Neeraj Grover | Thapar University, Patiala (original) (raw)
Papers by Neeraj Grover
Journal of Aerospace Engineering, 2015
ABSTRACT A generalized finite element modeling of recently developed secant function based shear ... more ABSTRACT A generalized finite element modeling of recently developed secant function based shear deformation theory is formulated and implemented for free vibration and buckling characteristics of laminated-composite and sandwich plates. The shear deformation is expressed in terms of a secant function of thickness coordinate. The theory inherently satisfies the zero transverse shear conditions on top and bottom surfaces of the plate. An eight-noded C-0 continuous element is chosen by an adequate choice of nodal field variables. The governing equations are obtained for the free vibration and buckling responses of laminated-composite and sandwich plates. Intensive numerical experiments are conducted to investigate the influence of span-thickness ratio, boundary conditions, etc. on the free vibration and buckling behavior. The comparison of present results with the published results indicates the performance and range of applicability of the present theory in the framework of finite element analysis.
Latin American Journal of Solids and Structures, 2014
A secant function based shear deformable finite element model is developed for the flexural behav... more A secant function based shear deformable finite element model is developed for the flexural behavior of laminated composite and sandwich plates with various conditions. The structural kinematics of the plate is expressed by means of secant function based shear deformation theory newly developed by the authors. The theory possesses non-linear shear deformation and also satisfies the zero transverse shear conditions on top and bottom surfaces of the plate. The field variables are elegantly utilized in order to ensure C0 conti-nuity requirement. Penalty parameter is implemented to secure the constraints arising due to independent field variables. A biquadratic quadrilateral element with eight nodes and 56 degrees of freedom is employed to discretize the domain. Extensive numerical tests for the flexural behavior of laminated composite and sandwich plates are conducted to affirm the validity of the present finite element model in conjunction with the improved structural kinematics. Influences of boundary conditions, loading conditions, lamination sequences, aspect ratio, span-thickness ratio, etc on the flexural behavior are investigated specifically and compared with the existing results in order to indicate the performance of the present mathematical treatment.
Journal of the Indian Institute of Science 93 (4), 603-620
The involvement of various processes/parameters in the manufacturing and fabrication of laminated... more The involvement of various processes/parameters in the manufacturing and fabrication of laminated composites and the lack of control over these constituent processes cause the uncertainty in the system parameters. Therefore, the consideration of these random parameters in the analysis of composite structures is essential. The objective of the present study is to present state-of-the-art on the stochastic modeling of composite structures. The various techniques available for the uncertainty characterization and their propagation in the deterministic solver are discussed. The significance of various approaches is presented and their applicability to quantify various uncertainties is concluded. The essential requirements to accurately model the multilayered structures are discussed by presenting the classification of available theories. The incorporation of the uncertainty quantification techniques with the deterministic structural mechanics solvers leads to the stochastic techniques such as stochastic finite element analysis. The wide range of applicability and the accuracy of finite element analysis in deterministic environment are both—an added advantage and a priori requirement of an accurate stochastic solver. The finite element method in the stochastic framework is presented to determine the governing equations for the structural behavior of laminated composite and sandwich plates. The stochastic finite element method is then presented in the context of Monte Carlo simulation and perturbation technique. Further, the influence of various uncertain parameters such as material properties, loading conditions etc. on the structural behavior of laminated composite structures is discussed by presenting the observations made in the available literature on such analyses. It is hoped that the present work could facilitate the research community involved in stochastic or deterministic analysis of laminated composites.
A computationally efficient C0 finite element model is developed for laminated composite and sand... more A computationally efficient C0 finite element model is developed for laminated composite and sandwich plates by implementing the inverse hyperbolic shear deformation theory recently developed by the authors. This model is used to determine responses of general laminates subjected to various combinations of boundary conditions. The present formulation has been generalized for all existing shear deformation theories involving shear strain function. An eight noded serendipity element with 56 degrees of freedom is used to discretize the plate domain. Influences of lamination sequence (cross ply and angle ply), span to thickness ratio, and boundary conditions are investigated for the flexural behavior of laminated composite and sandwich plates. Further, the stability behavior of plates subjected to in-plane loads (uni-axial and bi-axial) is investigated for a variety of examples. Effects of boundary conditions and applied loads on the critical buckling loads and buckling mode shapes are also assessed for a class of laminates in order to show the efficacy of the present mathematical technique to predict the buckling mode shapes.
