New seals test bench under reciprocating and oscillatory movement with capacity to test with different lubrication systems and different temperatures. Prosthesis simulators involving real components for evaluating tribological properties of hip prosthesis coatings and synovial fluids, adapted to FALEX and SRV machines.
Car wash type test, cleaning and abrasive testing of glass ISO and solar mirrors internal protocols. It is also possible to measure the gas tribodesorption detected by mass spectra, during friction and wear tests. This machine allows complex tribological characterization of materials and coatings in a wide range of gas pressures from atmospheric to ultrahigh vacuum and loads 0.
This system can be used to study tribological behavior of the coatings under gradually varying gas pressure and composition, simulating the environments on the various stages of the service life of the real aerospace systems. It can be possible to quantify the gas tribodesorption from materials and coatings Figure 1.
The flexibility of the machine allows to modify working conditions. Drag friction test is for the determination of the drag friction torque of antifouling paints or surface treatments e.
The torque before and after fouling and with different surface treatments can be compared at different rotating speeds, simulating either laminar or turbulent flow. Tribocorrosion testers have been developed combining a tribometer and a potentiostat. The test equipment allows monitoring and control both mechanical and electrochemical parameters. A tribometer creates relative motion, either unidirectional rotatory or bidirectional reciprocating , rubbing two surfaces against each other.
The electrochemical cells are used to record and control the electrochemical parameters. These cells are usually composed of three electrodes: a reference electrode, a counter-electrode, and the working electrode. The reference electrode has a stable, well-defined potential, and it is used to register the potential of the working electrode, i. The counter-electrode is used to measure or control the current and is usually made of inert materials such as platinum, gold, or graphite.
The electrodes are connected to a potentiostat to register the potential between the reference electrode and the working electrode or the current between the counter-electrode and the working electrode.
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A typical tribocorrosion test setup is schematically shown in Figure 4 [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. A test bench is built with the objective to carry out friction test and wear test in plain bearings.
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Ball on rod machine is built with the objective to study the point rolling contact fatigue of the bearing materials and coatings, to apply to ball rolling bearings. Hoo, D. The typical pressure applied is 5. Alternatively, other lubrication systems can be selected. The balls can be made from steel and ceramic and with or without coatings with a diameter of The ball on rod machine has a double testing device for parallel testing. The time to reach the micropitting or pitting is recorded and monitored by an increase of the vibrations.
Cylinder on cylinder machine, built to study the pitting phenomena in roller bearings, simulates the line contact rolling fatigue behavior of the materials. The duration of the test until reaching the micropitting or pitting phenomena is recorded for different types of materials and coatings of the rollers.
The test stops, when the level of vibration increases, due to generation of pitting in the contact. The thermal fatigue test bench has been built to simulate thermal cycles of high temperature generated by induction heating and low temperature cooled with spray. The machine has been developed to simulate the heating and cooling cycles of the high pressure die casting dies.
The time to thermal fatigue crack failure mainly depends on a the maximum temperature, b the temperature gradient, c the geometry, and d the designed cooling channels inside the mold testing block. The machine can simulate a time to thermal fatigue failure similar to the real applications Figure 8 [ 20 ]. Brake disc testing machine is built with the objective of carrying out friction, wear, and thermal fatigue tests of disc brakes and brake drums.
During the test, the torque and the temperature and wear are recorded. Different protocols from automotive suppliers can be applied e. Clutch dynamometer test has been built with the objective to measure the friction and wear of the clutches at fixed or variable conditions of load and speed.
Measurement of force, the friction loss between the cylinder and braking films, and temperatures at different points, forces, torque, and speeds are recorded. The specific power, specific energy, the dynamic and static torques, the sliding time, and initial speed can be monitored during breaking or evaluated during the test Figure 10 [ 22 ].
The machine has been adapted to work under variable temperature integrating a climatic chamber.see url
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The test chamber is modular, and it has the capability to measure the differential pressure between the two sides of the seals for pistons and rollers and evaluate the leakage. Glass and mirror wash test has been built to evaluate the scratch abrasion resistance of coatings used in glass of the cars and solar mirrors. In automotive sector, the glass car wash resistance is assessed. A machine-based washing is simulated in the laboratory environment using a rotating brush and synthetic dirt. The test conditions have been designed to be as close as possible to the real conditions in a car wash and solar mirrors, in order to evaluate the cleanability, the abrasion resistance, and their durability.
