Brittle strength

In materials science, fracture toughness is a property which describes the ability of a material containing a crack to resist fracture, and is one of the most important properties of any material for many design applications. The linear-elastic fracture toughness of a material is determined from the stress intensity factor (${\displaystyle K}$) at which a thin crack in the material begins to grow. It is denoted K_Ic and has the units of ${\displaystyle {\text{Pa}}{\sqrt {\rm {m}}}}$ or ${\displaystyle {\text{psi}}{\sqrt {\rm {in}}}}$. Plastic-elastic fracture toughness is denoted by J_Ic, with the unit of J/cm² or lbf-in/in², and is a measurement of the energy required to grow a thin crack.

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