Good morning! In most cases, when plotting a graph, the independent variable is indeed placed on the x-axis, while the dependent variable is placed on the y-axis. However, in the context of stress-strain curves in materials science and mechanics, the convention is reversed.

In stress-strain curves:

• Stress is typically plotted along the y-axis (vertical axis).
• Strain is usually plotted along the x-axis (horizontal axis).

This convention is widely followed in material science and engineering because stress (force applied per unit area) is often considered the dependent variable, responding to the applied strain (deformation) of a material.

When a material is subjected to an external force, it deforms and experiences strain as a result. The stress applied to the material is then measured in response to this strain. As stress is the dependent variable influenced by the applied strain, it is plotted on the y-axis, while strain, the independent variable, is plotted on the x-axis.

This convention ensures consistency in how stress-strain relationships are represented and analyzed, making it easier to interpret and compare material properties and behaviors.