Wyniki wyszukiwania dla: UNIAXIAL TENSION STRESS TEST (UTST)
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EXPERIMENTAL STUDY OF SURFACE ROUGHNESS EFFECT ONTHE RHEOLOGICAL BEHAVIOR OF MR FLUID
PublikacjaPaper presents the results of shear stress measurements of a commercial magnetorheological fluid using a plate-plate type geometry with a modified working surface. The purpose of the study was to determine the effect of changing the roughness of the measuring plate on the obtained shear stress results. Controlled shear rate tests and Magneto Sweep measurements were carried out for three MR fluid layer heights. The tests were...
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Discrete element method simulations of fracture in concrete under uniaxial compression based on its real internal structure
PublikacjaThe paper describes experimental and numerical results of concrete fracture under quasi-static uniaxial compression. Experimental uniaxial compression tests were performed on concrete cubic specimens. Fracture in concrete was detected at the aggregate level by means of three non-destructive methods: three-dimensional X-ray microcomputed tomography, two-dimensional scanning electron microscope and manual two-dimensional digital...
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Mechanical Properties of Human Stomach Tissue
PublikacjaThe dataset entitled Determination of mechanical properties of human stomach tissues subjected to uniaxial stretching contains: the length of the sample as a function of the corresponding load (tensile force) and the initial values of the average width and average thickness of the sample. All tests were conducted in a self-developed tensile test machine: PG TissueTester. The dataset allows the coefficients of various models of...
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Shaft friction from the DMT and direct shear interface tests
PublikacjaThe article presents preliminary attempt to create tri-linear transfer curves for describing pile behaviour under axial loading. Transfer curves would use the parameter measured in dilatometer test, particularly a constrained modulus MDMT. The proposed method is based on concrete rough and smooth interface tests performed in a direct shear apparatus. Based on the obtained mobilization curves, relationships were created between...
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Mechanical testing of technical woven fabrics
PublikacjaThis article presents a review of technical fabrics testing methods used by the authors on the basis of their experience with research on properties of polytetrefluoroethylene-coated fabrics used for Forest Opera in Sopot (Poland). First, the different types of testing methods used for description of mechanical properties (uniaxial tensile tests, biaxial tensile tests and shear tests) of technical woven fabrics are described. The...
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OCENA NOŚNOŚCI STAREGO MOSTU ŁUKOWEGO W JAGODNIKU
PublikacjaArtykuł opisuje przeprowadzoną analizę statyczno-wytrzymałościowa 95-letniego betonowego mostu łukowego zlokalizowanego w Jagodniku w północnej Polsce. Trwałość i wytrzymałość starego betonu są określane na podstawie wybranych właściwości mechanicznych, fizycznych i chemicznych. Program badań laboratoryjnych składał się z następującego zestawu badań: pomiary głębokości strefy skarbonatyzowanej i gęstości w stanie suchym, badania...
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Strength parameters of polyester reinforced PVC coated fabric after short term creep loading in biaxial mode
PublikacjaThis study addresses the analysis of tensile strength parameters of the technical fabric VALMEX, which is composed of two orthogonal polyester thread families (named the warp and fill) and both sides PVC coated. The material was firstly subjected to 48-hour biaxial creep loading with the equal stress level in both orthogonal directions of the fabric. The stress levels were established as follows: 4.6 kN/m, 10.4 kN/m, 16.4 kN/m,...
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LCF behavior of 2024AA under uni- and biaxial loading taking into account creep pre-deformation
PublikacjaThis study presents the results of experimental low-cycle fatigue (LCF) tests of aluminum 2024 alloy T3511 temper in uni- and biaxial loading states. Tests were carried out on both the as-received material (hardened extruded rods) and material with different pre-deformation histories. These deformations were carried out in the creep process at 200 °C and 300 °C for two different levels of at each temperature. The pre-deformed material’s...
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Numerical modelling of the mesofracture process of sintered 316L steel under tension using microtomography
PublikacjaThis paper concerns numerical modelling of the deformation process, taking into account the local fracture of porous 316L sinters at the mesoscopic scale using the finite element method. Calculations are performed with the use of geometrical models, to map the realistic shape of the porous mesostructure of the material, obtained by means of computed microtomography. The microtomographic device has limited and insufficient measurement...
