Which ABD entries are responsible for shear coupling and how can it be avoided?
A16 and A26
Can be avoided by a balanced laminate (every layer angle also apears with an opposite sign)
Which ABD entries are responsible for Bending extension coupling?
B11 and B22
Can be avoided by using a symmetric laminate
Which ABD entries are responsible for bending twisting coupling?
D16 and D26
Can be avoided by using an orthotropic laminate (only 0° and 90° layers)
Give the constitutive law for laminates in symbolic notation, give names for the quadrants and denote parts arising from disc and from plate analysis.
Give the displacement field in a laminate and describe how it behaves w.r.t. discs and plates?
Vor u and v the first terms -0 are the displacements known from discs. The second term dependent on the deflection w is a term known from the Kirchhoff plate. The Classical laminated plate theory is a combination of disc and plate analysis
Give the strains of the laminate at an arbitrary height in
Derrivatives
symbolic notation w.r.t. middle plane
Describe how the strain formulation relate to disc and plate kinematics
Give Hooke´s law for layerwise stresses in a laminate.
(Q-bar -> reduced stiffness for off axis system)
How are edge force and moment flows determined?
Summation of the layerwise integrals of the layer stresses. For the moments a leverarm is added. Insertion of Hookes law allows to directly calculate edge force and moment flows from the strains. Here the Build up of the ABD Matrix can already be seen.
What is the main issue with classical laminated plate theory and how can it be compensated.
CLPT models a shear stif plate. No shear deformation is allowed. This leads always to non conservative results. For shear compliant materials or thick structures higher order laminate theories should be used.
Give examples for higher order laminate plate theories.
As with general higher order plate theories the first advancement is the First order shear deformation theory (FSDT)
A further advancement is provided by third order shear deformation theory (TSDT), not widely used in practice.
Last changed4 months ago
