Muotoutumiskäyrän

Muotoutumiskäyrä, known in English as the stress-strain curve, is a graphical representation of a material's mechanical behavior under tensile or compressive load. It plots engineering stress on the y-axis against engineering strain on the x-axis. Engineering stress is defined as the applied force divided by the original cross-sectional area of the material, while engineering strain is the change in length divided by the original length.

The initial part of the curve, often referred to as the elastic region, typically exhibits a linear relationship between stress and strain. In this region, the material deforms elastically, meaning it will return to its original shape once the load is removed. The slope of this linear portion is known as the Young's modulus or modulus of elasticity, a fundamental property indicating the material's stiffness.

Beyond the elastic limit, the material enters the plastic region. Here, deformation is permanent, and the material will not fully recover its original shape after the load is released. Within the plastic region, some materials show a yield point, where a significant amount of deformation occurs with little or no increase in stress. For other materials, yielding is more gradual.

As the strain increases further, the stress may continue to rise until it reaches the ultimate tensile strength (UTS), which is the maximum stress the material can withstand before it begins to neck or thin down. After reaching the UTS, the stress decreases as the material continues to deform plastically until it fractures, marking the end of the curve. The area under the stress-strain curve represents the toughness of the material, its ability to absorb energy before fracturing.