Applied Mechanics and Materials Vol. 827

Abstract: The paper involves the subject and the chosen results of up to now solving of work package “Development of advanced surface treatment of components used in parts of turbines working under the condition of operational temperatures of steam using the HP/HVOF technology of thermal spraying” of the Competence Centre project “Centre of Research and Experimental Development of Reliable Energy Production”. The subject belongs to the field of material engineering and results of solving contribute to fulfilling the main project aim, which is a long time safeguarding of safe, reliable and financially available both classical thermal and nuclear sources of electric power, which consists in extending service life of existing and building new turbo generator blocks. The erosion wear resistance is one of the areas, which were observed. The impact of hard particles on the surface under variable impact angles was simulated in laboratory conditions using an in-house equipment. The wear resistance of selected HVOF sprayed hardmetal and super-alloy coatings was measured and the wear mechanism was evaluated. A strong influence of impact angle on both material volume loss and wear mechanism was monitored. The superior erosion wear properties of super-alloy coatings were proved, regardless the higher hardness of hardmetal coatings.

Abstract: Innovative development and production trends particularly in automotive and aerospace industries significantly influence also design of opening panels assemblies (doors, windows, stiffened panels etc.). New trends show that metal constructions of these modules will be gradually replaced by new material conceptions leading to hybrid plastic material-composite-metal constructions. This fact is logically reflected by methods and methodologies in testing, used both in pre-development, prototype and finally even in batch phase of the development and production. The main topic of the paper deals with presentation of several testing devices and used measurement methods for testing of qualitative parameters of rigidity and strength of both the whole module groups and their fundamental reinforcing components made of composite materials.

Abstract: The monitoring of stiffened composite panels behavior using resistance strain gauges (SG), fibre optic Bragg grating sensors (FOBG) and contactless optical measurements based on digital image correlation (DIC) principle is discussed in the paper. Both the panel structure and different load cases are specified. Mechanical tests include different load-scenarios like static and fatigue loading in compression of reference and impacted panels. The main reason of failure is buckling. The measurements taken from the sensors captured all changes in the buckling modes of the panel. Moreover, they showed a good correlation between FOBG and SG strain measurements.

Abstract: This paper is focused on determination of load sharing in planetary transmission during the test and usual operation. Load sharing is one of examined items in transmission. That is investigation of power flow uniformity through satellites in planetary transmission.

Abstract: In this work the mechanical performance of various sandwich constructions with respect to core material were experimentally evaluated. Sandwich structures were made of glass prepreg and three types of plastic core using vacuum bagging, technology traditionally used for production of parts for transport industry. The aim of this study is to analyze the impact of the core material type and its thickness on bending behavior at different environmental temperatures. Moreover, the effect of core layers compared to one layer core of same thickness was determined. Conducted research provided useful information of bending behavior and showed specific failure modes of individual sandwich constructions.

Abstract: The presented paper introduces the application of the Electronic Speckle Pattern Interferometry (ESPI) technique for measurements of contours of strains and stresses on 3-D surfaces. The paper focuses on three selected applications. Firstly, the methodology for determining the Poisson ratio of a material from tensile tests is described. Secondly, results of calibration verification of a biaxial extensometer used for measurements of shear strain in comparison with the ESPI measurements are presented. Finally, the experimental analysis of stresses in welds is discussed. As mentioned in the paper, the method is very useful for material testing, as well as for measurements on structural parts in service.

Abstract: 3D printed plastic components are nowadays frequently used parts in all areas of industrial sphere. These components are often made by FDM technology. The main advantage of this technology is quick manufacturing process, price and also possibility of producing complex parts. This paper is aimed to the component made by FDM technology from the view of their strength. Specially designed chair was loaded by different force and the maximum load before destruction was measured. Chair was under inspection of two different optical strain measurement systems working on different principles. System PONTOS working on the principle of digital photogrammetry and system ARAMIS working on the principle of digital image correlation were used. These systems were used in order to investigate and identify weak places of this chair.

Abstract: Experimental and numerical analysis describes the design of noise removal effect of the friction pair of trapezoidal screw in a special device call Stick-Slip effect. Solution of the problems builds on previous measurements and testing sliding pairs, which was testing in last analysis. The pair worked in the special bath oil, its characteristics is that it does not support the mechanical lubrication. Measurements and calculations showed that it is necessary to enlarge the diameter for 32 kN load trapezoidal screw. This will reduce the contact pressure, which leads to polish the contact surfaces. You then slip together better and are not as easily stick slip effect.

Abstract: This paper analyses the uncertainty of pressure measurements in-cylinder and in injection pipe conducted during the studies of a compression ignition engine. Type A and type B evaluations were used to determine the uncertainties of the results. The results are presented for the engine running on diesel or bio-fuel and operating under full load conditions. The results of normality tests provide grounds to reject H0 in some cases. Slightly lower standard uncertainty of the maximum pressure measurement calculated using type A evaluation were acquired for the engine running on bio-fuel.

Abstract: This article includes the brief analysis of the problems in area of long-time process loading measuring in service and also explains the processing of the measured strain state without re-calculation the strain into stress in detail and presents the results from the installed in-time monitoring system of the fatigue damage in a real operation of gas pipelines.