The displacement fields u_x,u_y at growing crack tip of LYI2-M specimens with double edge cracks are measured using moire method.The experimental singularity fields are compared with GH theoretical field [12-14].The s...The displacement fields u_x,u_y at growing crack tip of LYI2-M specimens with double edge cracks are measured using moire method.The experimental singularity fields are compared with GH theoretical field [12-14].The size and shape of the experimental GH singularity fields are obtained.The error in both the experimental and theoretical evaluations is controlled within ±10%.The experiments show that there is (In A/r)^(+1)singularity dominant around a growing crack tip.The shape of this dominant region ranges from butterfly wing to oblate and circular.Inside GH-field,there is a 3-D deformed damage zone where no GH sin- gularity exists.展开更多
The aim of this paper is to derive the power law type nonlinear viscoelastic crack-tip fields.For the requirement of later derivation,the HRR singular fields and the high-order asymp- totic fields are first examined.T...The aim of this paper is to derive the power law type nonlinear viscoelastic crack-tip fields.For the requirement of later derivation,the HRR singular fields and the high-order asymp- totic fields are first examined.That they are essentially the isotropic,incompressible,power law type nonlinear elastic crack-tip fields is illustrated.After a concise review of the elasticity recov- ery correspondence principle for solving the nonlinear viscoelastic problems,the correspondence principle for solving the crack problems of power law type nonlinear viscoelastic materials under the first type boundary condition is proposed.The solution of the crack-tip stress,strain fields for the power law type nonlinear viscoelastic materials,especially for the modified polypropylene, is obtained.展开更多
The singularity of stress and strain at the tip of three-dimensional notch isanalysed by the power expansion method .the eigenquation of the notch is gainedthrough the boundary conditions of the notch, the eigenvalue...The singularity of stress and strain at the tip of three-dimensional notch isanalysed by the power expansion method .the eigenquation of the notch is gainedthrough the boundary conditions of the notch, the eigenvalues under different innerangles of the notch are obtained, the expression of stress and strain at the tip of thenotch is finally derived .展开更多
In this note we give a geometrical presentation to the 4D Riemannian curvature as it relates to the Newtonian gravity in the 4D Lorentz manifold. The compacting of the proper time as is necessary for the unification w...In this note we give a geometrical presentation to the 4D Riemannian curvature as it relates to the Newtonian gravity in the 4D Lorentz manifold. The compacting of the proper time as is necessary for the unification with the Maxwell electrodynamics, as given by Einstein and Kaluza-Klein, should the universe be only of 4D space-time, led to the concept of gravitational field singularity sinks known as black holes, that would not be acceptable under a 5D homogeneous manifold through which the 4D Lorentz manifold evolved by application of the Perelman-Ricci Flow entropy mapping, which is consistent with both Maxwell suggested magnetic monopole, the quantum Higgs vacuum theory and the Gell-Mann standard model for hadrons.展开更多
The singular integration occurred in sound field calculation with BEM is discussed in this article. The method to deal with 1st and higher order singular integration is given. The numerical results show that this meth...The singular integration occurred in sound field calculation with BEM is discussed in this article. The method to deal with 1st and higher order singular integration is given. The numerical results show that this method can simplify the program and improve the precision.展开更多
基金The project suppoted by National Natural Science Foundation of China
文摘The displacement fields u_x,u_y at growing crack tip of LYI2-M specimens with double edge cracks are measured using moire method.The experimental singularity fields are compared with GH theoretical field [12-14].The size and shape of the experimental GH singularity fields are obtained.The error in both the experimental and theoretical evaluations is controlled within ±10%.The experiments show that there is (In A/r)^(+1)singularity dominant around a growing crack tip.The shape of this dominant region ranges from butterfly wing to oblate and circular.Inside GH-field,there is a 3-D deformed damage zone where no GH sin- gularity exists.
基金Project supported by the Hunan Natural Science Foundation(Nos.01JJY3001 and 01JJY2001)Research Item of the Hunan Education Committee(No.01C083)and the Key Item of Hunan Science and Technology Department.
文摘The aim of this paper is to derive the power law type nonlinear viscoelastic crack-tip fields.For the requirement of later derivation,the HRR singular fields and the high-order asymp- totic fields are first examined.That they are essentially the isotropic,incompressible,power law type nonlinear elastic crack-tip fields is illustrated.After a concise review of the elasticity recov- ery correspondence principle for solving the nonlinear viscoelastic problems,the correspondence principle for solving the crack problems of power law type nonlinear viscoelastic materials under the first type boundary condition is proposed.The solution of the crack-tip stress,strain fields for the power law type nonlinear viscoelastic materials,especially for the modified polypropylene, is obtained.
文摘The singularity of stress and strain at the tip of three-dimensional notch isanalysed by the power expansion method .the eigenquation of the notch is gainedthrough the boundary conditions of the notch, the eigenvalues under different innerangles of the notch are obtained, the expression of stress and strain at the tip of thenotch is finally derived .
文摘In this note we give a geometrical presentation to the 4D Riemannian curvature as it relates to the Newtonian gravity in the 4D Lorentz manifold. The compacting of the proper time as is necessary for the unification with the Maxwell electrodynamics, as given by Einstein and Kaluza-Klein, should the universe be only of 4D space-time, led to the concept of gravitational field singularity sinks known as black holes, that would not be acceptable under a 5D homogeneous manifold through which the 4D Lorentz manifold evolved by application of the Perelman-Ricci Flow entropy mapping, which is consistent with both Maxwell suggested magnetic monopole, the quantum Higgs vacuum theory and the Gell-Mann standard model for hadrons.
文摘The singular integration occurred in sound field calculation with BEM is discussed in this article. The method to deal with 1st and higher order singular integration is given. The numerical results show that this method can simplify the program and improve the precision.
