The Experts below are selected from a list of 2178 Experts worldwide ranked by ideXlab platform
Tanish Dey - One of the best experts on this subject based on the ideXlab platform.
-
non linear stability analysis of cnt reinforced Composite Cylindrical Shell panel subjected to thermomechanical loading
Composite Structures, 2021Co-Authors: Sumeet Chakraborty, Tanish DeyAbstract:Abstract The present study explores the nonlinear stability characteristics of simply supported carbon nanotubes (CNTs) reinforced Composite (CNTRC) Cylindrical Shell panel subjected to combined axial compressive loading and localized heating using semi-analytical approach. The thermomechanical properties of CNTRC panel are considered to be temperature-dependent and are evaluated using extended rule of mixture method. Higher order shear deformation theory and von Karman type nonlinearity are employed to model the CNTRC Cylindrical panel. Two types of localized heating profiles such as rectangular and circular are considered along with full heating. The pre-buckling stresses generated because of applied localized heating are determined using Airy’s stress function by satisfying the strain compatibility relations. The governing equations for stability problem of CNTRC panel are derived using variational principle incorporating the obtained pre-buckling stresses. The partial differential equations obtained are converted to a set of nonlinear algebraic equations by employing the Galerkin’s technique. The buckling temperature and nonlinear equilibrium paths are determined by solving the abovementioned equations using appropriate methods. The obtained results using present semi-analytical approach demonstrated the influence of various dispersion profiles of CNTs, CNT volume fraction and heating profiles on the buckling and post-buckling characteristics of CNTRC Cylindrical Shell panel subjected to thermomechanical loadings.
-
computation of worst geometric imperfection profiles of Composite Cylindrical Shell panels by minimizing the non linear buckling load
Applied Mathematical Modelling, 2019Co-Authors: Tanish Dey, L S RamachandraAbstract:Abstract In this article the “most unfavorable” shape of initial geometric imperfection profile for laminated Cylindrical Shell panel is obtained analytically by minimizing the limit point load. The partial differential equations governing the Shell stability problem are reduced to a set of non-linear algebraic equations using Galerkin's technique. The non-linear equilibrium path is traced by employing Newton–Raphson method in conjunction with the Riks approach. A double Fourier series is used to represent the initial geometric imperfection profile for the Cylindrical Shell panel. The optimum values of these Fourier coefficients are determined by minimizing the limit point load using genetic algorithm. The results are determined for simply supported Composite Cylindrical Shell panel. Numerical results show that more number of terms is needed in Fourier series representation to obtain the “worst” geometric imperfection profile which gives lower limit load compared to single term representation of imperfection. We have incorporated constraints on the shape of imperfection to avoid unrealistic limit point loads (due to imperfection shape) as we have assumed that the imperfection is due to machining/manufactuting.
-
stability and vibration analysis of cnt reinforced functionally graded laminated Composite Cylindrical Shell panels using semi analytical approach
Composites Part B-engineering, 2019Co-Authors: Sumeet Chakraborty, Tanish Dey, Rajesh KumarAbstract:Abstract The present paper examined the buckling, postbuckling and vibration characteristics of pre-buckled and post-buckled laminated CNT reinforced Composite (CNTRC) Cylindrical Shell panel made up of single walled carbon nanotubes (SWCNTs) and isotropic matrix. The effective material properties of CNTRC panel are computed using extended rule-of mixture (ROM) method. Higher order shear deformation theory (HSDT) with von Karman type of nonlinearity is adopted to model the CNTRC Cylindrical Shell panel. Four different boundary conditions are considered. Besides uniform loading, different types of non-uniform in-plane load distribution such as triangular, trapezoidal, parabolic and partial edge loadings are considered. The internal stress distribution within the Shell panel due to applied non-uniform loadings is evaluated by prebuckling analysis. Subsequently, via Hamilton's principle the governing partial differential equations of CNTRC laminated Cylindrical Shell panel are derived. Employing Galerkin's method and by neglecting the inertia terms the partial differential equations are reduced to a set of non-linear algebraic equation for the static problem. However, for dynamic problem the partial differential equations are converted to a set of ordinary differential equations. Beside parametric study the obtained numerical results from the present semi-analytical study illustrates the effects of CNT volume fraction, CNT dispersion profile, non-uniform load distribution and boundary conditions on the stability and vibration characteristics of CNTRC Cylindrical panel.
