The Bulk modulus is the ratio of volumetric/bulk strain to volumetric/bulk stress, represented by K and mathematically given by-. Elastic moduli for some common materials: The volume of a gas changes when pressure applied on it is varied. It is denoted by the letter ‘K’. The bulk modulus is a constant the describes how resistant a substance is to compression. It is the ratio of compressive stress to volumetric strain. Where, C, N or G – Modulus of Rigidity. It is also called shear modulus of elasticity. C, N or G=τ/es. Bulk Modulus Elasticity. As compressibility of a fluid is expressed as inverse of bulk modulus, higher the bulk modulus less is the compressibility of the fluid. So far, the bulk modulus has been defined as the simple quotient of an applied hydrostatic stress to the resulting volumetric strain P/θ as shown in Figure 1. When a body is subjected to the three mutually perpendicular forces of equal intensity, then there will be a change in the volume of the body due to these external forces. It is denoted by K. σ = Direct stress (dV/V) = Volumetric strain ... Modulus. corresponding volumetric strain within elastic limit. Therefore, strain is a dimensionless number. This is true, but one must also be careful about the conditions under which the experiment is carried out. Together with Young's modulus, the shear modulus, and Hooke's law, the bulk modulus describes a material's response to stress or strain. Bulk Modulus/Volumetric Compression Testing Instrumented device to measure bulk modulus The bulk modulus of a material describes the volumetric deformation behavior of a material and is important when high hydrostatic pressures are present (high-pressure seals, deep sea exploration, etc. Bulk Modulus. Modulus of Rigidity.
It may be defined as the ratio of normal stress (on each face of a solid cube) to volumetric strain and is denoted by the letter K. K=σn/ev. Bulk Modulus of Elasticity is the ratio of stress to change in volume of a material subjected to axial loading. Bulk or Volume Modulus of Elasticity. It is defined as the ratio between pressure increase and the resulting decrease in a material's volume. There are 3 strain states which are particularly useful in characterizing dense elastomers. Bulk Modulus of Elasticity: Within the elastic limit, the ratio of volumetric stress to the corresponding volumetric strain in a body is always constant, which is called as Bulk modulus of elasticity. Hope you understood the relation and conversion between Young’s modulus and the Bulk modulus of an object. They are simple tension, pure shear and equal biaxial extension. S.no. Bulk Modulus When a body is subjected to three mutually perpendicular stresses, of equal intensity, then the ratio of the direct stress to the corresponding volumetric strain is known as bulk modulus . The value of bulk modulus equals the pressure change x 100 required to cause a one percent change in volume. The bulk modulus of a gas is defined as the ratio of volumetric stress to the volumetric strain i.e, \begin{align} B=-\frac{\Delta p}{(\Delta V/V)}\nonumber \end{align} where $\Delta p$ is a change in pressure and $\Delta V$ is change in volume.

1. Young’s Modulus. Bulk Modulus is a measure of the resistance of a fluid to compression. For example, air in a … It is relatively easy to compress gases and extremely difficult to compress liquids and solids. The strain in the x direction in a material subjected to three mutually perpendicular stresses in the x, y and z directions is given by. es – Shear Strain. ), or when plastic deformation is not volume conserving. An object will be compressed in all directions if inward forces are applied evenly on all its surfaces as in the figure below. The greater the stress, the greater the strain; however, the relation between strain and stress does not need to be linear. τ – Shear Stress. If the elastomer is confined in its application and the compressible nature of the elastomer is a concern, a volumetric compression experiment (bulk modulus) may also be advisable. Changes in Volume: Bulk Modulus. Poisson's ratio v being defined as the ratio of lateral strain to longitudinal strain and bulk modulus K as the ratio of volumetric stress to volumetric strain. Strain under a tensile stress is called tensile strain, strain under bulk stress is called bulk strain (or volume strain), and that caused by shear stress is called shear strain. Generally, … It is defined as the ratio of pressure stress to volumetric strain.