In classical laminate theory, symmetric stacking sequences primarily reduce coupling between bending and which response?

In classical laminate theory, symmetric stacking sequences primarily reduce coupling between bending and which response?

• A. Axial tension
• B. Transverse shear
• C. Bending-extension coupling
• D. Torsion

Answer: (C)

In classical laminate theory, how bending of a laminate couples with in-plane stretching is captured by the coupling terms in the stiffness relationship between bending curvatures and in-plane strains. When the stacking is symmetric about the mid-plane, the contributions from plies above and below cancel in these coupling terms, causing the coupling matrix to effectively disappear. With this symmetry, bending moments no longer induce in-plane strains and, conversely, in-plane loads don’t generate bending through that cross-coupling. That’s why symmetric stacking sequences primarily remove bending-extension coupling. Other potential couplings, like those involving transverse shear or torsion, aren’t eliminated by this symmetry.

In classical laminate theory, how bending of a laminate couples with in-plane stretching is captured by the coupling terms in the stiffness relationship between bending curvatures and in-plane strains. When the stacking is symmetric about the mid-plane, the contributions from plies above and below cancel in these coupling terms, causing the coupling matrix to effectively disappear. With this symmetry, bending moments no longer induce in-plane strains and, conversely, in-plane loads don’t generate bending through that cross-coupling. That’s why symmetric stacking sequences primarily remove bending-extension coupling. Other potential couplings, like those involving transverse shear or torsion, aren’t eliminated by this symmetry.