Development of damage detection parameters over the lifetime of a rolling element bearing

This paper presents the trends of damage detection parameters over the lifetime of a rolling element bearing. In the experimental part, a series of bearing tests was performed using the twin-disc test device, until the monitored bearing was severely worn. This was followed by the analysis of measured acceleration and acoustic emission data in a constant-load condition, but also as loaded with impact-type loading. The results showed that traditionally used parameters, such as kurtosis and RMS, can indicate whether the bearing is damaged or not in a non-impact load condition. However, especially under impact-loading, the parameters based on acoustic emission data showed good performance and enabled monitoring of progress of the bearing damage.

Inhibition Evaluation of 5-(4-(1H-pyrrol-1-yl)phenyl)-2-mercapto-1,3,4-oxadiazole for the Corrosion of Mild Steel in an Acidic Environment: Thermodynamic and DFT Aspects

In this investigation, an oxadiazole namely 5-(4-(1H-pyrrol-1-yl)phenyl)-2-mercapto-1,3,4-oxadiazole (PMO), was synthesized and explored as an inhibitor against the corrosion of mild steel in 1.0 M hydrochloric acid environment at various solution temperature 303-333 K. gravimetric, and microscopic techniques, namely, weight loss (WL), and scanning electron microscopy (SEM), have been used to evaluate the inhibitive performance of the tested PMO. The results of the WL method displayed that the inhibition efficiency (%IE) was found to increase with the inhibitor concentration, while it reduced with increasing temperature. Furthermore, the WL results reveal that PMO inhibits corrosion display an IE of 95% at the highest concentration of 0.005 M. The SEM images of the mild steel surface coupon after adding PMO revealed a wide coverage of PMO molecules on the mild steel surface. Hence, the high inhibiting efficiency acquired by the tested inhibitor was explained by the strong adsorption of PMO molecules on the surface of mild steel. A protective layer has been constructed and it separating the mild steel surface from the hydrochloric acid solution, and such adsorption was found to obey Langmuir adsorption isotherm. Moreover, the thermodynamic parameters suggested that the adsorption nature of PMO molecules on the coupon surface was chemo-physisorption. Quantum chemical calculations were conducted by density functional theory (DFT) which help correlate the methodological findings with the theoretical investigations. The mechanisms of PMO molecules as corrosion inhibitor for mild steel surface in the corrosive environment was also discussed.

Tribological studies of different bioimplant materials for orthopedic application using Taguchi experimental design

In this research ball on disc wear tests have been carried out with ASTM G-99 standard at room temperature in simulated body fluid. The tribological property such as the coefficient of friction and wear weight loss was studied by using the Taguchi design of experiments. The design of the experiment was done using L8 orthogonal array to determine the collective contribution of the wear parameters. An analysis of variance demonstrated that the individual contribution of type of material factor was 97.15% and 66.66% for the coefficient of friction and wear weight loss respectively, which is the highest individual contribution as compared to other factors. It was concluded that the coefficient of friction and wear weight loss is mainly influenced by type of material factor. The analysis of the signal-to-noise ratio shows that the optimal coefficient of friction and wear weight loss was obtained with CoCrMo material at an applied normal load of 5 N with a sliding velocity of 0.05 m/s for a track diameter of 30 mm. To check the accuracy of results a confirmation test was carried out which indicates that predicted values are very close to the experimental values and the model is significant to predict the coefficient of friction. The results showed that the coefficient of friction and wear weight loss increases with increasing the applied load and sliding velocity. The microstructure of all substrates materials was analyzed using a scanning electron microscope. Wear track study showed that adhesive dominant wear mechanism for all four different substrate materials.

Wear and Friction properties of H-Al-17Si alloy with dry, lubrication and coated (DLC-Star) conditions under HFRR

Dry, lubrication (SAE15W40), and coated (DLC-Star) reciprocating tribological tests on rapid solidified AlSi17Cu3.5-4Mg0.6-0.8 alloy was conducted using a high frequency linear reciprocating rig (HFRR) at ambient temperature. The alloy fabricated with the rheo-stir squeeze casting procedure under T-6 condition. However, at different loading (0-30 N) conditions, wear and friction properties of rapid solidified H-Al-17Si alloy are investigated. It is observed that the lower friction coefficient value obtained for DLC-Star coated H-Al-17Si alloy compared to dry and lubrication conditions. Though, for dry and lubricated sliding, the obtained wear coefficient values are 2.9X10-3 mm3/N.m and 4.0X10-4 mm3/N.m. A lower coefficient of wear value of 5.4X10-5 mm3/N.m was recorded with DLC-star coating under dry conditions. The alloy wear coefficient values first increases with applied load (up to 20 N) and then decreases (20 N to 30 N). EDS, AFM surface roughness profilometer, SEM, and advanced metallurgical microscope (AMM) analysis techniques used for the characterization of surface morphologies. The developments in friction and wear coefficients were fundamentally ascribed to the dispersion and size of primary Si elements and the development of tribo-oxide films on the rapid solidified AlSi17 alloy coated (DLC-Star) surfaces.

