By considering the effect of interfacial damage and using the variation principle, three-dimensional nonlinear dynamic governing equations of the laminated plates with interfacial damage are derived based on the gener...By considering the effect of interfacial damage and using the variation principle, three-dimensional nonlinear dynamic governing equations of the laminated plates with interfacial damage are derived based on the general sixdegrees-of-freedom plate theory towards the accurate stress analysis. The solutions of interlaminar stress and nonlinear dynamic response for a simply supported laminated plate with interfacial damage are obtained by using the finite difference method, and the results are validated by comparison with the solution of nonlinear finite element method. In numerical calculations, the effects of interfacial damage on the stress in the interface and the nonlinear dynamic response of laminated plates are discussed.展开更多
An accurate determination of intedaminar transversal stresses in composite multilayered plates, especially near free-edge, is of great importance in the study of inter-ply damage modes, mainly in the initiation and gr...An accurate determination of intedaminar transversal stresses in composite multilayered plates, especially near free-edge, is of great importance in the study of inter-ply damage modes, mainly in the initiation and growth of delamination. In this paper, interlaminar stresses are determined by layer-wise mixed finite element model. Each layer is analyzed as an isolated one where the displacement continuity is ensured by means of Lagrange multipliers （which represent the statics variables）. This procedure allows the authors to work with any single plate model, obtaining the interlaminar stresses directly without loss of precision. The FSDT （first shear deformation theory） with transverse normal strain effects included is assumed in each layer, but Lagrange polynomials are used to describe the kinematic instead of Taylor＇s polynomial functions of the thickness coordinates, as is common. This expansion allows the authors to pose the interlaminar displacements compatibility simpler than the second one. The in-plane domain of the plate is discretized by four-node quadrilateral elements, both to the field of displacement and to the Lagrange multipliers. The mixed interpolation of tensorial components technique is applied to avoid the shear-locking in the finite element model. Several examples were carried out and the results have been satisfactorily compared with those available in the literature.展开更多
The interlaminar stresses are analyzed by combining the first shear theory with the layerwise theory method. And the plate subjected to a uniform axial strain is studied by the simplified displacement field. Using the...The interlaminar stresses are analyzed by combining the first shear theory with the layerwise theory method. And the plate subjected to a uniform axial strain is studied by the simplified displacement field. Using the simplified displacement field, the equations of finite element method is developed by the principle of virtual work. And the amount of calculation is reduced by using the linear element. Then, some numerical examples are given to verify the accuracy of the method and analyze the distribution of interlaminar stresses along y-axis and z-axis. The shapes of the stresses’ curves in the vicinity of the free edge are very different from the interior area. Moreover, the influence of the ply angle on the interlaminar stresses is analyzed for the plate [θ/-θ]s. It can be found that the shapes of the stresses along z-axis are similar when the angle is different, while the values of the interlaminar stresses are changed apparently with the ply angle.展开更多
The energy method has been successfully applied to solving interlaminar stresses of laminated composite lap joint with an adhesive layer of a certain thickness. This method has the merit of reckoning not only the stre...The energy method has been successfully applied to solving interlaminar stresses of laminated composite lap joint with an adhesive layer of a certain thickness. This method has the merit of reckoning not only the stress component σ_y, in adherents but also the variation of stresses through the thickness of the adhesive layer. Thus we have the possibility to rectify some mistakes that have long frustrated the solution to joint problems. As all the series encountered can be summed, the solutions are, as usual, neat in closed forms. Furthermore, solutions can be confirmed by the load to be taken by the joint.展开更多
Polyethylene-steel Composite Pipes is widely used in conveying corrosive media occasions,but the pipe may lose effectiveness in the process of transporting hot and cold media,so the research of stress distribution and...Polyethylene-steel Composite Pipes is widely used in conveying corrosive media occasions,but the pipe may lose effectiveness in the process of transporting hot and cold media,so the research of stress distribution and variation in polyethylene-steel composite pipes is very necessary.This article first assume that a thin adhesive layer is in between the polyethylene and steel,the adhesive layer along the axial shear stress is the major cause of the polyethylene layer and the steel pipe off sticky.Secondly,we use a method of finite element to computer simulation by ANSYS,and verify initial assumptions.Finally,based on simulation data,we analyse the adhesive layer stress distribution and the variation with different parameters to change.Through the above research,preliminarily summarize the variation and distribution of interlaminar stress,and provide technical support for future design and process improvement of polyethylenesteel pipe.展开更多
基金the National Natural Science Foundation of China (10572049)Hunan Provincial Natural Science Foundation of China (07JJ3009)National 985 Special Foundation of China
文摘By considering the effect of interfacial damage and using the variation principle, three-dimensional nonlinear dynamic governing equations of the laminated plates with interfacial damage are derived based on the general sixdegrees-of-freedom plate theory towards the accurate stress analysis. The solutions of interlaminar stress and nonlinear dynamic response for a simply supported laminated plate with interfacial damage are obtained by using the finite difference method, and the results are validated by comparison with the solution of nonlinear finite element method. In numerical calculations, the effects of interfacial damage on the stress in the interface and the nonlinear dynamic response of laminated plates are discussed.
