Finite element analysis of elasto-plastic plate bending problems using transition rectangular plate elements

In this work, the finite element analysis of the elasto-plastic plate bending problems is carried out using transition rectangular plate elements. The shape functions of the transition plate elements are derived based on a practical rule. The transition plate elements are all quadrilateral and can be used to obtain efficient finite element models using minimum number of elements. The mesh convergence rates of the models including the transition elements are compared with the regular element models. To verify the developed elements, simple tests are demonstrated and various elasto-plastic problems are solved. Their results are compared with ANSYS results.

A MIXED VARIATIONAL FORMULATION FOR LARGE DEFORMATION ANALYSIS OF PLATES

A mixed vuriational formulation for large deformation analysis of plates is introduced. In this formulation the equilibrium ami compatibility equations are satisfied identically by means of stress functions and displacement components, respectively, and the constitu,lye equations are satisfied in a least square sense. An example is solved and the results are compared with those available in the literature.Further, the functional is particularized for buckling analysis of plates and a simple example is solved to illustrate the theory.

THE ELASTO-PLASTIC STRAIN ANALYSIS OF NOTCHED PLATE UNDER CYCLIC LOADING—AN APPLICATION OF PLASTIC ANISOTROPIC HARDENING THEORY

In order to predict the life of engineering structures, it is necessary to investigate the strain distribution in notched members. In gineral, the Uauschinger Effect of materials under cyclic loading is not negligible, and so the anisolropic hardening model has been suggested. From the comparison between the calculated and experimental results in this paper, we can see that even the linear kinematic hardening model is quite suitable for strain analysis under cyclic loading.

NUMERICAL-PERTURBATION ANALYSIS OF EDGE EFFECT IN BENDING LAMINATED PLATE

In this paper, we consider a bending laminated plate. At first, the dimensionless variables are used to transform the equilibrium equations of any layer to perturbation differential equations. Secondly, the composite expansion is used and the solution domain is divided into interior and boundary layer regions and the mathematical models for the outer solution and the inner solution are yielded respectively. Then, the inner solution is expressed with the boundary intergral equation.

A SEKIES BOUNDARY INTEGRATION METHOD FOR THE BENDING ANALYSIS OF ANISOTROPIC PLATES

A series boundary integration method is given which exactly satisfies the fundamental equation of bending analysis of general anisotropic plates or laminated plates in Kirchhoffs sense. With a unified deflection series, the method may be applied to the plates having different planforms and support conditions. Several groups of representative examples are calculated. The examples include circular, square and triangular plates, and their boundaries include clamped edges, simply supported edges, free edges and free corner. Numerical results indicate rapid convergency for both deflection and stress resultants and demonstrate wide applicability of the method.

Elasto-plasticity and pore-pressure coupled analysis on the pullout behaviors of a plate anchor

A numerical method is proposed for the elasto-plasticity and pore-pressure coupled analysis on the pull- out behaviors of a plate anchor. The bounding-surface plasticity （BSP） model combined with Blot＇s consol- idation theory is employed to simulate the cyclic loading induced elasto-plastic deformation of the soil skeleton and the accompanying generation/dissipation of the excess pore water pressure. The suction force generated around the anchor due to the cyclic variation of the pore water pressure has much effect on the pullout capacity of the plate anchor. The calculated pullout capacity with the proposed method （i.e., the coupled analysis） gets lower than that with the conventional total stress analysis for the case of long-term sustained loading, but slightly higher for the case of short-term monotonic loading. The cyclic loading induced accumulation of pore water pressure may result in an obvious decrease of the stiffness of the soil-Plate anchor svstem.

PERTURBATION ANALYSIS FOR THE POSTBUCKLING OF RECTANGULAR ORTHOTROPIC PLATES

In this paper, applying perturbation method to von Karman-type nonlinear large deflection equations of orthotropic plates by taking deflection as perturbation parameter, the postbuckling behavior of simply supported rectangular orthotropic plates under in-plane compression is investigated. Two types of in-plane boundary conditions are now considered and the effects of initial imperfections are also studied. Numerical results are presented for various cases of orthotropic composite plates having different elastic properties. It is found that the results obtained are in good agreement with those of experiments.

