A multidirectional laminate is constructed from number of unidirectional plies
engineering
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
