A NOVEL STRESS ANALYSIS METHOD FOR LAMINATED COMPOSITE STIFFENER WITH ASYMMETRIC Z-SECTION UNDER MECHANICAL AND THERMAL LOADING CONDITIONS

Abstract

Composites structures are being used as load carrying members in latest aircrafts and performance automobiles, the design validation for such structures can be a time consuming and expensive process, if done by testing. Validation of a structure by analysis saves time and money for a design process and validation by analysis can be done by comparing the analytical solution with the finite element analysis of the structure, which requires availability of analytical expressions for every cross-sectional arrangement of the structural members.

This research focuses on stress analysis of laminated composite stiffener with asymmetric Z-sections, where closed form analytical expressions are developed to determine the sectional properties of composite Z stiffener. The equations for sectional properties such as centroid, equivalent axial stiffness and equivalent bending stiffness are validated by comparing the analytical and finite element analysis results. The effects of different temperature gradients on different sections of the composite Z stiffener are also studied and equations are developed and validated for temperature induced moments in the stiffener. The sectional properties were used to calculate stresses in layer of sub-laminates and are compared with the stresses obtained from finite element analysis of the beam under same conditions. A finite element model is developed on academic version of software ANSYS 16.0 and ANSYS 17.0 classic. The stress and strain results obtained by analytical method shows excellent agreement with the results obtained from finite element analysis.