Wear Studies Research Articles

Study of Contact Strength, Tooth Wear and Metal-Polymer Life of Worm Gears

Study of Contact Strength, Tooth Wear and Metal-Polymer Life of Worm Gears

Wear and 3D Micro-Morphological Studies on CAD/CAM Milled Dental Zirconia for Post-Fabrication Dental Processes

The post-fabrication processes on CAD/CAM milled dental Zirconia result in surface roughening, micro-cracking, a decline in surface texture, and loss of strength. Also, the hydrothermal stresses formed due to water, blood, and synovial fluid infiltration into the crack space initiate crack propagation. The present work makes an effort to study the effect of surface morphology due to the post-processing of Yttrium-stabilized tetragonal Zirconia (Y-TZP) after CAD/CAM milling by studying the height, spatial, functional parameters (volume & Stratified surfaces), and 3-D surface roughness parameters in detail. Five groups based on post-processing combinations currently used in clinical conditions were selected for the study. Group 1(G1-S) involved the milling of pre-sintered blocks followed by sintering. Group 2(G2-S+P) consisted of sintering followed by the polishing process. Group 3(G3-S+P+S.B) consisted of sintering, polishing, and sandblasting with Aluminium Oxide (Al2O3) with a particle size of 110µm. Group4 (G4- S+S.B) involved sintering followed by sandblasting. Group5 (G5-S+S.B+P) consisted of sintering, sandblasting, and polishing. The surfaces were evaluated using a 3-D surface profilometer before and after wear. Before wear, the G4 process group responded with the highest surface roughness value, (Average roughness) Sa=1.378±0.409μm, and it was within the limit, which supported osseointegration. Valleys were predominant in almost all the groups, except G4. Also, the peak and core parameters for G3 &G4 were higher and will be of interest for further bone-implant contact (BIC) studies. The groups with sandblasting fabrication processes (G3, G4) exhibited relatively higher 3-D roughness parameters when compared to the groups with fabrication processes (G1, G2, G5). After wear, there was a considerable decline in the material peak. The research revealed that the methods with sandblasting could be suitable for osseointegration, BIC, and in-vivo performance for crown applications. Also, sandblasting followed by polishing (G5) was found to be optimal. Dentists will be able to determine the right clinical adjustments for their chairside CAD/CAM dentistry using 3-D surface roughness morphological analyses. It will also aid researchers in conducting in-depth studies on the issues related to oral cavity.

Experimental Investigation of Effect of Fiber Length on Mechanical, Wear, and Morphological Behavior of Silane-Treated Pineapple Leaf Fiber Reinforced Polymer Composites

The development of the best properties in polyester composite from pineapple leaf fiber (PALF) as a reinforcing material is a subject of interest. The properties of PALF are reliant upon fiber length, wherein technical difficulties in production of long fibers and processing for better characteristics in polyester composites possess inherent challenges. The PALFs are subjected to silane treatment for altering fiber properties. This research attempts to analyze the impact of silane-treated PALF with varying fiber lengths (5, 10, 15, 20, and 25 mm) on the performance of natural fiber composites (NFC) properties. Open mold and hand lay-up techniques were employed to develop the polyester composites. The prepared PALF-based polyester composites were examined for different properties (impact, flexural, tensile strength, and wear rate). Coefficient of friction and wear studies are performed on the prepared composites subjected to different loads (10, 20, and 30 N) via a pin on disc test rig. Polymer composite fracture surfaces were analyzed to observe the interfacial bonding between fibers and matrix via scanning electron microscopy (SEM). SEM results showed that the application of silane treatment resulted in better surface topography (fiber length of 5–10 mm showed smooth surface resulted in crack proliferation possessing low fracture toughness of 15–32 MPa; whereas a 15–20 mm fiber length resulted in better fiber–matrix bonding, improving the fracture toughness from 42–55 MPa) as a result of change in chemical structure in PALF. The 20 mm length of PALF resulted in better properties (flexural, tensile, impact, and wear resistance) which are attributed to fiber–matrix interfacial bonding. These properties ensure the developed polymer composites can be applied to walls, building insulation, and artificial ceilings.

