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perpendicular compression fail

perpendicular compression fail

perpendicular compression fail

New York Times and others have published that wood slices skull-bone.
Steel compression fail is 100-350Mpa, wood is 1.2-20 Mpa and skull-bone 170-200Mpa.If wood can be surface fire-hardened so that a sharp edge transfers the cut impact to the full thickness of a blade then maybe the compression can be reduced in a thicker wooden weapon.  So a 10Mpa failure wood at 20 times the .5mm sharp edge may cut the bone.  Is this how it works as a general argument in this situation? 

RE: perpendicular compression fail

"Growing in desert conditions leave these [Australian] woods with a hardness and density comparable to desert ironwood.
Gidgee (Acacia cambadgei) – Janka Hardness Scale – 4270  
Mulga (Acacia aneura) – Janka Hardness Scale – 3820 (NOTE: I’ve seen many references to this wood being used as a weapons wood by original Australians)".
Lignum vitae wood ranks highest, Janka hardness of 4500 lbf.  Traditional food from animals including kangaroo, emus, wild turkey, rock wallaby, yams, mulga seeds and wattle seeds. Crocodiles were defeated in wrestling matches and eaten raw, the teeth were chewed like gum as were bones and claws.

RE: perpendicular compression fail

correct answer:

"The application of a hardened wooden edge to a brittle bone will not slice the bone, which means a localised shearing of fibres, it will crack and crush the bone, involving a distribution of impact forces onto the extended shape of the bone, not the local impact point.  The bone would shatter first, as a preferred lower-energy route to failure. Sharp steel blades can shear bone fibres and will cause more damage that way than by impact.. I can't explain how the same damage as a sharp sword could be done with even a hardened wooden tool or weapon. ."

Newspapers do NOT print fake news but some anthropologists may do so, sometimes, or never.

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