CONTINUOUS ELEMENT FORMULATIONS FOR COMPOSITE RING-STIFFENED CYLINDRICAL SHELLS

2018 ◽  
Vol 56 (4) ◽  
pp. 515 ◽  
Author(s):  
Nam Bich Le ◽  
Cuong Manh Nguyen ◽  
Thinh Ich Tran
Keyword(s):  
Dynamic Stiffness ◽  
Equations Of Motion ◽  
Cylindrical Shells ◽  
Governing Equations ◽  
Composite Ring ◽  
Annular Plates ◽  
Proposed Model ◽  
Assembly Procedure ◽  
Stiffened Cylindrical Shells ◽  
Ring Stiffener

This research studies the free vibration of composite ring-stiffened cylindrical shells by the continuous element method (CEM). The dynamic stiffness matrix (DSM) of the investigated structure has been constructed based on the analytical solutions of the governing equations of motion for composite cylindrical shells and annular plates. By applying the powerful assembly procedure of continuous elements method, natural frequencies and harmonic responses of composite ring-stiffened cylindrical shells have been obtained. In addition, the proposed model allows extracting exactly ring-stiffener vibration modes by choosing appropriate points of response. Numerical examples have confirmed many advantages of the developed model.

Development of beam modal function for free vibration analysis of FML circular cylindrical shells

2017 ◽  
Vol 24 (14) ◽  
pp. 3026-3035 ◽  
Author(s):  
Masood Mohandes ◽  
Ahmad Reza Ghasemi ◽  
Mohsen Irani-Rahagi ◽  
Keivan Torabi ◽  
Fathollah Taheri-Behrooz
Keyword(s):  
Free Vibration ◽  
Shell Theory ◽  
Volume Fraction ◽  
Equations Of Motion ◽  
Cylindrical Shells ◽  
Free Vibration Analysis ◽  
Governing Equations ◽  
Fiber Metal Laminate ◽  
Circular Cylindrical Shells ◽  
Fiber Metal

The free vibration of fiber–metal laminate (FML) thin circular cylindrical shells with different boundary conditions has been studied in this research. Strain–displacement relations have been obtained according to Love’s first approximation shell theory. To satisfy the governing equations of motion, a beam modal function model has been used. The effects of different FML parameters such as material properties lay-up, volume fraction of metal, fiber orientation, and axial and circumferential wavenumbers on the vibration of the shell have been studied. The frequencies of shells have been calculated for carbon/epoxy and glass/epoxy as composites and for aluminum as metal. The results demonstrate that the influences of FML lay-up and volume fraction of composite on the frequencies of the shell are remarkable.

Modeling of Human Lower Extremity Musculo-Skeletal Structure Using Bond Graph Approach

2007 ◽  
Author(s):  
Ali Selk Ghafari ◽  
Ali Meghdari ◽  
Gholam Reza Vossoughi
Keyword(s):  
Sagittal Plane ◽  
Equations Of Motion ◽  
Bond Graph ◽  
Skeletal Structure ◽  
Governing Equations ◽  
Straight Line ◽  
Proposed Model ◽  
In Series ◽  
Muscular Function ◽  
Mechanical Linkage

A vector bond graph approach for dynamic modeling of human musculo-skeletal system is addressed in this article. In the proposed model, human body is modeled as a ten-segment, nine degree of freedom, mechanical linkage, actuated by ten muscles in sagittal plane. The head, arm and torso (HAT) are modeled as a single rigid body. Interaction of the feet with the ground is modeled using a spring-damper unit placed under the sole of each foot. The path of each muscle is represented by a straight line. Each actuator is modeled as a three-element, Hill-type muscle in series with tendon. The governing equations of motion generated by the proposed method are equivalent to those developed with more traditional techniques. However the models can be more easily used in conjunction with control models of neuro-muscular function for the simulation of overall dynamic motor performance. In the proposed structure, segments can be easily added or removed. Such a model may have applications in clinical diagnosis and modeling of paraplegic patients during robotic-assisted walking.

Some basic theorems on a recent model of linear thermoelasticity for a homogeneous and isotropic medium

2018 ◽  
Vol 24 (8) ◽  
pp. 2444-2457 ◽  
Author(s):  
Om N Shivay ◽  
Santwana Mukhopadhyay
Keyword(s):  
Heat Conduction ◽  
Isotropic Medium ◽  
Equations Of Motion ◽  
Governing Equations ◽  
Conduction Model ◽  
Proposed Model ◽  
Present Context ◽  
Linear Thermoelasticity ◽  
Thermoelastic Problems ◽  
The Uniqueness Theorem

This paper investigates a thermoelasticity theory based on the recent heat conduction model proposed by Quintanilla ( Mech Res Commun 2011; 38: 355–360). Taylor’s expansion of this model leads to an interesting problem of heat conduction. Serious attention has been paid by researchers in the last few years to investigating various heat conduction models. We have considered this newly proposed model of heat conduction given by Quintanilla and employed for coupled thermoelastic problems. We derive the basic governing equations for a homogeneous and isotropic medium and aim to derive some important theorems. Firstly, the uniqueness theorem of a mixed initial and boundary value problem of linear thermoelasticity in the present context is proved. A variational principle is derived for the basic governing equations of motion on the basis of a functional in the context of the present problem. A reciprocity theorem is established by using Laplace transformation. Furthermore, generalization of Somigliano and Green’s theorem for this model is proved on the basis of our reciprocity relation.

