Stingers Have Achieved Optimal Pointiness, Physicists Show:
The spines of a cactus, the proboscis of a mosquito, the quills of a porcupine: straight, pointed objects serve a plethora of functions in nature. Yet no matter the size, from bacteriophages' nanometer-scale tail fibers to narwhals' two- or three-meter-long tusk, these structures tend to be long and slender cones whose base diameter is much smaller than their length. Now researchers have used physics to explain why this narrow shape is optimal for stingers and other piercing objects—including human-made tools such as hypodermic needles.
A stingerlike object's dimensions are limited by two opposing constraints. To puncture its target, it must apply a force large enough to overcome the pressure created by friction. At the same time, this force must be smaller than the "critical load," the maximum force that the structure can support without bending or breaking. A large range of geometries, from long and narrow to short and wide, satisfy both constraints. Yet living organisms do not exhibit all the possible variability. Instead nature seems to prefer narrow designs with a base-diameter-to-length ratio of around 0.06.
[...] Jensen and his graduate student Anneline Christensen devised a simple theoretical model for a solid conical stinger at the edge of stability. Their calculations predicted that the optimal base diameter depended on only three factors: the object's length, the stiffness of its material and the friction from the pressure of the target tissue. The dependence on stiffness and pressure was weak: doubling the stiffness would allow the base diameter to decrease by only 21 percent, for instance. It was primarily the relationship between diameter and length that intrigued the duo.
[...] To see if a linear relationship held in the natural world, Jensen's team compiled the dimensions of nearly 140 stingers, spikes and spines in living organisms. Vertebrates and invertebrates, land and sea creatures, and plants, algae and viruses all had structures that matched the new model. Almost 100 human-made "stingers" such as needles, nails and arrows also aligned with the researchers' predictions. "It's always nice when you do some kind of theoretical work, and then you see it applies to something in real life," Christensen says. "It's not just an equation on a piece of paper."
Journal Reference:
Kaare H. Jensen, Jan Knoblauch, Anneline H. Christensen, et al. Universal elastic mechanism for stinger design, Nature Physics (DOI: 10.1038/s41567-020-0930-9)
(Score: 5, Insightful) by linuxrocks123 on Monday July 06 2020, @10:02PM (4 children)
For once, penises aren't off-topic.
(Score: 1, Touché) by Anonymous Coward on Monday July 06 2020, @10:33PM (2 children)
If your penis is stinging, you are doing it wrong.
(Score: 1, Touché) by Anonymous Coward on Tuesday July 07 2020, @12:32AM (1 child)
your mom says hi
(Score: 1, Informative) by Anonymous Coward on Tuesday July 07 2020, @01:21AM
She always liked taking pity on the less endowed.
(Score: 0) by Anonymous Coward on Tuesday July 07 2020, @02:08AM
My faith in this community just grew. Dick joke top billing.
(Score: 0) by Anonymous Coward on Monday July 06 2020, @10:05PM (1 child)
Structural engineers have known this stuff forever.
And beside that, hypodermic needles and mosquito stingers are not tapered (except at the end for piercing).
(Score: 0) by Anonymous Coward on Monday July 06 2020, @10:29PM
Of course engineers can't spell (for some reason my spell checker doesn't work in the Subject box...)
(Score: 2) by FatPhil on Monday July 06 2020, @10:13PM
Modelling them as beams, the ability to resist a bending force is proportional to the width times the thickness cubed, and assuming rotational symmetry, that's a 4-th power.
21% less width/thickness gives you only 39% (so 61% less) strength, so I'd want 2.5x more stiffness.
(I can't read the paper on my phone now, and there's some chance the number has become mangled and the comparison is that instead the larger one is 21% larger, bringing a 114% increase in stiffness because of the dimensions, which is closer to the 2:1 ratio of the intrincip stiffness of the materials they're balancing.)
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Monday July 06 2020, @11:04PM (1 child)
critics show.
That's kinda harsh, isn't it? I mean, yeah, with quantizing and auto tune, you hardly need them anymore, but still, you know a musician's talent by their singing
(Score: 0) by Anonymous Coward on Monday July 06 2020, @11:14PM
Don't you be bad-mouthing the next President, Kanye West.
(Score: 1) by Zinnia Zirconium on Monday July 06 2020, @11:41PM
Suicide mission against vampires: poison your own blood with blood thinners and bait strigoi to sting you with their stingers.
Sorry it's a The Strain reference.
(Score: 0) by Anonymous Coward on Tuesday July 07 2020, @01:13AM (1 child)
A sting most foul! Murder Hornets with Optimal penetrating stingers, trying to Destroy America! Rioting and burning, and eating all the honeybees!
(Score: 0) by Anonymous Coward on Tuesday July 07 2020, @03:56AM
Not to worry, I guess you missed the video of the preying mantis eating out the head of a murder wasp.
(Score: 0) by Anonymous Coward on Tuesday July 07 2020, @07:00AM (1 child)
who has ever tried to stab someone in the throat with a Rubik's cube.
(Score: 1) by RandomFactor on Tuesday July 07 2020, @12:04PM
I can neither confirm nor deny....
В «Правде» нет известий, в «Известиях» нет правды
(Score: 0) by Anonymous Coward on Wednesday July 08 2020, @06:08PM
also works the other way around?
if you dont want object A to penetrate into object B (like a good stinger would) then stay away from that ratio?
does it also mean that it gives a hint of "optimal support" and "no penetration"?
take two "best stingers", cut in half each of them stingers and then clue them two narrow ends together to get a optimal columne that won't "stinger into the ground" and won't scewer the beam laid on top?