Stochastic free vibration analysis of smart random composite plates

B. N. Singh,N. Vyas,P. Dash 국제구조공학회 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.31 No.5

The present study is concerned with the stochastic linear free vibration study of laminated composite plate embedded with piezoelectric layers with random material properties. The system equations are derived using higher order shear deformation theory. The lamina material properties of the laminate are modeled as basic random variables for accurate prediction of the system behavior. A C0 finite element is used for spatial descretization of the laminate. First order Taylor series based mean centered perturbation technique in conjunction with finite element method is outlined for the problem. The outlined probabilistic approach is used to obtain typical numerical results, i.e., the mean and standard deviation of natural frequency. Different combinations of simply supported, clamped and free boundary conditions are considered. The effect of side to thickness ratio, aspect ratio, lamination scheme on scattering of natural frequency is studied. The results are compared with those available in literature and an independent Monte Carlo simulation.

Second-order statistics of natural frequencies of smart laminated composite plates with random material properties

B. N. Singh,Atul Umrao,K. K. Shukla,N. Vyas 국제구조공학회 2008 Smart Structures and Systems, An International Jou Vol.4 No.1

Nowadays developments in the field of laminated composite structures with piezoelectric have attracted significant attention of researchers due to their wide range of applications in engineering such as sensors, actuators, vibration suppression, shape control, noise attenuation and precision positioning. Due to large number of parameters associated with its manufacturing and fabrication, composite structures with piezoelectric display a considerable amount of uncertainty in their material properties. The present work investigates the effect of the uncertainty on the free vibration response of piezoelectric laminated composite plate. The lamina material properties have been modeled as independent random variables for accurate prediction of the system behavior. System equations have been derived using higher order shear deformation theory. A finite element method in conjunction with Monte Carlo simulation is employed to obtain the secondorder statistics of the natural frequencies. Typical results are presented for all edges simply supported piezoelectric laminated composite plates to show the influence of scattering in material properties on the second order statistics of the natural frequencies. The results have been compared with those available in iterature.

Reproductive Biotechnologies for Improvement of Buffalo: The Current Status

Purohit, G.N.,Duggal, G.P.,Dadarwal, D.,Kumar, Dinesh,Yadav, R.C.,Vyas, S. Asian Australasian Association of Animal Productio 2003 Animal Bioscience Vol.16 No.7

Reproductive biotechnologies continue to be developed for genetic improvement of both river and swamp buffalo. Although artificial insemination using frozen semen emerged some decades back, there are still considerable limitations. The major problem appears to be the lack of efficient methods for estrus detection and timely insemination. Controlled breeding experiments in the buffalo had been limited and similar to those applied in cattle. Studies on multiple ovulation and embryo transfer are essentially a replica of those in cattle, however with inherent problems such as lower number of primordial follicles on the buffalo ovary, poor fertility and seasonality of reproduction, lower population of antral follicles at all stages of the estrous cycle, poor endocrine status and a high incidence of deep atresia in ovarian follicles, the response in terms of transferable embryo recovery has remained low with 0.51 to 3.0 per donor and pregnancy rates between 15 to 30%. In vitro production of buffalo embryos is a valid alternative to recovery of embryos by superovulation. This aspect received considerable attention during the past decade, however the proportion of embryos that develops to the blastocyst stage is still around 25-30% and hence the in vitro culture procedures need substantial improvement. Embryo cryopreservation procedures for direct transfer post thaw need to be developed for bubaline embryos. Nuclear transfer and embryo cloning is a technique that has received attention in various species during recent years and can be of immense value in buffaloes as they have a low rate of embryo recoveries by both in vitro and in vivo procedures. Gender pre-selection, genome analysis, gene mapping and gene transfer are a few of the techniques that have been studied to a limited extent during recent years and are likely to be included in future studies on buffaloes. Very recently, reproductive biotechnologies have been applied to feral buffaloes as well, but the results obtained so far are modest. When fully exploited they can play an important role in the preservation of endangered species.

