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This paper aims at the problems of poor motion continuity and abrupt acceleration of small diameter deep well rescue robot in the process of motion characteristics analysis. According to the movement characteristics and structural forms of the grasping mechanism and bracket mechanism of the deep well rescue robot, the finite element analysis of the key mechanism is carried out based on Hyperworks-Optistruct solver, according to the analysis results, the specific parameters to be optimized are obtained. And the topology optimization of the key mechanism is carried out, the optimal design scheme of clamping mechanism and bracket mechanism of deep well rescue robot are obtained. The optimization results show that on the premise of meeting the strength requirements, the grid density distribution law is obtained. According to the variation law of lightweight curve, the overall weight of grasping mechanism and bracket mechanism decreases obviously. The whole optimization process is completed and the final optimization result is obtained.

This paper describes experimental measurements of travel rollers on a polyurethane thread. This exper-iment took place at the CTU Faculty of Mechanical Engineering in the laboratory of the Department of Design and Machine Parts. The experiment was performed within the project of a lightweight type of sampler, designed by a team of collaborators from our institute for OK Servis BioPro, s.r.o. For the new-ly designed type of sampler, it was necessary to determine the operation of a newly designed grain sampler. The load of the rollers is different in each environment. This paper presents the average values from the measurement, including its evaluation. Moreover, the paper compares different temperatures that can be achieved in the practice. Negative temperature values were not performed, as this meas-urement would be expensive and inefficient.

The article deals with the wear of the blades of the delimber device of harvester head. An input analysis of the materials of the fixed knife and movable arm parts was performed. It consisted of chemical analysis, evaluation of microstructure and hardness measurement by HRC and HB methods. The original welded joint was analyzed, which ensured the connection of the blade and the fixed, resp. movable arm mechanism. Based on the findings, two blade replacement solutions have been proposed. The first was the application of hard metal by an OK 84.58 electrode and second use HARDOX 450 by welding with a fixed part or a mechanical gripping with screws. This was recommended based on previous research at the Faculty of Technology. The hardnesses of the original blade material were compared with the proposed solutions. The correctness of the proposed methods will be verified in the future and in operation.

The effects of punch radius, deep-drawing speed and amplitude on the friction coefficient were studied on an improved drawing-bulging friction coefficient testing device on basis of ultrasonic vibration. A contact friction model based on the tribology theory of adhesion and plowing was constructed and used to explain the friction reduction phenomenon of applied out-of-plane normal vibration. The results show that the friction coefficient decreases with the increase of ultrasonic vibration amplitude. At the same deep-drawing height, the friction coefficient decreasing rates at amplitude of 7.8um and 10.1 um on the deep-drawing speed of 0.1 mm/s and 10 mm/s, were 6.7% and 18.8%, respectively. the friction coefficients at the punch radii R0.3 and R1.5 declined from 0.18 to 0.13 and from 0.12 to 0.11. The friction coefficients of thin specimens were larger than thick specimens whether ultrasonic vibration was applied or not. The average friction coefficient from theoretical modeling (μ_v) was smaller than the friction coefficient without ultrasonic vibration (μ_0), and the relative friction coefficient ratio declined with the rise of amplitude and was inversely proportional to time.

Hard-to-machine materials conclude a variety of materials. In this group of materials are high-strength, hardness-resistant steels, such as austenitic steels, but also non-ferrous alloys with high cor-rosion, heat resistance and strength based on nickel, titanium or cobalt, etc. For machining of these materials, it is necessary to choose suitable tools. The improper cutting tool can cause an increase in geometric inaccuracies, rapid wear, etc. Cutting material is an important factor during designing of cutting tools. A combination of a proper cutting tool with the trochoidal milling can reduce maching time, extend tool lifetime and reduce production costs.

High deposition rate with minimal heat input is one of the primary emphases in wire arc additive manufacturing. This study aims to determine the optimal input parameters of micro plasma welding for single-layer deposition. The stability of a single layer is crucial as it serves as the foundation relative to the deposition of layers to avoid a discontinuous multi-layer material. The study focuses on wire feeding speed, welding speed, and pulse and their interaction between the input and response variables. Based on the study, the regression equation between the three key parameters and the response using the Box-Behnken Design response surface methodology was proposed. The outcome demonstrates that the op-timized sample deposition produces a smooth surface appearance with no apparent defects.

