The paper presents the results of tests carried out on Aluminium-SiliconCarbide composite by taking 15 percent of silicon carbide using Taguchi Technique. This experiment is conducted on this composite to successfully determined the optimum parameters for wear removal rate and coefficient of friction for 15% of SiC to the weight of the composite. In the experiment firstly input values are identified through which wear resistance and coefficient of friction optimum value comes, after identification the values are putting in the formula to find the theoretical calculated value and then experiment is being performed and confirmation test has been done to check whether the theoretical calculated value are experimentally feasible or not and after comparing given and calculated values. The aim of the experimental plan is to find the important factors and combination of factors influencing the wear process to achieve the minimum wear rate and coefficient of friction. The experiments were developed based on an orthogonal array, with the aim of relating the influence of sliding speed, applied load and sliding distance. These design parameters are distinct and intrinsic feature of the process that influence and determine the composite performance.

A method for the analysis of nonlinear vibration of shallow shells of arbitrary shape is presented. The method is based upon the concept of constant deflection contours on the surface of the shallow shell. The constant deflection contour method has previously been found to be a simple tool for the study of linear vibration analysis of shallow shells of arbitrary shape. A new approach has been made here to utilize this concept to study the large amplitude vibration of shallow shells in conjunction with the Galerkin method. A number of illustrative examples are included to demonstrate the accuracy of the proposed method.

Many industrial processes (i.e., concentrated solar power [CSP] plants) require indirect heating of the product to temperature above ambient temperature. A heat transfer fluid (HTF), such as a mineral-based fluid like GlobalthermTM M (Global Heat Transfer; Staffordshire, UK), is used in such plants and flows from the heater to source requiring the heat. Not all HTFs are the same, however, and so understanding the difference between fluids is important to ensure that end-users use the correct fluid for the correct operation. This is especially true in CSP plants where HTFs operate at high temperatures for long periods of time and therefore need to be stable under such conditions. Indeed, biphenyl diphenyl oxide (BDO) mixtures are commonly used in CSP plants as they can be heated to 400 degrees Celsius, which is higher than the upper operating temperature for a mineral-based HTF (i.e., ~400 degrees Celsius). It is a fact that all HTFs will thermally degrade over time and so it is important to monitor this to ensure that an early intervention can be taken if a problem starts to appear. The objective of HTF monitoring being to keep the HTF and plant operational for as long as is possible. Routine sampling and chemical analysis is used to assess the physiochemical properties of a HTF. For this to be done effectively, it is important to understand the properties of a virgin HTF and then to assess the rate of thermal degradation over time. Carbon residue, total acid number and closed flash point temperature are routinely measured in the laboratory and the current study proposes their use to assess the extent of thermal cracking and oxidation, two common pathways through which a HTF thermally degrades. This was done for mineral and BDObased HTFs to emphasize the background as to why BDO-based HTFs are used in CSP plants. The findings of this assessment are presented herein. Future work should consider using a similar approach to assess the condition of other HTFs commonly used in industrial applications.

An investigation has been launched in to the performance of a rough porous parabolic slider bearing under the presence of a magnetic fluid lubricant. The bearing surfaces are assumed to be transversely rough and this random roughness of the bearing surfaces has been characterized by a random variable with non-zero mean, variance and skewness. The concerned stochastically averaged Reynold’s equation is solved with appropriate boundary conditions to obtain the pressure distribution resulting in the calculation of load carrying capacity. Further, the friction, the position of centre of pressure and temperature rise has been calculated. The results show that the effect of magnetization characterized by the magnetization parameter induces an improvement in the steady state performance as compared to the traditional conventional lubricant case, in spite of the fact that the transverse roughness adversely affects the bearing system. Further, a comparison of this investigation with the case of plane inclined slider bearing indicates that the magnetization results in a higher load carrying capacity and reduced friction. Also, the negatively skewed roughness and variance (-ve) enhance the already increased load carrying capacity due to magnetization.

