In this paper, an analytical solution for whirling analysis of axial-loaded Timoshenko rotor is presented and corresponding basic functions are derived. The set of governing equations for whirling analysis of the rotor consists of four coupled partial differential equations; using complex displacements, these equations can be reduced to two coupled partial differential equations. The versatility of the proposed solution is confirmed using published results and the effect of angular velocity of spin, axial load, slenderness and Poisson & apos; s ratio on the natural frequencies of the rotor are investigated.

Serviceable engineering components not only rely on their bulk material properties but also on the design and the characteristics of their surface. These characteristics influence directly the surface quality of the machined products. In terms of surface roughness, the influence of the tool material can be also caused by its tribological properties, i.e. a contact behavior between cutting tool and workpiece. This study presents a formulation of the nominal’s coefficient and friction forces generated in machining between workpiece and cutting tool using cutting force profiles. The obtained equations led to the evaluation of coefficient, frictional forces and cutting inserts characterization in terms of better surface finish and lowest frictional forces. Indeed, results show that the contact between cutting tool and workpiece depends on the materials cutting tool nature, and that the cutting tool type can influences the surface roughness of the machined surface.

The linear governing equations of a micropolar thermoelastic medium without energy dissipation are solved for surface wave solutions. The appropriate solutions satisfying the radiation conditions are applied to the required boundary conditions at the free surface of the half-space of the medium. A frequency equation is obtained for Rayleigh wave in the medium. The non-dimensional speed of the propagation of Rayleigh wave is computed for a specific model of the material and are shown graphically against frequency and non-dimensional parameter.

This article provides a method of acoustic emission (AE) technique to detect leakage in pipeline and locate the position of the leakage. The AE sensor is made of piezoelectric effect transducer to pick up the acoustic emission signal which is generated from the turbulent flow at the leak position. The signal conditioning unit is used to enhanced and eliminate the background noise from the leak location sources. The main acoustic emission processing unit is used to acquire and process the extracted AE characteristic parameters from preprocessing waveform. The leak pipeline is simulated by drilling the hole and plugged with M8 screw at different locations. The results show that the proposed AE method can detect and locate simultaneous leak condition in pipeline with promising results.

This paper presents an analytical and a numerical thermomechanical investigation of a thick-walled cylinder made of the functionally graded materials (FGMs). The hollow cylinder is subjected to a pressure and a thermal load and the properties of this material are varying across the thickness from the inner face that is a ceramic to the outer one which is a metal. After validating the current results by the analytical results, the thermomechanical behavior of the cylinder in the transient condition is investigated and the hoop and radial stresses and also temperature distribution are reported. The results reveal that the use of FG material causes a decrease in the stress; thus, it significantly improves thermomechanical behavior of the domain, thanks to using FG materials.

Zirconia/ veneer bi-layered components are extensively used in dental restoration technology to improve resistance of tooth’s surface from decay. The direction of the fracture propagation at the interface of zirconia and veneer is investigated in this paper. Finite element analysis is performed on a bi-material four point bend specimen in different geometries, and the fracture initiation angle is obtained using maximum tangential stress (MTS) criterion. The effect of specimen geometry on the fracture initiation angle is discussed. Because an interface crack may propagate through interface or kink into one of the materials, some comments are given to determine under which condition “interface de-bounding” will be happened.

An Eddy current damper uses magnets to suppress vibrations due to external excitations. These dampers also called electromagnetic dampers, have advantages of no mechanical contact, high reliability and stability, but require a relatively large volume and mass to attain a given amount of damping. The magnets respond to an external excitation field. Along with the construction of the damper, COMSOL software is used for analysis of the eddy current damper and got various results like magnetic flux density, eddy current intensity, velocity and acceleration of the moving magnet. For this a standard dimension of an automotive vehicle damper is used so that the prototype could be tested on a damper testing machine. The standard dimension is chosen to increase the adaptability, compatibility and to ease of testing the damper. After this task the response of damper under various loads is observed. Different materials of housing tube are taken to observe the effects of various parameters like flux density, current intensity and, of course, the damping capability of the prototype damper.

In the present world stiffeners are widely used to fulfill the requirement of high stiffness. Stiffened plates are used in most of the mechanical structures. In this paper free vibration analysis of eccentric and concentric stiffened isotropic plate with central stiffener and double stiffener has been studied and effect of various parameters such as boundary conditions, aspect ratio on non-dimensional frequency parameter of plate are investigated. Comparison of non-dimensional frequency parameter for eccentric and concentric isotropic stiffened plate with effect of number of stiffener at different mode shapes, aspect ratios and boundary conditions is studied using ANSYS parametric design language (APDL) code. A ten nodded element (SOLID 187) from ANSYS element library is used for the discretization of proposed stiffened isotropic plate. Convergence study of developed model with respect to the number of modes has been done and results are compared from the related available published literature. Non dimensional frequencies are higher for fully clamped boundary condition for eccentric and concentric stiffened isotropic plate in comparison to other boundary condition. It is also seen that non dimensional frequencies are increases in a moderate value for eccentric and concentric isotopic plate with double stiffener in comparison to the central stiffener.

The aim of this research is to investigate the impact of crumb rubber and Styrene-Butadiene-Styrene (SBS) on rutting potential of porous asphalt mixtures. Optimal binder content of control mix, 5% SBS, and mixtures containing 10%, 15%, and 20% of crumb rubber were determined using Cantabro Loss test. Dynamic creep, wheel tracking, draindown, and falling-head permeability tests were then carried out on specimens to examine rutting resistance, resistant to draindown, and permeability. SBS modified and 10% rubberized asphalt satisfied all the requirements of porous asphalt design criteria. They also have similar rutting performance, permeability. Except for rutting performance, 10% rubberized asphalt has the best performance. Instead, asphalt mixture containing 20% crumb rubber was the most mixture against rutting resistance.