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The need to determine actual fiber volume ratio of the real composite part manufactured in the semi-closed mold led to application of the alternative procedures than the widely used Burn-off method. The low cost one, which is required preferably by any manufacturer, is based on Archimedes law (AL) and the most accurate determination of volume of displaced water. The more complex method which is based on the reverse engineering approach where the 3D scan technique is used to determine the volume of the part. Both are nondestructive methods. And finally the last method mentioned in this study is a sophisticated optical visualization technique and Figure post-processing by mathematical software (it was used NIS Elements and Wolfram Mathematica). Figures for mathematical post-processing were taken using light optical microscope (LOM) and scanning electron microscope (SEM). While better contrast between matrix and fibers is achieved in case of composites filled by transparent fibers, SEM figures provide better image contrast for non-transparent fibers.
The AL and 3D measurement methods are very precise and suitable for orientative control during production, but they give only an average values of the fiber volume ratio in whole product. The mathematical post-processing of image is suitable for laboratory designing of composite part. It is destructive investigation method and image thresholding is time consuming, but on the other hand image processing gives the resultant fiber volume ratio in a particular cross section of the part. That makes the technique a good tool to find the weakest place of the part in meaning of the mechanical properties.

This research paper deals with an influence of reinforcing polymer ribs on selected mechanical properties of sandwich structures. Reinforcing epoxy ribs are produced directly by the vacuum infusion technology when resin during its flow fills the prepared holes in the polymer core. In the experiment, two rib sizes (diameters) were tested as well as two variants of hole patterns on the core surface. The possible influence of the core material was evaluated on two core material types with different thicknesses. In addition to the observed mechanical properties observed, the types of failure and changes of the sandwich panels weight were also characterized. The obtained results show a significant increase in flexural strength and stiffness of all types and shapes of prepared reinforcing polymer ribs. Positive effect was also observed in the case of edgewise compression load capacity.

This article deals with the thermal stability of the PTFE coating and the composite coating composed with the PTFE matrix and titanium dioxide particles. These coatings have application in production of aluminium moulds in the automotive industry, specifically in the vulcanization of rubber materials. The first type of coating (PTFE coating) is already applied in the production and thanks to its application on the Al mould surface, the maintenance interval was increased by up to 400% compared to the uncoated state. Vulcanization of rubber compounds usually take place at a temperature 150 - 170°C. This temperature can be increased after addition of additives to a temperature 220°C. For this reasons, there is the research focused on degradation of these coatings at various thermal loads. Thermal stability was tested on coatings - PTFE a PTFE + TiO2 - applied on aluminium substrate (type Al - Si). Experimental samples were loaded at temperatures 150°C, 200°C, 250°C, 300°C, 350°C, 400°C a 500°C at a time 30 minutes and 60 minutes. The samples after thermal load were performed to tribometric analysis, and to the surface roughness measurement of selected parameters. The samples were also evaluated from the point of view of surface morphology and state of the surface with SEM and EDS analysis.

. Spot welding is a commonly used technology in practice to join metal material. It applies to all types of production, mass, series and piece production. Its biggest advantage is the high productivity, with which it is possible to weld. As with other welding methods, the cleanliness of the welded surfaces is important. The aim of the tests performed was to evaluate the influence surface treatment on the firmness of the test specimens of spot welds. The test specimens were made from steel. Welding was done while using manual clamp welders. Four sets of metal sheets were prepared before the welding, with different surface treatment - surface without treatment (original, not degreased), only degreased, grinded and degreased, blasted and degreased. The test specimens were made using different welding times, from 0.1 sec. to 2.0 sec. Then, they were loaded on a universal test instrument until destruction. All measured values were statistically evaluated. The evaluations show that although it is possible to weld sheets without surface treatment, it is not recommended. There is no statistically significant difference between the results of other types of pre-treatments.

