Analysis of interlaminar stress and nonlinear dynamic response for composite laminated plates with interfacial damage

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.

THE ANALYSIS OF INTERLAMINAR STRESSES FOR COMPOSITE LAMINATED SHALLOW SHELLS WITH INTERFACIAL DAMAGE

Based on the general six-degrees-of-freedom plate theory towards the accurate stress analysis and nonlinear theory of shallow shells, considering the damage effect of the interlaminar in- terface and using the variation principle, the three-dimensional non-linear equilibrium differential equations of the laminated shallow shells with interfacial damage are derived. Then, considering a simply supported laminated shallow shell with damage and under normal load, an analytical solution is presented by using finite difference method to obtain the interlaminar stresses. Numer- ical results show, the stiffness of the shell is weakened, greater absolute values of displacements as well as smaller interlaminar stresses are obtained by interfacial damage. When the interfacial damage is further increased, delamination occurs obviously under normal pulling load and pure shear slip occurs under normal pressure load. The portion of the load undertaken by the two sides of the interface is more different. Different mechanical behaviors are shown in both sides of the interface, and the discontinuation of stresses and displacements takes place in the interface.

A QICAR Model for Metal Ion Toxicity Established via PLS Method

The partial least squares（PLS） method was employed to establish a quantitative ion characteristics-activity relationship（QICAR） model for metal ion toxicity（EC50 of 15 metal ions）. The ion characteristics included AN（the atomic number）, AIP（the change in ionization potential, eV）, Xm（the electronegativity, eV）, AW（the atomic weight）, Xm2r（the covalent index）, △E0（the absolute difference between electrochemical potential of the ion and that of its first stable reduced state, eV）, ｜lgKoH｜ （the absolute value of the lg of the first hydrolysis constant）, AR（the atomic radius, nm）, AR/AW（the ratio between atomic radius and atomic weight） and ap（the softness index） selected based on relative correlation analysis. The simulated and tested（with the other four metals） efficiency coefficients of the model are 0.88 and 0.96, respectively. The information revealed from the QICAR model indicates that the value of the metal ion toxicity was positively correlated with variables AN, AlP, Xm, AW and Xm2r; negatively correlated with variables AE0, ｜IgKoH｜, AR/AW, AR and ap, and ion characteristics △E0, Xm, σp and Xm2r were found to contribute more to the toxicity of metal ions via the accurate analysis method provided by PLS. The model could be used to predict the toxicity of the target metals and preliminary to assess combined pollution and environmental risk for heavy metals in the environments.