Final answer:
The normal stress in a beam under pure bending varies across the cross-section. The beam's geometry and material properties influence the distribution of normal stress.
Step-by-step explanation:
In the context of a general beam under pure bending, the normal stress varies across the cross-section. The distribution of normal stress is influenced by the beam's geometry and material properties.
Let's consider a beam with a section defined as 4.1.1. In this scenario, the normal stress is highest at the top and bottom surfaces of the beam, and it decreases towards the neutral axis. This variation in normal stress is due to the bending moment that causes tension on the outer fibers and compression on the inner fibers of the cross-section.
The beam's geometry, such as its shape and dimensions, determine the distribution of normal stress. For example, a beam with a larger depth will have a broader neutral axis and a more uniform distribution of stress. Material properties, such as the elastic modulus and yield strength, also play a role in determining the normal stress distribution. A material with a higher elastic modulus will experience less deformation under the same bending moment, resulting in a more concentrated stress distribution near the extremities of the cross-section.