The iron causes the formation of intermetallic phases in Al-Si alloy. These phases are most often present in the form of Al5FeSi phase platelets and degrade alloys properties, especially mechanical. By applying additive elements - correctors (e.g. Mn, Cr, V) we can achieve the change of intermetallic phases morphology to more suitable form. Presented article deals with the influence of manganese as iron corrector on AlSi7Mg0.3 alloy microstructure and length of Al5FeSi phase. The increasing the manganese content reduces the length of Al5FeSi phase, but with higher contents, mainly the skeletal formations was observed instead of the Al5FeSi phase. The evaluation of mechanical properties didn't confirmed, that the higher amount of iron in the alloy significantly decreases a mechanical properties even with the use of a corrector.

The main topic of the presented paper is review of the mostly used tools in designing of composite structures. Consequently, practical demonstration of their using has been done on an example of a bending test of the wound, thin-walled composite rod. Further methods of definitions individual layers and the associated interface properties using the cohesive elements, based on that it is possible to detect arising delamination. Unlike conventional approaches, there is not possible to define a definite strength limit or nonlinear plasticity. For this purpose, the so-called failure criteria exist for the composite materials. In this way, it is possible to describe the real stress/ strain situation for the composite parts. Composite materials, due to their anisotropy, offer by suitable layer composition the possibility of significantly improving the efficiency of material utilization. Just in such cases, some advanced numerical tools like e.g. DOE, response surface and genetic algorithms could be used. Based on the above described methods, the experimental results of the carried three point flexure test have been numerically verified and the properties of the tested rod optimized.

In the case of constructing combustion engines, it is possible to use not only classical crank mechanisms, but also non-conventional mechanisms. Article deals with description of non-conventional piston mechanism with ring, which may be suitable for special applications in the engineering industry. Investigation of kinematic parameters of the machines is important step to know its basic movement behaviour, and from this, it is then possible to create the alternate dynamic model or force analysis. The aim of this analysis is to investigate the movement of several points on a wobble plate. The next section will deal with the analysis of waveforms of the piston stroke depending on connection with a specified point on wobble board.

One of the basic principles of railway vehicles is their carrying and guiding. In the contact pair of a wheel and a rail, one body is rolled on the surface of the other part and all main forces are transmitted in this contact. Contact between wheel and rail is also important from an economic aspect as it is related to the wear of the track rails and the wheel thread itself, including the wheel flange, and has caused the necessary maintenance of the track and the vehicles themselves. Therefore, our article focuses on simulating the influence of a flat wheel on changes in wheel forces. The model was created in the CATIA program and was consequently imported into the SIMPACK program, which was followed by analysis of the passage of the vehicle along the track. In the simulation, we considered an ideal track and a wheel flat on the right front wheel. We also plan to work with these results by adding and comparing them with results obtained by applying irregularity to our ideal track.

Two methods of fabrication of Al-Mg-Sc alloy are compared - conventional casting followed by cold-rolling and twin-roll casting. To the advantages of twin-roll casting belong the lower material and energy requirements during the production. However, twin-roll cast material exhibits different initial microstructure and routes established for conventionally cast materials cannot be applied. In twin-roll cast material the distribution of primary particles is more inhomogeneous - they form segregation near the center and edges of the sheet and their average size is smaller. On the contrary, the average sub-grain size is much higher in the twin-roll cast material.

Machining has long been the most used technology in manufacturing processes. On the other hand, new materials are being developed or new ways of preparing them are being developed. One of such materials is High Speed Steel (HSS). The article deals with experimental study of a cutting tool durability prepared via powder and casting metallurgy. Durability of cutting tips produced from HSS Vanadis 30 (SN 41 9830) were tested during the short-term radial tests. Three modifications of the HSS steel were studied, while two types of them were prepared via powder metallurgy and the third one was made via casting metallurgy. The measured values were statistically processed and submitted to the remoteness testing according to Grubbs. The results have shown that the most appropriate material for production of cutting tips, ranked based on three studied steels from the durability point of view, appears Vanadis 30 produced via powder metallurgy alloyed by component Nb.

