tilavuusjäykkyyden
Tilavuusjäykkyys, also known as bulk modulus, is a measure of a substance's resistance to uniform compression. It quantifies how much a material's volume changes when subjected to hydrostatic pressure. Mathematically, tilavuusjäykkyys (K) is defined as the ratio of the applied pressure (P) to the relative change in volume (-ΔV/V), where V is the original volume and ΔV is the change in volume. The negative sign indicates that an increase in pressure leads to a decrease in volume. A high tilavuusjäykkyys signifies that a large pressure is required to produce a small change in volume, meaning the material is stiff and difficult to compress. Conversely, a low tilavuusjäykkyys indicates that the material is easily compressible. This property is analogous to Young's modulus for tensile or compressive stress, but it applies to volumetric changes caused by pressure acting equally in all directions. Tilavuusjäykkyys is an important material property used in various fields, including solid mechanics, fluid dynamics, and geophysics, to characterize the compressibility of solids, liquids, and gases. Its unit in the International System of Units (SI) is Pascals (Pa).