Simulation Modeling of a Prototype Designed to Address the Congestion of Passengers and Items at the Composure Area of Security Checkpoints

Discrete event simulation is used to evaluate a novel configuration of the exit roller in the composure area of security checkpoints, which is designed to address the failures of the current exit roller configuration. The paper presents in detail the conceptual modeling of a two-lane system with the current configuration, and an additional model, featuring the new design in one of the lanes. The second model is used to evaluate statistically whether there is any reduction in the passengers’ system time from directing the passengers to the lane having the new design, based on the number of items passengers carry. Lastly, we perform an analysis to examine the range of arrival rates for which a single lane, featuring the new design, could replace a traditional two-lane system.

An unscented Kalman filter-based rolling radius estimation methodology for railway vehicles with traction

Monitoring the conditions of railway vehicle systems plays an important role in the maintenance of safety and performance of railway vehicles. Rolling radius is one of the properties that should be monitored continuously for the predictive maintenance of a railway vehicle since it changes with time due to wheel wear. In this study, a model-based condition monitoring methodology, which is based on an unscented Kalman filter, is proposed. The model includes the torsional dynamics of an independently rotating tram wheel with a traction motor and a contact model. The rolling radius is estimated by considering the traction effort of the motor and the angular velocity measurements. The proposed methodology is tested on a tram wheel test stand (roller rig), which has a wheel on roller configuration. First, a mathematical model is validated by the measurements taken from the test stand. Second, the unscented Kalman filter is applied as a parameter estimator. The results demonstrate that the proposed scheme is a promising option to be used in the predictive condition monitoring of the wheel profile for traction vehicles.

Optimization of Tribological Properties of Electroless Ni-P Coatings under Lubrication Using WPCA

This work presents an experimental study of tribological performance of electroless Ni-P coating under lubricated condition. Mild steel specimens are used as the substrate material for the deposition of Ni-P coating. Tribological tests are carried out based on L27 orthogonal array (OA) varying three test parameters viz. normal load, sliding speed and sliding time in a multi-tribotester using block-on-roller configuration in lubricated condition. The experimental results for friction coefficient and wear are analysed using weighted principal components analysis (WPCA). An optimal test parameter combination is found out for minimum wear and friction coefficient. It is seen that the optimum combination of parameters are found at higher level of normal load, sliding speed and sliding time at 99% confidence level. Finally, a confirmation test is carried out to validate the analysis.

Design and Selection of Chemically Deposited Ni-P-W Coatings for Optimum Tribological Behavior

Chemically deposited nickel coatings possess superior tribological properties such as high hardness, good wear, and corrosion resistance. The quest for improved tribological performance has led to the design and selection of newer variants of these coatings. The present chapter deals with the development of Ni-P-W coating on mild steel substrate and the improvement of tribological characteristics through modification of the coating process parameters. Three coating process parameters, concentration of nickel source, concentration of reducing agent, and concentration of tungsten source along with the annealing temperature, are optimized for minimum friction and wear of the coating. Friction and wear tests are carried out in a multi-tribotester using block on roller configuration under dry conditions. Taguchi-based grey relational analysis is employed for the optimization of this multiple response problem using L27 orthogonal array. Analysis of variance shows that the concentration of nickel source, the interaction between nickel source concentration, and reducing agent concentration, and also the interaction between nickel source concentration and tungsten source concentration have significant influence in controlling the friction and wear behavior of chemically deposited Ni-P-W coating. It is observed that wear mechanism is a mild adhesive in nature. The structural morphology, composition, and phase structure of the coating are studied with the help of Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray analysis (EDX), and X-Ray Diffraction analysis (XRD), respectively.

Optimization of Electroless Ni-P-W Coatings for Minimum Friction and Wear Using Grey-Taguchi Method

The present experimental investigation deals with the deposition of electroless Ni-P-W coating on mild steel substrate and optimization of tribological parameters for better tribological behaviour like minimization of wear depth and coefficient of friction. Three tribological test parameters, namely, load, speed, and time, are optimized for minimum friction and wear of the coating. Friction and wear tests are carried out in a multitribotester using block on roller configuration under dry conditions. Taguchi based grey relational analysis is employed for optimization of this multiple response problem using L27 orthogonal array. Analysis of variance shows that load, speed, time, and interaction between load and speed have significant influence on controlling the friction and wear behavior of Ni-P-W coating. It is observed that wear mechanism is mild adhesive in nature. The structural morphology, composition, and phase structure of the coating are studied with the help of scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and X-ray diffraction analysis (XRD), respectively.

Friction Performance Optimization of Chemically Deposited Ni-P-W Coating Using Taguchi Method

The present study considers the friction behavior of chemically deposited Ni-P-W coatings and optimization of the coating process parameters for minimum friction using Taguchi method. The study is carried out by varying the combination of four coating process parameters, namely, concentration of nickel source, concentration of reducing agent, concentration of tungsten source, and annealing temperature. The friction tests are conducted in a plate-on-roller configuration by keeping the coated sample fixed against a rotating steel roller. The optimum combination of process parameters for minimum friction coefficient is obtained from the analysis of S/N ratio. Furthermore, a statistical analysis of variance reveals that the concentration of nickel source solution has the most significant influence in controlling friction characteristics of Ni-P-W coating. The surface morphology and composition of coatings are also studied with the help of scanning electron microscopy, energy dispersed x-ray analysis, and x-ray diffraction analysis.

Friction Performance of Al-10%SiCp Reinforced Metal Matrix Composites Using Taguchi Method

The present paper considers the friction performance of Al-10%SiCp reinforced metal matrix composites against steel for varying tribological test parameters. The composite is prepared by stir-casting process using aluminium alloy LM6 being mixed with 10% silicon carbide by weight. The tribological tests are performed by varying applied load, sliding speed, and time. The friction performance is studied using plate-on-roller configuration in a multitribotester and optimized using Taguchi L27 orthogonal array. Analysis of variance (ANOVA) is performed to observe the significance of test parameters and their interactions on friction performance. It is observed that normal load and the interaction between normal load and speed influence the friction behaviour, significantly. The wear tracks are analyzed with the help of scanning electron microscopy.