scholarly journals DAMPING OF THE AXISYMMETRIC RESONANT VIBRATION AND DISSIPATIVE HEATING OF THE FIXED SHEAR COMPLIANT INELASTIC CYLINDRICAL SHELL WITH PIEZOACTUATOR

2020 ◽  
pp. 42-46
Author(s):  
Y. Zhuk ◽  
A. Tarasov
Keyword(s):  
Cylindrical Shell ◽  
Shear Strain ◽  
Material Properties ◽  
Constitutive Relations ◽  
Dissipative Heating ◽  
Iterative Approach ◽  
Resonant Vibration ◽  
Problem Statement ◽  
Thermal Dependence ◽  
Complex Moduli

Damping problem for axisymmetric resonant vibration of the shear compliant inelastic cylindrical shell with piezoactuator under electromechanical monoharmonic excitation is considered. The problem is solved for the refined problem statement accounting for shear strain, rotation inertia and thermal dependence of the material properties. Problem statement is based on the application of the amplitude constitutive relations for cyclically deformed material and complex moduli concept. The moduli for both piezoactive and piezopassive material are considered to be the functions of temperature. The nonlinear problem is solved numerically with the use of the iterative approach. The possibility of active damping of the forced vibration by means of the piezoactivator with account of shear strain is studied.

scholarly journals Formulation of the problem of thermomechanics for a flexible cylindrical shell with piezoactive layers with taking into account to displacements

2019 ◽  
pp. 78-81
Author(s):  
I. F. Kirichok ◽  
Y. A. Zhuk ◽  
O. A. Chernyshok ◽  
A. P. Tarasov
Keyword(s):  
Constitutive Relations ◽  
Geometrical Nonlinearity ◽  
Active Material ◽  
Core Layer ◽  
Dissipative Heating ◽  
Axisymmetric Vibration ◽  
Problem Statement ◽  
Coupled Problem ◽  
Complete Set ◽  
Resolving System

The formulation of problem on the forced resonant vibration and dissipative heating of layered element of structure containing both piezoelectric and electrically passive layers is considered. The improved problem statement taking account of both shear strain and rotatory inertia as well as geometrical nonlinearity is developed. Particular statement of the problem of axisymmetric vibration and dissipative heating of three layer cylidrical shell is formulated. It is assumed that the core layer of the shell is composed of the electrically passive material while the outer layers are manufactured from the piezoceramics. Theory of coupled thermo-electro-viscoelasticity is used to derive the problem statement in the case of monoharmonic loading. Within this theory, the concept of complex-value modulae is applied to formulate the relations between main field characteristics. It is also supposed that the piezo-active material characteristics do not depend on the temperature. Then the coupled problem is reduced to the problem of mechanics on the forced nonlinear vibrations and dissipative heating of the layered plate. Complete set of complex analogs of motion equations, geometric equations and constitutive relations was used to derive the resolving system of equations. Numerical method to attack this nonlinear system of ordinary differential equations supplemented with necessary boundary conditions is developed.

Theoretical Meso-Model of Al2O3/ZrO2 Ceramic Response under Compression

2014 ◽  
Vol 601 ◽  
pp. 92-95
Author(s):  
Tomasz Sadowski ◽  
Liviu Marsavina
Keyword(s):  
Grain Boundary ◽  
Material Properties ◽  
Mechanical Model ◽  
Constitutive Relations ◽  
Ceramic Composites ◽  
Theoretical Modeling ◽  
Polycrystalline Structure ◽  
Two Phase

This paper presents theoretical modeling of two-phase ceramic composites subjected to compression. The meso-mechanical model allows for inclusion of all microdefects in the polycrystalline structure that exists at the grain boundary interfaces and inside the grains. The constitutive relations for the Al2O3/ZrO2composite with the gradual degradation of the material properties due to different defects development were formulated.

scholarly journals Structural Design for a 10-GWh SMES Vacuum Vessel

1978 ◽  
Vol 100 (3) ◽  
pp. 263-270
Author(s):  
J. G. Bennett ◽  
C. A. Anderson
Keyword(s):  
Cylindrical Shell ◽  
Approximate Solution ◽  
Elastic Deformation ◽  
Material Properties ◽  
Structural Design ◽  
Shell Thickness ◽  
Construction Cost ◽  
Vacuum Vessel ◽  
Nonlinear Elastic

An approximate solution to the problem of the nonlinear elastic deformation of a periodically point-supported cylindrical shell is obtained. This solution is used to investigate the structural design of the vacuum vesssel for the large underground SMES concept. Vacuum vessel designs are evaluated by varying such parameters as shell thickness, support, spacing, material properties and physical configuration to keep the amount of material used and construction cost to a minimum.

