The assumptions made in theory of bending The following are the assumptions made in theory of bending: 1. The material of beam is homogeneous and isotropic. (Isotropic means having the properties same in all directions.) 2. The beam is straight before loading. 3. The beam is of uniform cross section throughout its length. 4. Transverse sections, which are plane before loading, remains plane even after loading. 5. The material is elastic and Hooke's law is applicable. 6. The effect of shear is neglected. Therefore the analysis is meant for pure bending. 7. The modulus of elasticity, E has same value in tension and compression. 8. Each layer is free to expand or contract having no influence in the neighbouring layers for their extension or contraction. 9. The beam is initially straight and all longitudinal filament bend into circular arcs with a common centre of curvature.
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