-
static and dynamic instability analysis of Composite Cylindrical Shell panels subjected to partial edge loading
International Journal of Non-linear Mechanics, 2014Co-Authors: Tanish Dey, L S RamachandraAbstract:Abstract The postbuckling and dynamic instability behavior of simply supported Composite Cylindrical Shell panels subjected to dynamic partial edge loadings and transverse patch loadings is studied in this paper considering von Karman type of non-linearity. The stress distribution within the panel due to the applied partial edge loadings is evaluated by panel׳s membrane analysis. Subsequently using these stress distribution and via Hamilton׳s variational principle, the equations governing the instability behavior of Shell panel are derived. Neglecting inertia terms, governing equations for the postbuckling analysis of panel are obtained. Galerkin׳s method is used in the solution procedure. It is observed from the postbuckling analysis that the Cylindrical Shell panel subjected to partial edge compression behaves as an imperfect Shell panel as the partial edge compression in the x-direction induces tensile stress in the y-direction which makes the Shell panel to deflect out-of-plane. It is also observed that by suitably adjusting the lamina number and lamina layup, the snap through behavior of Shells can be altogether avoided. Dynamic instability regions of simply supported Composite Shell panels are traced by the method suggested by Bolotin. The linear and non-linear dynamic responses of the Shell in stable and unstable regions are studied. This brings out various features of the instability problem such as, existence of beats and its dependence on forcing frequency and initial conditions, and effect of non-linearity on the response. It is found that for certain value of dynamic partial edge loading, the panel exhibits chaotic behavior.
L S Ramachandra - One of the best experts on this subject based on the ideXlab platform.
-
computation of worst geometric imperfection profiles of Composite Cylindrical Shell panels by minimizing the non linear buckling load
Applied Mathematical Modelling, 2019Co-Authors: Tanish Dey, L S RamachandraAbstract:Abstract In this article the “most unfavorable” shape of initial geometric imperfection profile for laminated Cylindrical Shell panel is obtained analytically by minimizing the limit point load. The partial differential equations governing the Shell stability problem are reduced to a set of non-linear algebraic equations using Galerkin's technique. The non-linear equilibrium path is traced by employing Newton–Raphson method in conjunction with the Riks approach. A double Fourier series is used to represent the initial geometric imperfection profile for the Cylindrical Shell panel. The optimum values of these Fourier coefficients are determined by minimizing the limit point load using genetic algorithm. The results are determined for simply supported Composite Cylindrical Shell panel. Numerical results show that more number of terms is needed in Fourier series representation to obtain the “worst” geometric imperfection profile which gives lower limit load compared to single term representation of imperfection. We have incorporated constraints on the shape of imperfection to avoid unrealistic limit point loads (due to imperfection shape) as we have assumed that the imperfection is due to machining/manufactuting.
-
post buckled vibration characteristic of Composite Cylindrical Shell panels under parabolic in plane edge compression
International Journal of Applied Mechanics, 2015Co-Authors: Sarat Kumar Panda, Rajesh Kumar, L S RamachandraAbstract:In this paper, post-buckled vibration of cross-ply thick laminated Cylindrical Shell panels subjected to nonuniform (parabolic) uniaxial and biaxial compression is studied. The mathematical model is based on a higher order shallow Shell theory incorporating von Karman-type geometric nonlinearities and initial geometric imperfections. In the first step, the plate membrane problem is solved to evaluate the stress distribution within the plate in the pre-buckling range as the applied in-plane edge load is nonuniform. By using the above stress distributions, the governing Shell panel post-buckling equations are derived through Hamiltonian principle. The governing nonlinear partial differential equations are reduced into a set of nonlinear algebraic equations for post-buckling analysis and nonlinear ordinary differential equations in the case of free vibration analysis using Galerkin's method. The equilibrium paths through limit points are traced using Newton–Raphson method in conjunction with Riks approach. The free vibration frequency of pre-bucked and post-buckled Cylindrical panels loaded with uniaxial or biaxial nonuniform in-plane edge load are studied. Free vibration frequency for symmetric (0/90/0) cross-ply laminated Cylindrical Shell panels under uniaxial and biaxial parabolic in-plane load with initial imperfections are presented for different post-buckled deflections. Limit loads and snap-through behavior of Shell panels and corresponding free vibration results are co-related for better understanding of the problem.
