Stability of parametric vibrations of laminated composite plates
The dynamic stability of laminated composite plates subjected to arbitrary periodic loads is studied based on the first-order shear deformation plate theory. The in-plane load is taken to be a combination of periodic biaxial and bending stress. A set of second-order ordinary differential equations with periodic coefficients of Mathieu-Hill type is formed to determine the regions of dynamic instability based on Bolotin's method. Numerical results reveal that the dynamic instability is significantly affected by the modulus ratio, number of layer, static and dynamic load parameters. The effects of various important parameters on the instability region and dynamic instability index are investigated.
Hygrothermal response on parametric instability of delaminated bidirectional composite flat panels
Abstract The present study deals with the finite element analysis of parametric instability characteristics of delaminated bidirectional Glass/Epoxy composite panels exposed to hygrothermal field with harmonic in-plane loading based on first order shear deformation theory. An 8-noded isoparametric finite element model was developed which takes account of the influences of area delamination and hygrothermal environment for predicting dynamic instability regions of composite flat panels. Validation of numerical results from finite element analysis was done with those available from previous researches. The influences of various parameters like static load factor, area of delamination, temperature, moisture, fiber orientations, boundary conditions and stacking sequence on the dynamic instability regions of bidirectional Glass/Epoxy flat panels were investigated. Significant effects of these parameters on the dynamic stability characteristics of composite plates were observed and discussed.
Numerical Simulation of Thermal Sensitivity for Explosives
In order to compare the thermal sensitivity of several typical explosives, this article solved numerically one-dimensional transient heat conduction equation including thermal decomposition for explosives with finite difference method. The explicit difference equations under different boundary conditions were established, and the corresponding stability criterion was derived. The ignition times for typical explosives were calculated, which was used to evaluate thermal sensitivity of explosives.