# Finding Major and Minor Strain from Mohr Circle of Stress

• mjocalla
In summary, the conversation is about using the Mohr circle of stress to find the major and minor strains. One person asks if they can use Young's Modulus equation and value to find the strains, while the other person suggests using the principal stresses to determine the corresponding principal strains. They also mention that the only difference between Mohr's Circle for plane stress and plane strain is that the Y axis for strain is half of the shear strain.

#### mjocalla

Hey everyone.

Quick question about the Mohr circle.

If I have got the major and minor stress from a Mohr Circle of stress how do you go about finding the major and minor strains?

Can you just use Young's Modulus equation and value for Young's Modulus or will I need to construct Mohr Circle of Strain?

Thanks for any help.

mjocalla said:
Can you just use Young's Modulus equation and value for Young's Modulus or will I need to construct Mohr Circle of Strain?

I don't see why you would construct another Mohr circle. If you have Young's modulus given, and if you know the stresses, you can find the strain.

The question I was trying to ask was would the major/minor strain occur when the stress corresponds to the major/minor stress and vice versa?

Yes. The principal strains will lie in the same direction as the principal stresses. The only real difference between the Mohr's Circle for plane stress and plane strain is that for the circle in strain, the Y axis (shear strain) is equal to half of the shear strain.

## 1. What is the purpose of using the Mohr circle of stress?

The Mohr circle of stress is a graphical representation used to determine the state of stress at a specific point in a material. It helps in understanding the stress distribution and identifying the principal stresses and their corresponding directions.

## 2. What is major and minor strain?

Major and minor strain refer to the two principal strains that occur in a material under stress. Major strain is the largest strain in a material, while minor strain is the smallest. They are perpendicular to each other and represent the maximum and minimum elongation or compression of a material in different directions.

## 3. How do you find major and minor strain from the Mohr circle of stress?

To find major and minor strain from the Mohr circle of stress, you need to plot the given stress values on the circle and draw a line connecting them. The point where this line intersects the circle represents the center of the circle and the major and minor strains can be read from the horizontal and vertical axes, respectively.

## 4. What is the relationship between stress and strain in the Mohr circle?

In the Mohr circle, stress is represented by the distance from the center of the circle to the plotted point and strain is represented by the angle between the stress line and the horizontal axis. This relationship helps in understanding the stress-strain behavior of a material and determining its strength and stiffness.

## 5. How can the Mohr circle of stress be used in real-world applications?

The Mohr circle of stress is widely used in engineering and geology to analyze the stress and strain distribution in different types of structures and materials. It is also used in designing and testing materials for various applications, such as in construction, manufacturing, and geological studies.