The issue of accident analysis in relation to railway vehicles of urban mass transportation is highly accentuated at the moment. In terms of designing the frontal area of trams, adequate attention should be paid to the optimal front end design in order to reduce the risk of pedestrian injury. The properly used shape and materials can minimize the consequences of the pedestrian’s contact with the vehicle, or the eventual dragging of the pedestrian under the vehicle. For the front end to be tested and optimized, it is necessary to develop and validate a pedestrian model for performing calculations even in the design preparation stage. From a historical perspective, impact tests and pedestrian protection were not paid significant attention. There should also be a methodology for data collection and evaluation across the public transit company. The data collected within the Czech Republic is inconsistent and hard to analyze. At the beginning of our research, we addressed the question of which dummy configuration with respect to the tram is most appropriate for our crash tests.

The paper presents the results of experimental work on the assessment of 3D geometry of surface stereometry obtained as a result of Water Jet (AWJ) water-abrasive beam cutting using an Eckert Opal WaterJet COMBO hydro-abrasive cutter. Studies of geometric structures were conducted using the Alicona Infinite Focus microscope. The article analyses selected spatial roughness parameters of the multilayer structure surfaces combined as a result of the vulcanization process with an aluminium alloy surface. The results of the research work are summarized in the technological function of the WJ cutting conditions, such as the cutting speed and the mass flow of the abrasive material.

Nowadays, the tendency to survey and accelerate technological processes in order to increase produc-tion efficiency on the one hand and to reduce the ecological impact of production on the environ-ment on the other hand is increasingly prevailing. These aspects encourage both the applilcation of mathematical modelling of production processes and utilization of new material types ensuring suffi-cient strength and ductility while reducing the overall weight of the final asembly. This paper focuses on investigation and evaluation of the mechanical properties of the material under plane shear stress conditions. Specifically, it concerns the testing of a dual-phase high-strength steel DP500 (designa-tion according to EN 10346) having structure based on a ferritic-martensitic matrix. The test material is loaded by means of a testing machine with a continuous static load and condition of the plane shear stress is achieved due to the geometry of the test specimen (ASTM B831). In the experimental part of this paper, plane shear tests are performed to determine the basic mechanical properties and stress-strain characteristics of the material with respect to the given loading conditions. These deter-mined parameters and material characteristics can be further used as important input data to improve results of the numerical simulations regarding the aspect of metal forming technologies – basically stamping process.

The continuous development of construction due to the great needs of society and industry, the need to build newer and more durable buildings have meant that scientists all the time look for new opportunities to improve the quality of materials used in this field. Above all, concrete, as material commonly used in construction, has been the subject of research for many years in order to improve the properties. Already in antiquity there were the first attempts to modify the building material with fibers. Initially, they were organic fibers. However, the first patent dates from 1874, when A. Bernard patented the idea of strengthening concrete with steel filings [1]. Then, attempts were made to strengthen the concrete with long steel fibers, which was done by H. Alfsen in 1918. Further researches led N. Zitkiewic to test the strength and impact toughness of concrete with the use of pieces of mild steel wire [2]. Steel fibers in concrete were used for the first time by Romuladi and Baston in 1963. In the paper a comparative analysis of selected mechanical properties for concrete and fiber-reinforced concrete, e.g. compressive strength and Young's modulus, was presented. It was checked how the value of Young's modulus and the compressive strength of concrete change depending on the content of steel fibers. Three types of samples were tested: 1 - concrete, 2 – fiber-reinforced concrete containing 0.25% of steel fibers, 3 – fiber-reinforced concrete containing 0.50% of steel fibers. As the analysis has shown, the greater number of steel fibers is not directly proportional to the increase in its compressive strength or the value of Young's modulus.

The article deals with new types of coatings and their mechanical properties. CTRN and CRONAL are newly developed coatings intended for active parts of forming tools. Their behavior and mechanical properties are still under investigation. Coatings are used for functional components in various areas of industries, their de-velopment is constantly in process. The aim of the study and the experimental solution provides a compari-son of the mechanical properties of the new coatings with the well-known coatings DLC, TiN and TiSiN. The aim of the work was to perform an analysis of CTRN and CRONAL coatings and compare their me-chanical properties with other coatings. We chose the methods of nanoindentation, hardness measurement, scratch test and layer roughness. The results will allow easy determination of the proper coating for a suitable material. The results present the specific functionality of the individual coatings.