-
static and dynamic instability analysis of Composite Cylindrical Shell panels subjected to partial edge loading
International Journal of Non-linear Mechanics, 2014Co-Authors: Tanish Dey, L S RamachandraAbstract:Abstract The postbuckling and dynamic instability behavior of simply supported Composite Cylindrical Shell panels subjected to dynamic partial edge loadings and transverse patch loadings is studied in this paper considering von Karman type of non-linearity. The stress distribution within the panel due to the applied partial edge loadings is evaluated by panel׳s membrane analysis. Subsequently using these stress distribution and via Hamilton׳s variational principle, the equations governing the instability behavior of Shell panel are derived. Neglecting inertia terms, governing equations for the postbuckling analysis of panel are obtained. Galerkin׳s method is used in the solution procedure. It is observed from the postbuckling analysis that the Cylindrical Shell panel subjected to partial edge compression behaves as an imperfect Shell panel as the partial edge compression in the x-direction induces tensile stress in the y-direction which makes the Shell panel to deflect out-of-plane. It is also observed that by suitably adjusting the lamina number and lamina layup, the snap through behavior of Shells can be altogether avoided. Dynamic instability regions of simply supported Composite Shell panels are traced by the method suggested by Bolotin. The linear and non-linear dynamic responses of the Shell in stable and unstable regions are studied. This brings out various features of the instability problem such as, existence of beats and its dependence on forcing frequency and initial conditions, and effect of non-linearity on the response. It is found that for certain value of dynamic partial edge loading, the panel exhibits chaotic behavior.
-
stability and vibration behavior of Composite Cylindrical Shell panels under axial compression and secondary loads
Journal of Applied Mechanics, 2008Co-Authors: J Girish, L S RamachandraAbstract:The nonlinear static response and vibration behavior of cross-ply laminated Cylindrical Shell panels subjected to axial compression combined with other secondary loading are examined. The Shell theory adopted in the present case is based on a higher-order shallow Shell theory, includes geometric imperfection and von Karman-type geometric nonlinearity. The solutions to the governing nonlinear partial differential equations are sought using the multiterm Galerkin technique. The nonlinear equilibrium paths through limit points and bifurcation points are traced using the Newton–Raphson method coupled with the Riks approach. The free vibration frequencies of post-buckled Cylindrical panels about the static equilibrium state are reported by solving the associated linear eigenvalue problem. Results are presented for simply supported cross-ply laminated Cylindrical Shell panels, which illustrates the influence of initial geometric imperfection, temperature field, lateral pressure loads, and mechanical edge loads on the static response and vibration behavior of the Shell panel.
-
nonlinear response of laminated Cylindrical Shell panels subjected to thermomechanical loads
Journal of Engineering Mechanics-asce, 2006Co-Authors: M K Singha, L S Ramachandra, J N BandyopadhyayAbstract:The nonlinear response of multi-layered Composite Cylindrical Shell panels subjected to thermomechanical loads are studied in this article. The structural model is based on the first order shear deformation theory incorporating geometric nonlinearities. The nonlinear equilibrium paths are traced using the arc-length control algorithm within the framework of finite element method. Hashin’s failure criterion has been adopted to predict the first-ply failure of Cylindrical laminates. Both temperature independent and temperature dependent elastic properties are considered in the analysis. Specific numerical results are reported to show the effect of radius-to-span ratio, thickness-to-span ratio, laminate stacking sequence, and boundary condition on stability characteristics of laminated Cylindrical Shell panels subjected to combined thermal and mechanical transverse loads.
