DERIVATIVE BASED APPROXIMATION FOR PREDICTING THE EFFECT OF CHANGES IN LAMINATE STACKING-SEQUENCE

Derivatives of buckling loads of stiffened panels with respect to ply thicknesses are easy to calculate. Consequently, such derivatives are often available in computer programs that calculate buckling loads of composite structures. These derivatives can be used to construct appro ximations of the dependence of the buckling load on ply thicknesses. T he present work demonstrates the use of derivatives of buckling loads with respect to ply thicknesses to approximate the effects of changes in stacking sequence and ply orientations on buckling load of a lamina te. Examples of unstiffened and stiffened panels are used to demonstra te the effectiveness of the proposed approximation.