Finding Nonlinear Variation Equation of Fiber Path in Curved Laminates

Abstract

 It is possible to manufacture high quality reinforced composite laminates using advanced steering machines. The variation of fiber angle orientation inside plies results in variable stıffness propertıes, unlike traditional composite plates with straight fibers. Tailoring variable stiffness laminates allows us completely to exploit directional properties of materials.

There is a clear effect of curved fibers on improving buckling load of variable stiffness composite plates, so we demonstrated two paths of curved fibers: the first path is linear variation of fiber angle [±𝜑(𝑥)]𝑛𝑠 where the path functions according to one variable, while the second path is nonlinear variation of fiber angle [±𝜑(𝑥, 𝑦)]𝑛𝑠(constant curvature path) where the fiber path variates spatially at each point over plate and is related to (x,y) coordinates.

The main objective of this paper is finding fiber orientation angle equation inside a curved composite ply and its connection with curved plate coordinates as a function to local coordinates.

We found out nonlinear variation of fiber path on elliptical, cylindrical, and conical composite plates because this type of plates is very common in planes, rockets, and satellites, and gives a wide space of multiple variable coefficients. We can study optimal distribution of fibers under buckling load on curved laminates .