Comparisons in finite element analysis of minimally invasive, locking,and non-locking plates systems used in treating calcaneal fractures of Sanders type Ⅱ and type Ⅲ

Background Calcaneal fractures are relatively common but complex,while the treatment of these fractures is still controversial.The objective of this study was to compare the biomechanical stability of minimally invasive,locking,and non-locking plating systems used for fixing Sanders type Ⅱ and type Ⅲ calcaneal fractures.Finite element analysis was used for comparing the three types of plating systems.This study helped in guiding the clinical management of calcaneal fractures.Methods The CT data acquired from a volunteer was used to construct a finite element model of calcaneus.The fracture lines were made according to Sanders type Ⅱ （A,B,C） and type Ⅲ （AB,AC,BC） and six calcaneal fractures models were constructed accordingly.Three fixation methods used in clinical treatment were simulated by design tools （minimally invasive plating with percutaneous screws,Y-size non-locking plating,and locking plating） and then fixed to these fracture models with the help of clinical principles.The single minimally invasive plating fixation was also tested to compare the function of percutaneous screws.Then,the neutral force was applied on established methods.The displacement and presses distribution condition in various plating models were analyzed and compared.Results The levels of displacement and compressive press on the bone around fixation or strains on plating were within the physiological limit,indicating that the three methods were suitable for application.Compared with the locked and unlocked plates,the minimally invasive plating caused a relatively lower displacement without the high stress in bone or fixation.The minimum stress in fixation was observed in locking plate as the distribution of stress was concentrated in the anterior part of locking plate.Conclusions The minimally invasive plating method could be a better alternative method in treating Sanders type Ⅱ and type Ⅲ calcaneal fractures.The observed stiffness of locking plate was not obviously stronger than unlocked plate.

Experimental analysis of acousto-ultrasonic wave propagation mode in thin plate

in the acousto-ultrasonic technique, a broadband ultrasonic wave is injected onto the surface at one location of the tested plate with the help of a longitudinal transducer and a receiving transducer is coupled to the same surface at another location. Thus, understanding the propagation characteristics of the ultrasonic wave is essential for successful application of the technique. It has been found that the dominant acousto-ultrasonic waves produced experimentally in thin plate are multi-mode Lamb waves. The broadband generation and detection of Lamb waves have been performed in two aluminum plates with different thickness using the acousto-ultrasonic method.

Paleocontinental Reconstruction:Methodology,Computer Software and an Example of Application

Paleocontinental reconstruction is of the nature of multidisciplinary analysis . This paper discusses the significance of some more important disciplines , including paleomagnetism , paleoclimatology and paleobiogeography. Top attention should be paid to the synthetic analysis and geological explanation of geophysical data . Reassembling of the paleocontinents by geometric similarities is preliminary, geological considerations should receive more attention . Several rules constraining the reconstruction are proposed and Eider poles used to reassemble some separated Precambrian median massifs to their mother continents are given . A computer software for paleocontinental reconstruction , GUDALU , is introduced . The software is flexible in that it gives the user maximum freedom to demonstrate his or her geological opinions by providing means of organizing geographic data and rotational parameters ,many kinds of map projection of different features and dynamic editing of the reconstruction maps . Finally, an example of Mesoproterozoic reconstruction is demonstrated .

Vibrational power flow analysis on combined plates partially covered layer of discontinuous material

Vibrational power flow on combined plates with a change in mass and stiffness or with viscoelastic damping layer used widely in engineering is studied. The expressions of flexural displacement and other physical quantities are obtained using Laplace transformation and transfer matrix approach, then influences of changes in mass and stiffness of discontinuous material and the free damping layer on the input power flow and the transmitted power flow are discussed. The conclusions provide theory basis for structural optimization design and reducing noise and vibration

Analytical Solution for Time-dependent Flow of a Third Grade Fluid Induced Due to Impulsive Motion of a Flat Porous Plate

The aim of the present communication is to discuss the analytical solution for the unsteady flow of a third grade fluid which occupies the space y 〉 0 over an infinite porous plate. The flow is generated due to the motion of the plate in its own plane with an impulsive velocity V（t）. Translational symmetries in variables t and y are utilized to reduce the governing non-linear partial differential equation into an ordinary differential equation. The reduced problem is then solved using homotopy analysis method（HAM）. Graphs representing the solution are plotted and discussed and proper conclusions are drawn.