The article deals with a possibilities of an enhancement of functional properties of highly stressed components by specific combination of surface technology. Two surface technologies such as plasma nitriding and laser shock peening were selected for the experiment. Those technologies were applied upon steel 42CrMo4 frequently utilized in manufacturing of strained components. Properties obtained by applied surface technologies were tested by following experimental methods. The chemical composition was verified by optical emission spectrometer Tasman Q4 Bruker. The surface morphology was inspected by scanning electron microscope TESCAN MIRA 4. The microstructure of heat treated as well as of nitrided specimens was observed by opto-digital microscope Olympus DSX500i. The microhardness profiles were measured by microhardness tester LM247 AT LECO. The friction coefficient was tested on tribometer Bruker UMT 3 TriboLab. For an assessment of the surface wear resistance the profilometer Talysurf CLI 1000 and Contour GT were utilized. The experimental results show that although the proposed surface technology combination manifests itself to be disadvantageous, both technology LSP, as well as plasma nitriding, applied separately, can lead to a significant wear reduction.

This paper describes some tools usable for quality control in plastic injection moulding. The introductory part presents tools for quality management, the use of which is demonstrated in the next part using a practical example. The selection of suitable methods was based on proven methods for quality management. They were selected to work in synergy. The author's contribution is the modification of the PDCAI method, which was enriched by another step, namely, innovation. The last part of the article presents is a demonstration of FMEA, Ishikawa diagram, and Pareto diagram.

The quenching and partitioning (Q&P) process is an advanced method of heat treatment of high-strength steels. The resulting properties of Q&P-processed steels are dictated by their microstructure which consists of tempered martensite, fresh martensite and retained austenite (RA). These phases arise from individual steps of the Q&P-process. An important step is stabilization of retained austen-ite because RA raises ductility to above the levels found in conventional steels upon quenching and tempering. If the desired stability of RA is to be achieved, Q&P processing must not initiate compet-ing processes associated with carbide precipitation or austenite decomposition into bainite-like mi-crostructure. Yet, it appears that the very decomposition of austenite into bainite is an accompanying process that takes place at the partitioning stage, the stage which plays an important role in terms of mechanical properties of Q&P-processed steels.

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.

The works deals with a study of fillers influence on chosen mechanical properties of polyamide and the given influence was investigated by using of atomic force microscopy (AFM). Atomic force microscope NT-206 in a complex with control and image processing software is intended for measurement and analysis of surface microrelief and submicrorelief, objects of the micrometer and nanometer range with high resolution. Using AFM it is possible to scan spectroscopic curves that show dependence of composite action force of the probe and surface of the sample on distance between them - they are curves of approach /moving off. In presented measurements by using of spectroscopic curves, the homogeneity and ratio of Young's modulus for polyamide samples were evaluated. For each sample, the curve was created by using of five different places - points. We employed the general approximation and Snedonn's formula for analysis of data and calculation of Young's modulus off complete rake curve. The Sneddon's model gives the relationship between load gradient dP/dh and Young's modulus E.

This paper presents a development and design of new multifunctional clamping jaws for thermomechanical simulator. In the article there is presented what the thermomechanical simulator is and what is it used for. The article also describes the requirements for the thermomechanical simulator jaws and how they were achieved. All important parts of which the thermomechanical simulator jaws are assembled and used are described in detail. Finally, thermal simulations of the jaws were performed under operating loads. This technical solution is protected as a utility model registered on The Industrial Property Office - Czech Republic.

Laboratory fatigue testing is an important part of the fatigue design of machine components that are supposed to work under cyclic loading. These tests are used to confirm whether the tested component matches the required fatigue life and they also serve as a verification of the numerical calculations. This paper describes a fatigue life testing of a welded steel construction. The testing was carried out in the Regional Technological Institute (RTI) using an electro-hydraulic loading system, which allows realization of the tests simulating a real service. An integral part of the fatigue tests is a pre-scheduled inspection of the crack initiation and propagation. The tested construction was checked using non-destructive magnetic particle testing before the fatigue test and also during and after the performed test. Some cracks were observed, especially in the weld area. The biggest crack had the length of approximately 40 cm. This crack was cut out and underwent detailed metallographic and fractographic analysis to estimate the effect of material purity and quality of the weld on the fracture.