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Fatigue of titanium alloy Ti6Al4V with diamond structure obtained by Laser Power Bed Fusion method
PublikacjaThis paper presents the results of fatigue tests conducted on Ti6Al4V titanium alloy with diamond structure obtained by the Laser Power Bed Fusion method. Samples used in tests were printed with porosities: 81%, 73%, 50%, 34% and near-zero porosity. Samples were subjected to cyclic tests with a constant stress amplitude. The number of cycles until sample failure was registered. Obtained fatigue test results made it possible to...
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Prediction of flow boiling heat transfer coefficient for carbon dioxide in minichannels and conventional channels
PublikacjaIn the paper are presented the results of calculations using authors own model to predict heat transfer coefficient during flow boiling for carbon dioxide. The experimental data from various researches were scrutinised conducted for a full range of quality variation and wide range of mass velocity. The aim of the study was to test the sensitivity of the in-house model. The work shows the importance of taking into account surface...
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Experimental observations on the creep behaviour of frozen soil
PublikacjaConstitutive models in the literature for creep of frozen soil are based on the direct use of time counted from the onset of creep. An explicit time dependence in a constitutive equation violates the principles of rational mechanics. No change in stress or temperature is allowed for during creep, using the time-based formulations. Moreover, the existing descriptions need much verification and improvement on the experimental side...
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Entire fracture surface topography parameters for fatigue life assessment of 10H2M steel
PublikacjaIn this paper, the entire fracture surface approach was used to assess an effect of 280,000 h of exploitation under internal pressure of 2.9 MPa and high temperature of 540 °C on the fatigue response of 10H2M (10CrMo9–10) power engineering steel. The mechanical testing was carried out on the hourglass specimens produced from the as-received, unused pipeline and the same material after long-time exploitation. The uniaxial tensile...
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Badania mieszanek mineralno-asfaltowych w niskiej temperaturze
PublikacjaW artykule przedstawiono metody badań w niskiej temperaturze betonu asfaltowego przeznaczonego do warstwy ścieralnej. Przedstawione zostały wyniki badań dla 4 różnych metod badawczych: zginania, pełzania, pośredniego rozciągania oraz rozciągania termicznego przy ograniczonym odkształceniu (test TSRST). Próbki betonu asfaltowego były przygotowywane w laboratorium z wykorzystaniem 3 rodzajów asfaltów: asfaltu zwykłego, asfaltu modyfikowanego...
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The influence of combination of binding agents on fatigue properties of deep cold in-place recycled mixtures in Indirect Tensile Fatigue Test (ITFT)
PublikacjaThe publication presents fatigue properties of cold recycled mixtures for eight combinations of binding agents (cement and bituminous emulsion). Cold recycled mixtures were evaluated in Indirect Tensile Fatigue Test (ITFT) at the temperature of 20 C in controlled stress mode. As a function of horizontal stress, fatigue life is strongly influenced by combination of the binding agents. When fatigue life is analyzed as a function...
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Textile reinforced concrete members subjected to tension, bending, and in-plane loads: Experimental study and numerical analyses
PublikacjaTextile reinforced concrete has raised increasing research interest during the last years, mainly due to its potential to be used for freeform shell structures involving complex load situations. Yet, most experimental work has focused on test setups with primarily uniaxial loading. In the current work, such setups are complemented with a novel test setup of deep beams, including in-plane bending and shear. Further, nonlinear finite...
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Experimental study and numerical simulation of the dynamic penetration into dry clay
PublikacjaTests of dry clay were carried out in a uniaxial stress state using the experimental setup which implements the split Hopkinson pressure bar method. Based on the results of these experiments, the compressive strength of clay was determined as an important element of S.S. Grigoryan’s model of the soil medium. In addition, the parameters of this model are determined from the results of experiments using the modified Kolsky method...
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Direct design of Controlled Modulus Columns (CMC) based on in-situ testing
PublikacjaIn this paper, the serviceability limit state and bearing capacity of tension screw displacement piles were analyzed using the results of static pile load tests, carried out on the test plot near the Elbląg city, and field, and laboratory tests. The paper presents the methodology of determining the pile load-settlement curve using different types of t-z transfer functions. The new method of constructing the pile load-settlement...
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Influence of service ageing on polyester-reinforced polyvinyl chloride-coated fabrics reported through mathematical material models
PublikacjaIn this paper the coupled service (constructional tension) and environmental (sunlight, rainfalls, temperature variations) ageing influence on the polyester-reinforced polyvinyl chloride (PVC)-coated fabric VALMEX is studied. Two cases of the same fabric have been analyzed: one USED for 20 years on the real construction of the Forest Opera in Sopot (Poland), and one kept as a spare material (NOT USED). The following tests have...
