Dynamic hardness of rock materials under strong impact loading

摘要

There have been numerous methods to test the hardness value of a piece of material. However, these methods are invalid when the target is under hypervelocity penetration. The physical nature of dynamic hardness is discussed and a new method to calculate the dynamic hardness values of rock materials under hypervelocity penetration is given. The mathematical expressions of dynamic hardness are derived based on the ideal elastoplastic model and the internal friction model, respectively. The results show that under hypervelocity penetration the dynamic hardness is proportional to the dynamic shear strength, and the coefficient is a function of the bulk modulus and the shear modulus of the target itself. The results also show great agreement with test data.