scholarly journals On the torsion of conical shells

1937 ◽  
Vol 163 (914) ◽  
pp. 337-355 ◽  
Keyword(s):  
Cylindrical Shell ◽  
Shear Strain ◽  
Cylindrical Tube ◽  
Theory Of Elasticity ◽  
Torsion Problem ◽  
Uniform Thickness ◽  
Thin Cylindrical Shell ◽  
Conical Shells ◽  
Circular Tubes ◽  
Cylindrical Form

1—In my “Introduction to the Theory of Elasticity” (Chap. V) I have approached the torsion problem for circular shafts by way of the simpler case of a thin cylindrical shell. A rectangular plate of uniform thickness (fig. 1 a ) will distort into a nearly rectangular parallelogram (fig. 1 b ) under the action of uniform shearing stresses q applied to its four edges, and if the distorted plate with stresses operative is bent into a cylindrical form (fig. 1 c ) the pair of opposite faces which are thereby brought into contact may be cemented together. Then their externally applied shear will cancel, leaving us with a cylindrical tube subjected to torsion; and the twist in the tube can be related with the shear strain in the originally flat plate. An advantage of this treatment is that we can equally imagine the plate to be bent into a non-circular cylinder. Then by the same argument we arrive at the Bredt-Batho formula for non-circular tubes, viz.

STOCHASTIC THERMAL POST-BUCKLING RESPONSE OF LAMINATED COMPOSITE CYLINDRICAL SHELL PANEL WITH SYSTEM RANDOMNESS

2012 ◽  
Vol 04 (01) ◽  
pp. 1250009 ◽  
Author(s):  
ACHCHHE LAL ◽  
B. N. SINGH ◽  
SUSHIL KALE
Keyword(s):  
Cylindrical Shell ◽  
Order Statistics ◽  
Material Properties ◽  
Laminated Composite ◽  
Composite Cylindrical Shell ◽  
Random System ◽  
Second Order Statistics ◽  
Post Buckling ◽  
Shell Panel ◽  
System Properties

The effect of random system properties on thermal post-buckling temperature of laminated composite cylindrical shell panel with temperature independent (TID) and dependent (TD) material properties subjected to uniform temperature distribution is examined in this study. System properties such as material properties, thermal expansion coefficients and lamina plate thickness are modeled as independent basic random variables. The basic formulation is based on higher-order shear deformation (HSDT) theory with von-Karman nonlinearity using modified C0 continuty. A direct iterative-based C0 nonlinear finite element method (FEM) combined with Taylor series-based mean-centered first-order perturbation technique (FOPT) developed by the authors for composite plate is extended for shell panel with reasonable accuracy to compute second-order statistics of post-buckling temperature of cylindrical shell panel. Typical numerical results for second order statistics (mean and coefficient of variance) of thermal post-buckling temperature of laminated cylindrical shell panel are obtained through numerical examples for various support conditions, amplitude ratios, shell thickness ratios, aspect ratios, lamination lay-up sequences, curvature to length ratios, types of material properties with the effect of random system parameters. The performance of outlined approach has been validated with those results available in the literatures and independent MCS.

scholarly journals State Variables in Saturated-Unsaturated Soil Mechanics

2016 ◽  
pp. 3-17
Author(s):  
Delwyn G. Fredlund
Keyword(s):  
Stress State ◽  
Continuum Mechanics ◽  
Unsaturated Soil ◽  
Material Properties ◽  
Soil Mechanics ◽  
Constitutive Relations ◽  
Saturated Soil ◽  
Clear Distinction ◽  
State Variables ◽  
Unsaturated Soil Mechanics

The description of the stress state in soils is the foundational point around which an applied science should be built for engineering practice. The stress state description has proven to be pivotal for saturated soil mechanics and the same should be true for unsaturated soil mechanics. Continuum mechanics sets forth a series of principles upon which a common science base can be developed for a wide range of materials. The principles require that there be a clear distinction between state variables and constitutive relations. Constitutive relations relate state variables and incorporate material properties. State variables, on the other hand, are independent of the material properties. It has been possible to maintain a clear distinction between variables of state and constitutive relations in the development of saturated soil mechanics and the same should be true for unsaturated soil mechanics. This paper presents a description of the source and character of stress state variables for saturated and unsaturated soils. The descriptions are consistent with the principles of multiphase continuum mechanics and provide an understanding of the source and importance of stress state variables.

