Jännitysvenytyskäyrä

Jännitysvenytyskäyrä, often translated as stress-strain curve or tension-compression curve, is a fundamental graphical representation used in materials science and engineering. It illustrates the relationship between the stress applied to a material and the resulting strain or deformation it undergoes. Stress is defined as the force applied per unit area, while strain is the measure of deformation relative to the original dimensions.

The curve typically begins with a linear elastic region where stress is directly proportional to strain, following Hooke's Law. Beyond this point, the material may enter a plastic deformation phase, meaning the deformation is permanent and will not fully recover upon removal of the stress. Key points on the stress-strain curve include the yield strength, which marks the transition from elastic to plastic behavior, and the ultimate tensile strength, representing the maximum stress the material can withstand before fracturing. The area under the curve can also provide information about the material's toughness, a measure of its ability to absorb energy before fracturing.

Different materials exhibit distinct stress-strain curves, reflecting their unique mechanical properties. For example, brittle materials like glass show a short elastic region and fracture with little plastic deformation, while ductile materials like steel undergo significant plastic deformation before failure. Understanding the stress-strain curve is crucial for selecting appropriate materials for specific applications and for predicting how structures will behave under load. It is a primary tool for material characterization and quality control.