{ "title": "Beam Bending Stress Calculator", "author": "Carlos Acosta", "version": "1.0.0", "description": "Interactive calculator for maximum bending stress in rectangular wooden beams under uniform load. Implements classical beam theory: σ = M/S where M = wL²/8 and S = bh²/6.", "formulas": { "maximum_bending_moment": { "symbol": "M", "equation": "M = (w × L²) ÷ 8", "units": "ft-lbs", "description": "Maximum moment at mid-span for simply-supported beam with uniform distributed load" }, "section_modulus": { "symbol": "S", "equation": "S = (b × h²) ÷ 6", "units": "in³", "description": "Geometric property of rectangular cross-section resisting bending" }, "bending_stress": { "symbol": "σ", "equation": "σ = (M × 12) ÷ S", "units": "psi", "description": "Maximum tensile/compressive fiber stress at extreme fibers of beam" } }, "inputs": { "beam_width": { "id": "beamWidth", "symbol": "b", "units": "inches", "default": 3.5, "range": [0.5, 24] }, "beam_height": { "id": "beamHeight", "symbol": "h", "units": "inches", "default": 9.25, "range": [1.5, 36] }, "span_length": { "id": "spanLength", "symbol": "L", "units": "feet", "default": 12, "range": [2, 100] }, "uniform_load": { "id": "uniformLoad", "symbol": "w", "units": "lbs/ft", "default": 50, "range": [10, 5000] } }, "outputs": { "moment_result": { "id": "momentResult", "symbol": "M", "units": "ft-lbs" }, "section_modulus_result": { "id": "sectionModulus", "symbol": "S", "units": "in³" }, "stress_result": { "id": "stressResult", "symbol": "σ", "units": "psi" } }, "grounding": { "wikidata_entity": "Q49167267", "entity_slug": "bending-stress", "verification_urls": [ "https://mechanicalc.com/reference/beam-analysis", "https://4ort.xyz/entity/bending-stress" ] }, "worked_example": { "scenario": "2x10 Douglas Fir roof beam", "inputs": { "beam_width": 1.5, "beam_height": 9.25, "span_length": 12, "uniform_load": 50 }, "outputs": { "moment_result": 900.0, "section_modulus_result": 21.66, "stress_result": 503.0 }, "allowable_reference": "1000-1500 psi (species/grade dependent)" }, "limitations": [ "Assumes simply-supported boundary conditions", "Does not account for shear stress or deflection limits", "Material homogeneity assumed (no knots, defects)", "Linear elastic behavior only" ], "published_at": "2026-07-17T14:00:00Z", "location": "/load-calculator.html" }