Linear openings that form in materials to relieve stress are called cracks. Cracks develop as a response to internal stresses when a material is stretched, shrinks, or otherwise deforms beyond its strength limits. They serve as a mechanism to release or redistribute stress within the material to prevent catastrophic failure
. Key points about cracks as stress-relief features:
- In elastic materials , cracks often form with characteristic angles (e.g., 120° joints where three cracks meet), reflecting the uniform stress distribution and sudden failure in multiple directions
- In inelastic materials , cracks tend to be straight and form to relieve stress along specific directions. Existing cracks may open further under continued stress, and new cracks can form at right angles to old ones, indicating the material's response to stress orientation
- In brittle materials like ceramics and certain polymers, similar linear openings called stress relief cracks or crazing appear to dissipate internal tension and reduce overall stress, which can either help prevent failure or indicate material degradation
- The pattern and growth of cracks can also indicate material properties, such as elasticity or toughness, and are influenced by microstructural features like fibers in wood bark that interrupt crack propagation
Thus, the fundamental linear openings that form in materials to relieve stress are cracks , which can vary in form and behavior depending on the material type and stress conditions
