Check out the video for in-depth understanding: https://youtu.be/M-U-Qg_5wsg

Based upon the intensity of external forces the body develops internal forces. These internal forces then create internal stresses on the members.

If the internal stresses are greater than the strength of the material the structure will fail. If however, the strength of the material is greater than the internal stress, the structure is Safe.

The above concept is simple enough to understand if you know what the internal stresses look like and the strength of the material. In order to calculate the internal stresses on any member, one must have a basic understanding of what these internal stresses look like.

Based upon the internal forces that are generated on a member the internal stresses could be:

1. Normal Stresses

These normal stresses could be:

2. Shear stresses

These shear stresses could be:

These internal stresses can be calculated using different formulae. However, one must have a very clear understanding of the nature, direction, and impact of these internal stresses.

The strength of the material is very closely attached to the internal stresses since strength is nothing but the maximum stress a body can handle. Hence, for different types of internal stresses, the body has different strengths.

For example, the shear strength of concrete is very much different from the bending strength. More so the direction of the stresses is also vitally important when it comes to the stability of the structure. For example, the concrete has a lot of bending compression strength, i.e. normal bending stresses that cause compression stresses. 

However, the same concrete is assumed to have negligible strength when it comes to normal bending stresses that cause tensile stress.

Check out the video for in-depth understanding: https://youtu.be/M-U-Qg_5wsg

Thanks,
Kushal

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