Stress acting parallel to a surface, tending to cause sliding deformation between adjacent material layers.
Shear stress τ = F/A where F acts parallel to area A. Shear modulus G = τ/γ (γ = shear strain). For isotropic materials G = E / [2(1+ν)]. Pure shear causes angular distortion without volume change. The Tresca and von Mises yield criteria both depend on accurate shear stress determination.
In FDM, interlayer bonds fail primarily in shear. Z-direction shear strength is typically only 30-60% of XY. Fastener holes, press-fits, and adhesive joints transfer loads in shear. Torsion generates shear across cross-sections, critical for shafts and axles.
Shear failure is often sudden with no visible warning. For a rectangular cross-section, shear stress is parabolic, not uniform: τ = F/A underestimates peak shear at the neutral axis by 50%. Design adhesive bonds for shear loads rather than tensile loads where possible.
Related terms: Stress, Von Mises Stress, Torsion, Young's Modulus
| Field | mechanics, engineering |
|---|---|
| Also called | Tangential Stress |
Engineer, author of The Big Book of 3D Printing and additive manufacturing expert