Observation and identification of products of transformation of austenite during austempering, Q-P processing, or quenching and tempering are often challenging. The reason is that the resulting microstructures are typically very fine and provide insufficient contrast between microstructural components. Their analysis requires scanning or transmission electron microscopy which demand rather complex sample preparation procedures and involve high costs of maintenance of microscopes and accessories. However, in-process inspection of products of heat treatment calls for simpler and rapid methods of microstructure analysis using a light microscope.

Biological soft tissue is a non-linear and viscoelastic material and its mechanical properties can greatly affect quality of life. Many external mechanical factors can alter the tissue, for example the tissue of talipes equinovarus congenitus, also known as clubfoot, which is the most frequent congenital deformity affecting lower extremities with pathological changes of connective tissue. In clubfoot, the presence of disc-like mass of fibrous tissue, resembling intervertebral disc tissue, is described to be between the medial malleolus and the medial side of the navicular bone. The clubfoot tissue is often referred to be stiffer or rigid by clinicians, or it is referred to as contracted and less contracted tissue, however relevant evidence about mechanical properties is missing. Therefore, the description "disc-like" is informing only about relative mechanical properties of clubfoot tissue. We aim to prepare methodical approach to quantify mechanical properties of biological tissue with uniaxial tensile stress-relaxation test, in order to help clinicians and scientist to identify precisely the mechanical properties of normal and pathological tissue and their structural behaviour during mechanical testing. In this study, we test and tune the uniaxial tensile stress-relaxation test on biological tissue with high content of connective tissue such as collagen. The model tissue is porcine pericardium. The tissue has clear collagen fibres aligning parallel to the force applied. Modulus of elasticity measured here is comparable to other studies.

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.

The give paper is closely connected with the analysis of the normal force relating to the winding mechanism referring to production or manufacturing of raw tyres. The attention is mainly paid to the calculation of normal force during the manufacturing process when the individual constituents of raw tyre are pressed-in. The dynamic analysis as well as the calculation of the given normal force was done for raw truck tyre. The simulation of the movement and dynamic analysis for the given kinematic conditions as well as appropriate input values were solved in Solid Works - modeling computer program. Courses of normal forces for the first one set and the second one set of winding arms in dependence on lever position are in graphitic form. Based on the dynamical analysis, it can be concluded that, the second one set of winding arms does not have any influence on the quality of the produced car tyre.

Effect of addition of cryogenic treatment to a standard heat treatment of aluminium alloy AW 7075 was tested in this work. Used heat treatment consisted of solution annealing at 470 °C for two hours and precipitation aging treatment at 130°C for 14 hours, 120 °C for 24 hours or natural aging at room temperature for 60 days. One set of samples was processed by solution annealing and aging treatment and the second set of samples incorporated 24 hours long cryogenic treatment at -185 °C between the same solution annealing and aging. Both sets of samples were characterised by tensile testing, notch impact testing, hardness measurement, microstructure analysis and wear and corrosion resistance tests. Obtained results were compared for corresponding processing with and with-out cryogenic treatment. While impact toughness and corrosion resistance were decreased by cryogenic treatment, tensile strength and wear resistance were on the other hand improved.

Customer requirements represent the driving force in the market, dictating the directions of development, production and processing of forged parts. Meeting these requirements is of paramount importance to forge shops as a precondition for their continuing operation and competitiveness. Consequently, optimization of manufacturing operations and their rapid response to market requirements are necessary for the forge shops to survive. However, any production stoppage for optimization results in extra costs. Forge shops thus strive to carry out optimization in as few steps as possible and within the shortest possible timeframe. A viable solution emerges in the form of material-technological modelling which involves laboratory-based optimization taking place away from the forge shop without any constraints on the production operations. This paper deals with selection of a material for a forged part to be controlled-cooled from the finishing temperature to substitute a C45-steel part treated by normalizing. One criterion was that the entire forged part should contain ferritic-pearlitic microstructure.

