The comparisons were performed between codes, based on dose rate in the unique detection positions and using a 3D map of neutron and photon fluxes, using the so called meshtallies. The comparison between the simulated and measured data was performed based on the measured neutron count rate

This paper presents the Metrological Laboratory for Thermophysical Quantities (MLTV) and its actual measurement possibilities. The MLTV is located in the Department of Thermal Engineering and Energy of the Institute of Nuclear Sciences VINCA in Serbia. It was founded in 1963, accredited by the National Accreditation Body in 2007 and became the national designated laboratory for thermophysical quantities and received the status of a EURAMET Associate Member in 2015. Today, the laboratory develops, maintains and disseminates traceability of different national standards, such as those for thermal conductivity of insulations and poorly conductive solid materials from 250 K to 350 K, thermal diffusivity of a large variety of solid materials from 200 K to 1450 K and specific heat and specific electrical resistivity from 250 K to 2400 K of electroconductive solid materials. Total hemispherical and spectral normal emissivity from 1200 K to 2400 K of electroconductive solid materials are also measured in the MLTV. The methods and experimental setups for the realization and measurement of all of these standards and quantities are described with corresponding examples.

The measurement of the Higgs production cross-section times the branching ratios for its decays into mu(+)mu(-) and ZZ* pairs at a 1.4 TeV CLIC collider is investigated in this paper. The Standard Model Higgs boson with a mass of 126 GeV is dominantly produced via WW fusion in e(+)e(-) collisions at 1.4 TeV centre-of-mass energy. Analyses of both decay channels are based on a full simulation of the CLIC_ ILD detector. All relevant physics and beam-induced background processes are taken into account. An integrated luminosity of 1.5 ab(-1) and unpolarised beams are assumed. For the H - GT ZZ* decay, the purely hadronic final state (ZZ* - GT q (q) over barq (q) over bar) is considered as well as ZZ* decays into two jets and two leptons (ZZ* - GT qql(+)l(-)). It is shown that the branching ratio for the Higgs decay into a muon pair times the Higgs production cross-section can be measured with 38% statistical uncertainty. It is also shown that the statistical uncertainty of the Higgs branching ratio for decay into a Z boson pair times the Higgs production crosssection can be measured with a precision of 18.3% and 5.6% for the hadronic and semi-leptonic ZZ* decays, respectively.

This paper presents the Metrological Laboratory for Thermophysical Quantities (MLTV) and its actual measurement possibilities. The MLTV is located in the Department of Thermal Engineering and Energy of the Institute of Nuclear Sciences VINCA in Serbia. It was founded in 1963, accredited by the National Accreditation Body in 2007 and became the national designated laboratory for thermophysical quantities and received the status of a EURAMET Associate Member in 2015. Today, the laboratory develops, maintains and disseminates traceability of different national standards, such as those for thermal conductivity of insulations and poorly conductive solid materials from 250 K to 350 K, thermal diffusivity of a large variety of solid materials from 200 K to 1450 K and specific heat and specific electrical resistivity from 250 K to 2400 K of electroconductive solid materials. Total hemispherical and spectral normal emissivity from 1200 K to 2400 K of electroconductive solid materials are also measured in the MLTV. The methods and experimental setups for the realization and measurement of all of these standards and quantities are described with corresponding examples.

The measurement of the Higgs production cross-section times the branching ratios for its decays into mu(+)mu(-) and ZZ* pairs at a 1.4 TeV CLIC collider is investigated in this paper. The Standard Model Higgs boson with a mass of 126 GeV is dominantly produced via WW fusion in e(+)e(-) collisions at 1.4 TeV centre-of-mass energy. Analyses of both decay channels are based on a full simulation of the CLIC_ ILD detector. All relevant physics and beam-induced background processes are taken into account. An integrated luminosity of 1.5 ab(-1) and unpolarised beams are assumed. For the H - GT ZZ* decay, the purely hadronic final state (ZZ* - GT q (q) over barq (q) over bar) is considered as well as ZZ* decays into two jets and two leptons (ZZ* - GT qql(+)l(-)). It is shown that the branching ratio for the Higgs decay into a muon pair times the Higgs production cross-section can be measured with 38% statistical uncertainty. It is also shown that the statistical uncertainty of the Higgs branching ratio for decay into a Z boson pair times the Higgs production crosssection can be measured with a precision of 18.3% and 5.6% for the hadronic and semi-leptonic ZZ* decays, respectively.