Search

Turn milling is one of the machining processes used to mill circular work pieces while the work piece rotates about its own axis. Orthogonal milling is one of the turn milling processes where the bottom part of cutter removes material from the rotating work piece with high metal removal rate. In this article, tool condition was studied by analyzing surface roughness and vibration of cutter with the use of response surface methodology. According to design of experiments, 16 experiments were conducted on ASTM B139 phosphor bronze with high-speed steel end mill cutter on four-axis milling machine. The response surface methodology was used to find out significant parameters that are affecting surface roughness and amplitude of cutter vibration. A multi-response optimization technique was used to identify optimum cutting parameters for less surface roughness and amplitude of cutter vibration. [ABSTRACT FROM AUTHOR]

This paper describes the comparison between Vibration Analysis (VA) and Acoustic Emission (AE) method to predict the defect severity in rolling element bearings with respect to the gradual increase of defect size. In bearing fault diagnosis vibration based methods are very popular, but the signals acquired by its transducers from the bearings are distorted by other faults and mechanical noise from the equipment. Vibration based methods are effective when the defect in the bearings has already become severe. AE is a non destructive testing (NDT) technique used in structural health monitoring and its application for bearing defect diagnosis is gaining momentum as an alternate diagnostic tool because of its inherent high signal-to-noise-ratio (SNR). A bearing test rig was designed and set up to study the various defects in rolling element bearings in real environment. In earlier cases, though the researchers studied on different types of seeded defects with random sizes, they could not ascertain the correlation between their defect sizes and the vibration amplitude. The experimental investigation reported in this paper is centered on seeded defect of same type with gradual increase of its size on outer race of radially loaded cylindrical roller bearings and running the defective bearing at different speeds and loads. Data acquired through AE & vibration probes simultaneously for better diagnosis. Comparisons between AE and VA over a range of speed and load conditions at gradual increase of defect size are presented and from them it is concluded that AE method is superior to identify the severity of defect. [ABSTRACT FROM AUTHOR]

This paper proposes the use of a simulated annealing (SA) approach to the optimal design of multilayered composite plate structures. The orientation fibres and the number of layers in laminated composites play a major role in determining strength and stiffness. Therefore, the basic design problem is to determine the optimum stacking sequence of the composite laminate. The SA technique is employed to obtain the optimum fibre orientation of multilayered composite plates, so as to maximize fundamental natural frequency. The composite plate is discretized and analysed by a finite element (FE) analysis procedure using a computer program written in C language. The inverse iteration method is employed to obtain the fundamental frequency of a laminated plate with a given number of layers and fibre orientations in each layer. Both symmetric and antisymmetric fibre angles are considered. The optimum results of fibre orientations are compared with the conventional random walk (RW) method. [ABSTRACT FROM AUTHOR]