Excessive Wear Research Articles

Stretch flangeability of AHSS automotive grades versus cutting tool clearance, wear, angle and radial strain gradients

Stretch flangeability tests are performed on cold rolled AHSS automotive steel grades for crack sensitivity evaluation. The ISO16630 tests procedure is used with different cutting edge conditions including cutting clearance, cutting tool wear, cutting tool angle and hole expansion punch tool geometry. Among all influence parameters, the cutting clearance is considered to be the most critical to control. Low (<10%) and high (>20%) clearances are significantly detrimental to hole expansion ratio (HER). An optimum in HER is reached around 15% clearance. Both cutting punch wear and cutting die wear each affect negatively the HER values in comparison to new sharp cutting tools. Varying the cutting angle with concave and convex hole punching tool geometries instead of orthogonal cutting has a rather negative effect on stretch flangeability due to irregular cut edge quality along hole perimeter and excessive tool wear in the concave configuration. The influence of hole expansion punch geometry (flat R25, biaxial Nakajima R25 vs. ISO16630 60° conical) on the HER values is also investigated. The (true) HER values are proportional to the FE simulated logarithmic radial strain gradient at fracture.

STUDY OF THE CLINICO-RADIOLOGICAL OUTCOME OF PCL RETAINING TOTAL KNEE ARTHROPLASTY IN SEVERE VARUS DEFORMITY: A PROSPECTIVE OBSERVATIONAL STUDY.

Introduction: The role of the posterior cruciate ligament (PCL) in total knee arthroplasty (TKA) has been widely discussed in the orthopedic literature. It has been suggested that PCLretaining can produce femoral rollback, which increases the range of exion and prevents posterior translation. This in effect, reduces loosening and excessive polyethylene wear by decreasing the shear stresses at the xation surfaces. With consideration proper selection of patients, adequate attention to surgical technique and asepsis, proper Intra-operative soft tissue balancing, correct alignment of prosthesis and postoperative rehabilitation of patients, cruciate retaining total knee replacement has yielded excellent results Aim: The aim of this prospective study is to evaluate the clinic-radiological outcome of PCL retaining total knee arthroplasty in severe varus deformity Materials and Methods: This is a prospective study in which patients were randomly selected, and PCL retaining surgery was done for those knees with severe varus deformity and assessed the functional outcome using functional knee scores and oxford knee score and WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) questionnaires during the period between July 2016 to June 2018. Conclusion: PCL-retaining total knee arthroplasty appears to provide better range of motion and stair-climbing ability similar to anatomical knee.

The detection of generator bearing failures on wind turbines using machine learning based anomaly detection

In this research an early warning methodological framework is developed that is able to detect premature failures due to excessive wear. The methodology follows the data-driven Normal Behavior Model (NBM) principle, in which one or more data-driven models are used to model the normal behavior of the wind turbine. Anomalous behaviour of the turbine is identified by analyzing the deviation between the observed and predicted normal behaviour. The framework consists of two pipelines, a statistics and machine learning based pipeline. The former is based on techniques like ARIMA, OLS and CUSUM. The latter makes use of techniques like Random Forest, Gradient Boosting, … Each pipeline has its strengths and weaknesses, but by combining them in an intelligent way, a more capable detector is developed. The methodology is validated on 10-minute SCADA data from a real operational wind farm. The validation case focuses on generator (front/rear) bearing failures. The goal is to predict these failures well in advance (ideally at least a month) using the developed framework, which should allow for timely adjustments to the maintenance plan. The results show that the methodology is able to accomplish this reliably.

Current status and future potential of wear-resistant coatings and articulating surfaces for hip and knee implants.