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A coupled constitutive model for fracture in plain concrete based on continuum theory with non-local softening and eXtended Finite Element Method
PublikacjaThe paper presents a constitutive model for concrete which combines a continuous and discontinuous fracture description. In a continuum regime, two different constitutive laws were used. First, a plasticity model with a Rankine failure criterion and an associated fl ow rule was used. Second, a constitutive law based on isotropic damage mechanics was formulated. In order to capture the width of a localized zone and to obtain mesh-independent...
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Selected problems of experimental investigation of dynamically loaded journal bearings
PublikacjaIn the paper some problems concerning relations between external bearing loadings and critical lining stresses are described for test stand with rotating load vector. According to the standard ISO 7905/1 this type of test stand, for dynamically loaded slide bearing, is recommended as a basic research unit for material testing in a complete bearing unit. The lining stress calculation results occurred being dependent on applied calculation...
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Simple empirical formula to estimate the main geomechanical parameters of preplaced aggregate concrete and conventional concrete
PublikacjaPreplaced aggregate concrete (PAC) or two-stage concrete is a specific type of concrete successfully employed in many projects including underwater concrete structures, massive concrete structures, structures made of reinforced concrete, and improvement of concrete structures. PAC is significantly different than the conventional concrete. In this type of concrete, aggregates are initially poured into the mold, the voids between...
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Nośność konstrukcji gruntowo-łukowej prefabrykowanego wiaduktu w świetle obliczeń numerycznych i badań „in situ”
PublikacjaWartykule przedstawiono analizy przeprowadzone dla wiaduktu WK-15 Pomorskiej Kolei Metropolitalnej wykonanego w technologii łuków prefabrykowanych przykrytych gruntem (system TechSpan). W celu weryfikacji obliczeń numerycznych wykonano próbne obciążenie konstrukcji. Przedstawiono wyniki pomiarów naprężeń i prezmieszczeń konstrukcji. Odniesiono się krytycznie do zastosowanego modelu obliczeniowego.
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Verification of the new viscoelastic method of thermal stress calculation in asphalt layers of pavements
PublikacjaThe new viscoelastic method of thermal stress calculations in asphalt layers has been developed and published recently by the author. This paper presents verification of this method. The verification is based on the comparison of the results of calculations with results of testing of thermal stresses in Thermal Stress Restrained Specimen Test. The calculations of thermal stresses according to the new method were based on rheological...
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Effect of coarse grain aggregate on strength parameters of two-stage concrete
Publikacja. Two-stage concrete (TSC) is a special type of concrete that the method of its construction and implementation is different from conventional one. In TSC, coarse aggregate particles are first placed in the formwork and voids between them are subsequently injected with a special cementations mixture. TSC has been successfully used in many applications, such as underwater construction, casting concrete sections congested with reinforcement...
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Shear band evolution phenomena in direct shear test modelled with DEM.
PublikacjaA direct shear test is widely used in the geotechnical engineering field. It is an easy and quick test to measure the shear properties of soil. This test often replaces more expensive and difficult tri-axial shear test. Despite that the direct shear test is known and used for a long time, it is still not well investigated at the grain scale. This paper deals with the micro behaviour of the cohesionless sand inside the direct shear...
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Numerical modelling and analysis of steel specimens subjected to marine immersed corrosion and tensile load
PublikacjaThe present study develops numerical models to analyse the behaviour of steel specimens subjected to marine immersed corrosion degradation and tensile load. The finite element method with the use of the explicit dynamic solver LS-DYNA, satisfying the quasi-static conditions, is employed. Two numerical models are developed, where in the first one, the scans of surfaces gathered from corroded plate specimens are implemented directly...
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Prediction of flow boiling heat transfer coefficient for carbon dioxide in minichannels and conventional channels
PublikacjaIn the paper presented are the results of calculations using authors own model to predict heat transfer coefficient during flow boiling of carbon dioxide. The experimental data from various resea rches were collected. Calculations were conducted for a full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in-house model. The results show the importance of taking into...
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Investigations on strength and fracture in RC beams scaled along height or length
PublikacjaThe objective of the present paper is to identify experimentally and theoretically differing failure mechanisms in reinforced concrete beams subjected to four-point bending for a separate variation of the depth and length at the constant thickness. Experiments were performed on reinforced concrete beams under four-point bending. Different failure mechanisms included steel yielding, diagonal tension or shear- compression depending...
