E. Stupak

Manganite Sensor for Measurements of Magnetic Field Disturbances of Pulsed Actuators

Magnetic field sensors based on polycrystalline La0.83Sr0.17MnO3 films were used to measure the magnetic field distribution and disturbances during the operation of an electromagnetic launcher. Hollow cylinders made from dural aluminum and iron were used as propelled objects inside the solenoidal coil. The obtained results revealed the ability of manganite sensors to rapidly measure changing high magnetic fields of arbitrary waveforms.

SENSITIVITY OF DYNAMIC BEHAVIOUR OF THE FE MODEL: CASE STUDY FOR THE IGNALINA NPP REACTOR BUILDING

Abstract The 3D thin‐walled finite element model of Ignalina NPP Unit 2 reactor building was developed aimed at the evaluation of the global dynamic behaviour with a focus on the seismic response. The model comprises description of the monolithic structures, while prefabricated frame structures are ignored and replaced by external masses. Sensitivity study of the selected dynamic characteristics of the model with respect to data uncertainties is considered. Uncertainty of the model is considered in terms of masses of removed structures and wall stiffness. Seismic input is represented by the site specific free‐field ground response acceleration spectra. The sensitivity study concerns variations of frequencies and acceleration of in‐structure horizontal response spectra at specified points. Maximal bending moments are also considered. It was obtained that the reactor level is not sensitive to the uncertainties considered, while discernable sensitivity was detected at the top level of the structure.

Thermal Stresses and End-Bulging in Cylindrical Laser Rods Under Longitudinal Diode Laser Pumping

Three-dimensional thermo-mechanical finite element analysis of conventional and composite cylindrical laser rods under the conditions of longitudinal pumping of the continuous wave diode laser is presented. First, the heat conduction problem with prescribed cooling boundary conditions is solved. Then, the 3D stress and bulging of entrance and exit faces are analyzed. It is shown that the frequently used plane strain and plane stress approximations significantly overestimate the values of face bulging of conventional and particularly composite laser rods under the conditions of homogeneous and inhomogeneous heating.

On Efficiency of Parallel Solvers for the Blood Flow through Aortic Valve

Mathematical modelling of cardiac haemodynamics presents a great challenge to the computational scientists due to numerous numerical issues and required computational resources. In this paper, we study the parallel performance of 3D simulation software for the blood flow through the aortic valve. The fluid flow problem with the open aortic valve leaflets is formulated and solved in parallel. The choice between the segregated and coupled numerical schemes is discussed and investigated. We present and compare the parallel performance results of both types of parallel solvers. We investigate their strong and weak scalability.

Coupled Finite Element Analysis of Composite Laser Rods Thermal Characteristics under Longitudinal Diode Pumping

Diode laser pumped solid-state lasers are covering a wide range of applications. The longitudinal pumping geometry of laser rod is particularly favorable as it provides a high degree of spatial overlap between pump and lasing modes. However, high pump-power densities are required to achieve sufficient inversion in the laser material. This produces high thermal loading in laser crystals, which, in turn, leads to undesirable thermal effects, such as temperature-dependent index change, temperature-dependent stresses, and end-surface deformation. All those effects are qualified as thermal lensing in laser material.