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maximum load-carrying capacity in bending
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the breaking point of wood when subjected to a bending force
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measured in megapascals, MPa
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why important
- critical for structural applications: beams, bridges, trusses
- tells you how much bending a wood can take before it snaps
- higher MOR = safer for heavy loads, longer spans, fewer supports
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structural strength class (S1–S6)
based on combined values for MOR (modulus of rupture), MOE (stiffness), and compressive strength — aligned with how wood is used structurally (posts, beams, load-bearing components)
class description typical uses MOR range (MPa) example species S1 ultra-weak models, packaging, insulation < 25 balsa, dadap S2 light-duty crates, panelling, garden stakes 25–50 paulownia, pinus S3 medium general carpentry, furniture frames 50–80 oak, teak, shorea S4 strong beams, bridges, heavy joinery 80–110 acacia, merbau, robinia S5 very strong long-span trusses, heavy loads 110–140 ipe, casuarina, vitex S6 ultra-strong structural columns, extreme tension >140 ulin, mesua ferrea