Modeling of a geocell-reinforced pavementSamo Peter Medved
, Bojan Žlender
, Stanislav Lenart
, Primož Jelušič
, 2016, izvirni znanstveni članek
Opis: This article details how the serviceability of a flexural pavement structure is improved by incorporating the Cellular Confinement System (geocells). For this purpose, two different pavement structures, with and without embedded geocells, were manufactured in a laboratory and an accelerated traffic type of loading was applied. The vertical and horizontal cyclic loads were applied simultaneously to simulate the effect of principal stress rotation. A comparative study between the conventional flexible pavement and the geocell-reinforced flexible pavement is presented. Additionally, numerical models of the laboratory tests were built and the results were compared. The simulation of the experimental tests using the Traffic Load Simulator (TLS) are carried out using the FEM and advanced models that describe the permanent strain behavior of the unbound granular material. The development of permanent deformation within the pavement structure, with and without the geocells, is also presented through the numerical model, which was verified by the experimental results.
Ključne besede: flexible pavement, reinforcement, geocell, traffic load simulator, permanent deformation, numerical modeling
Objavljeno: 18.06.2018; Ogledov: 88; Prenosov: 12
Celotno besedilo (1,39 MB)
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Nonlinear control of a one-dimensional self-balancing system with an inertia wheelMarko Boršić
, 2019, magistrsko delo
Opis: The master’s thesis describes the development of a one-dimensional self-balancing system with an inertia wheel. The plan was to establish all the theoretical knowledge that was gathered throughout the process of studying at the University and to finish the practical model which has the ability to balance in one dimension. The paper contains a description of constructing the mechanical part of the pendulum, developed in SolidWorks software. It also contains the execution of the mathematical model of the inverted pendulum. The simulation was conducted in Matlab/Simulink software. Based on the results of the simulation, the design of the controller for the EC motor was made. Designed controllers and measured data required for the active balance of the system were implemented on the microcontroller STM32F4. To measure the angle and angle velocity, the gyroscope and accelerometer on the MPU6050 sensor were used. The results of the simulation and of the practical model are presented in this paper.
Ključne besede: modeling, inertia wheel, backstepping, state space, sliding mode
Objavljeno: 29.03.2019; Ogledov: 259; Prenosov: 85
Celotno besedilo (3,00 MB)
Numerical analysis of fluid flow in a vialŽiga Časar
, 2019, magistrsko delo
Opis: Lyophilization or freeze-drying is a widely used process in the pharmaceutical and food industry. In the process the solvent will be removed under extreme conditions of low temperature and low system pressures, whereby sublimation happens, the transition from the solid phase to the gas phase, with skipping the liquid phase, which happens bellow the triple point. This study focuses on numerical modeling at the start of the process, the so called primary drying. For this stage the highest mass flow rates of vapor are typical, since the driving force of the process is the pressure difference between the sublimation front and surrounding area. In this stage the non-bonded solvent is removed. Because of the extreme conditions the typical computational fluid dynamics approach is not suitable anymore and has to be corrected. One way to do this is to use additional models for fluid behavior at the solid wall. The study focuses on the influence of different boundary conditions on the solid wall, No-Slip, Free Slip and Maxwell Slip, and their effect on fluid flow inside the vial. A quantitative and qualitative comparison of the results is presented.
Ključne besede: Lyophilization, Knudsen number, computational fluid dynamics, fluid flow, numerical modeling, slip boundary condition
Objavljeno: 09.07.2019; Ogledov: 93; Prenosov: 9
Celotno besedilo (2,66 MB)