Research on Elastic-Plastic Contact Behavior of Hemisphere Flattened by a Rigid Flat.

The contact behavior of a hemisphere pressed by a rigid plane is of great significance to the study of friction, wear, and conduction between two rough surfaces. A flattening contact behavior of an elastic–perfectly plastic hemisphere pressed by a rigid flat is researched by using the finite element method in this paper. This behavior, influenced by different elastic moduli, Poisson’s ratios, and yield strengths, is compared and analyzed in a large range of interference values, which have not been considered by previous models. The boundaries of purely elastic, elastic–plastic, and fully plastic deformation regions are given according to the interference, maximum mean contact pressure, Poisson’s ratio, and elastic modulus to yield strength ratio. Then, a new elastic–plastic constitutive model is proposed to predict the contact area and load in the elastic–plastic range. Compared with previous models and experiments, the rationality of the present model is verified. The study can be applied directly to the contact between a single sphere and a plane. In addition, the sphere contact can also be used to simulate the contact of single asperity on rough surfaces, so the present proposed model can be used to further study the contact characteristics of rough surfaces.

Anti-Wear and Anti-Erosive Properties of Polymers and Their Hybrid Composites: A Critical Review of Findings and Needs.

Erosion caused by the repeated impact of particles on the surface of a substance is a common wear method resulting in the gradual and continual loss of affected objects. It is a crucial problem in several modern industries because the surfaces of various products and materials are frequently subjected to destructively erosive situations. Polymers and their hybrid materials are suitable, in powdered form, for use as coatings in several different applications. This review paper aims to provide extensive information on the erosion behaviors of thermoset and thermoplastic neat resin and their hybrid material composites. Specific attention is paid to the influence of the properties of selected materials and to impingement parameters such as the incident angle of the erodent, the impact velocity of the erodent, the nature of the erodent, and the erosion mechanism. The review further extends the information available about the erosion techniques and numerical simulation methods used for wear studies of surfaces. An investigation was carried out to allow researchers to explore the available selection of materials and methods in terms of the conditions and parameters necessary to meet current and future needs and challenges, in technologically advanced industries, relating to the protection of surfaces. During the review, which was conducted on the findings in the literature of the past fifty years, it was noted that the thermoplastic nature of composites is a key component in determining their anti-wear properties; moreover, composites with lower glass transition, higher ductility, and greater crystallinity provide better protection against erosion in advanced surface applications.

Influence of varying nitrogen content on the structural, tribomechanical properties and machining performance of CrNx-WS2 nanocomposite coatings

This study reports the reactive co-sputtering of CrN and WS2 in order to develop CrNx-WS2 solid lubricant nanocomposites. The nitrogen flow rate during the deposition process was varied within a range of 10–50 sccm and its influence on crystal structure, composition, surface morphology, mechanical properties and tribological properties were systematically analysed. Grazing Incidence X-Ray Diffraction (GIXRD) studies revealed a change in the preferred orientation (200) with varying nitrogen flow rates along with significant broadening of peaks to demonstrate the formation of CrNx-WS2 nanocomposite thin films. The maximum nanohardness of the CrNx-WS2 nanocomposites was observed to be 29 GPa. Scratch test studies revealed a highest critical load of 222 GPa for CrNx-WS2 films which is three times more than that of the pristine WS2. The frictional coefficient of the CrNx-WS2 nanocomposite thin films was observed to be 0.16 while pristine WS2 had a frictional coefficient of 0.08. The wear studies of CrNx-WS2 nanocomposite thin films showed an improvement by 2.9 times when compared to pristine WS2 and 2.5 times when compared to pristine CrN. Machining studies carried out using the CrNx-WS2 coated tools showed reduction in cutting force by 8–12 % when compared to commercial tools. Tool life studies revealed an increase in tool life by 19 % for CrNx-WS2 coated tools in comparison to commercial tools owing to the reduction in tool-chip contact length.