Hip and knee joint replacements are common and largely successful procedures that utilise implants to restore mobility and relieve pain for patients suffering from e.g. osteoarthritis. However, metallic ions and particles released from both the bearing surfaces and non-articulating interfaces, as in modular components, can cause hypersensitivity and local tissue necrosis, while particles originating from a polymer component have been associated with aseptic loosening and osteolysis. Implant coatings have the potential to improve properties compared to both bulk metal and ceramic alternatives. Ceramic coatings have the potential to increase scratch resistance, enhance wettability and reduce wear of the articulating surfaces compared to the metallic substrate, whilst maintaining overall toughness of the implant ensuring a lower risk of catastrophic failure of the device compared to use of a bulk ceramic. Coatings can also act as barriers to inhibit ion release from the underlying material caused by corrosion. This review aims to provide a comprehensive overview of wear-resistant coatings for joint replacements – both those that are in current clinical use as well as those under investigation for future use. While the majority of coatings belong predominantly in the latter group, a few coated implants have been successfully marketed and are available for clinical use in specific applications. Commercially available coatings for implants include titanium nitride (TiN), titanium niobium nitride (TiNbN), oxidized zirconium (OxZr) and zirconium nitride (ZrN) based coatings, whereas current research is focused not only on these, but also on diamond-like-carbon (DLC), silicon nitride (SiN), chromium nitride (CrN) and tantalum-based coatings (TaN and TaO). The coating materials referred to above that are still at the research stage have been shown to be non-cytotoxic and to reduce wear in a laboratory setting. However, the adhesion of implant coatings remains a main area of concern, as poor adhesion can cause delamination and excessive wear. In clinical applications zirconium implant surfaces treated to achieve a zirconium oxide film and TiNbN coated implants have however been proven comparable to traditional cobalt chromium implants with regards to revision numbers. In addition, the chromium ion levels measured in the plasma of patients were lower and allergy symptoms were relieved. Therefore, coated implants could be considered an alternative to uncoated metal implants, in particular for patients with metal hypersensitivity. There have also been unsuccessful introductions to the market, such as DLC coated implants, and therefore this review also attempts to summarize the lessons learnt.

Failure analysis of scraper conveyor based on fault tree and optimal design of new scraper with polyurethane material

The scraper conveyor is an important equipment in modern coal mining process. Traditional alloy steel scrapers, as one of the main components of the scraper conveyor, are disadvantageous in that they are not only vulnerable to failures such as fracture and wear, but also take up over 35% of the output power to rotate themselves, resulting in excessive idle load. In order to improve the running state of the scraper and the overall loading of the scraper conveyor and extend the service life of the scraper, a transportation system fault tree of the scraper conveyor was drawn based on fault tree analysis. The minimum cut set of the fault tree was calculated. The Fussel–Vesely importance (FV) of scraper failure to transportation system was 0.458. Failure of the original scraper primarily includes wear and fatigue, as result from the excessive wear caused by the sliding friction between the scraper and the middle trough. A new optimized scraper design was developed: the support was forged from PU material to reduce self-weight and increase buffer capacity; the scrape was restructured to include rolling elements and a detachable support, which transformed sliding friction to rolling friction. Use of the new scraper in a mine reduced the idling rate of the scraper conveyor to 23% and increased the scraper service life by around 3 times. The research result of this paper could provide reference for further application of lean design theory in the updating of coal mining equipment.

The Use of the Permutation Algorithm for Suboptimising the Position of Used Nozzles on the Field Sprayer Boom

The worn-out nozzles of field sprayers cause agricultural treatment to be uneven and therefore ineffective. Spray nozzles are consumable elements of the field sprayer that are subject to inspection and in the event of their excessive wear should be replaced with new ones to ensure the proper execution of agricultural treatment. The aim of the study is to propose, using operational research methods, an expert methodology allowing further operation of worn-out and often expensive sprayer nozzles, including standard, universal, anti-drift, or ejector nozzles. The previous attempts, performed with the use of the random computer optimisation method, did not guarantee a global solution in the entire population of all possible permutations without repetitions of 24 worn-out nozzles (for a field boom with a width of 12 m) or even estimating approximation to this solution. The process of measuring the wear of nozzles, the simulation of the entire virtual field boom, and the permutation algorithm proposed here allow you to specify a suboptimal solution of an NP-hard problem separately for each sprayer, i.e., to indicate in a very short time such a permutation out of 24! ≈ 6.20448 × 10+23 permutations of nozzles with variable degrees of wear, which is close to the optimal permutation of used nozzles on the field sprayer boom, in terms of the coefficient of variation. The use of expert methodology allows for reducing the operating costs of sprayers by using a relatively cheap automated expert service instead of the costly purchase of a set of new nozzles for field sprayers. Many areas of application of this methodology have been indicated.

