Experimental study of a percussive process for rock fragmentation

A drifting impact oscillator with periodic impulsive loading: Application to percussive drilling

“…Furthermore, the idealization of this law by a history-dependent bilinear model, i.e. a linear spring with larger unloading stiffness than loading one, has been shown to capture the essential response observed in single impact indentation experiments as confirmed by measurements [13] and by the matching of numerical results to experimental ones in the analysis of stress waves traveling in drill steels [25].…”

“…authors have proposed physics-based arguments to the development of interaction laws, based notably on the cavity expansion model [22], scaling arguments [23] or numerical evidence [14,16], percussion drilling experiments have highlighted two common trends: (i) the force/penetration law consists of two successive phases, one associated with the loading and the other with the unloading of the interface [9,11,13,24], and (ii) this law is rate-independent, i.e. it does not depend on the penetration velocity of the indenter [10,24].…”

Dynamic cone penetration tests in granular media: Determination of the tip's dynamic load-penetration curve

“…Supposing zero skin friction along the rods, the information about ε d (t) and ε r (t) allows us to calculate the signals of the force F N (t) and the velocity v N (t) for every point N situated under the measurement point A, especially at the tip, according to the solution proposed by (Karlsson et al 1989). …”

Analysis of Elastic Flexural Waves in Non-Uniform Beams Based on Measurement of Strains and Accelerations

“…Lagerkvist and Lundberg [6], Lagerkvist and Sundin [7] and Sundin [8] used the method to determine mechanical point impedance. The method was also used by Karlsson et al [9] in a study of the interaction of rock and bit in percussive drilling. It was extended to non-uniform bars by Lundberg et al [10], and this version of the method was used for determination of force}displacement relationships for di!erent combinations of drill bits and rocks by Carlsson et al [11] and for high-temperature fracture mechanics testing by Bacon et al [12,13].…”