Analysis of sliding behavior of coated surfaces under shear traction

The tribological behavior of non conformal coated contacting surface i.e. rigid sphere on the coated flat material surface normal force and shear traction is studied through numerical results. The non-conforming contact is a fundamental problem in the contact mechanics, which has a wide range of applications. Contact is the science behind tribology, the interdisciplinary study of friction, wear and lubrication with major applications in particle handling or friction between contacting rough surfaces, brakes, Bearings and so on. In the present investigation, the contact between the coated flat and the rigid sphere under the combination of normal and tangential loading is analyzed using finite element software ABAQUS. The substrate material is chosen for the analysis High speed steel, Titanium alloy and coating material is TiN (E=305GPa) of 5µm thick with a bonding material is Chromium (379GPa) of 1µm thick at the interface between the coating and substrate is modeled by three dimensional finite element method (3DFEM) in order to optimize coating coated surface and bonding layer to coating fracture. The elastic-perfectly plastic contact is assumed on the flat model. The results obtained from the FEA are used in the understanding of the tribological behavior of the contact pair.

Influence of boron carbide content on dry sliding wear performances of AZ91D magnesium alloy

In this study, AZ91 magnesium alloy based metal matrix composites are made-up of bottom pouring stir casting with 0 wt.%, 1.5 wt.% and 3 wt.% boron carbide (B4C) particles reinforcements. The influence of hard reinforcements on mechanical properties such as hardness and tensile strength has been investigated for the casted composites samples. It was found that by adding 1.5 wt. % and 3 wt.% B4C particles, the Rockwell hardness value of 3.2% and 4.6%, Ultimate Tensile Strength (UTS) values of 15.5% and 26.3% of the composites increased respectively. The influence of B4C contents on AZ91D mg alloy wear study was carried out using pin on disc apparatus. Also, the effect of applied load (5N, 10N, and 20N) on wear properties was investigated. The results of the dry sliding wear tests show that AZ91D- B4C magnesium composite has less wear loss than the unreinforced AZ91D magnesium alloy. X-ray diffraction (XRD) analysis were performed for finding the various compounds such as MgO, B4C and Mg17Al12 present in the developed composites. Further, scanning electron microscopy (SEM) analysis were performed on the worn-out pin surfaces to investigate the wear pattern. These findings indicate that the addition of B4C content improved mechanical characteristics and wear resistance, which may also be used in the automotive and aerospace industries.

Investigation of the resistance, durability and abrasion of printed elements applied to sports equipment

The work investigated the durability of the labelling of sports equipment made of composite materials. Professional hockey sticks were taken for research. Research has been done on hockey stick wear for different players: centre and winger and defender. In addition, a study was made of hockey sticks for left-handers and right-handers. In the study of the wear of printed elements, sports equipment of various lengths was used. Contact research was carried out during training and competition. The study of the number of contacts was carried out on the basis of video recordings of trainings and games of the teams “Energija” - Elektrėnai (Lithuania) and the national team of the Belarusian Republic. The study carried out showed that the hockey stick wear of the centre striker and the winger during the competition and training is similar. During the competition, the hockey sticks of the centre strikers are most often in contact. It was found that the difference between contacts during training and playing depends on the intensity of the game, penalty time and strategy. When conducting a study of the wear of the printed elements applied to the hockey stick, depending on the position of the player, it was found that the wear of the sticks of the winger and the defender is the same, but that of the centre striker is different. When conducting a study of hockey stick wear depending on its length, the following conclusion was made: the taller the player, the longer his hockey stick and the maximum contact area. Research has shown that hockey stick wear is not affected by how the player holds the hockey stick, i.e. whether he is left-handed or right-handed. To study the abrasion of elements using the UGRA method, an original stand was created. With the help of this stand, studies of the abrasion of printed elements were carried out. Based on the study, it was concluded that the abrasion of printed elements most often occurs at the moment of contact of the objects of research, both with each other and with objects on the playing field. As a result, the printed elements split, peel off and become less noticeable, in addition, the name of the manufacturer's company is worn out and the hockey stick loses the player's personal identification data printed on the hockey stick. Recommendations are given on the peculiarities of printing and the location of printed elements on sports equipment.

