Data for some calcs
Hello
After talking to Zoran Ive decided to do some hand calculations.
The aim is to calculate, for 3 layers of sinew and single core wood, wich is the wood core thickness necessary so that the horns work only under compression.
The data needed is:
Sinew and hide glue composite DATA ->
Specific Gravity
Average Weight
Average Volumetic Shrinkage 11,9%
Modulus of Elasticity
For the wood i will choose maple, whose characteristics I have already, same for horn.
The calcs will be based on elasticity theory under shear and flexion stresses.
At some time, if I have the energy, Ill try to model the half bow (since it is symmetric) in ANSYS finite elements to see what we get from that.
Thanks if you can add some data. Much appreciated.
After talking to Zoran Ive decided to do some hand calculations.
The aim is to calculate, for 3 layers of sinew and single core wood, wich is the wood core thickness necessary so that the horns work only under compression.
The data needed is:
Sinew and hide glue composite DATA ->
Specific Gravity
Average Weight
Average Volumetic Shrinkage 11,9%
Modulus of Elasticity
For the wood i will choose maple, whose characteristics I have already, same for horn.
The calcs will be based on elasticity theory under shear and flexion stresses.
At some time, if I have the energy, Ill try to model the half bow (since it is symmetric) in ANSYS finite elements to see what we get from that.
Thanks if you can add some data. Much appreciated.
great idea !
I also wonder where the "zero-plane" is in a drawn composite bow.
You suppose the zero plane to be somewhere between wood and horn.
An alternative hypothesis would be that:
the wooden core is almost exclusively -compressed- rather than -extended- in the drawn bow.
so the zero-plane would be in the wood
and always close to the sinew layer -
no matter how thin the core is
(this idea comes just from looking at "experimental" bending of sinew-backed wood and regarding the huge difference in E-modulus between sinew and wood - that would explain why the backing can so much protect the wood from breaking : wood is compressible more than extensible (cracks always on back)
so:
what about finding the zero-plane from experimental measure of
%compression of belly versus
%extension of back
in a real composite bow ?
I also wonder where the "zero-plane" is in a drawn composite bow.
You suppose the zero plane to be somewhere between wood and horn.
An alternative hypothesis would be that:
the wooden core is almost exclusively -compressed- rather than -extended- in the drawn bow.
so the zero-plane would be in the wood
and always close to the sinew layer -
no matter how thin the core is
(this idea comes just from looking at "experimental" bending of sinew-backed wood and regarding the huge difference in E-modulus between sinew and wood - that would explain why the backing can so much protect the wood from breaking : wood is compressible more than extensible (cracks always on back)
so:
what about finding the zero-plane from experimental measure of
%compression of belly versus
%extension of back
in a real composite bow ?
Can you tell me the data for horn and source you got that info?
I have seen some data. Ottoman t?rkish bows also has some data (none that I trust).
I have seen some data. Ottoman t?rkish bows also has some data (none that I trust).