OPTIMIZATION OF THE FRICTION DRILLING TOOL FOR HOLE MAKING IN COMMERCIAL COPPER PLATE

In friction drilling technique, friction is developed in between work material and rotating tool. In this method, friction heat is generated. Also, material heat is generated and due to this, tool was penetrated without formation of chip and hence this method is classified as a chip less hole making method. One of the issues faced in friction drilling process is excessive wear of tool. To address this issue in the context of copper plate, two different materials of H13 steel tool and HSS tool with two combinations (straight and conical profile) were investigated and compared. For this process, CNC 3 axis machine was used for drilling hole on a 3[Formula: see text]mm thick copper plate. This study validated that HSS straight profile tool displayed lesser wear of 0.093[Formula: see text][Formula: see text]m at 50[Formula: see text]mm/rev feed rate and 3000[Formula: see text]rpm spindle speed.

Wear law of Q345 steel under the abrasion–corrosion synergistic effect of cemented paste backfill

Excessive pipe wear affects the continuity and safety of the delivery of cemented paste backfill (CPB). However, the dominant factors affecting the wear of CPB transportation pipelines are not well understood. The goal of this study is to determine the wear law of the Q345 steel pipeline under the abrasion–corrosion synergistic effect of CPB at varying mass fractions (76–82%), flow velocities (1–2.5 m/s), and rheological parameters. A mini cathodic protection system was installed in the slurry pot tester to simultaneously acquire the total wear and pure abrasion, while pure corrosion was obtained via immersion testing. The results indicate that the total wear and pure abrasion exhibit a power-law increase according to flow velocity and grow exponentially as the CPB mass fraction increases. CPB with increasing yield stress and plastic viscosity leads to an exponential growth in the total wear and pure abrasion. However, a higher solid fraction not exceeding a certain critical value effectively alleviates pipe wear and resistance. In most cases, the synergistic effect of abrasion–corrosion contributed to more than 50% of the total wear. CPB mass fraction and the abrasion-corrosion synergistic effect are the dominant factors affecting the total wear of the CPB-transporting pipeline and should be properly controlled in practice. CPB with a solid fraction ranging between 76 and 78% at a flow velocity of 1.57 m/s and pipelines made of corrosion-resistant materials are recommended for the mine of interest. The findings are conducive to the selection of appropriate pipeline materials and CPB transportation parameters.

Hubungan Antara Riwayat Pekerjaan Dengan Derajat Osteoarthritis Pada Wanita Usia Di Atas 65 Tahun

Introduction: Osteoarthritis is a chronic degenerative disease characterized by pain and joint cartilage damage. Osteoarthritis is a disease that disrupts the homeostasis of cartilage metabolism so that it damages the proteoglycan structure in cartilage caused by age, excessive joint wear, anatomic defects, mechanical or chemical stress, obesity, genetics and humoral. Osteoarthritis generally occurs in the knees, feet, shoulders, hands, spine, and hips. Certain work conditions that require more strenuous physical movements such as lifting heavy weights and going up and down stairs are a risk factor for osteoarthritis. The purpose of this study was to determine the relationship between work history and the degree of osteoarthritis in women aged over 65 years. Methods: This is an analytical observational research with cross sectional study design. The Subject in this research is medical record patient RSUD DR MOEWARDI SURAKARTA Hospital who have met the criteria. Sampling was done using simple random sampling technique. Data was collected and then analyzed using Spearman correlation test. Results: The analysis result from 46 samples using Spearman correlation test obtained a p value of less than 0.05 indicating that there is a significant relationship between work history and the degree of osteoarthritis in women aged over 65 years. Conclusion: There is a significant relationship between work history and the degree of osteoarthritis in women aged over 65 years. Keywords: Osteoarthritis; Occupational History; Degree of OA

