Theoretical and Experimental Investigation of Continuous Jet Penetration of Solids

Abstract

The study attempts to develop a theory for the penetration of a wide range of solid materials by continuous high-velocity water jets. The theory is based on a control volume analysis to determine the hydrodynamic forces acting on the solid boundaries of the cutting slot. A Bingham model is used to describe the time-dependent stress-strain relationship of the solid material. The coupled fluid-solid mechanics equations are simplified to yield a closed-form solution in the form of a nondimensional cutting equation zdn=1−σcρV122Cf√π [1−e−(2Cf/√π)·(ρV1/η)·(V1/u)] which satisfies all the limiting conditions of practical cutting applications. Published experimental results from cutting tests with a wide range of fibrous, granular and crystalline material are used to obtain mean values of the friction (Cf ) and damping coefficients (η) which are used with the compressive yield strength (σc ) to characterize different materials. The theory presents a basis for developing more exact cutting equations by choosing the optimum rheological model for a particular material.