4 ms·
Not sure about the actual function that defines the wave, but let’s assume they are convex and concave semi circles. Then to make a wall of length L with bricks
by tonmoy 3y ago
Not sure about the actual function that defines the wave, but let’s assume they are convex and concave semi circles. Then to make a wall of length L with bricks of l length, we need piL/l number of bricks. The linked Reddit post says a straight wall needs to be 2 bricks wide to have the same length, which needs 2L/l number of bricks which is fewer than the wavy walls
- contravariant 3y agoSemicircles seem excessive. At no point does the wall have an angle over 45 degrees, so a semi-circle which would be at a 90 degree angle for every inflection point seems way too wavy. A sine wave is probably closer, which would give an arc length of sqrt(1+cos(2pix/L)^2). This has no reasonable closed form I can find but it seems like it would be about 21% longer than a straight line. Edit: Also a semicircle is pi/2 times as long as its diameter, not pi times.
- hinkley 3y agoSines are about 1/.7 (40%) longer aren’t they?
- contravariant 3y agoWhat would be about what you'd get if you made a sawtooth out of straight sections, pretty sure that's quite a bit longer than a sine wave would be.
- hinkley 3y agoYeah I'm thinking of electricity. A right isosceles triangle has a hypotenuse that's √2 (1.41) and 1/√2 = 0.71. Stack Overflow seems to think it's around 2.4x, but I am not sure I could ever follow the math and I certainly can't now. I think the amplitude makes the difference here and SO is answering a different question, otherwise this article would be wrong and that wasn't my impression the first time I encountered this topic. second edit: The article linked from this article says: So a crinkle wall with amplitude 1.4422 uses about as many bricks as a straight wall twice as thick.
- tln 3y agoArticle links to this post with another derivation. https://www.johndcook.com/blog/2019/11/19/crinkle-crankle-calculus/ https://www.johndcook.com/blog/2019/11/19/crinkle-crankle-ca... I'd like to know if this wavy wall technique requires non-square bricks to be stronger. And is it stronger against sideways forces along the concave and convex sections. If it's only the same strength as a straight wall then I'd think it'd be worse as a retaining wall?
- eastof 3y agoIt's not one giant semi circle. Lets say each semi-circle has a radius of about 2 ft (judging by the pictures). Every 8 ft section (1 wave/one full cicle) takes 2pi2 ~= 12.56, while the straight wall takes 8*2 = 16 bricks.