Polymer composite honeycomb sandwich panels (PCHSPs) are used in many sectors of industry, such as in aerospace, defense and public transport factory. Sandwich panels consist of two facing skins and the core. Products of all industry sectors have to meet requirements on their dependability. This research paper deals with a proposal of the most appropriate methodology for dependability testing of PCHSPs products used in transport industry. Dependability is a global concept that includes terms such as availability, reliability, durability, maintainability, supportability, etc. The experiments have shown S-N curves with damages and without damages of PCHSPs. An important part of dependability is to be fonded the limit states of the studied object, which are for PCHSPs are characterized by fiber cracking and (core) delamination. Dependability evaluation consists of analysis and tests. For every test, it is necessary to be developed its test plan. Facing skin components of the sandwich panels may particularly be damaged. There are several methods of non-destructive testing, which can be used to determine the damage of facing skins of sandwich panels. Infrared thermography (IRNDT) is one of them. IRNDT utilizes thermo-physical properties of the materials, including thermal diffusivity.

Surface modification of polystyrene and polyethylene naphthalate by a KrF pulse excimer UV laser under the angles of incidence of the laser beam in the range of 0 to 60° with a step of 7.5° was studied in this paper. The influence of the angle of incidence on the period of the resulting surface structures and the modified refractive index of the substrates was determined with all the other parameters of the laser radiation held constant. All data was acquired on the basis of surface analysis. Atomic force microscopy was used to study the morphological changes in the laser treated samples and to determine the period of the ripple-like surface structures, from which the modified refractive index was subsequently calculated. Selected samples were metallized with gold with aim to determine the influence of patterned substrate on consequently formed nanolayer. These information may be useful for consequently constructed SERS system based on ripple-metal system.

Rapidly solidified AlFe7Mm4 ribbons were prepared by melt spinning process. The ribbons were composed from super saturated solid solution of alloying elements in Al matrix, stable intermetallic phases and metastable quasicrystalline phases. Both metastable phases can potentially provide self-healing properties to the material - super saturated solid solituon by precititation and quasicrystals by decomposition to stable phases. Key problem of processing such materials is to preserve the microstructure of rapidly solidified material during its compaction. Spark plasma sintering enables powder solidification in very short time - in range of few minutes. This article describes the best way of raidly solidified ribbons before SPS compaction to obtain bulk material. The ribbons were solidified in the initial state and after cryo-milling. Ball-milling before of rapidly solidified ribbons was also tested. Vickers hardnes HV0.01 was also evaluated. Cryo-milling was chosen as an optimal pre-treatment before compaction by SPS.

This article investigated the influences of the cutting edge microgeometry on durability. Combination of cutting edge geometry, cutting conditions and the properties of the machining material all influences the cutting process. It is necessary to modify the cutting edge to increase of cutting tool life and cutting process efficiency when machining materials, which are difficult to machine, such as Inconel 718 nickel alloy. Increasing the cutting tool durability and resistance are the main goals with difficult to machine materials. The cutting edge radius is the main parameter, which is modified during the experiment described in this article. After modification of the cutting edge radius, the cutting tools are tested when milling Inconel 718. Twelve cutting tools are tested. The radii of the cutting edge of these cutting tools are 15 μm, 20 μm and 25 μm. Drag finishing and abrasive water jet are used to modify the cutting edge. The cutting tool durability was evaluated by wear measurement on the clearance surface on the cutting tool. The critical cutting tool wear was 150 μm. Linear type of wear (VBB) was measured on a Multicheck optical microscope.

Titanium aluminides with various amounts of aluminium were prepared by Self-propagating High-temperature Synthesis (SHS). Ti-20 wt. % Al, Ti-38 wt. % Al and Ti-63 wt. % Al were chosen according to Ti-Al phase diagram, because these chemical compositions represent Ti3Al, TiAl and TiAl3 phase, respectively. The effect of the amount of aluminium on the combustion temperatures, microstructure and phase composition was studied. Heating of compressed samples was observed by optical pyrometer to determine exothermic reaction which is associated with SHS reaction. It was found that reaction temperatures increased with increasing addition of aluminium as well as reaction time and the start of ignition. The expected dominant phases were determined in all systems after SHS reaction. However, other phases accompanied their formation. The largest variety of phases formed in Ti-38 wt. % Al system.

