Suggestion of the DLV dimensionless number system to represent the scaled behavior of structures under impact loads

A group of dimensionless numbers, termed density-length-velocity (DLV) system, is put forward to represent the scaled behavior of structures under impact loads. It is obtained by means of the Buckingham pi\ theorem with an essential basis. The distinct features of this group of dimensionless numbers are that it relates physical quantities of the impacted structures to essential basis of the density, the length and the velocity, and thus it can represent the scaled influence of material property, geometry characteristic and velocity on the behavior of structure. The newly 15 proposed dimensionless numbers reflect three advantages: (1) the intuitively clear physical significance of these dimensionless numbers, such as the ratios of force intensity, force, moment of inertia to the corresponding dynamic quantities, the Johnson's damage number Dnand Zhao's response number Rnare naturally included; (2) the property of directly matching the dimensionless expression of response equations of dynamic problems with these dimensionless numbers through simple equation analysis; (3) the addressing ability of non-scaling problems for different materials and strain-rate-sensitive materials through adjusting impact velocity of the scaled model or adjusting density of the scaled model, as well as the VSG (initial impact velocity-dynamic flow stress-impact mass G) system. Four classical impact models are used to verify the directly matching property and the non-scaling addressing ability of the DLV system by equation analysis. The results show that the proposed dimensionless number system is simple, clear and efficient, and we suggest using it to represent the scaled behavior of structures under impact loads.