Hui-shen Shen - One of the best experts on this subject based on the ideXlab platform.
-
torsional postbuckling of nanotube reinforced Composite Cylindrical Shells in thermal environments
Composite Structures, 2014Co-Authors: Hui-shen ShenAbstract:Abstract A postbuckling analysis is presented for a functionally graded Composite Cylindrical Shell reinforced by single-walled carbon nanotubes (SWCNTs) subjected to torsion in thermal environments. The multi-scale model for functionally graded carbon nanotube-reinforced Composite (FG-CNTRC) Shells under torsion is proposed. A singular perturbation technique along with a two-step perturbation approach is employed to determine the buckling load and postbuckling equilibrium path. The numerical illustrations concern the torsional buckling and postbuckling behavior of perfect and imperfect, FG-CNTRC Cylindrical Shells under different sets of thermal environmental conditions. The results for uniformly distributed CNTRC Shell, which is a special case in the present study, are compared with those of the FG-CNTRC Shell. The results show that the linear functionally graded reinforcements can increase the buckling torque as well as postbuckling strength of the Shell under torsion when the reinforcement has a symmetrical distribution. The results reveal that the carbon nanotube volume fraction has a significant effect on the buckling load and postbuckling behavior of CNTRC Shells under torsion.
-
postbuckling of 3d braided Composite Cylindrical Shells under combined external pressure and axial compression in thermal environments
International Journal of Mechanical Sciences, 2008Co-Authors: Zhimin Li, Hui-shen ShenAbstract:Abstract A postbuckling analysis is presented for a three-dimensional (3D) braided Composite Cylindrical Shell of finite length subjected to combined loading of external pressure and axial compression in thermal environments. Based on a micro–macro-mechanical model, a 3D braided Composite may be a cell system and the geometry of each cell is highly dependent on its position in the cross-section of the Cylindrical Shell. The material properties of epoxy are expressed as a linear function of temperature. The governing equations are based on a higher order shear deformation Shell theory with a von Karman–Donnell-type kinematic nonlinearity and includes thermal effects. A singular perturbation technique is employed to determine interactive buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the postbuckling behavior of perfect and imperfect, braided Composite Cylindrical Shells with different values of Shell geometric parameter and of fiber volume fraction under combined loading conditions. The results show that the Shell has lower buckling loads and postbuckling paths when the temperature-dependent properties are taken into account. The effects of temperature rise, fiber volume fraction, Shell geometric parameter, load-proportional parameter, as well as initial geometric imperfections are studied.
Jingyu Zhai - One of the best experts on this subject based on the ideXlab platform.
-
vibration analyses of symmetrically laminated Composite Cylindrical Shells with arbitrary boundaries conditions via rayleigh ritz method
Composite Structures, 2015Co-Authors: Xuyuan Song, Qingkai Han, Jingyu ZhaiAbstract:Abstract In this paper, the free vibrations of the symmetrically laminated Composite Cylindrical Shells with arbitrary boundaries are analyzed by employing a set of artificial springs. Firstly, by employing a set of orthogonal polynomials as the admissible function, the Rayleigh–Ritz method is used to derive the equations of motion of the Composite Cylindrical Shells with classical boundary conditions. Then, the equivalent elastic constraint is imposed on cylinder edges and to be used to simulate the arbitrary boundary conditions of the symmetrically Composite Cylindrical Shell, and so as to formulate the frequency equations of it, in which the potential energy of the artificial springs is considered. Several comparisons are carried out to validate the approach method in current study, and the convergence investigations are checked at the same time. At last, the influence of boundary stiffness and lamination schemes on natural frequencies of the symmetrically laminated Composite Cylindrical Shells is investigated. The results indicate that the present method is powerful to analyze the vibrations of the Shells subjected to various boundaries including the classical constraints, elastic constraints and the combination of them efficiently.
