What is the function of shear webs in aircraft structures?

Shear webs are thin, flat structural elements that primarily carry shear loads in beams, ribs, and frames. In wing spars, the web transfers vertical shear from aerodynamic loads while the spar caps carry bending through tension and compression. Shear webs must be designed to resist buckling under shear loading, often using stiffeners to divide them into smaller panels. The shear flow (shear force per unit length) in webs is critical for analyzing torsion boxes and determining fastener loads in joints. Web design balances thickness (weight) against stiffener spacing.