Thermal behavior of friction discs in dry clutches based on a non-uniform pressure model

To investigate the thermal behavior of friction discs in dry clutches during long-term slipping, a two-dimensional transient thermal model was established using the finite element method. Because the pressure distribution on the friction interface is important, a dimensionless non-uniform pressure model was proposed based on measured data using Fuji Prescale pressure-sensitive films arranged on the friction disc. Subsequently, the frictional heat flux, which varied nonlinearly with the radius, was determined. The heat conduction processes of the friction pairs were analyzed in detail. The results of the temperature distribution calculated using the non-uniform pressure model agree well with those obtained from dynamometer experiments. The results reveal that high temperatures exist near the high-pressure region on the friction interface. Compared to the results of two conventional models, those of the non-uniform pressure model are closer to the experimental data. The maximum temperature error is reduced by 23.23% and 34.03% relative to the uniform pressure and uniform wear models, respectively, after a 15 s slipping period. Therefore, by using the non-uniform pressure model, the thermal analysis can be more effective in avoiding excessive wear and prolonging the service life of dry clutches.

Wear Study of Cubic Boron Nitride (cBN) Cutting Tool for Machining of Compacted Graphite Iron (CGI) with Different Metalworking Fluids

Due to its desirable mechanical properties, compacted graphite iron (CGI) has been used to replace conventional gray cast iron (CI) in various applications, such as automotive engine blocks and cylinder heads. However, the poor machinability of CGI can lead to excessive tool wear and consequently high manufacturing costs. Various strategies have been developed to improve the machinability of CGI, including optimizing machining parameters and the development of novel metalworking fluids. In this study, machining of CGI was conducted using cubic boron nitride (cBN) tools under different cutting speeds, with both soluble and full-synthetic water-based metalworking fluids at different levels of sulfur addition and water dilution. The effects of the metalworking fluids on the tool wear behavior were examined. Results showed that at 200 m/min cutting speed, the soluble metalworking fluid at 4% dilution and 0.3% sulfur compound exhibited the best performance, with a cutting distance reaching 23.8 km. In contrast, the least effective soluble metalworking fluid at 9% dilution and 0.3% sulfur compound resulted in a 28.6% decrease in the cutting distance (17.0 km) compared to the best one. At a higher speed (300 m/min), the cutting distance for all metalworking fluids dropped to less than 6.0 km, with the full-synthetic metalworking fluid showing the shortest cutting distance of 4.8 km.

Prediction of Dynamic Stick-Slip Events in Belt-Drives Using a High-Fidelity Finite Element Model

AbstractA high-fidelity dynamic finite element model of a one-pulley belt-drive system is used to study how Coulomb friction coefficient and adhesion stress affect belt stick-slip events over driver and driven pulleys. The model shows that at Coulomb friction coefficient below a certain critical value, the belt undergoes pure sliding in the slip arc on driver and driven pulleys with no stick-slip dynamic events. Above that critical friction coefficient value dynamic stick-slip events start to occur in both driver and driven pulleys resulting in torque pulses, which for practical belt-drives may cause nonsmooth operation, excessive belt noise and/or excessive belt wear. For driver pulleys the dynamic stick-slip events are in the form of Schallamach waves, while for driven pulleys the dynamic stick-slip events are in the form of expansion pulses. The model results are validated using recently generated experimental results.

