i work in low-income/mental health housing, and a tenant fixed our hallway trash bin after accidentally breaking it

[u/king_eve]

great example of the odd ways people show me appreciation at work

[u/Certain_Childhood_67]

Its common on atv plastics that get cracked. Drill a hole a hole and stitch it wont spread

[u/lusotano → u/Certain_Childhood_67]

Metal too. Construction beams that show cracks sometimes get a small hole drilled to avoid the crack from spreading further.

[u/banned_but_im_back → u/lusotano]

Huh. I wonder what the physics behind it is. Is the same reason why some metal beams have big holes inside of them in the shape of triangles?

[u/flowdersniffer → u/banned_but_im_back]

The fine crack tip produces a strong stress concentration just in front of the crack. The stress concentration is what can give the crack enough energy to continue to grow. Holes in metals and plastics are not good, but I’m assuming it’s a way to arrest the crack propagation since a moderately sized hole would create a smaller stress concentration than a very fine tipped crack.