Study on Solid Particle Erosion of Pump Materials by Fly Ash Slurry using Taguchi’s Orthogonal Array

Various grades of stainless steel are used to fabricate the pump impeller, casings, and seals used in heavy-duty erosion and corrosion conditions. In the present study, stainless steel (SS316L, SS304, SDSS2507) and grey cast iron used in the fabrication of heavy-duty pump impellers were taken for the analysis of solid particle erosion. Experiments were conducted on the lab-scale slurry pot tester. Fly ash slurry was prepared of different concentrations (wt%). Taguchi’s orthogonal array is used to design the experiments of erosion wear for the variation of rotational speed, solid concentration, time, and particle size. Results showed that SS316L showed superior microhardness and wear behavior against the fly ash slurry followed by SS304, SDSS2507 and Grey cast iron.

Effect of Boron Carbide on wear resistance of graphite containing Al7029 Based Hybrid Composites and its Dry Sliding Wear Characterization Through Experimental, Response Surface Method and ANOVA

Composites are often chosen for tribological applications due to its tailored material properties. The development of hybrid metal matrix composites and the study of their wear behavior has been a prominent focus of materials science research. Present paper deals with fabrication of Al-7029/B4C/Gr hybrid composite using stir casting. Particle distribution and material phase are identified by SEM and XRD. Hardness of the composite increased to 101 BHN while base alloy with 63 BHN. Pin-on-disc Tribometer used to carry wear test and the experimentation conducted by considering three input wear control parameters: 15–35 N (load), 1.5–3.5 m/s (speed) and 200–600 m (distance). Addition of 6%B4C/3%Gr, wear rate of hybrid composites reduced. ANOVA confirmed that load as the most influencing parameter on wear rate. RSM results correlates with mean effect plots of ANOVA and experiments and found that the results are in good compliance. SEM graphs of worn surface confirms that more wear occurred with increased load.

Study On Effect of Boron Carbide, Aluminium Oxide and Graphite On Dry Sliding Wear Behaviour of Aluminium Based Metal Matrix Composite at Different Temperature

The present research has been conducted to study the impact of boron carbide (B4C), aluminium oxide(Al2O3) and graphite on Aluminium 2219 (Al2219). According to current research, B4C and graphite material be a good substitute for Al2219.Reinforced composites and unreinforced Al2219 prepared by a stir casting process. A scanning electron microscope was used to analyze the reinforcement and distribution in the matrix and worn surface of the specimen. Exceptional wear resistance (30%) exhibited by B4C and graphite-reinforced hybrid composite at 150 ºC in contrast with the unreinforced Al2219. The B4C and Gr reinforcement particulate existence improves the strengthening kinetics in the matrix phase at 150 °C. The artificial neural network used to get the test significance, normalized factor importance and absolute relative error of less than 1%.

The analysis of fretting fatigue in forced-in joint with the induction-hardened shaft

Subject to the analysis was a tribological kinematic pair consisting of shaft and sleeve, both made of C45 steel. The elements were joined by pressing with the 0.02 mm tolerance. The shaft was subjected to the finishing and strengthening treatment consisting in induction hardening. The tribological kinematic pair made in such way was tested on a fatigue testing machine, which permitted obtaining a rotational bending moment. Macroscopic investigations of the unhardened shaft demonstrated, on the shaft surface, the traces of fretting wear in the form of a ring of the uniform width comprising the entire axle seat circumference. Based on the test results, it may be concluded that the use of the shaft induction hardening process has caused the reduction of fretting wear development compared to shafts without additional treatment. In this case, Wear traces in the form of small diameter ring comprising the entire shaft circumference are observed on one side of the shaft axle seat.

Mechanical and the effect of oil absorption on tribological properties of carbon-based brake pad material

This research focuses on the mechanical and effect of oil absorption on the tribological properties of carbon-based brake pad material (CBP). Carbon-based materials, including those at a nanosize, are combined for developed brake pad material. The mechanical properties related to wear properties such as compression strength, stiffness, hardness, and absorption properties were determined. The effect of oil absorption on the tribological properties of carbon-based materials was investigated. The obtained properties are compared with that of a ceramic-made brake pad (commercial). The experimental results show that the mechanical and absorption properties of the developed brake pad material varied with the combination and quantity of additives used to develop each brake pad material. CBP material offered higher performance than ceramic-made brake pads. The CBP material showed a higher shear strength of about 110%, 51% enhanced compressive strength, 35% greater modulus, comparative statistical hardness, 98% lesser water intake, and 97% oil absorption rate than ceramic made brake pad. The tribological properties of friction material after soaked in oil proved that absorption properties affect tribological properties of brake pads, which can be attributed to the oil content in the material system. The effect of oil uptakes on wear rate and friction of the commercial brake pad was higher than CBP materials, implying that the loading of carbon-based materials is a viable way to reduce absorption rate, which helps in increasing brake pad performance. The improved properties are suggestive of materials combinations that may be used to develop brake pad materials.

Wear and corrosion interaction of AISI D2 in an acidic environment

The tribological, electrochemical and tribo-electrochemical behavior of bare AISI D2 was studied. The tribological aspects were tested by pin on disc with an aluminum oxide ball as counter body, the electrochemical tests were performed in an aqueous solution of citric acid and the tribo-electrochemical evaluation was through a combination of both tests. AISI D2 steel presented abrasive wear in dry and wet conditions, such type of wear occurred due to stick-slip motion, moreover, in wet conditions the alloy corroded at corrosion current values around 10-6 A/cm2. The damage produced over the wear track was larger under wet conditions than for the dry conditions.