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Calculation method for flow boiling and flow condensation of R134a and R1234yf in conventional and small diameter channels
PublikacjaThe paper presents the results of calculations performed using the authors’ model to predict the heat transfer coefficient during flow boiling for two refrigerants R134a and R1234yf. The experimental data from various past studies have been collected and the calculations have been conducted for the full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in-house...
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EXPERIMENTAL VERIFICATION OF THE METHOD OF FLOW BOILING AND FLOW CONDENSATION HEAT TRANSFER PREDICTION FOR SELECTED FLUIDS
PublikacjaIn the paper presented are the results of calculations using authors own model to predict heat transfer coefficient during flow boiling of different refrigerants. The experimental data from various research studies from literature were collected. Calculations were conducted for a full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in- house developed model....
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Management Psychology 2022
Kursy OnlineDuring the Management Psychology course, the focus is placed on how psychological science, research, and knowledge can support management. The course topics include elements pertaining to individual differences, decision-making, leadership, group work, stress management, and more. Course participants have to take a mid-term test and submit the final project at the end of the semester. During our first meeting, you have learned...
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Validation of lumbar spine finite element model
Dane BadawczeThe functional biomechanics of the lumbar spine have been better understood by finite element method (FEM) simulations. However, there are still areas where the behavior of soft tissues can be better modeled or described in a different way. The purpose of this research is to develop and validate a lumbar spine section intended for biomechanical research....
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Properties of surface layers of duplex stainless steel after burnishing processes
PublikacjaStress corrosion cracking resistance of cold worked layers of 25 Cr duplex stainless steel grade UR52N+ has been investigated. The surface layers were performed through burnishing treatment. The residual stresses at surface layers were determined using grazing angle incidence X-ray diffraction method (g-sin2 Ψ). Corrosion tests were performed with the use of Slow Strain Rate Test technique in boiling 35% MgCl2 solution. It has...
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On the crack front curvature in bonded joints
PublikacjaStandard tests of adhesively bonded specimens are likely to produce heterogeneous stress distribution along the crack front and its vicinity. High separation rate mode I dominated fracture test is performed.Observation of post mortem fractured surfaces with an optical microscope reveals characteristic features of mixed mode I/III fracture near the sides of the specimen but not in the middle. At first, finite elements calculations...
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Three-Dimensional Printing of Bone Models
PublikacjaThe trabecular bone occurs, for example, in the femoral heads. Understanding the phenomenon of bone tissue degeneration can be the basis for the possibility of looking for alternative methods of surgical treatment of bone loss. The paper presents the results of the trabecular bone model, which was produced in additive manufacturing method with fused filament fabrication technology. The verification of the mechanical behavior of...
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Prediction of flow boiling heat transfer data for R134a, R600a and R290 in minichannels
PublikacjaIn the paper presented is the analysis of the results of calculations using a model to predict flow boiling of refrigerants such as R134a, R600a and R290. The latter two fluids were not used in development of model semiempirical correction. For that reason the model was verified with present experimental data. The experimental research was conducted for a full range of quality variation and a relatively wide range of mass velocity....
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Influence of the femoral offset on the muscles passive resistance in total hip arthroplasty
PublikacjaBackground Soft tissue tension is treated as a crucial factor influencing the post-THA dislocation. The femoral offset is regarded as one of the major parameters responsible for the stabilization of the prosthesis. It is unclear which soft tissue is mostly affected by the offset changes. Methods A finite element model of the hip was created. The model comprised muscles, bones, a stem, the acetabular component and a liner. The muscles...
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Mechanical properties of polyester reinforced PVC coated fabric subjected to biaxial loading of creep type
PublikacjaThe goal of the current study is to analyze the basic mechanical properties of the architec-tural fabric VALMEX, which is a composite material built of reinforcing polyester thread families and both sides PVC coated. The material was firstly subjected to biaxial loading of creep type for about 48 hours. The stress levels of the creep loading in two main or-thogonal directions of the fabric (commonly called the warp and fill directions)...
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Experimental-Numerical Analysis of the Effect of Bar Diameter on Bond in Pull-Out Test
PublikacjaBar diameter is one of the basic factors affecting bond behavior, which is still of interest due to opposing opinions regarding its effect on bond behavior in the pull-out test. This paper presents an experimental and numerical bond analysis of ribbed reinforcing bar in concrete. The aim was to experimentally evaluate the effect of bar diameter on the bond behavior in the pull-out test and to perform numerical simulations of the...
