the 'cho', 'kaura' or 'kaudi' is usually thought of as a cow's hoof-print partially across the blade, cows being sacred in hindu. the 'vee is thus actually the space between the cows toes. some have this shape as more of a pagoda, or other shapes like a fleur-delee. they are either cut or punched, but if done improperly can have a very acute (sharp) inside angle which is indeed a crack inducing stress raiser. if you have one like that a small jeweler's round file can be used to radius & round off that sharp corner. the closed cho of course doesn't have that problem, so should be the best stress reducer. sharp OUTSIDE corners like the point of the Vee are NOT a stress raiser and are not a problem.
if the punching or cutting of the cho causes stress cracks, as above, they also can be filed back to good metal. in the above photo, the rounded corners of that 'pagoda' shaped on would have been perfect, except for those tiny cracks.
View attachment 231345
more chos:
View attachment 231348
more buzz words and concepts:
the locii of points along a stressed beam which are not under stress is called the neutral axis. the area above or below that axis is either in compression or tension, which is higher the further you get from that neutral axis. in an i-beam or simple flat beam, that axis runs down the middle of the web of the beam. drilling a reasonable sized hole in the web centred on the neutral axis will reduce the beam's strength negligibly. if you ever need to drill an access hole in a beam, drill it on the neutral axis on the web, not on the flange. conversely drilling away from the neutral axis or removing material away from the neutral axis will reduce the bending strength of a beam, the further you drill, the worse it is. note again that sharp inside corners in a hole are stress concentrators, oval or round holes are best. square holes are poor , jagged holes left by a acetylene torch are worst.