/sci/ - Science & Math » Thread #11235535

52KiB, 1280x1024, combined axial and shear.png

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combined stress, ultimate strength?

Anonymous Wed 18 Dec 12:52:44 2019 No.11235535 View Reply Original Report

Quoted By: >>11235578 >>11235680

Would the tensile or compression strength be integrated with the shear & bending? So you find the total deflection due to all loads; but WHAT DOES IT FAIL IN? do you see in an increase in ultimate strength of tension & compression or are those not applicable past the deflection?

Anonymous

Anonymous Wed 18 Dec 2019 13:36:33 No.11235578 Report

Quoted By: >>11235645

>>11235535
How your structure fails depends on the material you're using. Very brittle materials tend to fail due to normal/principal stresses, for example, while ductile metals tend to fail almost entirely due to shearing. So, if your material is brittle, you should calculate the maximum principal stress, and if it's a ductile metal, you should use a shear failure criterion, like Von Mises stress.

Also, if the block pictured is slender along the axis of compressive loading, you should do a beam-column check to ensure stability.

Anonymous

Anonymous Wed 18 Dec 2019 14:35:24 No.11235645 Report

Quoted By: >>11235681

>>11235578
not what i asked

Anonymous

Anonymous Wed 18 Dec 2019 15:01:12 No.11235680 Report

Quoted By:

>>11235535
Normal forces and bending moments cause normal stress. Shear forces cause shear forces. Do you know how to draw a shear-moment diagram? For a point on the beam far from the edge, stresses are given by
$\sigma=\frac{P}{A}-\frac{yM}{I} \\ \tau=\frac{VQ}{It}$
From here, you can determine if allowable normal/shear stress is exceeded. For a point close to the free end, you are dealing with concentrated stresses which is a different ballgame.
Lmk if you dont know what these symbols represent.

Anonymous

Anonymous Wed 18 Dec 2019 15:01:49 No.11235681 Report

Quoted By:

>>11235645

Not him, but all the relevant stresses are obviously integrated. The material will fail first in whichever load type is the first to surpass its respective ultimate strength.

e.g. Assuming a shear force and a Compressive force are both applied from the same vector, both in equal amounts and rates, the relatively brittle material will fail when its UCS is surpassed by the compression force, whereas a more ductile material will fail when its USS is surpassed by the shear force.

Anonymous

View Same Google iqdb SauceNAO Screenshot_2019-12-18-09-39-45.png, 236KiB, 1024x600

Anonymous Wed 18 Dec 2019 15:41:52 No.11235753 Report

Quoted By:

this

Anonymous

Anonymous Wed 18 Dec 2019 16:26:03 No.11235824 Report

Quoted By:

https://en.m.wikipedia.org/wiki/Von_Mises_yield_criterion

Anonymous

Anonymous Wed 18 Dec 2019 18:07:35 No.11235985 Report

Quoted By:

op here i'll do the calcs in a while and post
should surprise you

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