The study of chip characteristics and tool wear in milling of SKD61 mold steel

The study of chip characteristics and tool wear in milling of SKD61 mold steel

Titanium boride and titanium silicide phase formation by high power diode laser alloying of B4C and SiC particles with Ti: Microstructure, hardness and wear studies

In this work a novel multiphase titanium metal matrix composite (TMMC) coating was developed by high power diode laser assisted alloying of Cp-Ti with the preplaced Boropak powder consisting of B4C and SiC ceramic particles. The XRD, optical microscopy, scanning electron microscopy, EDAX, microhardness and wear testing techniques were employed to investigate structural phase, hardness and wear properties of the alloyed coating. Under the influence of multipass laser alloying, the B4C and SiC ceramic particles decompose to yield boron, silicon and carbon species that react with molten titanium to form TiB2, TiB, TiC and Ti5Si3 phases in the laser alloyed coating. In addition, the un-melted B4C and SiC ceramic particles are dispersed in the titanium matrix. Microstructure of the alloyed coating consists of dendrites and coralline-like structure. The tips of the coralline-like structure are in the range of 150–500 nm. The ceramic multiphase TiB2, TiB, TiC and Ti5Si3 formation resulted in average microhardness around 800–2200 HV0.2 at different regions of the TMMC coating cross section. To correlate the phase formation and microstructural features, surface temperature evolved at the interaction area during laser surface alloying was estimated by a simple equation. Activation energy for the laser melted track was calculated using the Arhennius equation. The linear reciprocating wear test performed on laser alloyed coating against WC ball showed wear rate value of 1.623 х 10−4 mm3/N.m which is 6 times lower compared to the untreated titanium.

Research on rail wear of small radius curve in EMU depot

PurposeWith the help of multi-body dynamics software UM, the paper uses Kik–Piotrowski model to simulate wheel-rail contact and Archard wear model for rail wear.Design/methodology/approachThe CRH5 vehicle-track coupling dynamics model is constructed for the wear study of rails of small radius curves, namely 200 and 350 m in Guangzhou East EMU Depot and those 250 and 300 m radius in Taiyuan South EMU Depot.FindingsResults show that the rail wear at the straight-circle point, the curve center point and the circle-straight point follows the order of center point > the circle-straight point > the straight-circle point. The wear on rail of small radius curves intensifies with the rise of running speed, and the wearing trend tends to fasten as the curve radius declines. The maximum rail wear of the inner rail can reach 2.29 mm, while that of the outer rail, 10.11 mm.Originality/valueWith the increase of the train passing number, the wear range tends to expand. The rail wear decreases with the increase of the curve radius. The dynamic response of vehicle increases with the increase of rail wear, among which the derailment coefficient is affected the most. When the number of passing vehicles reaches 1 million, the derailment coefficient exceeds the limit value, which poses a risk of derailment.

Determination of a Wear Law for Uncoated Cutting Tools

The wear of cutting tools is one of the main current problems, especially when it comes to new materials called "difficult to machine" or with high added value. Tool wear is caused by extreme thermomechanical loads applied to the contact areas of tool chips and tool parts. During milling, turning or drilling operations, for example, large deformations, high deformation rates and high temperatures can be observed near the surface of the cutting tool. The objective of our work is to respond to the problem of abrasion wear by developing a predictive tool, based on knowledge of the physical and tribological mechanisms of workpiece-tool contacts, allowing us to quantitatively estimate the wear of the tool and its service life. To achieve this, we base our approach on previous studies carried out in the field of machining and metalworking. The modeling work was first applied to the wear case, then extended to the study of the crater wear occurring on the cutting face. By taking into account the mechanical load applied and the geometry of the contacts involved (plane-plane contacts), we have developed a two-dimensional approach in orthogonal cut configuration.