In metals processing, 3D printing is a relatively new technology. It brings many advantages into production thanks to its additive principle on which it is based. One of the intended applications of 3D printing is especially regenerative medicine and aerospace industry that require products of very complex shapes. In these domains, titanium along with its alloys belongs among the most frequently used materials. When printing a Ti6Al4V alloy, very high cooling rates during the successive laser melting of an initial powder material result in high internal stresses. These stresses are followed with several problems, such as low material plasticity, possible cracking of built products, deformations of thin parts and similarly. Therefore, after the 3D printing process itself, a thermal treatment is applied to relief the stresses. The object of this study is to show the influence of atmosphere in thermal treatment process on the quality of final parts. The results show that oxygen absence is essential in terms of material plasticity.

This article deals with the experimental grinding of cemented carbide cutting tools. Several carbide milling tools with the same geometry were ground under the different grinding conditions and strategy described in this research. The main aim is to determine the influence of the grinding process on the quality of the cutting edge. Different grinding conditions and strategies were used in grinding of the primary radial relief on the peripheral cutting edge. The cutting edge was analysed after grinding by an optical-scanning device and an electron microscope to determine the quality of the cutting edge and radial relief face of the tool. EDX analysis was used for the chemical characterization of the ground surface. The chipping of the cutting edge occurred when the grinding feed rate and the wheel spin direction was changed. The influence of the grinding conditions and strategy on the chipping formation was determined. The mean radius of the cutting edge after grinding was also measured. The results of this work will be used for further research and cutting experiments.

During the period of use, there are in the dental implants, the limit conditions of the primary structure and later on its disruption created. The aim of the work was to study microscopic defects in the proposed materials in which the unwanted defects arose and led to early end of the lifetime. It is a dental implant, which had to be prematurely taken from the oral cavity due to limit conditions of the patient pain.
Investigation of chemical elements of dental implant materials has shown the presence of such components, which lead to create undesirable intermediate phases in the structure and therefore the analysis of the implants has been complemented by microscopic evaluation.
There are on the part of the dental implant, which interacts with a bone of a patient, the corrosion destruction of the material was visually observed. For this reason, the character and thickness of oxide layer, that negatively affects the living cells of the organism, was also examined on more detail.

The aim of this paper is to compare the microstructure, mechanical and fatigue properties of three types of the nodular cast irons - unalloyed nodular cast iron, nodular cast iron alloyed by Si and Mo and nodular cast iron alloyed by Si and Cu. For all the types, microstructure, mechanical properties and fatigue properties were investigated. Microstructure of the specimens was evaluated according to STN EN ISO 945 and by automatic image analysis. The image analysis system NIS Elements, interfaced with the light microscope, was used for the evaluation of the shape factor, equivalent diameter of graphite, count of graphitic nodules and content of ferrite. The mechanical properties were evaluated by the tensile test, impact bending test and Brinell hardness test. Fatigue tests were realised at sinusoidal cyclic push-pull loading (stress ratio R = -1) at ambient temperature (T = 20 ± 5 °C). They were carried out in the high cycle fatigue region (from 105 to 107 cycles) at frequency f ≈ 75 Hz using the fatigue experimental machine Zwick/Roell Amsler 150HFP 5100. The relationship between the amplitude of stress σa and the number of cycles to failure N, as well as the fatigue strengths, were determined.

The firefighting ladders belong to essential tools used by members of the Fire Rescue Service of the Czech Republic. In the past, wooden ladders were used although their applicability and duration were strongly limited. Formerly used wooden ladders were then replaced with steel-made. However, the weight of such ladders caused big problems during the firefighting and therefore an aluminium ladders made of AA 6063 alloy are nowadays used. The ladders are however susceptible to thermal effects during firefighting and may reduce its mechanical properties. The present paper reports the microstructural change of two different ladders both made of AA 6063 alloy when annealed at different temperatures and duration. Both the ladders showed almost similar behaviour reaching the highest decrease in theirs TYS and UTS when exposed to a temperature of 400 °C reducing its initial TYS of 229 MPa for ladder no.1 and 237 MPa for ladder no.2 down to 71 MPa and 81 MPa, respectively.