If failure occurs in gear wheels in a racer motorcycle gearbox, the possible causes are manifold: inadequate material, improper care (poor lubrication, incorrect assembly) or inadequate thermochemical treatment procedure. This investigation focused on spur wheels of chromium-nickel Czech Standard (ČSN) 16720 steel containing 0.18 % C, 0.4 % Mn, 1.5 % Cr, 4.25 % Ni and 1 % W. The steel had been quenched to 60-62 HRC and the case hardening depth was 0.8 mm. The client requested that these wheels have a life of 100 hours. The failure occurred while the wheels were in operation. The fracture surfaces in the wheels were examined in a scanning electron microscope (SEM). The fracture surfaces were prominent in the failure locations. EDS point analysis in the SEM revealed spots with higher chromium levels on the fracture surfaces. The average size of these spots was several dozen micrometres. The spots were suspected to have caused or contributed to the failure. A hardness profile across one tooth was measured using a microhardness tester. In addition, the thickness of the carburized layer was determined. Quality of the surface was assessed using macrophoto-graphs taken with a low-power stereomicroscope. In addition, metallographic sections were prepared and observed in a scanning electron microscope (SEM) and light microscope.

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.

This paper is focused on research in the field of grinding VACO 180 tool steel. Different grinding conditions in terms of several cutting speeds and depths of cut were used for grinding tool steel with CBN grinding wheels. Two CBN grinding wheels with different grain sizes were used for several tests with the same grinding strategy. The influence of the cutting speed and depth of cut on the surface roughness was observed. The different behaviour of both grinding wheels was found during grinding in terms of achieved surface roughness. Higher grain size of the grinding wheel led to higher surface roughness, which increased with cutting speed. However, grinding with deeper cuts showed the opposite effect, and the surface roughness was better at higher cutting speeds. Lower grain size gave a more stable grinding process in terms of achieved surface roughness and lower influence of the cutting speed. However, greater wheel wear occurred during grinding with greater depth of cut. The grinding wheel was dressed before each test to ensure the same grinding ability. The results of this work will be used for a better understanding of the process of grinding tool steel.

Thanks to today’s computer programs, engineers can derive a large amount of information from chemical com-position of a material. This information includes phase transformation temperatures Ac1, Ac3, Ms and Mf. CCT and TTT diagrams for austenite decomposition can be determined as well. When steel is heated, austenite grains nu-cleate and grow in the initial microstructure. On cooling, the grains decompose into pearlite, ferrite, cementite and hardening phases. Transformations of this kind are thoroughly described in literature: the ways the individual phases form and the speed of their formation and temperatures involved. However, in-situ visual recordings of such transformations are relatively rare. With Linkam TS1400XY high-temperature stage and chamber integrat-ed in an optical microscope, one can observe phase transformations in situ during heating and cooling. This paper explores microstructural evolution in 42SiCr steel in the course of heat treatment in a high-temperature chamber on an optical microscope stage which offers observation of changes in the material right under the microscope objective.

This article deals with the influence of grinding conditions and tilting the spindle on changes in the spindle load when grinding tool steel on a 5-axis tool grinding machine. The experiment was designed to investigate any changes in cutting speed, feed rate or tilting of the spindle. The size of the load is very important, because the load can influence the tool life, the life of the machine components, quality of the surfaces and dimensional accuracy of the components. A medical femoral knee replacement was selected as the semi-finished component for the experiment, as its surface is a good representative of a complex-shaped surface. This article is limited only to the grinding of maraging steel MS1 with a CBN grinding wheel. The second part of this article is focused on the experiment where the spindle load is evaluated and the results of the experiments are compared.

This article deals with the experimental grinding of cermet materials. Two types of cermet materials from different suppliers were ground under constant grinding conditions using a diamond grinding wheel. The main aim was to determine the influence of the grinding on the degradation of the grinding wheel and changes in the grinding process. Both types of cermet were ground with the same strategy and the same number of passes. The grinding wheel was analysed during grinding using an optical scanning device to observe the changes on the grinding wheel surface. Clogging and wear of the grinding wheel occurred on the surface as the amount of material removed increased. All grinding tests were carried out without dressing or truing of the grinding wheel. Degradation of the grinding wheel had a big influence on the grinding process in terms of the spindle load during grinding. The roughness of the ground surface was also measured using the optical scanning device. The results from this work will be used for further research of cermet grinding.