文摘An accurate determination of intedaminar transversal stresses in composite multilayered plates, especially near free-edge, is of great importance in the study of inter-ply damage modes, mainly in the initiation and growth of delamination. In this paper, interlaminar stresses are determined by layer-wise mixed finite element model. Each layer is analyzed as an isolated one where the displacement continuity is ensured by means of Lagrange multipliers （which represent the statics variables）. This procedure allows the authors to work with any single plate model, obtaining the interlaminar stresses directly without loss of precision. The FSDT （first shear deformation theory） with transverse normal strain effects included is assumed in each layer, but Lagrange polynomials are used to describe the kinematic instead of Taylor＇s polynomial functions of the thickness coordinates, as is common. This expansion allows the authors to pose the interlaminar displacements compatibility simpler than the second one. The in-plane domain of the plate is discretized by four-node quadrilateral elements, both to the field of displacement and to the Lagrange multipliers. The mixed interpolation of tensorial components technique is applied to avoid the shear-locking in the finite element model. Several examples were carried out and the results have been satisfactorily compared with those available in the literature.
文摘The interlaminar stresses are analyzed by combining the first shear theory with the layerwise theory method. And the plate subjected to a uniform axial strain is studied by the simplified displacement field. Using the simplified displacement field, the equations of finite element method is developed by the principle of virtual work. And the amount of calculation is reduced by using the linear element. Then, some numerical examples are given to verify the accuracy of the method and analyze the distribution of interlaminar stresses along y-axis and z-axis. The shapes of the stresses’ curves in the vicinity of the free edge are very different from the interior area. Moreover, the influence of the ply angle on the interlaminar stresses is analyzed for the plate [θ/-θ]s. It can be found that the shapes of the stresses along z-axis are similar when the angle is different, while the values of the interlaminar stresses are changed apparently with the ply angle.
基金The project supported by the National Natural Science Foundation of China. The major part of this paper was reported at the International Conference of Composite Materials and Structures, June 10-13, 1986, Beijing.
文摘The energy method has been successfully applied to solving interlaminar stresses of laminated composite lap joint with an adhesive layer of a certain thickness. This method has the merit of reckoning not only the stress component σ_y, in adherents but also the variation of stresses through the thickness of the adhesive layer. Thus we have the possibility to rectify some mistakes that have long frustrated the solution to joint problems. As all the series encountered can be summed, the solutions are, as usual, neat in closed forms. Furthermore, solutions can be confirmed by the load to be taken by the joint.
文摘Polyethylene-steel Composite Pipes is widely used in conveying corrosive media occasions,but the pipe may lose effectiveness in the process of transporting hot and cold media,so the research of stress distribution and variation in polyethylene-steel composite pipes is very necessary.This article first assume that a thin adhesive layer is in between the polyethylene and steel,the adhesive layer along the axial shear stress is the major cause of the polyethylene layer and the steel pipe off sticky.Secondly,we use a method of finite element to computer simulation by ANSYS,and verify initial assumptions.Finally,based on simulation data,we analyse the adhesive layer stress distribution and the variation with different parameters to change.Through the above research,preliminarily summarize the variation and distribution of interlaminar stress,and provide technical support for future design and process improvement of polyethylenesteel pipe.
