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Four Point Bending. Other Types of Bending. Bending by Eccentric Loading. Cantilever Bending. Various Boundary Conditions of Beams. Features of Beam Deformation. Neutral Plane and Axis of Symmetry. Assumptions for Beam Theory. Kirchhoff Hypotheses--- The cross-sections remain
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Other Types of Bending Bending by Eccentric Loading Cantilever Bending
Assumptions for Beam Theory • Kirchhoff Hypotheses--- • The cross-sections remain • a straight plane perpendi- • cular to the mid plane. • The vertical segments • are not stretched. Bernoulli-Euler Beams
Curvature under Pure Bending Neutral Axis Constant Curvature
Strain Analysis for Bending ex = d / L = -y/r = -yk ex |max = c/r d = L’ – L = (r-y)q – rq = -yq ex = (-y/c) ex |max
Stress Distribution in Bending sx = (-y/c) sx |max = (-y/c)sm Neutral plane should pass through the centroid. sm= Mc/I
Section Modulus and Bending Stiffness { sm= Mc/I sx = (-y/c)sm sx= -My/I Define Section Modulus as S = I/c Then sm = M/S Also ex = -y/r = -yk My/I = Ey/r k = 1/r = M/EI (EI: BendingStiffness) Note: d/L = P/EA, f/L = T/GJ