Prediction and analysis of slurry shield TBM disc cutter wear and its application in cutter change time

Disc cutter is mainly used in cutting through hard rock. Disc cutter wear is inevitable during tunnel boring machine (TBM) tunneling, and excessive wear can lead to a decrease in tunneling efficiency and increase construction risks. Therefore, the importance of predicting the disc cutter wear accurately and arranging the cutter change plan can never be overemphasized. In this study, disc cutter wear data and replacement records for three shield chamber openings were analyzed, which were collected from a water conveyance tunnel project in Guangdong, China. It was found that the normal wear failure accounted for approximately 76.19%, while the abnormal wear failure accounted for 23.81%, and the range of tools to be replaced due to normal wear continues expanded as the tunneling distance increased. Based on the observed wear data, it is found that the wear rate of edge tools is much lower than that of center tools, which does not conform to the normal wear rules. Subsequently, a new disc cutter wear prediction model was developed considering energy conversion and uneven thrust distribution for explaining this problem. The determination method of the energy conversion coefficient k and thrust distribution coefficient b was proposed, and they had been obtained from the wear data in the first replacement. On the other hand, the proposed model has higher accuracy in both cutter wear and cutter change range prediction compared with the existing models. However, the prediction accuracy of the proposed model will decrease with the increase of the tunneling distance, so the undetermined coefficients k and b need to be updated in a timely manner.

Effects of submerged convective cooling in the turning of AZ31 magnesium alloy for tool temperature and wear improvement

Low melting point and material adhesion are associated challenges of magnesium alloy, leading to extreme built-up edge (BUE) and built-up layer (BUL) formations during machining process. Dry machining is favorable for machining magnesium alloy. However, this strategy inflicts excessive adhesive wear on the cutting tool. Therefore, this current work focuses on application of an innovative cooling technique, known as submerged convective cooling (SCC) for the turning of AZ31 magnesium alloy. Prior to cutting experiment, a computational fluid dynamics (CFD) simulation was conducted to evaluate internal structure of cooling module. Based on the CFD simulation, a small inlet/outlet diameter of 3 mm significantly contributed to the reduction of the tool temperature, due to high heat transfer coefficient of cooling fluid in the SCC. From the experimental results obtained, it was evident that SCC at high cooling water flow rate of 130 mL/min effectively reduced the tool temperature, chip temperature, and tool-chip contact length by approximately 50, 8, and 28%, respectively. Consequently, it improved the surface roughness by 37%, when compared with the dry cutting condition. Finally, both BUE and BUL were observed in dry and SCC conditions, but the severity of these wear mechanisms improved or decreased remarkably under SCC conditions.

Measurement and prediction of wear volume of the tool in nonlinear degradation process based on multi-sensor information fusion

Excessive tool wear seriously affects the surface quality of the workpiece and reduces the processing efficiency. Therefore, real-time monitoring of the tool wear status is very important. This paper proposes a new tool wear prediction method based on multi-sensor hybrid domain information fusion. First, the collected multi-sensor signals are decomposed by wavelet packet to extract the energy values of 16 frequency bands; in addition, the energy values are combined with the time domain and frequency domain features to construct a hybrid domain feature set; then, the gated recurrent unit model is used to adaptively explore the internal relationship between the hybrid domain features and tool wear, which overcomes the low efficiency of manual feature fusion monitoring; finally, the wear milling cutter data is used to verify the superiority of the proposed method. The results show that the prediction accuracy of tool wear based on multi-sensor feature fusion is significantly better than that based on a single sensor. Also, compared with traditional wear prediction methods, it again verifies the advancement of the proposed method in predicting tool wear.

