# Which stress counts when looking at yield

• wahaj
In summary, when looking at yield at the fixed end, you should take the biggest stress of the three. If you have shear and bending in 2 directions, you should calculate the von -Misses equivalent stress to combine the stresses.

#### wahaj

To makes things simple, consider a simple beam fixed at one end an a load applied at the other. This load will produce shear stress, bending stress, and torsional stress. When looking at yield at the fixed end, do I take the biggest stress of the three or do I add their magnitudes to see if it exceeds the yield stress of the beam? Also what do I do if I have shear and bending in 2 directions?

wahaj said:
To makes things simple, consider a simple beam fixed at one end an a load applied at the other. This load will produce shear stress, bending stress, and torsional stress. When looking at yield at the fixed end, do I take the biggest stress of the three or do I add their magnitudes to see if it exceeds the yield stress of the beam? Also what do I do if I have shear and bending in 2 directions?

If you have multiple stresses to sort out, the best thing to do is use Mohr's circle to combine them. Bending stresses usually act in the axial direction; shear stresses can occur in different planes. In general, you cannot simply add the magnitudes of stresses together unless they act in the same direction.

http://en.wikipedia.org/wiki/Mohr's_circle

I thought I could add them using vector addition. If I remember my Mohr's circle correctly, on the circle the maximum stress occurs when shear is 0 and max shear is when stress is 0. So after drawing the circle and finding the maximum stress and shear I look at them individually to see if either exceeds the yield stress, which I assume is different in normal and shearing conditions. Is my reasoning correct?

I had completely forgotten about that. That should solve my problem, thank you for helping.

## What is meant by "yield" in this context?

Yield refers to the amount of output or product that is obtained from a particular process or system.

## What do you mean by "stress" in relation to yield?

In this context, stress refers to any external factors or conditions that can affect the yield of a process or system.

## Do all types of stress have the same impact on yield?

No, different types of stress can have varying impacts on yield depending on the specific process or system being studied.

## Can you give some examples of stress that can affect yield?

Examples of stress that can affect yield include temperature changes, changes in humidity, exposure to certain chemicals or pollutants, and variations in nutrient availability.

## How can scientists determine which stress is most important for a particular yield?

Scientists use various methods such as controlled experiments and statistical analysis to determine which stress factors have the greatest impact on yield in a particular process or system.