Abstract: In this study, the dynamic analysis of viscoelastic plates with variable thickness is examined. The solutions of dynamic response of viscoelastic thin plates with variable thickness have been obtained by using the functional analysis method in the conjunction with the Gâteaux differential. The four-node serendipity element with four degrees of freedom such as deflection, bending, and twisting moments at each node is used. Additionally, boundary condition terms are included in the functional by using a systematic way. In viscoelastic modeling, Three-parameter Kelvin solid model is employed. The solutions obtained in the Laplace-Carson domain are transformed to the real time domain by using MDOP, Dubner & Abate, and Durbin inverse transform techniques. To test the performance of the proposed mixed finite element formulation, numerical examples are treated.
Abstract: This paper describes a new approach which can be
used to interpret the experimental creep deformation data obtained
from miniaturized thin plate bending specimen test to the
corresponding uniaxial data based on an inversed application of the
reference stress method. The geometry of the thin plate is fully
defined by the span of the support, l, the width, b, and the thickness,
d. Firstly, analytical solutions for the steady-state, load-line creep
deformation rate of the thin plates for a Norton’s power law under
plane stress (b→0) and plane strain (b→∞) conditions were obtained,
from which it can be seen that the load-line deformation rate of the
thin plate under plane-stress conditions is much higher than that
under the plane-strain conditions. Since analytical solution is not
available for the plates with random b-values, finite element (FE)
analyses are used to obtain the solutions. Based on the FE results
obtained for various b/l ratios and creep exponent, n, as well as the
analytical solutions under plane stress and plane strain conditions, an
approximate, numerical solutions for the deformation rate are
obtained by curve fitting. Using these solutions, a reference stress
method is utilised to establish the conversion relationships between
the applied load and the equivalent uniaxial stress and between the
creep deformations of thin plate and the equivalent uniaxial creep
strains. Finally, the accuracy of the empirical solution was assessed
by using a set of “theoretical” experimental data.
Abstract: When printing a plate (or dish) by an FDM 3D printer,
the process normally requires support material, which causes several
problems. This paper proposes a method for forming thin plates
without using wasteful support material. This method requires several
extraordinary parameter values when slicing plates. The experiments
show that the plates can, for the most part, be successfully formed
using a conventional slicer and a 3D printer; however, seams between
layers spoil them and the quality of printed objects strongly depends
on the slicer.
Abstract: In recent years many finite elements have been
developed for plate bending analysis. The formulated elements are
based on the strain based approach. This approach leads to the
representation of the displacements by higher order polynomial terms
without the need for the introduction of additional internal and
unnecessary degrees of freedom. Good convergence can also be
obtained when the results are compared with those obtained from the
corresponding displacement based elements, having the same total
number of degrees of freedom. Furthermore, the plate bending
elements are free from any shear locking since they converge to the
Kirchhoff solution for thin plates contrarily for the corresponding
displacement based elements. In this paper the efficiency of the strain
based approach compared to well known displacement formulation is
presented. The results obtained by a new formulated plate bending
element based on the strain approach and Kirchhoff theory are
compared with some others elements. The good convergence of the
new formulated element is confirmed.
Abstract: Arc welding is an important joining process widely used in many industrial applications including production of automobile, ships structures and metal tanks. In welding process, the moving electrode causes highly non-uniform temperature distribution that leads to residual stresses and different deviations, especially buckling distortions in thin plates. In order to control the deviations and increase the quality of welded plates, a fixture can be used as a practical and low cost method with high efficiency. In this study, a coupled thermo-mechanical finite element model is coded in the software ANSYS to simulate the behavior of thin plates located by a 3-2-1 positioning system during the welding process. Computational results are compared with recent similar works to validate the finite element models. The agreement between the result of proposed model and other reported data proves that finite element modeling can accurately predict the behavior of welded thin plates.
Abstract: Steel plate shear walls (SPSWs) in buildings are
known to be an effective means for resisting lateral forces. By using
un-stiffened walls and allowing them to buckle, their energy
absorption capacity will increase significantly due to the postbuckling
capacity. The post-buckling tension field action of SPSWs
can provide substantial strength, stiffness and ductility. This paper
presents the Finite Element Analysis of low yield point (LYP) steel
shear walls. In this shear wall system, the LYP steel plate is used for
the steel panel and conventional structural steel is used for boundary
frames. A series of nonlinear cyclic analyses were carried out to
obtain the stiffness, strength, deformation capacity, and energy
dissipation capacity of the LYP steel shear wall. The effect of widthto-
thickness ratio of steel plate on buckling behavior, and energy
dissipation capacities were studied. Good energy dissipation and
deformation capacities were obtained for all models.
Abstract: Analysis for the generalized thermoelastic Lamb
waves, which propagates in anisotropic thin plates in generalized
thermoelasticity, is presented employing normal mode expansion
method. The displacement and temperature fields are expressed by a
summation of the symmetric and antisymmetric thermoelastic modes
in the surface thermal stresses and thermal gradient free orthotropic
plate, therefore the theory is particularly appropriate for waveform
analyses of Lamb waves in thin anisotropic plates. The transient
waveforms excited by the thermoelastic expansion are analyzed for
an orthotropic thin plate. The obtained results show that the theory
provides a quantitative analysis to characterize anisotropic
thermoelastic stiffness properties of plates by wave detection. Finally
numerical calculations have been presented for a NaF crystal, and the
dispersion curves for the lowest modes of the symmetric and
antisymmetric vibrations are represented graphically at different
values of thermal relaxation time. However, the methods can be used
for other materials as well
Abstract: This paper describes a study of geometrically
nonlinear free vibration of thin circular functionally graded (CFGP)
plates resting on Winkler elastic foundations. The material properties
of the functionally graded composites examined here are assumed to
be graded smoothly and continuously through the direction of the
plate thickness according to a power law and are estimated using the
rule of mixture. The theoretical model is based on the classical Plate
theory and the Von-Kármán geometrical nonlinearity assumptions.
An homogenization procedure (HP) is developed to reduce the
problem considered here to that of isotropic homogeneous circular
plates resting on Winkler foundation. Hamilton-s principle is applied
and a multimode approach is derived to calculate the fundamental
nonlinear frequency parameters which are found to be in a good
agreement with the published results. On the other hand, the
influence of the foundation parameters on the nonlinear fundamental
frequency has also been analysed.