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Mechanical response of human thoracic spine ligaments under quasi-static loading: An experimental study
PublikacjaPurpose This study aimed to investigate the geometrical and mechanical properties of human thoracic spine ligaments subjected to uniaxial quasi-static tensile test. Methods Four human thoracic spines, obtained through a body donation program, were utilized for the study. The anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), capsular ligament (CL), ligamenta flava (LF), and the interspinous ligament and...
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ATTEMPT AT EVALUATING THE INFLUENCE OF BENDING STRESS ON SHAFT WEAR PROCESSES IN WATER LUBRICATED SLIDING BEARING WITH A RUBBER BUSHING
PublikacjaWater lubricated bearings find increasingly wide application in shipbuilding or hydro–power industry, the popularity stemming from their numerous advantages. Unfortunately, as it turns out, water lubricated bearings do not always meet expectations, as on occasion they become subject to intense, premature wear which requires costly repair. One of the still unexplained phenomena is the process of excessive bearing wear, in particular...
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Mechanical Properties of Additively Manufactured Polymeric Materials—PLA and PETG—For Biomechanical Applications
PublikacjaThe study presented herein concerns the mechanical properties of two common polymers for potential biomedical applications, PLA and PETG, processed through fused filament fabrication (FFF)—Material Extrusion (ME). For the uniaxial tension tests carried out, two printing orientations—XY (Horizontal, H) and YZ (Vertical, V)—were considered according to the general principles for part positioning, coordinates, and orientation typically...
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TiN coating in ring-on-ring sliding with saline solution (0.9%) lubrication 5MPa, 0.1m/s specimn. #B48/#A45
Dane BadawczeWear tests in sliding friction of TiN coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, TiN over TiN . Mean contact stress: 5MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: SALINE SOLUTION (0.9%). Tribometer: PT-3. Overall test time till coating penetration 12 min....
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TiC coating in ring-on-ring sliding with saline solution (0.9%) lubrication 5MPa, 0.1m/s specimn. #B41/#A39
Dane BadawczeWear tests in sliding friction of TiC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, TiC over TiC . Mean contact stress: 5MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: SALINE SOLUTION (0.9%). Tribometer: PT-3. Overall test time till coating penetration 9 min....
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CrN coating in ring-on-ring sliding with distlled water lubrication 5MPa, 0.1m/s specimn. #A23/#B22
Dane BadawczeWear tests in sliding friction of CrN coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, CrN over CrN . Mean contact stress: 5MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: DISTILLED WATER. Tribometer: PT-3. Overall test time till coating penetration 12 min. The...
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TiC coating in ring-on-ring sliding with distlled water lubrication 5MPa, 0.1m/s specimn. #B39/#A41
Dane BadawczeWear tests in sliding friction of TiC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, TiC over TiC . Mean contact stress: 5MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: DISTILLED WATER. Tribometer: PT-3. Overall test time till coating penetration 3 min. The test...
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SiC coating in ring-on-ring sliding with distlled water lubrication 5MPa, 0.1m/s specimn. #B34/#A33
Dane BadawczeWear tests in sliding friction of SiC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, SiC over SiC. Mean contact stress: 5MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: DISTILLED WATER. Tribometer: PT-3. Overall test time till coating penetration 3 min. The test...
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TiN coating in ring-on-ring sliding with saline solution (0.9%) lubrication 5MPa, 0.1m/s specimn. #A45/#B48
Dane BadawczeWear tests in sliding friction of TiN coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, TiN over TiN . Mean contact stress: 5MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: SALINE SOLUTION (0.9%). Tribometer: PT-3. Overall test time till coating penetration 12 min....
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TiC coating in ring-on-ring sliding with distlled water lubrication 5MPa, 0.1m/s specimn. #A41/#B39
Dane BadawczeWear tests in sliding friction of TiC coating on 1.4021 (EN 10088-1) heat treated stainless steel. Ring - on - ring contact in unidirectional sliding, TiC over TiC . Mean contact stress: 5MPa. Sliding velocity: 0,1 m/s. Mean friction radius: 9.5mm. Lubricant: DISTILLED WATER. Tribometer: PT-3. Overall test time till coating penetration 3 min. The...