Online Wear Particle Detection Sensors for Wear Monitoring of Mechanical Equipment—A Review

Online wear particle detectors have been widely studied due to their ability to monitor the wear state of machines, and to help to prevent serious mechanical failures caused by excessive wear of components. This paper presents a review of the state-of-the-art wear debris detectors based on different principles. That mainly includes optical/imaging particle detectors, electrical particle detectors, ultrasonic particle detectors and magnetic debris detection sensors. Meanwhile, the characteristics and the performance (sensitivity, maximum flow rate, and the detectable information) of each type of sensor are detailed discussed. In conclusion, the optical/imaging and magnetic debris detectors have become promising technologies in the field of wear monitoring. Meanwhile, that the rapid extraction algorithm and three-dimensional reconstruction method of wear debris for optical/imaging debris detectors, and improving the sensitivity and detectability of magnetic debris detectors are the two important research contents in the field. Besides that, it can be predicted that the integrated wear monitoring system that can collect multiple wear-information in-situ, and the intelligent wear particle detector that have the ability of wear monitoring, wear evaluation and fault warning are the main research directions in the future.

Investigation of Excessive Wear of Ashaka Coal Mill Riser Duct and Idendifying the Optimum Solution

Cement plants use fuel in burning limestone to make clinker in kilns. Due to high cost of fuels, most Cement plants are changing from high-cost liquid fuel like heavy fuel to cheap solid fuel like coal. Ashaka adopt the later. The coal is first pulverised in a ball mill and leaves the mill through a riser duct by pneumatic transport before been used in the kiln as fuel. The riser duct undergoes excessive wear which result in frequent downtime and affect the intendent purpose of fuel substitution. Also, the pulverised coal escaping under pressure through eroded areas on the duct increase the risk of fire and reduce the overall safety of the workshop. Current method which involved patching the duct by welding fail to solve the problem. This work investigates the root cause of the frequent wear of the riser duct by checking the abrasiveness of the coal being transported, checking the effect of the duct profile on wear through simulation using computational fluid dynamics (CFD). Checking the duct material rate of wear and providing the best solution in terms of cost and feasibility. After simulation using CFD it was revealed that the duct profile contributed to the wear rate. Since changing the profile will be costly, a different solution approach was considered i.e., surface finishing. Different Material samples suggested to be used as surface finishing on the duct were tested for wear at different angles using an abrasive test equipment. The test equipment which conforms with ASTM was designed, simulated using CFD and constructed. The best material with good wear resistance was found to be galvanised steel coated with automobile anti gravel and grounded with P1000. Coating the internal of the riser duct with the above material is considered to be the optimum solution in terms of cost and feasibility.

Robust Composite Dynamic Event-Triggered Control for Multiple USVs with DLLOS Guidance

In this paper, a robust composite dynamic event-triggered formation control scheme is proposed for multiple underactuated surface vehicles (USVs) from two aspects, i.e., guidance and control. In the guidance module, a novel dual-layer line-of-sight (DLLOS) guidance principle is incorporated into the leader–follower framework to generate the reference path. To overcome the problem of unavailable leader velocity information, an adaptive speed controller is designed to adjust the navigational speed of followers. As for the control part, by utilizing the dynamic event-triggered method, the operational frequency of actuators can be reduced in a flexible manner. That can effectively avoid the excessive wear and chattering phenomenon of actuators. Furthermore, by the fusing of the radial basis function neural networks (RBF NNs) and the robust neural damping technique, the model uncertainty, environmental disturbances and some unknown parameters can be remodeled, and only two gain-related adaptive laws need to be updated online. The serial–parallel estimation model (SPEM) is established to predict the velocity variables, and the approximation performance of NNs can be enhanced by virtue of the derived prediction error. Through the Lyapunov stable theorem, all control signals in the closed-loop system are guaranteed semi-globally uniformly ultimately bounded (SGUUB) stability. Finally, digital simulations are illustrated to verify the effectiveness and superiority of the proposed algorithm.

