3 – Lamina Analysis

Publisher Summary This chapter discusses the lamina analysis. A lamina is characterized by having all fibers oriented in the same direction. This model allows one to treat the lamina as an orthotropic material. In reality, fibers are not perfectly straight or uniformly oriented within the lamina. There are generally several layers of fibers nested within a single lamina. The model used to represent a lamina consists of a single fiber per layer. In developing relations between material response and applied loads the simplified model is an accepted representation. In order to evaluate the response of a lamina, each component of the stiffness matrix [C] must be determined. The stress-strain relationships needed to define [C] are obtained by experimental procedures. A uniform stress is easier to approximate than uniform strain; therefore, the stiffness matrix is established by first developing the compliance matrix [S] and inverting it to obtain [C]. The lamina is orthotropic; therefore, extension and shear are uncoupled in the principal material directions.