Isogeometric nonlinear bending and buckling analysis of variable-thickness composite plate structures

摘要

This paper investigates nonlinear bending and buckling behaviours ofcomposite plates characterized by a thickness variation. Layer interfaces aredescribed as functions of inplane coordinates. Top and bottom surfaces of theplate are symmetric about the midplane and the plate could be considered as aflat surface in analysis along with thickness parameters which vary over theplate. The variable thickness at a certain position in the midplane is modeledby a set of control points (or thickness-parameters) through NURBS (Non-UniformRational B-Spline) basic functions. The knot parameter space which is referredin modelling geometry and approximating displacement variables is employed forapproximating thickness, simultaneously. The use of quadratic NURBS functionsresults in C^1 continuity of modeling variable thickness and analyzingsolutions. Thin to moderately thick laminates in bound of first-order sheardeformation theory (FSDT) are taken into account. Strain-displacement relationsin sense of von-Karman theory are employed for large deformation. Riks methodis used for geometrically nonlinear analysis. The weak form is approximatednumerically by the isogeometric analysis (IGA), which has been found to be arobust, stable and realistic numerical tool. Numerical results confirm thereliability and capacity of the propose method.