Aeroelastic Behaviour of Aerospace Structural Elements with Follower Force

P. K. Datta,S. Biswas 한국항공우주학회 2011 International Journal of Aeronautical and Space Sc Vol.12 No.2

In general, forces acting on aerospace structures can be divided into two categories?a) conservative forces and b) nonconservative forces. Aeroelastic effects occur due to highly flexible nature of the structure, coupled with the unsteady aerodynamic forces, causing unbounded static deflection (divergence) and dynamic oscillations (flutter). Flexible wing panels subjected to jet thrust and missile type of structures under end rocket thrust are nonconservative systems. Here the structural elements are subjected to follower kind of forces; as the end thrust follow the deformed shape of the flexible structure. When a structure is under a constant follower force whose direction changes according to the deformation of the structure, it may undergo static instability (divergence) where transverse natural frequencies merge into zero and dynamic instability (flutter), where two natural frequencies coincide with each other resulting in the amplitude of vibration growing without bound. However, when the follower forces are pulsating in nature, another kind of dynamic instability is also seen. If certain conditions are satisfied between the driving frequency and the transverse natural frequency, then dynamic instability called ‘parametric resonance’ occurs and the amplitude of transverse vibration increases without bound. The present review paper will discuss the aeroelastic behaviour of aerospace structures under nonconservative forces.

Breeding of New Productive Bivoltine Hybrid, CSR12 $\times$ CSR6 of Silkworm Bombyx mori L.

Datta, R.K.,Basavaraja, H.K.,Reddy, N.Mal,Kumar, S.Nirmal,Kumar, N.Suresh,Babu, M.Ramesh,Ahsan, M.M.,Jayaswal, K.P. Korean Society of Sericultural Science 2001 International Journal of Industrial Entomology Vol.3 No.2

With an objective of evolving quantitatively and qualitatively superior bivoltine breeds/hybrids of silkworm Bombyx mori L. for tropical conditions, breeding work was initiated in Central Sericultural Research and Training Institute, Mysore during 1992 by utilizing two Japanese hybrids namely BNl8$\times$BCS25 and Shunrei$\times$Shogetsu along with Indian evolved breed, KA. The breed CSR12 which is characterized with sex-limited larval marking and white oval cocoons was evolved from the Japanese hybrid BNl8 ${\times}$ BCS25 by crossing with KA, while the breed CSR6 which is characterized with normal marking (marked larvae) and white dumbbell cocoons was extracted from the Japanese commercial hybrid Shunrei${\times}$Shogetsu through continuous inbreeding coupled with selection. After fixation, these breeds along with other newly evolved breeds were subjected to hybrid study under optimum environmental conditions in the laboratory for expression of full potential of the genotypes. These hybrids were evaluated by Multiple Trait Evaluation Index (Mano et al., 1993). The hybrid CSR12${\times}$CSR6 was selected based multiple trait evaluation index value. The hybrid CSR12$\times$CSR6 recorded survival of 96.0%, shell weight of 50.0 cg, shell ratio of 24.3%, raw silk percentage of 19.6, filament length of 1,216 m, boil off loss of 22.4% and renditta of 5.1. On the other hand, the control hybrid (KA ${\times}$ NB4D2) has recorded survival of 90.6%, shell weight of 42.1 cg, shell ratio of 20.4%, raw silk percentage of 15.9, filament length of 999 m, boil off loss of 24.8% and renditta of 6.3. The hybrid CSR12$\times$CSR6 was authorized during 1997 by Central Silk Board, Government of India for commercial exploitation during favourable months based on national level race authorization test.

Heterotic Expression in Silk Productivity of Newly Evolved Thermo-tolerant Bivoltine Hybrids of Silk worm Bombyx mori L.

( P. Sudhakara Rao ),( R. K. Datta ),( K. M. Vijaya Kumari ),( A. K. Palit ),( S. Z. Haque Rufaie ) 한국잠사학회 2004 International Journal of Industrial Entomology Vol.9 No.1

Aeroelastic Behaviour of Aerospace Structural Elements with Follower Force: A Review

Datta, P.K.,Biswas, S. The Korean Society for Aeronautical and Space Scie 2011 International Journal of Aeronautical and Space Sc Vol.12 No.2

In general, forces acting on aerospace structures can be divided into two categories-a) conservative forces and b) nonconservative forces. Aeroelastic effects occur due to highly flexible nature of the structure, coupled with the unsteady aerodynamic forces, causing unbounded static deflection (divergence) and dynamic oscillations (flutter). Flexible wing panels subjected to jet thrust and missile type of structures under end rocket thrust are nonconservative systems. Here the structural elements are subjected to follower kind of forces; as the end thrust follow the deformed shape of the flexible structure. When a structure is under a constant follower force whose direction changes according to the deformation of the structure, it may undergo static instability (divergence) where transverse natural frequencies merge into zero and dynamic instability (flutter), where two natural frequencies coincide with each other resulting in the amplitude of vibration growing without bound. However, when the follower forces are pulsating in nature, another kind of dynamic instability is also seen. If certain conditions are satisfied between the driving frequency and the transverse natural frequency, then dynamic instability called 'parametric resonance' occurs and the amplitude of transverse vibration increases without bound. The present review paper will discuss the aeroelastic behaviour of aerospace structures under nonconservative forces.