AIAA
"In the present study, new nonpolynomial shear-deformation theories are proposed and implemented ... more "In the present study, new nonpolynomial shear-deformation theories are proposed and implemented for structural responses of laminated-composite and sandwich plates. The theories assume nonlinear distribution of transverse shear stresses, and also satisfy the traction-free boundary conditions at the top and bottom layers of the laminates. The governing differential equations are derived for a generalized shear-deformation theory by implementing the dynamic version of principle of virtual work and calculus of variations. A generalized closed-form solution methodology of the Navier type is implemented to ensure the validity and efficiency of the present theories for bending, buckling, and free-vibration responses of the laminated-composite and sandwich plates. It is observed that the proposed formulation in conjunction with the solution methodology is capable of handling all existing five-degreeof-freedom-based shear-deformation theories. The comparison of results also shows that the adequate choice of shear deformation leads to an accurate prediction of structural responses. The influence of shear deformation on the type of analysis performed is also observed in this study. The theories are also capable of an efficient prediction of the responses of structures at a similar computational cost as that of other equivalent single-layer theories."
In present study, a new inverse hyperbolic shear deformation theory is proposed, formulated and v... more In present study, a new inverse hyperbolic shear deformation theory is proposed, formulated and validated for a variety of numerical examples of laminated composite and sandwich plates for the static and buckling responses. The proposed theory based upon shear strain shape function yields non-linear distribution of transverse shear stresses and also satisfies traction free boundary conditions. Principle of virtual work is employed to develop the governing differential equations assuming the linear kinematics. A Navier type closed form solution methodology is also proposed for cross-ply simply supported plates which limits its applicability. However, it provides accurate solution which is free from any numerical/computational error. It is observed that the present theory can be more accurately applied for the modeling of laminated composite and sandwich plates at the same computational cost as that of other shear deformation theories.
Recently developed inverse hyperbolic shear deformation theory by the authors is extended to anal... more Recently developed inverse hyperbolic shear deformation theory by the authors is extended to analyze the free vibration response of laminated composite and sandwich plates. Euler–Lagrange equations are derived employing the principle of virtual work for the dynamic problem. A Navier type and finite element solutions are proposed to obtain the free vibration response of laminated composite and sandwich plates. A C0-continuous isoparametric biquadratic-quadrilateral serendipity element is used for the finite element solution of generalized higher order shear deformation theory so as to ensure its applicability to general laminates subjected to different combinations of boundary conditions. Higher modes of vibration are obtained for laminated cross-ply and angle-ply plates and efficiency of the theory is ensured by comparing the results with the existing results. It is observed that both analytical and finite element solutions with the present theory are capable for accurate prediction of the free vibration response.► Newly developed inverse hyperbolic shear deformation theory is assessed for free vibration. ► Analytical and finite element solutions are developed for laminated composite and sandwich plates. ► A C0-continuous eight noded isoparametric element is implemented for the finite element model. ► The new results are obtained for general laminates with different boundary conditions. ► It is observed that both solution procedures are capable for efficient prediction of the response.
Journal of Aerospace Engineering, 2015
ABSTRACT A generalized finite element modeling of recently developed secant function based shear ... more ABSTRACT A generalized finite element modeling of recently developed secant function based shear deformation theory is formulated and implemented for free vibration and buckling characteristics of laminated-composite and sandwich plates. The shear deformation is expressed in terms of a secant function of thickness coordinate. The theory inherently satisfies the zero transverse shear conditions on top and bottom surfaces of the plate. An eight-noded C-0 continuous element is chosen by an adequate choice of nodal field variables. The governing equations are obtained for the free vibration and buckling responses of laminated-composite and sandwich plates. Intensive numerical experiments are conducted to investigate the influence of span-thickness ratio, boundary conditions, etc. on the free vibration and buckling behavior. The comparison of present results with the published results indicates the performance and range of applicability of the present theory in the framework of finite element analysis.
Latin American Journal of Solids and Structures, 2014
A secant function based shear deformable finite element model is developed for the flexural behav... more A secant function based shear deformable finite element model is developed for the flexural behavior of laminated composite and sandwich plates with various conditions. The structural kinematics of the plate is expressed by means of secant function based shear deformation theory newly developed by the authors. The theory possesses non-linear shear deformation and also satisfies the zero transverse shear conditions on top and bottom surfaces of the plate. The field variables are elegantly utilized in order to ensure C0 conti-nuity requirement. Penalty parameter is implemented to secure the constraints arising due to independent field variables. A biquadratic quadrilateral element with eight nodes and 56 degrees of freedom is employed to discretize the domain. Extensive numerical tests for the flexural behavior of laminated composite and sandwich plates are conducted to affirm the validity of the present finite element model in conjunction with the improved structural kinematics. Influences of boundary conditions, loading conditions, lamination sequences, aspect ratio, span-thickness ratio, etc on the flexural behavior are investigated specifically and compared with the existing results in order to indicate the performance of the present mathematical treatment.