Integral stringer panels can attain weight reduction in primary aircraft structures, but do not contain the physical barriers for a fatigue crack growth. One of the promising techniques for prolonging a fatigue crack growth is bonded crack retarders made of materials with high stiffness. An experimental study was done on two specimens with different geometries. High strength bonded straps made of corrosion resistant steel AISI 301 were adhesively bonded to Center-Cracked Tension (CCT) specimens made of aluminium alloy 2024-T351 and fabricated by a high-speed machining process to promote fatigue crack growth retardation. Specimens were tested at a constant amplitude load. The study concludes that the fatigue crack growth life can be significantly improved. Experimental results were compared with a prediction based on the VCCT technique and the NASGRO equation.

When a micro-hole of high aspect-ratio is required, in addition to machining problems, special attention should be paid to controlling the quality of the manufactured products. Dimensional and surface metrology in the field of micromachining can be as critical as machining itself, therefore several new measurement methods have been developed. However, many of these methods suffer from application limits when used in the case of a deep hole. Replication can be a useful approach, which has well-proven validity in the time-consuming case of the sectioned hole. The method of through replicas, to be pulled out of the unsectioned hole, still needs verification.
In the present paper, the surface roughness of deep small electrodischarge drilled holes is measured, and the effectiveness of the use of both open- and through-replicas is evaluated, versus direct measurements on the micro-drilled surfaces. Through-hole replicas, by means of injection and extraction of a silicone, are proven reliable for reproducing the surface morphology of holes down to 0.8 mm diameter with an aspect ratio of 12.5. The findings show that the operative range of the considered techniques may be extended with respect to the previous cases mentioned in literature

This paper presents numerical simulation of blanking process using finite element method and comparison of results obtained by analytical solution commonly used in engineering practice. The problem was modeled using axial symmetry. Experimental measurement was used to create multi-linear plastic material model. Results of numerical simulation were used to create history of blanking force vs. tool displacement.

The paper deals with the strength conditions assessment of new design of modern railway bogie through FEM analysis. The bogie, which was developed as part of European structural funds project, is characterized mainly by better dynamic properties while driving on the track, higher safety against derailment and lower negative effect on the track (reduction of wear). For analysis of bogie frame, there has been created a substitute simulation model. Results from calculations and prototype tests prove, that investigated design of new construction satisfies strength conditions.

The main aim of this scientific article is to assess the contribution of surface layers by determining the experimental investigation and practical measurement of surface roughness Ra and selected components of cutting forces while external turning of AlCu3MgMnPb aluminium alloy. In these experimental procedures, a number of turning tests have been carried out by using a universal lathe machine tool and cutting forces and surface roughness scientific measuring devices. These realized measurements have been successively investigated and experimentally verified with the prepared trial samples. These presented experimental measurements describes the authors investigation of cutting forces while turning by the piezoelectric dynamometer Kistler type 5001 and surface roughness Ra with the Talysurf CLI 100 measuring device. This scientific article, together with measured and calculated results, is the fundamental that will help to optimizing the quality and used other technological and cutting parameters of turning technological process.

The surface quality of ceramic items produced via powder injection moulding (PIM) at processing conditions varying in injection moulding temperature and debinding route is investigated. The analysis is performed on aluminium oxide part design containing complicated rotational areas, where a smooth surface of an internal spiral is a critical quality factor. Surface properties of the final sintered parts are examined with the help of a contactless scanner. Then, the obtained surface roughness data are treated with suitable statistical analytical tools in order to reveal the effect of the processing conditions during the PIM process on the final parts. Relating surface properties of final sintered parts to processing parameters might provide a powerful tool to control particular steps of PIM process.