-
traveling wave analysis of rotating cross ply laminated Cylindrical Shells with arbitrary boundaries conditions via rayleigh ritz method
Composite Structures, 2015Co-Authors: Xuyuan Song, Jingyu Zhai, Yugang Chen, Qingkai HanAbstract:Abstract This paper presents the analysis on free vibration of rotating cross-ply laminated circular Cylindrical Shells under arbitrary elastic boundary conditions via Rayleigh–Ritz method. Based on the Donnel’s Shell theory, the energy equations of the Composite Shell which take into account of initial hoop tension, centrifugal and Coriolis forces are derived. By employing a set of orthogonal polynomials as the admissible function, the Rayleigh–Ritz method is used to formulate the equations of motion of the rotating Composite Cylindrical Shell with traditional boundary conditions. Then, the assumed elastic springs applying on boundaries of the Shell are employed to simulate the arbitrary elastic supports of the rotating Composite Shells, which contribute the total system energy as elastic spring potential energy. Further, some numerical examples are presented to confirm the influence of variations elastic boundary conditions and lamination schemes on the frequency of rotating Composite cylinders. The current strategy is excellent to investigate the traveling waves of rotating Composite Shell with various boundaries including the classical constrains, elastic cases and the combinations of them availably and accurately.
Qingkai Han - One of the best experts on this subject based on the ideXlab platform.
-
vibration analyses of symmetrically laminated Composite Cylindrical Shells with arbitrary boundaries conditions via rayleigh ritz method
Composite Structures, 2015Co-Authors: Xuyuan Song, Qingkai Han, Jingyu ZhaiAbstract:Abstract In this paper, the free vibrations of the symmetrically laminated Composite Cylindrical Shells with arbitrary boundaries are analyzed by employing a set of artificial springs. Firstly, by employing a set of orthogonal polynomials as the admissible function, the Rayleigh–Ritz method is used to derive the equations of motion of the Composite Cylindrical Shells with classical boundary conditions. Then, the equivalent elastic constraint is imposed on cylinder edges and to be used to simulate the arbitrary boundary conditions of the symmetrically Composite Cylindrical Shell, and so as to formulate the frequency equations of it, in which the potential energy of the artificial springs is considered. Several comparisons are carried out to validate the approach method in current study, and the convergence investigations are checked at the same time. At last, the influence of boundary stiffness and lamination schemes on natural frequencies of the symmetrically laminated Composite Cylindrical Shells is investigated. The results indicate that the present method is powerful to analyze the vibrations of the Shells subjected to various boundaries including the classical constraints, elastic constraints and the combination of them efficiently.
-
traveling wave analysis of rotating cross ply laminated Cylindrical Shells with arbitrary boundaries conditions via rayleigh ritz method
Composite Structures, 2015Co-Authors: Xuyuan Song, Jingyu Zhai, Yugang Chen, Qingkai HanAbstract:Abstract This paper presents the analysis on free vibration of rotating cross-ply laminated circular Cylindrical Shells under arbitrary elastic boundary conditions via Rayleigh–Ritz method. Based on the Donnel’s Shell theory, the energy equations of the Composite Shell which take into account of initial hoop tension, centrifugal and Coriolis forces are derived. By employing a set of orthogonal polynomials as the admissible function, the Rayleigh–Ritz method is used to formulate the equations of motion of the rotating Composite Cylindrical Shell with traditional boundary conditions. Then, the assumed elastic springs applying on boundaries of the Shell are employed to simulate the arbitrary elastic supports of the rotating Composite Shells, which contribute the total system energy as elastic spring potential energy. Further, some numerical examples are presented to confirm the influence of variations elastic boundary conditions and lamination schemes on the frequency of rotating Composite cylinders. The current strategy is excellent to investigate the traveling waves of rotating Composite Shell with various boundaries including the classical constrains, elastic cases and the combinations of them availably and accurately.