This paper will give a short survey about topology optimization of structures. It is particularly focused on topological shape optimization of structures using level-set methods, including the level-set based standard methods and the level-set based alternative methods. The former often directly solve the Hamilton-Jacobi partial differential equation (H-J PDE) to obtain the boundary velocity field using Finite Differential Methods (FDM), and the later commonly employ parametric or equivalent methods to evaluate the velocity field without directly solving the H-J PDE. The unique characteristics of the level-set based topology optimization methods are discussed, and a future perspective and prospects in this research area is also included. A benchmark numerical example is used to showcase the effectiveness of the level-set based methods.

Two-dimensional heat transfer in a fin was modeled with acceptable accuracy and optimized. Bezier curve was used to estimate the fin geometry. The finite volume method coupled with the artificial neural network was developed to predict the temperature distribution through the fin with -1.5% to +1% and ± 0.5% accuracy for fin efficiency and rate of heat transfer, respectively. Locations of four control points in the Bezier curve were considered as design variables. Then, fast and elitist non-dominated sorting genetic algorithm (NSGA-II) was applied to find the maximum fin efficiency and the rate of heat transfer as two objective functions. The results of optimal designs were a set of multiple optimum solutions, called ‘Pareto optimal solutions’. The maximum 72 percent for fin efficiency was found with 739W as its rate of heat transfer while the maximum rate of heat transfer was 962.3 W with 57 percent efficiency. In addition, the optimum results of two-dimensional heat transfer were compared with one-dimensional and the average 14.7 percent decreases in fin efficiency and the rate of heat transfer was found that show the deficiency of the one-dimension modeling. In the second case study, the Pareto front was derived for the rate of heat transfer and fin surface area as two objective functions. It was observed that the results of optimum fin configuration in the case of fin efficiency as objective function are the same with the results of fin surface area as objective function.

In this paper, the peristaltic flow of a power law fluid in a cylindrical channel is studied analytically. The governing equations consist of continuity and momentum equations are solved mathematically by perturbation method. The zeroth and first order in amplitude ratio of the stream function is considered for perturbation series. The effects of flow behavior index (n) flow rate and amplitude ratio (e) on the flow field are investigated. The results show that increment of power law index predicts more flow rate and less pressure rise in peristaltic motion. Trapping phenomenon is form by closed stream line depending on peristaltic motion.

The responses to changes of bearing length-to-diameter ratio and supply pressure of hybrid air journal bearings are investigated numerically for rotor dynamic instability. Different types of external pressure compensations, including multi-array of 1, 2, 3, 4, or 5-row orifice bearings and porous bearings, are analyzed to obtain more insight to optimum designs of journal bearings to improve the problem of whirl instability of rotor mass. The results show that the long porous bearings (L/D>1.0) in the higher rotation speeds (Λ>0.5) have higher threshold load capacities W before the onset of whirl instability and thus are more stable than orifice bearings. On the contrary, the short 5-row orifice bearings (L/D ≤ 1.0) are more stable than the porous bearing in the lower rotation speeds (0.1 ≤ Λ ≤ 0.5). The results also show that the change of supply pressure from Ps=2.0 to Ps=8.0 makes no difference to orifice bearing with whirl instability of rotor but that the porous bearing is the most stable for the lower supply pressure Ps=2.0 and becomes unstable as the supply pressure Ps increases in the higher rotation speeds (Λ>0.5).

In EU regions with intense seismic activity imposing building code improvements like the EC2 and EC8-part3,introduced the use of high performance reinforced steel for example the dual phase B500c steel bar. In particularly earthquake-prone areas, like Greece has been over the past decade, the use of steel B500c is exclusively used in all structures from reinforced concrete. The present study focuses on investigating the mechanical behaviour of the material in the elastic region, through a series of mechanical tensile tests. In the elastic region of most of the steel specimens (15 pre-corroded and 5 non-corroded) a “knee” was observed which appears to be related to the localized detachment of the martensitic cortex from the core of the material. The interesting mechanical behaviour at the interface limit of the martensitic and ferritic-perlitic core on B500c steel bars, was further examined by performing (non destructive) ultrasound testing (C-Scan) and failure analysis using SEM, which led to the confirmation of the structural internal failure.