This article deals with influence of chemical composition on depth of diffusion layers and porosity of compound layers after gas nitriding process. Experiments are focused on utilizing of gas nitriding processes for surface treatment. Gas nitriding technologies were applied to steels C 35 (sample A1), 34Cr4 (sample A2) and steel 42CrMo4 (sample A4), which were subsequently evaluated by electron microscopy, GDOES and microhardness methods. The measurements showed the influences of chemical composition of alloying elements in core of material after chemical-heat treatment process on depth of diffusion and influence of technology on development of porosity. Nevertheless, the main task was the description of the porosity development in compound layer after gas nitriding and the increasing of surface hardness and of the depth of diffusion layer according to chemical composition. Gas nitriding process was applied for increasing of surface hardness of material in depth and improving of mechanical properties. Mechanical properties of tested material were significantly increased.

This paper deals with the preparation, composition and mechanical resistance of inorganic-organic nanolayers with built-in hydrophobic groups through sol-gel synthesis. The components of the nanolayers are 3-(trimethoxysilyl)propyl methacrylate, tetraethyl orthosilicate and hydrophobic chains - hydrocarbon chains in the range of 8 to 16 carbons. The study is aimed at evaluating the mechanical properties of prepared nanolayers with different hydrophobic chains compared to a reference sample without any hydrophobic groups. An abrasion resistance test was performed on several selected nanolayers with the best hydrophobic and antifouling properties. In the framework of the research, nanolayers prepared with polymerization achieved by heating at 85 °C or 150 °C were compared. The best mechanical properties and hydrophobicity of prepared nanolayers was AF12 with a hexadecyl hydrocarbon chain polymerized at 150 °C. These nanolayers are suitable for marine, underwater or any other hydrophobic application results from performed research.

Radiation-induced microstructural defects cause degradation of mechanical properties and a life time reduction of reactor structural components during nuclear power plant operation. The effect of neutron irradiation fluence and flux, neutron spectrum, corrosion environment, etc. on mechanical properties is investigated under the NPP's surveillance programs and additional nuclear material research. The material strength typically increases while ductility and fracture toughness decrease after neutron irradiation. Transmission Electron Microscopy is one of the methods for Post Irradiation Examination (PIE) which helps to understand the material behaviour exposed to different reactor operating conditions. Therefore, such PIE methods are important to develope and optimize. In this study, we introduce the specimen preparation methodology and radiation-induced damage (RID) evaluation of stainless steel SSRT test specimens by the means of Scanning and Transmission Electron Microscopy (SEM, TEM). In austenitic microstructure, Frank interstitial dislocation loops, cavities or voids and radiation-induced precipitates are the dominant RID evolved under neutron irradiation. Futhermore, the material susceptibility to segregation related to the IASCC mechanism is widely studied within 300-series stainless steels. The proper determination of RID size distribution refers to degradation mechanisms in reactor materials. In our research, the RID characterization is demonstrated on the specimens irradiated to ~ 15 dpa in PWR conditions. Distribution of cavities, Frank loops and radiation-induced precipitates were evaluated in bright/dark field kinematical conditions and through-focal series. The nature of cavities, i. e. voids/He or H stabilized bubbles with the size less than 3 nm, was not recognized in the specimens prepared by standard electrolytic polishing method. Radiation-induced segregation in a narrow area up to 10 nm was detected by point STEM-EDS analysis. To evaluate RID size distribution, the automatic image-processing program was developed and compared to the visual analysis. So far, the results were optimized on Frank loops and precipitates and are in a good agreement with the manual processing.

Design and technological development of cutting tools represents a fluent process that combines new knowledge from all usable technical branches with actual needs and development results of component base, production technology and machine tools. The main factors which nowadays accelerate the development of cutting tools are constantly increasing demands to improve efficiency and productivity while reducing operation costs, the application of hard machinable materials, environmental protection issues, health and growing demands for greater safety. The article deals with methodology of measurement and evaluation of cutting forces and cutting torque at a special reaming head MT3 from FINAL Tools Inc. Solution of force loading during reaming by these modern tools enable to analyse the causes of cutting tool deficiencies starting from coating suitability up to weaknesses in their design. The article also analyses the significance of the reaming process from the reaming view point using a process liquid, including a tool life analysis combined with the tool wear.