Flexural stress, also known as bending stress, occurs when a material is subjected to a bending moment, causing it to experience both tension and compression. In a beam under bending, the material’s outermost fibers experience the highest stress, with one side in tension and the opposite side in compression, while the neutral axis (centerline) remains unstressed. The formula for bending stress in a beam is:
bending stress = (bending moment × distance from neutral axis) / moment of inertia
or σ = (M × c) / I,
where σ is the bending stress, M is the applied bending moment, c is the perpendicular distance from the neutral axis to the outermost fiber, and I is the moment of inertia of the beam’s cross-section.
Bending stress is a key factor in the design of beams, bridges, and structural members, ensuring that materials can resist bending loads without excessive deflection or failure. Engineers use bending analysis to select materials and shapes that provide sufficient strength and stiffness for load-bearing applications.