Line × Tester Analysis of Certain Quantitative Traits in Silkworm Bombyx mori L. under Optimum and Stress Rearing Conditions

P. Sudhakara Rao,R. K. Datta,K. M. Vijaya Kumari,A. K. Palit,S. A. Bhat 한국잠사학회 2004 International Journal of Industrial Entomology Vol.8 No.1

The combining abilities in the 5 newly evolved thermo tolerant breeds viz., SR6, SR7, SR8 SR9 and SR10 of silkworm Bombyx mori L. and their 15 hybrids were made in a line ´ tester crossing programme. Data were analysed for seven quantitative traits i.e., pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio, filament length and raw silk percentage under optimum room temperature (25 ± 1oC) conditions (In case of high temperature (36 ± 1oC) stress conditions five economic traits except filament length and raw silk percentage) with 3 widely adapted testers i.e., KA, CSR2 and CC1 as lines (females) and testers (males) respectively. The performance at high temperature and low humidity conditions are only taken into consideration for selecting the best lines/ hybrids. Among the lines SR6 exhibited positive General combining ability (GCA) effects for pupation rate, cocoon yield, cocoon weight and cocoon shell ratio traits, followed by SR7 for pupation rate, cocoon yield and cocoon shell weight and cocoon shell ratio. Among testers, KA exhibited positive GCA effects for two quantitative traits cocoon yield, cocoon weight and CSR2 for cocoon shell weight and cocoon shell ratio under adverse temperature conditions. The hybrid SR6 ´ CC1 and SR7 ´ CSR2 exhibited significant positive Specific combining ability (SCA) effects for majority of the traits in high temperature stress conditions of rearing. The better parent value of heterosis (Heterobeltiosis) was exhibited by the hybrid SR6 ´ CC1 for pupation rate, cocoon yield, cocoon weight and cocoon shell weight and SR7 × CSR2 for all the traits evaluated under high temperature conditions. Based on the results, the lines SR6 and SR7 was judged as best combiners and the hybrids SR6 ´ CC1 and SR7 ´ CSR2 can be selected

Buckling and vibration analysis of stiffened plate subjected to in - plane concentrated load

P.K.Datta,A.K.L.Srivastava,A.H.Sheikh 국제구조공학회 2003 Structural Engineering and Mechanics, An Int'l Jou Vol.15 No.6

Note : Line×Tester Analysis of Certain Quantitative Traits in Silkworm Bombyx mori L. under Optimum and Stress Rearing Conditions

( P. Sudhakara Rao ),( R. K. Datta ),( K. M. Vijaya Kumari ),( A. K. Palit ),( S. A. Bhat ) 한국잠사학회 2007 International Journal of Industrial Entomology Vol.8 No.1

The combining abilities in the 5 newly evolved thermo tolerant breeds viz., SR6, SR7, SR8 SR9 and SR10 of silkworm Bombyx mori L. and their 15 hybrids were made in a line×tester crossing programme. Data were analysed for seven quantitative traits i.e., pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio, filament length and raw silk percentage under optimum room temperature (25±1℃) conditions (In case of high temperature (36±1℃) stress conditions five economic traits except filament length and raw silk percentage) with 3 widely adapted testers i.e., KA, CSR2 and CC1 as lines (females) and testers (males) respectively. The performance at high temperature and low humidity conditions are only taken into consideration for selecting the best lines/hybrids. Among the lines SR6 exhibited positive General combining ability (GCA) effects for pupation rate, cocoon yield, cocoon weight and cocoon shell ratio traits, followed by SR7 for pupation rate, cocoon yield and cocoon shell weight and cocoon shell ratio. Among testers, KA exhibited positive GCA effects for two quantitative traits cocoon yield, cocoon weight and CSR2 for cocoon shell weight and cocoon shell ratio under adverse temperature conditions. The hybrid SR6×CC1 and SR7×CSR2 exhibited significant positive Specific combining ability (SCA) effects for majority of the traits in high temperature stress conditions of rearing. The better parent value of heterosis (Heterobeltiosis) was exhibited by the hybrid SR6×CC1 for pupation rate, cocoon yield, cocoon weight and cocoon shell weight and SR7×CSR2 for all the traits evaluated under high temperature conditions. Based on the results, the lines SR6 and SR7 was judged as best combiners and the hybrids SR6×CC1 and SR7×CSR2 can be selected for commercial exploitation in tropical climate.