A Study on the Effect of Inlet Air Pollution on the Engine Component Wear and Operation

This paper systematically reviews the research progress in the field of the influence of air pollutants in the engine inlet on the accelerated wear of the elements of the association: piston, piston rings, cylinder liner (P-PR-CL), and plain bearing (journal–panel). It was shown at the outset that the primary component of air pollution is road dust. Its main components are dust grains of hard minerals (SiO2, Al2O3), which penetrate the oil film area between two frictionally mating surfaces causing their abrasive wear. Therefore, the effect of three dust parameters (grain size and hardness, and dust concentration in air) on the accelerated wear of the friction pair: piston, piston rings, cylinder liner(P-PR-CL), and plain bearing (journal–pan) is presented extensively. It was noted that the wear values of the same component were obtained by different researchers using different testing techniques and evaluated by different indices. It has been shown that the greatest wear of two frictionally cooperating surfaces is caused by dust grains with sizes equal to the thickness of the oil film at a given moment, which in typical combustion engine associations assumes varied and variable values in the range of 0–50 µm. The oil film thickness between the upper ring and the cylinder liner varies and depends on the crankshaft rotation angle, engine speed and load, and oil viscosity, and takes values less than 10 µm. It was shown that the maximum wear of the cylinder liner, resulting from the cooperation with the piston rings, occurs in the top dead centre (TDC) area and results from unfavorable (high temperature, low piston speed) operating conditions of these elements. From the extensive literature data cited, it follows that abrasive wear is caused by dust grains of specific dimensions, most often 5–20 µm, the greater the wear the greater the hardness of the grains and the sulfur content of the fuel. At the same time, it was shown that the main bearing, crankshaft bearing, and oil ring experienced maximum wear by a different range of particle size, respectively: 20–40, 5–10, and 20–80 μm. It was shown that the mass of dust that enters the engine cylinders and thus the wear of the components is determined by the concentration of dust, the value of which is definitely reduced by the air filter. However, it was pointed out that the low initial filtration efficiency and the presence of large dust grains in the purified air in the initial period of the filter operation (after replacement of the filter element with a new one) may have an impact on the accelerated wear of mainly (P-PR-CL) association. The next stage of the paper presents the effects of excessive wear of the cylinder liner and piston rings of the engine, resulting from actual vehicle operation and bench tests on the decrease in compression pressure and engine power, increase in the intensity of exhaust gas blow-by into the oil sump and increase in oil consumption and exhaust gas toxicity. This paper addresses the current problem of the effect of engine inlet air contaminants on the performance of the air flow meter, which is an essential sensor of the modern internal combustion engine. The phenomenon of deposition of contaminants (mineral dust, salt, carbon deposit, and moisture) on the measuring element (wire or layer anemometer) of the air flow meter has been analyzed. The empirical results presented show that the mineral dust layer on the measuring element of the air flow meter causes a 17.9% reduction in output voltage, and the dust and oil layer causes a 46.7% reduction in output voltage. This affects the decrease in engine power and exhaust toxicity.

Reducing temperature, drag load and wear during aircraft tyre spin-up

PurposeDue to the static condition of the wheels at touchdown, they skid on the runway, which may cause the tyres to burn and wear. This phenomenon occurs in a fraction of a second, known as the spin-up period. The purpose of this paper is to introduce a new strategy to reduce the horizontal force, tyre temperature and wear during the spin-up period.Design/methodology/approachFirst, the dynamics of two different phases of landing, namely, spin-up and breaking phases, are reviewed. Second, a strategy to prevent excessive temperature and wear of the tyre is presented.FindingsIt is found that using a lubricant and coolant, such as water, at the spin-up stretch of the runway is a simple and practical solution to prevent excessive temperature and wear of the tyre. It is revealed that, despite increasing the spin-up period, the rise of the tyre temperature is eliminated and the material properties are preserved for effective braking. A rough quantitative analysis demonstrates that the wetting of tyres in the spin-up phase decreases the loads and tyre wear effectively.Practical implicationsWetting the touchdown region of the runway without significant areas of standing water is the most practical strategy with the technology available today.Originality/valueA new strategy is presented for landing with reduced tyre wear. It is the hope that this paper can inspire continuous efforts to realize the implementation of the strategy.