Posted: Mon Apr 19, 2010 7:44 pm
I've always wondered why horizontally laminated cores don't seem to be used.
Yes, the layers in a horizontally laminated core might seem like obvious sites for delaminations to occur. But, the strength of the joint between two pieces of wood glued together will be much stronger than the wood itself so the wood should break before the layers delaminate (providing the glue is not total crap or badly applied).
Regarding the test by clamping the wood to a bench aligned or transverse to the grain. I can see where you're coming from but a test like that won't represent what going on in the ski. Along the grain wood is stiff and strong, transverse to the grain it rubbish (just like a regular fibre reinforced composite). The test mentioned just demonstrates this. If you laminated some strips of wood horizontally and vertically and then flexed them their stiffness and strength would be the same (as long as the wood in each had the same properties, defect etc...).
I suspect the reason for not using horizontal laminations is (as already mentioned) difficulty in getting wide enough bit of wood without defects.
Yes, the layers in a horizontally laminated core might seem like obvious sites for delaminations to occur. But, the strength of the joint between two pieces of wood glued together will be much stronger than the wood itself so the wood should break before the layers delaminate (providing the glue is not total crap or badly applied).
Regarding the test by clamping the wood to a bench aligned or transverse to the grain. I can see where you're coming from but a test like that won't represent what going on in the ski. Along the grain wood is stiff and strong, transverse to the grain it rubbish (just like a regular fibre reinforced composite). The test mentioned just demonstrates this. If you laminated some strips of wood horizontally and vertically and then flexed them their stiffness and strength would be the same (as long as the wood in each had the same properties, defect etc...).
I suspect the reason for not using horizontal laminations is (as already mentioned) difficulty in getting wide enough bit of wood without defects.