lemd

On 7/29/2016 at 11:18 AM, Bronezhilet said:

I'm a better engineer than you apparently, since I do know what a thread is. "Thread similar to a series of disks attached.". ...what.

Also, are you familiar with the term "napkin calculation"?

But hey, welcome to SH I guess.

Better my ass, I am an inventor, enterpreneur, what did you do your whole life on my caliber?

I don't know napkin calculation, english is not my first language so my expression is not that good.

Being an inventor alone is far greater than anything an engineer like you can be, in both technology and financial achievement. Being a great inventor, who can influence the world, change how battlefield is fought, is not even in your dream, loser

When calculating the critical load under which the rod will fail with the use of Euler's critical load, you need the area moment of inertia. Which, for a circle, has the radius as quadrupled.

 

So calculating the area moment of inertia of the rod using your 110% we get:

0.25*pi*(10.4*1.1)⁴ = 13452.22 = I_rib

 

And for one without the rib:

0.25*pi*(10.4)⁴ = 9188.05 = I_smooth

 

Throwing this in Euler's formula (P_cr = (pi²*E*I)/(KL²)): (Values for DM63 rod)

P_rib = (pi²*530000*13452.22)/(1*646²) = 168618 N

P_smooth = (pi²*530000*9188.05)/(1*646²) = 115168 N

 

So a ribbed rod will buckle at ~168 kN, while a smooth one will buckle at ~115 kN.

 

Which is a 46,4% improvement.

 

 

...now that I'm done I notice I used the maximum diameter of a DM63 rod, instead of its minimum diameter. Values change, percentage should stay the same.

 

 

Disclaimer: This is a napkin calculation, do not use as scientific basis yadieyadieya, etc.

What kind of engineer are you? You failed at the basic engineering

In order to increase the load, the increased diameter must run parallel continuously to the axis of the rod, e.g. a full rod, not discrete thread like that which is useless because the chain is as strong as its weakest link.

Your theory fails, imagine a steel rod with 1m diameter, but has a section with 1mm diameter. From your calculation, that rod is very strong and can not be broken, but actually it can be broken by human easily.

The thread is similar to a 1mm rod with many 1m disks attached discretely along its length, the disks are useless in increasing bending load of the rod, even the diameter is huge.