**1 . Analysis of the Orthotropic Lamina**

**1.1. Introduction**

**1.2. Hooke’s Law**

**1.3. Relationships between elastic constants and Matrix of Elasticity**

**1.4. Matrix of elasticity**

** **

**2. Classical theory of Laminates**

**2.1. Introduction**

**2.2. Basic Formulas**

**2.3. Laminate stiffener matrix**

**2.4. Calculation of Stress and deformation**

**2.5. Thermal Stress**

**2.6. Calculation of Elastic Constants**

>> Composite Analysis Tool

**Classical theory of Laminates**

The use of simple plates with unidirectional reinforcement is unsatisfactory in most engineering applications due to a very low strength and stiffness in the direction cross . The resistance and the transverse stiffness of a unidirectional lamina, in fact , closely dominated by the strength and stiffness of the matrix , are generally insufficient to ensure , even in the presence of limited ( negligible ) transverse loads , the absence of phenomena of damage , the shape stability and the its integrity.

This drawback is overcome by resorting to composite laminates consisting of N plates with unidirectional reinforcement, oriented in certain direction as to meet the various needs in strength and stiffness.

For the proper design of a composite laminate is necessary to know the relationships, for given type of foils and packaging sequence , between the mechanical characteristics of each lamina and the laminate obtained. By some simplifying assumptions , such Relationships are identified by the so-called Classical theory of laminates.