Influence of Symmetrical Boundary Conditions on Free Vibration of Functionally Graded Cylindrical Shells With Ring Support

2009 ◽  
Author(s):  
M. R. Isvandzibaei ◽  
M. M. Najafizadeh ◽  
P. Khazaeinejad
Keyword(s):  
Free Vibration ◽  
Boundary Conditions ◽  
Equations Of Motion ◽  
Cylindrical Shells ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Governing Equations ◽  
Third Order ◽  
Graded Materials ◽  
Ring Support

In the present work, the free vibration of thin cylindrical shells with ring support made of functionally graded materials under various symmetrical boundary conditions is presented. Temperature and position dependent material properties are varied linearly through the thickness of the shell. The functionally graded cylindrical shell has ring support which is arbitrarily placed along the shell and imposed a zero lateral deflection. The third order shear deformation theory is employed to formulate the problem. The governing equations of motion are derived using the Hamilton’s principle. Results are presented on the frequency characteristics and influence of the boundary conditions and the locations of the ring support on the natural frequencies. The present analysis is validated by comparing the results with those available in the literature.

scholarly journals A New Analytical Approach for Nonlinear Global Buckling of Spiral Corrugated FG-CNTRC Cylindrical Shells Subjected to Radial Loads

2020 ◽  
Vol 10 (7) ◽  
pp. 2600
Author(s):  
Tho Hung Vu ◽  
Hoai Nam Vu ◽  
Thuy Dong Dang ◽  
Ngoc Ly Le ◽  
Thi Thanh Xuan Nguyen ◽  
...  
Keyword(s):  
Analytical Approach ◽  
Cylindrical Shells ◽  
Equation System ◽  
Functionally Graded ◽  
Governing Equations ◽  
Reinforced Composite ◽  
Global Buckling ◽  
Homogenization Model ◽  
Corrugated Structure ◽  
The Galerkin Method

The present paper deals with a new analytical approach of nonlinear global buckling of spiral corrugated functionally graded carbon nanotube reinforced composite (FG-CNTRC) cylindrical shells subjected to radial loads. The equilibrium equation system is formulated by using the Donnell shell theory with the von Karman’s nonlinearity and an improved homogenization model for spiral corrugated structure. The obtained governing equations can be used to research the nonlinear postbuckling of mentioned above structures. By using the Galerkin method and a three term solution of deflection, an approximated analytical solution for the nonlinear stability problem of cylindrical shells is performed. The linear critical buckling loads and postbuckling strength of shells under radial loads are numerically investigated. Effectiveness of spiral corrugation in enhancing the global stability of spiral corrugated FG-CNTRC cylindrical shells is investigated.

scholarly journals Vibration of rotating circular cylindrical shells with distributed springs

2021 ◽  
Vol 37 ◽  
pp. 346-358
Author(s):  
Fuchun Yang ◽  
Xiaofeng Jiang ◽  
Fuxin Du
Keyword(s):  
Boundary Conditions ◽  
Galerkin Method ◽  
Shell Theory ◽  
Rotation Speed ◽  
Cylindrical Shells ◽  
Free Vibrations ◽  
Governing Equations ◽  
Natural Response ◽  
Circular Cylindrical Shells ◽  
The Galerkin Method

Abstract Free vibrations of rotating cylindrical shells with distributed springs were studied. Based on the Flügge shell theory, the governing equations of rotating cylindrical shells with distributed springs were derived under typical boundary conditions. Multicomponent modal functions were used to satisfy the distributed springs around the circumference. The natural responses were analyzed using the Galerkin method. The effects of parameters, rotation speed, stiffness, and ratios of thickness/radius and length/radius, on natural response were also examined.

Simulation of Engine Vibration on Nonlinear Hydraulic Engine Mounts

2005 ◽  
Author(s):  
A. R. Ohadi ◽  
G. Maghsoodi
Keyword(s):  
Equations Of Motion ◽  
Low Frequency ◽  
Governing Equations ◽  
Engine Mounts ◽  
Engine Vibration ◽  
Engine Mount ◽  
Rotational Motions ◽  
The Time Domain ◽  
Nonlinear Equations Of Motion ◽  
Four Cylinders

In this paper, vibration behavior of engine on nonlinear hydraulic engine mount including inertia track and decoupler is studied. In this regard, after introducing the nonlinear factors of this mount (i.e. inertia and decoupler resistances in turbulent region), the vibration governing equations of engine on one hydraulic engine mount are solved and the effect of nonlinearity is investigated. In order to have a comparison between rubber and hydraulic engine mounts, a 6 degree of freedom four cylinders V-shaped engine under inertia and balancing masses forces and torques is considered. By solving the time domain nonlinear equations of motion of engine on three inclined mounts, translational and rotational motions of engines body are obtained for different engine speeds. Transmitted base forces are also determined for both types of engine mount. Comparison of rubber and hydraulic mounts indicates the efficiency of hydraulic one in low frequency region.

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