Based on the refined triangular Mindlin plate elements developed by Chen, a new triangular composite stiffened plate element with 21 degrees of freedom has been proposed.

The formulation of sixteen nodded adhesive element,two nodded bolt element and eight nodded isoparametric plate element based on the first order transverse shear effect theory is deduced,which can be used to analyze the laminated shell joint structures by means of the coordinates transformation scheme. Meanwhile the relative coordinate system and modified virtual rotation stiffness techniques are also employed to overcome the ill condition problem of total stiffness matrix of the structures during analysis process successfully.

A 4 node plate element based on Mindlin first order shearing theory is presented to analyze delamination front contact effect on pre buckling and post buckling behavior of composite laminates with elliptical delamination damage.

2. A relevant formula of eight-node adhesive finite element is deduced in the paper, which is based on a separately interpolation scheme for Reissner- Mindlin plate element. A load capability analysis method for patched composite laminated structure is established by using Tsai- Hill failure criterion and Thai's reduced stiffness scheme, and corresponding computer code is also developed.

A finite element model based on Mindlin's theory is used for the geometriclly nonlinear analysis of laminated stiffened plate. Using the total Lagrangian description the incremental equations and nonlinear stiffness matrix of the isoparametric stiffened plate element are formulated. TheNewton-Raphson iteration procedure combined with the increment method is employed to trace the nonlinear equilibrium path.

The first element is a thin-plate element that is based on the Kirchhoff plate assumptions and captures both membrane and bending stiffness effects.

The results indicate the differences in the dynamic response of the transverse shear deformable eight-noded element as compared to a four-noded plate element.

The development of a shear-deformable laminated plate element, based on the Mindlin plate theory, for use in large reference displacement analysis is presented.

An eight noded composite plate element for the dynamic analysis of spatial mechanism systems

The results have been included for the first few frequencies of the plate element for all the boundary conditions viz.

In this paper two kinds of elements, triangular laminated plate element with nine degree of freedom based on multi-variable quasi-conforming and penalty element technigue and laminated beam element with six degree of freedom are presented.Effects of transverse shear deformation and rotational inertia are considered in these two elements.Free vibration, damping cha-racteristic and transient response of stiffened composite plate are investigated by using finite element method.Results...

In this paper two kinds of elements, triangular laminated plate element with nine degree of freedom based on multi-variable quasi-conforming and penalty element technigue and laminated beam element with six degree of freedom are presented.Effects of transverse shear deformation and rotational inertia are considered in these two elements.Free vibration, damping cha-racteristic and transient response of stiffened composite plate are investigated by using finite element method.Results obtained are valuable for the designs of stiffened composite plates.tiffened composite plate, Vibration, Damping, Response, Finite element

A finite element model based on Mindlin's theory is used for the geometriclly nonlinear analysis of laminated stiffened plate.Using the total Lagrangian description the incremental equations and nonlinear stiffness matrix of the isoparametric stiffened plate element are formulated.TheNewton-Raphson iteration procedure combined with the increment method is employed to trace the nonlinear equilibrium path.A variety of numerical examples are presented to demonstrate the precision and convergence of the method.All...

A finite element model based on Mindlin's theory is used for the geometriclly nonlinear analysis of laminated stiffened plate.Using the total Lagrangian description the incremental equations and nonlinear stiffness matrix of the isoparametric stiffened plate element are formulated.TheNewton-Raphson iteration procedure combined with the increment method is employed to trace the nonlinear equilibrium path.A variety of numerical examples are presented to demonstrate the precision and convergence of the method.All the results have a good agreement with those published.The effects of bounday condition, the size of transverse area of stiffener, the distribution of stiffener and the orientation angle of lamina on the geometri-caly nonlinear strength of stiffened composite plates are investigated.

Based on the theory of linear-elastic fracture mechanics, the crack tip stress field of orthotropic plate is still controlled by the stress-intensity factors, therefore to study the stress-intensity factors of orthotropic plate is an important problem in studying the fracture of composite materials. At present, not a few papers calculate the stress-intensity factors by finite element theory, but few by testing technique.With composite material fracture theory, the paper derives the relation formulas between...

Based on the theory of linear-elastic fracture mechanics, the crack tip stress field of orthotropic plate is still controlled by the stress-intensity factors, therefore to study the stress-intensity factors of orthotropic plate is an important problem in studying the fracture of composite materials. At present, not a few papers calculate the stress-intensity factors by finite element theory, but few by testing technique.With composite material fracture theory, the paper derives the relation formulas between the KI, KII and the v displacement with different fiber-reinforced directions. In this paper, the glass fiber-reinforced orthotropic plate is worked into the pure bending beam with a unilateral cut on it, which is tested by using the sticking film moire interferometry. Through testing, the full-field displacement of the moire pattern is given, the KI and KII values are further calculated from the displacement in the crack-tip. The patterns that the pure bending beam has different crack lengthes and is in different fiber-reinforced directions are given in this paper. Being exposed twice, the grating density of the moire pattern can reach 1260 line/mm. At the same time, the same specimen is calculated by using SAP-84 plate element program on microcomputer for inspecting the testing precision. At last, the test results are compared with the calculating ones in error.All of the testing and calculating results show: a. For isotropic materials, the formula of KI isb. For orthotropic materials, the stress-intensity factor varies with the fiber direction and/or the crack length, and the formula KI iswhere a is the crack length, w is the specimen's height, a is the flexibility matrix coefficient, a is the angle between the crack direction and the fiberreinforced direction.It can be seen from the moire pattern (a = 45°) that the moire pattern isn't symmetric when t e crack line isn't in the principal material direction, even if the structure and the force are symmetric. The displacement of crack tip is in mixed-mode, KI and KII exist simultaneously. From the moire pattern (a=45°), the orthotropic coupling effect is best explained.The test result shows that the sticking film moire interferometry can be not only used to test isotropic mitsrials but also orthotropic ones, therefore, this method can be spread to analyze the fracture of composite materials.