Mechanical Failure of a Truncated Cone

[DougieB39]

What data do you need to calculate the failure point of a truncated cone when it is under uniaxial stress acting downward on the cone? The cone will be under stresses of roughly 30 tonnes and probably constructed of plastic.

Thanks,

 

[Studiot]

Well let's see,

You need the material or its properties, the dimensions of the cone including whether it is solid or hollow, a knowledge of the loading conditions at the top to determine any eccentric loading.

Finally you need to establish you failure criterion.

Remember that with the conditions described, unless the cone is slender enough to buckle, the top slice will fail plastically before the slice underneath it and so on. So a squat cone will squash down plastically until either it is flat or it can support the load stress at a particular cross section.

 

[DougieB39]

The material will probably be ABS reinforced with galss fibres, the cone will be hollow and the load at the top will just be a static load evenly distributed.

Failure conditions will be after it reaches the point that it won't elastically return to its shape.

I'm more interested it what formulae you would need to use and what material properties will need to be found/calculated.

thanks again

 

[Studiot]

Since gravity is vertical and the sides of your cone are not, you have a thin walled shell loaded eccentrically, rather than axially. You will definitely have to consider buckling. The dimensions become rather critical.

 

[DougieB39]

1000m dia. base, 850mm dia. top, 3500mm height, 50mm wall thickness

Thanks