Structural Mechanics

How to Draw a Shear Force Diagram

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A shear force diagram (SFD) shows the internal transverse force V at every section along a beam. Start by finding the support reactions, move from one end of the beam to the other, and update V whenever a reaction, point load, or distributed load is encountered. Under one common sign convention, a downward point load … Read more

Second Moment of Area: Formulas and Examples

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The second moment of area describes how a cross-section’s area is distributed about a chosen axis. Moving material farther from that axis increases the value because distance is squared. In elastic beam theory, this geometric property combines with Young’s modulus as EI, the flexural rigidity that controls the relationship between bending moment and curvature. The … Read more