Papers by Keyword: Experimental Research

Abstract: The paper contains a modeling application with the help of factorial experiments of influence variations of some parameters of natural gases over the hourly flow delivered towards population. In order to completely and correctly draft the experiment we followed and highlighted the objective functions of the process to be analyzed, and then there were identified the factors that influence the objective function to be analyzed. In the end the experimental data was processed and solutions were proposed.

Abstract: The paper presents a comparative analysis of existing designs nozzle turbines. The advantages and disadvantages of existing designs nozzles. The description of the new nozzle design for axial microturbines. The analysis of the reasons for reducing the loss of kinetic energy of the flow of the working fluid in the nozzles of the proposed design offers.

Abstract: The article considers kinematic parameters of the 6R Bricard linkage characteristic point obtained analytically. Computer simulation of this mechanism resulted in diagrams of changes in the special orientation of the coordinate system of the characteristic point and a projection of its velocities to the basic coordinates system. In addition, we developed a prototype model for experimental studies. The difference between data obtained using the experimental model and the data obtained by computer analysis is less than 5%. This article describes the components of the experimental model. Using a stepper motor requires solving additional tasks: resonance, peaks at the first and the last steps, step dividing, ensuring the smooth acceleration of the motor shaft, smooth increasing of the shaft load, etc.

Abstract: More often Unmanned Ground Vehicles (UGV) support or replace human in dangerous tasks performing. Usually this operations are realizing in hard conditions in rough terrain. UGVs effectively use determines its ability to obstacle negotiating, to reach high adhesion force, drawbar pull and extra longitudinal and lateral stability of UGV. Variety missions determining of use in UGVs reconfigurable and control suspension system. It is able to meet this requirement thanks to use hydropneumatic components in them suspension system. However currently it is very hard to developed characteristic of such a suspension systems. In literature there is no clear guidelines for suspension systems of teleoperated UGVs. This paper presents results of hydropneumatic suspension system research on heavy UGV.

Abstract: By pull-out tests between GFRP bolts and concrete, the influence of the diameter and surface shape of GFRP bolts on the bonding performance was studied. By ANSYS analysis, the effects of anchorage length, diameter, geotechnical parameters and prestress on the bonding performance were studied. The experimental and numerical analysis results show that: with the increase of bolt diameter, the bonding strength of bolts decrease and the slippages increase. The bigger the parameters of rock-soil like modulus of elasticity, cohesion strength and internal friction angle are, the better is the bond behavior and the smaller is the slippage. The prestress plays an important role in the rock stability and the restriction of deformation. With the enhancement of the prestress of bolts, the peak shear stress increases but the effective anchorage length nearly stays the same.

Abstract: The article presents experimental data of microturbines nozzle boxes research. It describes mathematical models of nozzle outlet gas angle. Research results are analyzed and recommendations on design of nozzle boxes with small constructive outlet gas angle are given.

Abstract: The paper presents the results of calculations, taking into account a material model (isotropic reinforcement according to Misses), representing laboratory tests of additional reinforcement. Complying with PN-EN 1991-1-7:2008 (EC1) and PN-EN 1992-1:2004 (EC2) this reinforcement is applied in reinforced concrete slab-column structures in order to protect them against progressive collapses. Additionally, an analysis was carried out, considering, the effect of applying in the material model the true stress-strain curve. In the course of these experimental investigations the values of displacements caused by the exerted load were compared with the values of numerical calculations.

Abstract: This paper presents the results of laboratory tests concerning the central connection of the slab with the column, in which an additional reinforcement ensuring the structure against a progressive collapse was applied as to recommended in the standard PN-EN 1991-1-7:2008 as well as in PN-EN 1992-1-1:2008. Regulations concerning the necessity of such a reinforcement are also contained in the American and Australian standard as well as in the Bulletin FIB. The obtained results of investigations have been compared with calculations based on a spatial numerical model representing the analyzed phenomenon. The numerical model bases on predefined material models of steel and concrete, taking into account non-linear dependences of the strength of these materials. The values of displacements of the upper surface of the slab depending on the exerted load were compared with the values of numerical calculations.

Abstract: This paper presents the works carried out by the authors in the field of structural and functional optimization of industrial robot's numerically controlled (NC) axes. The study includes the results obtained in the research stage of the experimental measurements performed to evaluate the electrical servomotor's thermal behavior using a thermal (infrared) imaging camera. The analyzed servomotor is a brushless servomotor integrated in an experimental stand for linear motion NC axis experimental research, existing in the MMS department from EMTS faculty. Supplementary to the driving servomotor, the experimental stand includes a belt drive transmission, a ball screw - bearings assembly and a driven element guided by ball rail system. This experimental research phase is part of the doctoral thesis of first author and was conducted in order to validate the mathematical models developed in the PhD thesis. Thus, experimental results presented in the paper have been used to validate first mathematical models for electric motor's preliminary selection and checking, (performed by determining the total reflected inertia of the mechanical system on motor shaft level) as well as the mathematical models for final selection and checking (by evaluating the servomotor's thermal energy dissipation, and servomotor's internal and external maximum operating temperature). Second, the experimental results have been used to validate the assisted simulation for structural and functional optimization of industrial robot's NC axes based on both servomotor and drive's thermal behavior analysis, performed in the thesis by means of a dedicated commercial software package.

Abstract: The laser beam drilling is generally included in the larger group of laser beam machining methods based on the material removal. The problem addressed in this paper referred to the laser beam drilling of test pieces made of Plexiglas. Some theoretical aspects were highlighted by analyzing the physical effects developed in Plexiglas by the laser beam action. Experimental research was developed in order to highlight the influence exerted by the duration of the CO₂ laser beam action on the Plexiglas in obtaining blind and through-holes. Empirical mathematical models and graphical representations allowed formulation of some remarks concerning the results of experimental research.