Investigation of solid particle erosion behavior of Al-Al2O3 and Al-ZrO2 metal matrix composites fabricated through powder metallurgy technique

The proposed research article presents an experimental investigation of solid particle erosion wear of Al2O3 and ZrO2 ceramic oxide reinforced metal matrix composite developed via powder metallurgy method. Two different kinds of metal matrix composites, Al-Al2O3 and Al-ZrO2 were developed with different proportions (0, 2.5, 5 and 10 wt%) of micro-sized ceramic oxide reinforcement powders. Vickers Hardness (HV), experimental densities of sintered samples, XRD and EDS were evaluated for mechanical characterization of fabricated metal matrix composites. Solid particle erosion wear tests were carried out at impingement angles 30–90° at varying set impact velocities of 30–90 m/s on air-jet erosion wear test rig using tiny micro-sized Al2O3 powders as an erodent. Air–jet erosion experiments were conducted as per the G76 standard for study of the steady-state erosion wear. ANOVA test revealed that wt% of reinforced contents was a significant parameter followed by impact velocity. 5 wt% of ZrO2 was observed to be the best wt% of reinforcement of all the combination of fabricated composites.

Dry Sliding Wear Study on AA6061/SiCp Nano and AA6061/SiCp/Gr Hybrid Nanocomposites

Dry Sliding Wear Study on AA6061/SiCp Nano and AA6061/SiCp/Gr Hybrid Nanocomposites

Studies on Wear of a Milling Chuck for a Production Line of Specialized Elements Used in Lockstitch Machines.

The study aims to determine the wear intensity of selected milling chuck assembly surfaces covered with a protective DLC (Diamond Like Carbon) coating, used on the production line for elements of selected lockstitch machines, and to analyze the stress distributions in the object fixed with such a chuck for the characteristic load systems of this object during its processing. A model of the workpiece was developed using the finite element method. The boundary conditions, including the load and the method of clamping the workpiece, resulted from the parameters of the milling process and the geometric configuration of the milling chuck. Stress distributions in the workpiece for specific milling parameters and for various configurations of the milling chuck holding the workpiece are included in the article. The model experimental studies of wear were conducted in the contact zone between two surfaces covered with DLC: one on the element of the milling chuck pressing the workpiece and the other on the eccentric cams of this holder. The obtained wear values and shapes for the worn surfaces are also shown. The wear intensities for the steel plunger fins modelling swivel arm of the holder were by an order higher than those of corresponding steel shaft shoulders modelling eccentric cam of the holder. The linear wear intensities for these mating components may be expressed in terms of a function of average contact pressure and sliding speed in a corresponding contact zone. The indentation of eccentric cam into mating surface of the swivel arm of the holder increased nonlinearly with the enhancement of number of cycles of the eccentric cam.

Surface modification of hBN reinforced aluminum alloy Al 2024 through friction stir processing

The focus of this study is to see if Friction Stir Processing can improve the properties of an aluminium alloy with Boron Nitride (BN) particles on the surface. Friction Stir Processing (FSP) is a new surface alteration technique that uses friction to cause plastic deformation, resulting in grain refining and improved mechanical and surface properties. To process 2024 aluminium alloy plates, a straight cylinder tool was used under varying process parameters and to conduct tensile, hardness, wear and impact studies. The findings were evaluated in order to infer the significance of the process parameter and the reinforcement of the metal improvement properties. Friction Stir Processing was effectively processed by reinforcing the Boron Nitride plates and achieved significant changes in the mechanical and surface properties.

