Satya Bir Singh

Creep Analysis of an Isotropic Rotating Al—SiCp Composite Disc taking into Account the Phase-specific Thermal Residual Stress:

Analysis of steady-state creep in a rotating disc made of Al—SiCp composite has been carried out using isotropic Hoffman yield criterion and the results obtained are compared with those using von Mises yield criterion ignoring difference in yield stresses. The material parameters characterizing difference in yield stresses have been used from experimental results of other studies. The stress and strain rate distributions developed due to rotation have been calculated and compared for both the criteria. It is observed that the stress distribution is not too much affected due to presence of phase specific thermal residual stress. The presence of residual stress has contributed to an increase in the tangential strain rate particularly in the region near the outer radius of the disc, as compared to the tangential strain rate in the disc without residual stress. The radial strain rate, which is compressive, changes significantly due to the presence of residual stress and even becomes tensile in the middle of the disc. It is thus concluded that the presence of residual stress significantly affects the creep in an isotropic rotating disc.

Thermal creep transition stresses and strain rates in a circular disc with shaft having variable density

Purpose – The purpose of this paper is to present study of thermal creep stresses and strain rates in a circular disc with shaft having variable density by using Seth’s transition theory. Design/methodology/approach – Seth’s transition theory is applied to the problem of thermal creep transition stresses and strain rates in a thin rotating disc with shaft having variable density by finite deformation. Neither the yield criterion nor the associated flow rule is assumed here. The results obtained here are applicable to compressible materials. If the additional condition of incompressibility is imposed, then the expression for stresses corresponds to those arising from Tresca yield condition. Findings – Thermal effect increased value of radial stress at the internal surface of the rotating disc made of incompressible material as compared to tangential stress and this value of radial stress further much increases with the increase in angular speed as compared to without thermal effect. Strain rates have maxim...

CHANGE MANAGEMENT AND SOFTWARE REUSE SUPPORTIVE 'GENETIC INFORMATION SYSTEM DEVELOPMENT AND MAINTENANCE' MODEL

The aim of the present research work is to develop an information system development process and a model for the development of new generation information systems. New age information systems are those information systems that are capable of fulfilling the demand of highly dynamic information requirements derived from the competitive environments of business organizations and support controlling the complexity involved in their maintenance and software configuration management. Present research work analyzes the theoretical, financial, technical and practical problems related to the information system development, maintenance and change management to propose an appropriate system development process and a model for the development as well as maintenance of information systems with maximum software reuse. The proposed system development process and model provide inherent support to the business organizations in having total control over information system development, maintenance and software configuration management.

CREEP BEHAVIOR OF ANISOTROPIC FUNCTIONALLY GRADED ROTATING DISCS

The creep behavior of an anisotropic rotating disc of functionally gradient material (FGM) has been investigated in the present study using Hills yield criteria and the creep behavior in this case is assumed to follow Sherbys constitutive model. The stress and strain rate distributions are calculated for disc having different types of anisotropy and the results obtained are compared graphically. It is concluded that the anisotropy of the material has a significant effect on the creep behavior of the FGM disc. It is also observed that the FGM disc shows better creep behavior than the non-FGM disc.

Bio inspired congestion control mechanism for Wireless Sensor Networks

Problem of Congestion in Wireless Sensor Network (WSN) is an area which draws attention of various researchers in recent years. The challenge lies in developing a model for routing which can find the optimized route on the basis of distance between source and destination and the residual energy of the node. Various models have been proposed and developed from time to time and their merits and demerits have been discussed. This paper shows an implementation of the Improved Bat Algorithm which is based on the echolocation of bats to control congestion in Wireless Sensor Networks at transport layer. Simulation results have shown that as the number of hops in the path of data transmission increases the Queue length is decreases. The Congestion in the network decreases as the packets are transferred through different routes rather than collecting on a single node. Two important factors such as network lifetime and throughput are also compared with CODA (Congestion Detection and Avoidance) and PSO (Particle Swarm Optimization) algorithm.

Creep strain rates analysis in cylinder under temperature gradient materials by using Seth’s theory

Purpose The purpose of this paper is to present study of creep strain rates in a circular cylinder under temperature gradient materials by using Seth’s transition theory. Design/methodology/approach Seth’s transition theory is applied to the problem of creep stresses and strain rates in a cylinder under temperature gradient materials by finite deformation. Neither the yield criterion nor the associated flow rule is assumed here. The results obtained here are applicable to compressible materials. If the additional condition of incompressibility is imposed, then the expression for stresses corresponds to those arising from Tresca yield condition. Findings Thermal effect increases the values of axial stress at the external surface of a circular cylinder for incompressible material as compared to compressible materials. With the introduction of thermal effects, the maximum value of strain rates occurs at the external surface for incompressible material as compared to the compressible materials. Originality/value The model proposed in this paper is used commonly either as pressure vessels intended for storage industrial gases or media transportation of high pressurized fluids and the design of turbine rotors.