Description

Theoretical Determination of Properties: 3. Laminate Level 

• A multidirectional laminate is constructed from number of unidirectional plies 

• The laminas (plies) are stacked at various on- and off-axis angles relative to the global 1,2,6 axis 

• Stacking sequence is used to define the layup 

• Stacking sequence shows the individual plies of the laminate, from bottom to top in ordered sequence of angles such as [0/90/+45/-45]. 

• Usually all plies have the same thickness and same materials, if the thickness or the material is different, then a modification to the stacking seq. is required

Theoretical Determination of Properties: 3. Laminate Level 

• A multidirectional laminate may be orthotropic or anisotropic in its plane or out of its plane 

• It may has coupling between in-plane and out-of plane responses. 

• In plane response is known as extensional response and out of plane response is known as flexural response. 

Theoretical Determination of Properties: 3. Laminate Level 

• Classical lamination theory (CLT) is generally used as first approximation to describe the constitutive relations of a thin laminate 

• According to CLT, in-plane response is described by 3 extensional stress resultants and out of plane response is described by three flexural stress resultants 

• Correspondingly, there are six generalized strain resultants : the mid-plane strains, , and plate curvature 1 2 6 N , N , N 1 2 6 M , M , M 0 6 0 2 0 1  ,  ,  1 2 6