Author: Engineering Reference Compilation Date: April 17, 2026 Subject: Summary of fundamental equations for beam deflection, moment, shear, axial load, and stability. Abstract This paper presents a curated collection of fundamental formulas used in linear-elastic structural analysis. It covers equilibrium equations, beam shear and moment relationships, common deflection cases, column buckling, and truss analysis. The document is intended as a quick reference for students and practicing engineers. 1. Fundamental Equilibrium Equations For a structure in static equilibrium in 2D:
[ \sum F_x = 0, \quad \sum F_y = 0 ]
In 3D:
[ \sum F_x = 0 \quad \sum F_y = 0 \quad \sum M_z = 0 ]
[ \fracdVdx = -w(x) \quad \textand \quad \fracdMdx = V(x) ] structural analysis formulas pdf
Where: ( M ) = internal bending moment, ( y ) = distance from neutral axis, ( I ) = moment of inertia of cross-section. The differential equation:
[ \tau_\textmax = \frac3V2A ] Critical load for a slender, pin-ended column: The document is intended as a quick reference
Slenderness ratio: