This paper presents research on the impact of printing speed on the strength of a manufactured object and is the next stage of the author's research on the impact of technological parameters of 3D printing on the strength of printed models. The tested universal specimens were printed using the FDM (Fused Deposition Modeling) method from PLA (polylactic acid, polylactide). The paper presents the maximum breaking force of the samples and the time of printing samples depending on the printing speed, which varied from 20 mm·s−1 to 100 mm·s−1. The research indicates that the strength of samples decreases with increasing speed. In the range of 50-80 mm·s−1, the strength of the specimens remined at a similar level, however, above 80 mm·s−1, it decreased significantly.
This paper presents first short characteristics of underdeck corrosion process as well as a problem of its monitoring. Next is described an acoustic emission (AE) method elaborated by Department of Ship Technology, Quality Systems and Material Engineering, Gdańsk University of Technology in cooperation with partners of CORFAT project realized within 7th EU Frame Program. Further are presented short characteristics of the emission process, used measuring instrumentation of Vallen Systeme GmbH, as well as TESTER, corrosion testing device, and a corrosion solution used in the tests. Finally, results of the tests performed on selected marine units, are presented.
Dominik Sankowski, Marcin Bakala and Rafał Wojciechowski
The good quality of several manufactured components frequently depends on solidliquid interactions existing during processing. Nowadays, the research in material engineering focuses also on modern, automatic measurement methods of joining process properties, i.a. wetting force and surface tension, which allows for quantitative determination of above mentioned parameters. In the paper, the brazes’ dynamic properties in high-temperatures’ measurement methodology and the stand for automatic determination of braze’s properties, constructed and implmented within the research grant nr KBN N N519 441 839 - An integrated platform for automatic measurement of wettability and surface tension of solders at high temperatures, are widely described
Advances in technological development, since the 1990s, has been associated with the development of two basic domains of knowledge: information technology and material engineering. The development of material engineering is directly related to composite materials. One group of composite materials are fibre-reinforced composites. Due to their unique properties, they are used in various fields of engineering sectors. Composites reinforced with glass fibre (GFRP) are the second most commonly used composite after carbon fibre reinforced composites (CFRP). GFRP in many cases can replace traditional structural materials, which are usually made from metal. Of course, this material is exposed to damage both in production and operation phases. One method of non-destructive testing that effectively identifies defects in GFRP is active optical thermography. In this method, for thermal stimulation of the tested material, various types of heat sources are used for example: heating lamps, lasers etc. This article analyses the influence of the characteristics of the thermal optical sources on detection of typical defects in GFRP.
Valentin Petrescu, Florian Popescu and Alina Gligor
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3D NUMERICAL ANALYSIS OF HEAT EXCHANGE IN BUILDING STRUCTURES WITH CAVITIES
In the paper, the heat transfer inside a building block with cavities is analyzed and a brief overview of the relevant physical problem is given. The equations governing the heat exchange processes are presented and a numerical model is derived with the help of ANSYS software. The role of radiation and convection inside the cavities is emphasized throughout the work. The results show that in such cavities the radiation mechanism of heat transfer is dominant. The authors also examine the dependence of the effective heat conductivity on the properties of clay material. Using the numerical model, attempts have been made to improve the heat resistance of a building block. Possibilities of practical application of numerical modelling in the heat insulation material engineering are discussed.
Vlastimil Moni, Petr Klouda, Tomáš Miletič, František Helebrant, Luboš Donát, Jan Blata and Michal Řehoř
The expense of restoring of excavators cutting bodies is increasing these days in the Most Basin area, primarily the replacement of tooth because of abrasion expense. The main reason is the complicated geological situation of overburden rocks, first of all the occurrence of sands and hard structures in the overburden cuts rocks in the deep horizons of open pit mines. Description of the first part of the strength analysis and applicability of 3D models of the tooth serial number 2673 and the tooth ESCO Super V39VYH with application of finite element method (FEM) is the main topic of this article. This research is the stage of the project based on optimisation of the shape and primarily the material used during manufacturing of the mining and ground machines cutting bodies in concrete mining conditions. The research is going on with application of new knowledge in the field of material engineering, metallurgy, cryogenic and nanotechnology. The main target is the increasing of mining process efficiency and the mining machines key node lifetime. Research of the excavator tooth parameters described in this article is very important part of the research.
Musaddaq Azeem, Asif Javed, Hideaki Morikawa, Muhammad Tayyab Noman, Muhammad Qamar Khan, Muhammad Shahid and Jakub Wiener
Polyester is a popular class of material used in material engineering. With its 0.4% moisture regain, polyethylene terephthalate (PET) is classified as highly hydrophobic, which originates from its lack of polar groups on its backbone. This study used a parallel-plate nonthermal plasma dielectric barrier discharge system operating at medium pressure in dry air and nitrogen (N2) to alter the surface properties of PET fabrics to increase their hydrophilic capabilities. Water contact angle, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) were utilized to analyze any effect from the plasma treatment. The wettability analysis revealed a reduction in the contact angle of more than 80% within 5 min for both discharges. Scanning electron microscopy analysis showed no microscopic damage to the fiber structure, guaranteeing that the fabrics’ structural integrity was preserved after treatment. AFM analysis showed an increase in the nanometer roughness, which was considered beneficial because it increased the total surface area, further increasing the hydrophilic capacity. XPS analysis revealed a sharp increase in the presence of polar functional groups, indicating that the induced surface changes are mostly chemical in nature. Comparing that of untreated fabrics to treated fabrics, a Increase in water absorption capacity was observed for air-treated and N2-treated fabrics, when these fabrics were used immediately after plasma exposure.
Thermal-insulation properties of textile materials play a significant role in material engineering of protective clothing. Thermal-insulation properties are very important from the point of view of thermal comfort of the clothing user as well as the protective efficiency against low or high temperature. Thermal protective clothing usually is a multilayer construction. Its thermal insulation is a resultant of a number of layers and their order, as well as the thermalinsulation properties of a single textile material creating particular layers. The aim of the presented work was to investigate the relationships between the thermal-insulation properties of single materials and multilayer textile packages composed of these materials. Measurement of the thermal-insulation properties of single and multilayer textile materials has been performed with the Alambeta. The following properties have been investigated: thermal conductivity, resistance and absorptivity. Investigated textile packages were composed of two, three and four layers made of woven and knitted fabrics, as well as nonwovens. On the basis of the obtained results an analysis has been carried out in order to assess the dependency of the resultant values of the thermal-insulation properties of multilayer packages on the appropriate values of particular components.
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IŽDINSKÁ, Z., NASER, A., IŽDINSKÝ, K.: Materialsengineering-Materiálové inžinierstvo. - Vol. 17, No. 1 (2010), p. 11-16