Different case studies have been selected to cover examples of different tribological characterization tools and equipment used for material selection composition, topography, surface treatments, lubricants , making emphasis in the failure mechanism and friction simulation of a wide variety of materials, tribological systems, and environments. For example, it has been observed that it is possible to find non-halogen ionic liquids to lubricate steel under vacuum and ultrahigh vacuum conditions e.
The desorption of CF 3 detected in the mass spectra occurred just in the moment when the friction was reduced see Figure 13a. During the test, a TiFx tribolayer was generated. The reaction mechanism that explained the TiFx layer generation was elucidated see Figure 13c thanks to the fragments of the mass spectra see Figure 13b detected during the tribodesorption process.
The DEMETRA machine see Figure 2 was built to measure the outgassing under vacuum to screen and select the materials and lubricants that can work under these conditions. It has also been used to study dependence of outgassing of thermal fluids in function of the viscosity for heat exchangers see Section In this study, the torque of different antifouling paints before and after immersion in a ship or in the Motrico Port has been compared. The effect of biofouling, roughness, and fluid properties can be measured.
In the example, two fluids FX1 and FX2 were tested and being selected FX2 due to their lower drag friction in all the range of speeds tested. Comparative drag friction measurement of two antifouling coatings, before and after 1-year sea exposure in a ship. The coupling of standard tribometers with a potentiostat has been done to measure wear-corrosion behaviour, that means to study the mechanical, the chemical wear and the synergy between both phenomena. These results correlate well with the wear scars measured after the test, for both coatings see Figure High-strength low-alloy HSLA steels employed in offshore applications suffer high degradation due to their high corrosivity in seawater and the wear generated during mooring chain movement.
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The results, obtained in the frame of the FONDEO Adhoc project financed by the Spanish Minister of Science, showed an acceleration of corrosion during wear experiments, as consequence of the synergism generated between wear and corrosion. In Figure 17 i , it can be seen, how the sliding has modified the electrochemical behavior of both steels. The effect of several parameters such as seawater temperature or salinity have also been studied to understand their influence in the steel degradation [ 13 , 14 ]. In order to protect steels in mooring lines of floating structures, it has been developed some surface treatments based on thermally sprayed aluminum TSA coating with and without post-treatment by plasma electrolytic oxidation PEO.
In Figure 17 j , it can be highlighted the reduction of wear scar after tribocorrosion tests, can be highlighted and produced when the TSA coating on the steel is additionally treated by plasma electrooxidation Figure 17 jb [ 15 , 16 ]. Two testing benches have been constructed see Figure 4 for Mecauto company to study the torque and wear in axial and radial bearings.
Also, a standard tribotest has been adapted to study the limits of pressure and velocity of the tribological pair. In the frame of EREBIO EU Project, the reduction of friction and contact temperature has been proven when using a biodegradable low-viscosity and environmentally friendly engine oil for the lubrication of bearings using a basic thrust washer configuration [ 17 ]. The research methods and progress of AI in tribology were summarized as follows: design tribological system; design and optimize formula of friction materials; analyze typical tribological performance parameters such as friction coefficient, friction heat and wear rate; monitor and diagnose friction states and wear forms.
Results: In order to improve the efficiency and effectiveness of AI in solving tribological problems, current development and applications of AI in tribology are provided specifically. Conclusion: AI technologies are greatly beneficial to solve complex and nonlinear tribological problems. Owing to that various AI technologies have their advantages and shortcomings, combinations of different AI technologies must be more effective in solving tribological problems.
In this article, various patents have been discussed. Keywords: Artificial intelligence, fault diagnosis, friction material, performance prediction, state monitoring, tribology design. Abstract: Background: Tribological system is a complex nonlinear system. Purchase Instant Access. View Preview. Learn more Check out. Volume 11 , Issue 2 December Pages Related Information. Close Figure Viewer. Browse All Figures Return to Figure. Previous Figure Next Figure. Email or Customer ID. Forgot password? Old Password. New Password.