Breeding of New Productive Bivoltine Hybrid, CSR12×CSR6 of Silkworm Bombyx mori L.

( R. K. Datta ),( H. K. Basavaraja ),( N. Mal Reddy ),( S. Nirmal Kumar ),( N. Suresh Kumar ),( M. Ramesh Babu ),( M. M. Ahsan ),( K. P. Jayaswal ) 한국잠사학회 2001 International Journal of Industrial Entomology Vol.3 No.2

With an objective of evolving quantitatively and qualitatively superior bivoltine breeds/hybrids of silkworm Bombyx mori L. for tropical conditions, breeding work was initiated in Central Sericultural Research and Training Institute, Mysore during 1992 by utilizing two Japanese hybrids namely BNl8×BCS25 and Shunrei×Shogetsu along with Indian evolved breed, KA. The breed CSR12 which is characterized with sex-limited larval marking and white oval cocoons was evolved from the Japanese hybrid BNl8×BCS25 by crossing with KA, while the breed CSR6 which is characterized with normal marking (marked larvae) and white dumbbell cocoons was extracted from the Japanese commercial hybrid Shunrei×Shogetsu through continuous inbreeding coupled with selection. After fixation, these breeds along with other newly evolved breeds were subjected to hybrid study under optimum environmental conditions in the laboratory for expression of full potential of the genotypes. These hybrids were evaluated by Multiple Trait Evaluation Index (Mano et al., 1993). The hybrid CSR12×CSR6 was selected based multiple trait evaluation index value. The hybrid CSR12×CSR6 recorded survival of 96.0%, shell weight of 50.0 cg, shell ratio of 24.3%, raw silk percentage of 19.6, filament length of 1,216 m, boil off loss of 22.4% and renditta of 5.1. On the other hand, the control hybrid (KA×NB4D2) has recorded survival of 90.6%, shell weight of 42.1 cg, shell ratio of 20.4%, raw silk percentage of 15.9, filament length of 999 m, boil off loss of 24.8% and renditta of 6.3. The hybrid CSR12×CSR6 was authorized during 1997 by Central Silk Board, Government of India for commercial exploitation during favourable months based on national level race authorization test.

Seasonal Effects on the Performance of Newly Evolved Bivoltine Hybrids of the Silkworm (Bombyx mori L.) Under Tropics

Rao, P.Sudhakara,Datta, R.K.,Palit, A.K.,Haque Rufaie, S.Z. Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.9 No.2

Seasonal effects of the newly evolved bivoltine hybrid namely CSR$_2$${\times}$SR$_{5}$, SR$_1$ ${\times}$SR$_4$ and control hybrid KA${\times}$NB$_4$D$_2$ along with their parents SR$_1$, SR$_4$, SR$_{5}$, CSR$_2$ KA and NB$_4$D$_2$ were evaluated during different seasons of the year to understand genotype and environment interactions. Data were collected on five economic importance namely, pupation rate, cocoon yield, cocoon weight, cocoon shell ratio and filament length of the lines, hybrids and the control breeds/hybrid in three different seasons i.e., Pre-Monsoon, Monsoon and post-monsoon and subjected to relevant statistical methods. Seasonal performance of CSR$_2$, SR$_1$, SR$_4$ and SR$_{5}$ revealed superiority over control breeds KA and NB$_4$D$_2$. Both the hybrids i.e., CSR$_2$${\times}$SR$_{5}$ and SR$_1$${\times}$SR$_4$ performed well under diversified environmental conditions of tropical climate in a year indicating overall stability. These hybrids revealed highly significant (P < 0.01) variations for majority of the traits studied over the control hybrid KA${\times}$NB$_4$D$_2$.$.

Parametric Resonance Characteristics of Laminated Composite Curved Shell Panels in a Hygrothermal Environment

S.K Sahu,M.K.Rath,P.K Datta,R. Sahoo 한국항공우주학회 2012 International Journal of Aeronautical and Space Sc Vol.13 No.3

The present study deals with the parametric resonance behaviour of laminated composite curved shell panels in a hygrothermal environment using Bolotin’s approach. A simple laminated model is developed using first order shear deformation theory (FSDT) for the vibration and dynamic stability analysis of laminated composite shells subjected to hygrothermal conditions. A computer program based on the finite element method (FEM) in a MATLAB environment is developed to perform all necessary computations. Quantitative results are presented to show the effects of curvature, ply-orientations, degree of orthotropy and geometry of laminates on the parametric instability of composite curved shell panels for different temperature and moisture concentrations. The excitation frequencies of laminated composite panels decrease with the increase of temperature and moisture due to reduction of stiffness for all laminates.