A Theoretical Approach In The Analysis Of Multilayered Cross-Ply GRP Cylindrical Shell

1987 ◽  
pp. 26-36
Author(s):  
Dr. Daud Haji Abd. Rahman
Keyword(s):  
Cylindrical Shell ◽  
Constitutive Relations ◽  
Anisotropic Shell ◽  
Expansion Method ◽  
Plane Stress State ◽  
Complex Case ◽  
Isotropic Shell ◽  
Weight Support ◽  
Loading Case ◽  
Linear Shell Theory

The constitutive relations for the specially orthotropic lamina under a plane stress state are employed with a linear shell theory, to obtain the governing equations for the multilayered cross-ply cylindrical shell with through thickness symmetry. The well known Fourier expansion method, used extensively in the analysis of isotropic shell problems, are extended to handle the more complex case of the anisotropic shell subject to a general loading case. Attention is confined to those loads which are symmetric with respect to the generator passing through the lowest point of the shell, that is liquid-filled, self-weight, support loading, etc.

scholarly journals Viscoelastic Material Properties of the Myocardium and Cardiac Jelly in the Looping Chick Heart

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Jiang Yao ◽  
Victor D. Varner ◽  
Lauren L. Brilli ◽  
Jonathan M. Young ◽  
Larry A. Taber ◽  
...  
Keyword(s):  
Viscoelastic Material ◽  
Material Properties ◽  
Constitutive Relations ◽  
Computational Method ◽  
Heart Tube ◽  
Embryonic Tissues ◽  
Strain Energy Density Function ◽  
Modeling Techniques ◽  
Chick Heart ◽  
Intact Heart

Accurate material properties of developing embryonic tissues are a crucial factor in studies of the mechanics of morphogenesis. In the present work, we characterize the viscoelastic material properties of the looping heart tube in the chick embryo through nonlinear finite element modeling and microindentation experiments. Both hysteresis and ramp-hold experiments were performed on the intact heart and isolated cardiac jelly (extracellular matrix). An inverse computational method was used to determine the constitutive relations for the myocardium and cardiac jelly. With both layers assumed to be quasilinear viscoelastic, material coefficients for an Ogden type strain-energy density function combined with Prony series of two terms or less were determined by fitting numerical results from a simplified model of a heart segment to experimental data. The experimental and modeling techniques can be applied generally for determining viscoelastic material properties of embryonic tissues.

Innovative design of mechanical structures from first principles

1987 ◽  
Vol 1 (3) ◽  
pp. 169-189 ◽  
Author(s):  
Jonathan Cagan ◽  
Alice M. Agogino
Keyword(s):  
Material Properties ◽  
First Principles ◽  
Constitutive Relations ◽  
Solution Space ◽  
Optimization Techniques ◽  
Design System ◽  
First Principle ◽  
Innovative Design ◽  
The Creation ◽  
Monotonicity Analysis

In this paper a unique design methodology known as 1stPRINCE (FIRST PRINciple Computational Evalualor) is developed to perform innovative design of mechanical structures from first principle knowledge. The method is based on the assumption that the creation of innovative designs of physical significance, concerning geometric and material properties, requires reasoning from first principles. The innovative designs discovered by 1stPRINCE differ from routine designs in that new primitives are created. Monotonicity analysis and computer algebra are utilized to direct design variables in a globally optimal direction relative to the goals specified. In contrast to strict constraint propagation approaches, formal qualitative optimization techniques efficiently search the solution space in an optimizing direction, eliminate infeasible and suboptimal designs, and reason with both equality and inequality constraints. Modification of the design configuration space and the creation of new primitives, in order to meet the constraints or improve the design, are achieved by manipulating mathematical quantities such as the integral. The result is a design system which requires a knowledge base only of fundamental equations of deformation with physical constraints on variables, constitutive relations, and fundamental engineering assumptions; no pre-compiled knowledge of mechanical behavior is needed. Application of this theory to the design of a beam under torsion leads to designs of a hollow tube and a composite rod exhibiting globally optimal behavior. Further, these optimally-behaved designs are described symbolically as a function of the material properties and system parameters. This method is implemented in a LISP environment as a module in a larger intelligent CAD system that integrates qualitative, functional and numerical computation for engineering applications.

Analysis and Comparison of Pad Reinforcement of Pressure Vessel by Elastic and Elastoplastic FEM

2007 ◽  
Author(s):  
Lihua Liang ◽  
Zengliang Gao ◽  
Yangjian Xu ◽  
Kangda Zhang ◽  
Zhaohui Fan
Keyword(s):  
Cylindrical Shell ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Maximum Stress ◽  
Constitutive Relations ◽  
Contact Model ◽  
Integral Model ◽  
The Difference ◽  
Shell Intersections ◽  
Different Diameters

Considering reinforcement pad and the cylindrical shell as an integral model and a contact model, stress analysis for opening-reinforcement structures of a cylindrical shell is performed by elastic and elastoplastic FEM. By comparison of two sub-models and two material constitutive relations (elastic and elastoplastic), the stress distribution of cylindrical shell intersections by the contact model is similar to that by the integral model, but there are some differences of the stress at contact surfaces of the shell and the reinforcement pad between by the contact model and by the integral model. In general, the stress analysis of the integral model for pad reinforcement can approximately represent that of the contact model. Finite element analyses for different nozzle diameters and different oblique angles in nozzle and cylinder shell intersections are carried out. The stress distribution and the maximum stress are affected by oblique angle. But the difference of the maximum stress intensity among different diameters is small.

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