Journal of the Indian Institute of Science 93 (4), 603-620
The involvement of various processes/parameters in the manufacturing and fabrication of laminated... more The involvement of various processes/parameters in the manufacturing and fabrication of laminated composites and the lack of control over these constituent processes cause the uncertainty in the system parameters. Therefore, the consideration of these random parameters in the analysis of composite structures is essential. The objective of the present study is to present state-of-the-art on the stochastic modeling of composite structures. The various techniques available for the uncertainty characterization and their propagation in the deterministic solver are discussed. The significance of various approaches is presented and their applicability to quantify various uncertainties is concluded. The essential requirements to accurately model the multilayered structures are discussed by presenting the classification of available theories. The incorporation of the uncertainty quantification techniques with the deterministic structural mechanics solvers leads to the stochastic techniques such as stochastic finite element analysis. The wide range of applicability and the accuracy of finite element analysis in deterministic environment are both—an added advantage and a priori requirement of an accurate stochastic solver. The finite element method in the stochastic framework is presented to determine the governing equations for the structural behavior of laminated composite and sandwich plates. The stochastic finite element method is then presented in the context of Monte Carlo simulation and perturbation technique. Further, the influence of various uncertain parameters such as material properties, loading conditions etc. on the structural behavior of laminated composite structures is discussed by presenting the observations made in the available literature on such analyses. It is hoped that the present work could facilitate the research community involved in stochastic or deterministic analysis of laminated composites.
A computationally efficient C0 finite element model is developed for laminated composite and sand... more A computationally efficient C0 finite element model is developed for laminated composite and sandwich plates by implementing the inverse hyperbolic shear deformation theory recently developed by the authors. This model is used to determine responses of general laminates subjected to various combinations of boundary conditions. The present formulation has been generalized for all existing shear deformation theories involving shear strain function. An eight noded serendipity element with 56 degrees of freedom is used to discretize the plate domain. Influences of lamination sequence (cross ply and angle ply), span to thickness ratio, and boundary conditions are investigated for the flexural behavior of laminated composite and sandwich plates. Further, the stability behavior of plates subjected to in-plane loads (uni-axial and bi-axial) is investigated for a variety of examples. Effects of boundary conditions and applied loads on the critical buckling loads and buckling mode shapes are also assessed for a class of laminates in order to show the efficacy of the present mathematical technique to predict the buckling mode shapes.
AIAA
"In the present study, new nonpolynomial shear-deformation theories are proposed and implemented ... more "In the present study, new nonpolynomial shear-deformation theories are proposed and implemented for structural responses of laminated-composite and sandwich plates. The theories assume nonlinear distribution of transverse shear stresses, and also satisfy the traction-free boundary conditions at the top and bottom layers of the laminates. The governing differential equations are derived for a generalized shear-deformation theory by implementing the dynamic version of principle of virtual work and calculus of variations. A generalized closed-form solution methodology of the Navier type is implemented to ensure the validity and efficiency of the present theories for bending, buckling, and free-vibration responses of the laminated-composite and sandwich plates. It is observed that the proposed formulation in conjunction with the solution methodology is capable of handling all existing five-degreeof-freedom-based shear-deformation theories. The comparison of results also shows that the adequate choice of shear deformation leads to an accurate prediction of structural responses. The influence of shear deformation on the type of analysis performed is also observed in this study. The theories are also capable of an efficient prediction of the responses of structures at a similar computational cost as that of other equivalent single-layer theories."
In present study, a new inverse hyperbolic shear deformation theory is proposed, formulated and v... more In present study, a new inverse hyperbolic shear deformation theory is proposed, formulated and validated for a variety of numerical examples of laminated composite and sandwich plates for the static and buckling responses. The proposed theory based upon shear strain shape function yields non-linear distribution of transverse shear stresses and also satisfies traction free boundary conditions. Principle of virtual work is employed to develop the governing differential equations assuming the linear kinematics. A Navier type closed form solution methodology is also proposed for cross-ply simply supported plates which limits its applicability. However, it provides accurate solution which is free from any numerical/computational error. It is observed that the present theory can be more accurately applied for the modeling of laminated composite and sandwich plates at the same computational cost as that of other shear deformation theories.
Recently developed inverse hyperbolic shear deformation theory by the authors is extended to anal... more Recently developed inverse hyperbolic shear deformation theory by the authors is extended to analyze the free vibration response of laminated composite and sandwich plates. Euler–Lagrange equations are derived employing the principle of virtual work for the dynamic problem. A Navier type and finite element solutions are proposed to obtain the free vibration response of laminated composite and sandwich plates. A C0-continuous isoparametric biquadratic-quadrilateral serendipity element is used for the finite element solution of generalized higher order shear deformation theory so as to ensure its applicability to general laminates subjected to different combinations of boundary conditions. Higher modes of vibration are obtained for laminated cross-ply and angle-ply plates and efficiency of the theory is ensured by comparing the results with the existing results. It is observed that both analytical and finite element solutions with the present theory are capable for accurate prediction of the free vibration response.► Newly developed inverse hyperbolic shear deformation theory is assessed for free vibration. ► Analytical and finite element solutions are developed for laminated composite and sandwich plates. ► A C0-continuous eight noded isoparametric element is implemented for the finite element model. ► The new results are obtained for general laminates with different boundary conditions. ► It is observed that both solution procedures are capable for efficient prediction of the response.