Hi Everyone,
I don't know if this has been discussed before, but from reading material on the HI website I got the impression that the Cho cutout just above the handle of the khukuri is traditional and it's purpose is more or less lost to history.
I had a hunch that it could actually have a structural benefit, as the extremely narrow cross-section of the blade edge can cause stress concentration. The cho can move the stress to the thicker areas of the blade, reducing the maximum stress in the blade.
This morning I ran some Finite Element Simulations and saw that the Cho can reduce the maximum stress in the blade by ONE THIRD.
I did not use real values for the geometry. I used generic structural steel material properties and did not account for the variation in modulus from the differential heat treatment or hardening. I did not check for mesh convergence, or verify my results were in accordance with the beam equations. I did not apply realistic loading conditions. In other words, please take these results with a grain of salt!
I do think that the ratio of the maximum stresses is likely a good result. (although I would not publish this without doing a LOT more refinement and verification). At the very least it indicates that the strength of the blade can be improved by adding this feature.
Anyhow, I think it's cool that a traditional feature like this could have a significant positive effect on the strength of the blade.
If anyone is interested to help me to post it, I have a .pdf that shows some pictures of the stress concentrations.
--Justin
I don't know if this has been discussed before, but from reading material on the HI website I got the impression that the Cho cutout just above the handle of the khukuri is traditional and it's purpose is more or less lost to history.
I had a hunch that it could actually have a structural benefit, as the extremely narrow cross-section of the blade edge can cause stress concentration. The cho can move the stress to the thicker areas of the blade, reducing the maximum stress in the blade.
This morning I ran some Finite Element Simulations and saw that the Cho can reduce the maximum stress in the blade by ONE THIRD.
I did not use real values for the geometry. I used generic structural steel material properties and did not account for the variation in modulus from the differential heat treatment or hardening. I did not check for mesh convergence, or verify my results were in accordance with the beam equations. I did not apply realistic loading conditions. In other words, please take these results with a grain of salt!
I do think that the ratio of the maximum stresses is likely a good result. (although I would not publish this without doing a LOT more refinement and verification). At the very least it indicates that the strength of the blade can be improved by adding this feature.
Anyhow, I think it's cool that a traditional feature like this could have a significant positive effect on the strength of the blade.
If anyone is interested to help me to post it, I have a .pdf that shows some pictures of the stress concentrations.
--Justin