Implementation of Visual Clustering Strategy in Self-Organizing Map for Wear Studies Samples Printed Using FDM

In general, visual clusters are preferred over large data sets; this is an attempt to take advantage of cluster techniques to reduce the mathematical complexity of small data sets. To identify the possibility of implementing the clustering technique in a small dataset, the wear observations of PLA/Cu composite samples printed using the Fused Deposition Model (FDM) is taken into consideration. In this study, the Self Organizing Map (SOM) tool as a non-supervised Neural Network (NN) is used to visualize the data. Here, SOM combinations with vector quantification and projection are used to identify or rank the wear machinability parameters on the new composite filament printed under different FDM conditions. The competitive layer in SOM will classify the given parameters of the wear machine (vectors) at any number of dimensions may be into several groups of layer neurons. The limitation of SOM is map size which cannot exceed 1000 units of training. However, for the small data set under consideration, the extent of these limits will not affect performance. The SOM algorithm developed for the study of wear provides the outlet within the acceptable range. In addition, the linear regression analysis is carried out for the output response to measure the wear characteristics of the machining observation.

Effect of beryl and graphene nano platelets reinforcements on the wear behaviour of AL7075- beryl graphene particulate hybrid nano composites

The effect of beryl particles and graphene nano platelets (GNPs) on the wear behaviour of Al7075-beryl-graphene hybrid composites has been studied. The hybrid composites were developed containing Al7075 matrix as matrix materials and 6 weight percentage of beryl and varying 0.5 to 2 weight percentage of graphene by using novel two step stir casting technique and wear behaviour of the newly developed hybrid composites were studied. The dry sliding wear studies conducted using a pin-on-disc tribo-tester under atmospheric conditions revealed that the wear loss of Al7075-beryl-graphene hybrid composites are lower than that of the matrix Al7075 alloy and further with increasing weight percentage of graphene decreased the wear loss of the hybrid composites. The wear studies also showed that the increase in load, sliding speed and sliding distance, the wear loss of the composites increased. The microstructure of the worn out surface revealed that a huge amount of plastic deformation appeared on the unreinforced Al7075 alloy when compared to the reinforced hybrid composites. The incorporation of beryl and graphene into Al7075 showed worn out surface that is not smooth and grooves, scratches and parallel lines were observed. The addition of beryl and GNPs into the matrix reduces erosion and small grooves like structure were noticed in the hybrid composites which leads to a reduction in wear in Al7075-beryl-GNPs hybrid composites

A study of wheel wear on a high-speed railway motor car

Wheel/rail wear is one of the key issues in the safe operation of a high-speed railway motor car. This paper analyzes and predicts the wheel wear evolution of motor car during the long-term operation process. Firstly, the detailed motor car with gear transmission systems and trailer car of the high-speed train, which take into account various non-linear factors such as dampers, bump stops, wheel/rail contact relation, etc., are developed to obtain interaction force between wheel and rail. Secondly, according to the tread update strategy based on fixed travel distance, a novel wheel wear prediction model integrating the Archard wear model and previous dynamics system is established. In order to more accurately obtain the dynamic responses of the motor car, the comprehensive gear transmission system coupling with motor bogie is also built, which considers the time-varying mesh stiffness and gear shift coefficient. And the corresponding traction characteristic curve is also applied to the gear transmission system. Finally, the wheel wear evolution in one re-profiling cycle is simulated to verify the developed model, and the wheel wear mechanism is investigated in detail. Furthermore, the influence of traction velocity on wheel wear is also investigated. The simulation shows that the cumulative wear amount of both two cars increases gradually and the wear rate decreases gradually with traveling mileage, but the wear rate of the trailer car decreases faster than that of the motor car due to larger longitudinal creepage and longitudinal creep force induced by traction torque. Moreover, the max wheel wear depth and wear bandwidth for motor car gradually increase with traction velocity. While the discrepancies of the max wheel wear depth and wear bandwidth for trailer car are small under different speeds.