Second-order statistics of natural frequencies of smart laminated composite plates with random material properties

Singh, B.N.,Umrao, Atul,Shukla, K.K.,Vyas, N. Techno-Press 2008 Smart Structures and Systems, An International Jou Vol.4 No.1

Nowadays developments in the field of laminated composite structures with piezoelectric have attracted significant attention of researchers due to their wide range of applications in engineering such as sensors, actuators, vibration suppression, shape control, noise attenuation and precision positioning. Due to large number of parameters associated with its manufacturing and fabrication, composite structures with piezoelectric display a considerable amount of uncertainty in their material properties. The present work investigates the effect of the uncertainty on the free vibration response of piezoelectric laminated composite plate. The lamina material properties have been modeled as independent random variables for accurate prediction of the system behavior. System equations have been derived using higher order shear deformation theory. A finite element method in conjunction with Monte Carlo simulation is employed to obtain the secondorder statistics of the natural frequencies. Typical results are presented for all edges simply supported piezoelectric laminated composite plates to show the influence of scattering in material properties on the second order statistics of the natural frequencies. The results have been compared with those available in literature.

Stochastic free vibration analysis of smart random composite plates

Singh, B.N.,Vyas, N.,Dash, P. Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.31 No.5

The present study is concerned with the stochastic linear free vibration study of laminated composite plate embedded with piezoelectric layers with random material properties. The system equations are derived using higher order shear deformation theory. The lamina material properties of the laminate are modeled as basic random variables for accurate prediction of the system behavior. A $C^0$ finite element is used for spatial descretization of the laminate. First order Taylor series based mean centered perturbation technique in conjunction with finite element method is outlined for the problem. The outlined probabilistic approach is used to obtain typical numerical results, i.e., the mean and standard deviation of natural frequency. Different combinations of simply supported, clamped and free boundary conditions are considered. The effect of side to thickness ratio, aspect ratio, lamination scheme on scattering of natural frequency is studied. The results are compared with those available in literature and an independent Monte Carlo simulation.

Genetic Structure and Differentiation of Three Indian Goat Breeds

Dixit, S.P.,Verma, N.K.,Aggarwal, R.A.K.,Kumar, Sandeep,Chander, Ramesh,Vyas, M.K.,Singh, K.P. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.9

Gene flow, genetic structure and differentiation of Kutchi, Mehsana and Sirohi breeds of goat from North-Western India were evaluated based on 25 microsatellite markers so as to support breed conservation and improvement decisions. The microsatellite genotyping was carried out using an automated DNA sequencer. The gene diversity across the studied loci for the Kutchi breed varied from 0.57 (ILST 065) to 0.93 (OarFCB 304, OMHC 1, ILSTS 058) with an overall mean of 0.79${\pm}$0.02. The corresponding values for Mehsana and Sirohi breeds were 0.16 (ILST 008) to 0.93 (OMHC 1, ILSTS 058) with an average of 0.76${\pm}$0.04, and 0.50 (ILSTS 029) to 0.94 (ILSTS 058) with an average of 0.78${\pm}$0.02, respectively. The Mehsana breed had lowest gene diversity among the 3 breeds studied. All the populations showed an overall significant heterozygote deficit ($F_{is}$). The Fis values were 0.26, 0.14 and 0.36 for Kutchi, Mehsana and Sirohi goat breeds, respectively. Kutchi and Mehsana were more differentiated (16%) followed by Mehsana and Sirohi (13%).The measures of standard genetic distance between pairs of breeds indicated that the lowest genetic distance was between Kutchi and Sirohi breeds (0.73) and the largest genetic distance was between Mehsana and Kutchi (1.0) followed by Sirohi and Mehsana (0.75) breeds. Mehsana and Kutchi are distinct breeds and this was revealed by the estimated genetic distance between them. All measures of genetic variation revealed substantial genetic variation in each of the populations studied, thereby showing good scope for their further improvement.

공업자산관리란 무엇인가?

Amadi-Echendu. J,Brown. K,Hope. T,Lee. J,Mathew. J,Vyas. N,Willett. R,양보석 한국소음진동공학회 2007 소음 진동 Vol.17 No.3