durundal
Re:350 tons of of chocolate and wine arrive on world’s largest cargo s...
on Saturday April 13, 2024 @11:58AM (#40023975)
You’re burning it in air which has lots of nitrogen.
Re:Titanic tourist sub goes missing sparking search
on Tuesday June 20, 2023 @04:27PM (#36410008)
The fibers are strong in both tension and compression (not equally so, see figure 1: http://home.iitk.ac.in/~mohite/axial_compressive.pdf), but in compression their aspect ratio is very very very large so they buckle instantly… unless you glue them together so each strand is supporting the ones near it and the effective aspect ratio is much less. Aside from fiber wound pressure bottles just about any real world composite structure will experience bending forces which will put the top in compression and the bottom in tension. The designer might need to reinforce the compressive side more, depending on the application (e.g. if designing for stiffness the strength might end up with considerable margin for both tension and compression).
Re:Titanic tourist sub goes missing sparking search
on Tuesday June 20, 2023 @03:51PM (#36409547)
https://www.investacast.com/industries/safety-critical/
These folks, among others, make a lot of them. You are also incorrect about forging being used to introduce uniformity into the grain, it is typically (though not always, as some forging operations may just be for establishing shape) to stretch the grains such that they are oriented along the load path, resulting in higher allowable stresses. Look up highly loaded aircraft parts like landing gear, they are typically forged to establish the grain direction and then machined to final dimension. Nothing stops you from heat treating metal after it has been cast, either. Some heat treatments are also expressly to produce nonuniform conditions in the metal, case hardening for example.