Rao P.M.V.,Vignans University |
Subba Rao V.V.,Jawaharlal Nehru Technological University Kakinada
Journal of Composite Materials | Year: 2011
An analytical formulation is developed to estimate the strength of the fiber metal laminates (FML) consisting of cross-ply glass fiber reinforced plastic layers and aluminum sheets. Classical lamination theory is taken as basis for the formulation. A new degradation model based on Tsai-Hill terms is developed and used with analytical formulation to assess the progressive failure. Appropriate features are incorporated in the model to distinguish the matrix failure, the fiber matrix debonding, the fiber failure, and the failure of the isotropic layer. The formulation is used to predict the failure behavior of a FML under in-plane off-axis loading. Different strengths associated with the failure of the laminate like stress at first ply failure and yielding of isotropic layer are investigated. The results show that the new degradation model facilitated the detailed estimation of failure progression. These values of predicted strength are more accurate and closer to the actual experimental results than that of the values predicted by any other model. © 2010 The Author(s).
Murthy P.B.G.S.N.,Vignans University
Journal of Intelligent Manufacturing | Year: 2016
In this paper, statistical models were developed to investigate effect of cutting parameters on surface roughness and root mean square of work piece vibration in boring of stainless steel. A mixed level design of experiments was prepared with process variables of nose radius, cutting speed and feed rate. According to design of experiments, eighteen experiments were conducted on AISI 316 stainless steel with PVD coated carbide tools. Surface roughness, tool wear and vibration of work piece were measured in each experiment. A laser Doppler vibrometer was used to measure vibration of work piece in the form of acousto optic emission signals. These signals were processed and transformed in to different frequency zones using a fast Fourier transformer. Analysis of variance was used to identify significant cutting parameters on surface roughness and root mean square of work piece vibration. Predictive models like response surface methodology, artificial neural network and support vector machine were used to predict the surface roughness and root mean square of work piece vibration. Cutting parameters were optimized for minimum surface roughness and root mean square of work piece vibration using a multi response optimization technique. © 2016 Springer Science+Business Media New York
Satyanarayana D.,Vignans University |
Pramiladevi M.,Andhra University
International Journal of Industrial and Systems Engineering | Year: 2016
The multi-criteria flow shop scheduling problem with sequence dependent setup times (SDST) is one of the most difficult class of scheduling problems. Efficient supervision of heuristics with SDST is one of the significant features to enhance the performance of manufacturing system. In this work, we have formulated multi-criteria decision-making flow shop scheduling problem. It consists of weighted sum of total weighted squared tardiness, makespan, total weighted squared earliness and number of tardy jobs. It is a very effective decision-making for scheduling jobs in modern manufacturing environment. In the present work, three efficient special heuristics based hybrid genetic algorithms (i.e., SHGA1, SHGA2, and SHGA3) are proposed for multi-criteria SDST. Experiments are conducted on the benchmark problems (Taillard, 1993). The performance of three SHGAs are tested, analysed and compared with the help of a defined performance index, known as relative percentage deviation (RPD). The maximum size of the problem is limited to 100 jobs and ten machines. From the results and analysis, the performance of SHGA3 found to be the best. Copyright © 2016 Inderscience Enterprises Ltd.
Musala S.,Vignans University
International Journal of Applied Engineering Research | Year: 2014
Now a days Manchester encoding format is widely used in Ethernet, RFID and Near Field Communications. In this paper, six Manchester encoders are proposed using pass transistor logic and current sink and current source inverters. All the proposed circuits are simulated and compared with the existing circuits by Cadence 180 nm CMOS technology with the supply voltage range of 0.6 V to 1.8 V, from audio range of frequency to 5 GHz frequency. The simulation results show that the proposed Manchester encoders achieve a high performance and better driving capability with less number of transistors when compared to the existing circuits. © Research India Publications.
Chaitanya S.K.,Vignans University |
Dhanalakshmi K.,National Institute of Technology Tiruchirappalli
Smart Structures and Systems | Year: 2014
This paper proposes a new design of shape memory alloy (SMA) wire actuated gripper for open mode operation. SMA can generate smooth muscle movements during actuation which make them potentially good contenders in designing grippers. The principle of the shape memory alloy gripper is to convert the linear displacement of the SMA wire actuator into the angular displacement of the gripping jaw. Steady state analysis is performed to design the wire diameter of the bias spring for a known SMA wire. The gripper is designed to open about an angle of 22.5 when actuated using pulsating electric current from a constant current source. The safe operating power range of the gripper is determined and verified theoretically. Experimental evaluation for the uncontrolled gripper showed a rotation of 19.97. Forced cooling techniques were employed to speed up the cooling process. The gripper is simple and robust in design (single movable jaw), easy to fabricate, low cost, and exhibits wide handling capabilities like longer object handling time and handling wide sizes of objects with minimum utilization of power since power is required only to grasp and release operations. Copyright © 2014 Techno-Press, Ltd.