Modelling and characterisation of the high-rate behaviour of rock material

Simon Larsson,Masahiro Nishida,Gustaf Gustafsson,Tomoki Moroe,Shuhei Kurano,Hans-Åke Häggblad,Pär Jonsén,E Buzaud,A Cosculluela,E Cadoni,H Couque

doi:10.1051/epjconf/201818301040

Abstract

For future reliable numerical simulations of impact wear on steel structures caused by rock material, knowledge about the dynamic mechanical properties of rock material is required. This paper describes the experimental and numerical work to investigate the dynamic mechanical properties of diabase (dolerite), a subvolcanic rock material. In this study, diabase from southern Sweden was used. The impact compressive strength of diabase with a density of 2.63 g/cm3 was examined by using the split-Hopkinson pressure bar (Kolsky bar) method. Cylindrical specimens were used, with a diameter of 8.9 mm and a length of 14 mm. To characterise the rock material, uniaxial compression tests were performed, at high strain rates (150 s-1). Using an inverse modelling approach, material parameters for an elastic constitutive model, with a stress-based fracture criterion were determined. The constitutive model was used in a finite element simulation of a high strain rate uniaxial compression test. Results obtained from the numerical model were in line with the experimental results.

Highlights

Diabase, a subvolcanic rock material, is a very commonly used construction material
The material parameters were determined from experimental splitHopkinson pressure bar (SHPB) results and a finite element (FE) model of the same experiment, using an inverse modelling approach
By inverse modelling, comparing the simulated and experimental output bar strain, the value of the equivalent stress at failure was determined to 300 MPa, for the actual strain rate (150 s-1)

Summary

Introduction

Diabase (dolerite), a subvolcanic rock material, is a very commonly used construction material. The truck beds are exposed to impacts, often resulting in severe impact wear. To better predict the wear life of the truck beds the mechanical behaviour of both the steel and rock must be known. The authors concluded that further measurements of the dynamic mechanical properties of the rock materials were required to improve the wear models. Previous experimental investigation has shown that the mechanical characteristics and fracture of diabase are strongly dependent on the strain rate [2]. The experimental studies have been used for characterization and modelling of high strain-rate loaded materials [3,4,5,6]. The dynamic mechanical properties of diabase, subjected to high strain rate loading, were investigated experimentally and numerically. The material parameters were determined from experimental splitHopkinson pressure bar (SHPB) results and a finite element (FE) model of the same experiment, using an inverse modelling approach

SHPB test

FEM simulation

Results and discussion

Conclusions