Energy Dissipation Characteristic of Red Sandstone in the Dynamic Brazilian Disc Test with SHPB Setup

2020

Shock and Vibration

Self Cite

The elastic energy stored in deep rock in three-dimensional stress environment is the energy source of rockburst. To investigate the energy storage characteristics of deep rock under different confining pressures, a series of triaxial single-cyclic loading-unloading compression tests were conducted on red sandstone specimens under eight confining pressures. The input energy density, elastic energy density, and dissipative energy density of the specimen in axial, circumferential, and total directions can be obtained by the area diagram integration method. The results show that the input energy density in the axial direction accounts for the largest logarithmic proportion of the total input energy density, and the relationship between all energy density parameters and unloading level can be described by quadratic function. In the axial direction, there is a linear function relationship among elastic energy density, dissipative energy density, and input energy density. In the circumferential direction, there is a quadratic function relationship among elastic energy density, dissipative energy density, and input energy density. For the total energy density parameters of the rock specimen, the relationship among elastic energy density, dissipative energy density, and input energy density conforms to the quadratic function. According to the above correlation function, the elastic energy stored in deep rock under different confining pressures can be accurately obtained, which provides a foundation for studying the mechanism of rockburst under three-dimensional unloading from the energy perspective.

Section: Energy Storage and Dissipation Characteristics Of Redsupporting

confidence: 93%

Experimental Investigation on the Energy Storage Characteristics of Red Sandstone in Triaxial Compression Tests with Constant Confining Pressure

2020

Shock and Vibration

Self Cite

“…In the SHPB test, the absorbed energy is often used to represent the energy dissipated during the impact of the rock specimen. In fact, the calculated energy absorbed by the rock specimen is equal to the energy dissipated in the impact process of the rock specimen [28].…”

Section: Testingmentioning

confidence: 99%

“…Deng et al [27] conducted dynamic uniaxial compressive tests on granite and sandstone and obtained a similar result as Hong et al [26] did. Gong and Hu [28] found the dynamic linear energy dissipation law in the dynamic Brazilian disc tests on red sandstone.…”

Section: Introductionmentioning

confidence: 99%

Energy Dissipation and Particle Size Distribution of Granite under Different Incident Energies in SHPB Compression Tests

Jia

Zhang

et al. 2020

Shock and Vibration

Self Cite

To investigate energy dissipation and particle size distribution of rock under dynamic loads, a series of dynamic compression tests of granite specimens were conducted using a conventional split-Hopkinson pressure bar (SHPB) device with a high-speed camera. The experimental results show that the dissipated energy increases linearly with an increasing incident energy, following two different inclined paths connected by a critical incident energy, and the linear energy dissipation law in the dynamic compression test has been confirmed. This critical incident energy was found to be 0.29–0.33 MJ/m3. As the incident energy was smaller than the critical incident energy, the rock specimens remained unruptured after the impact. When the incident energy was greater than the critical incident energy, the rock specimens were ruptured or fragmented after the impact. In addition, the experimental results indicate that the dissipated energy and energy consumption ratio of a rock specimen, either unruptured or fragmented, increase with an increasing strain rate. Furthermore, it was found that fragment sizes at each mesh decrease with an increasing incident energy; that is, fragmentation becomes finer as incident energy increases.

“…The SHPB system is often used to test various dynamic parameters of rock materials [33][34][35][36]. In these tests, the dynamic fracture testing of the rock was conducted using a 50 mm diameter SHPB system (see Figure 3), which has been used in many dynamic tests [37,38]. c mm; this apparatus can simulate pulse waveforms to reduce high-frequency vibration and minimize the dispersion degree of the test results.…”

Section: Methodsmentioning

confidence: 99%

The Loading Rate Effect on the Fracture Toughness of Marble Using Semicircular Bend Specimens

Wang

2020

Geofluids

Self Cite

A series of dynamic fracture experiments on semicircular bend (SCB) marble specimens were conducted to characterize the loading rate effect using the INSTRON testing machine and the modified SHPB testing system. The fracture toughness of the marble specimens was measured from a low loading rate to a high loading rate (10-3~106 MPa·m1/2s-1). The results show that the fracture toughness will increase with the loading rate. Since the fracture toughness at a magnitude of 10-3 MPa·m1/2s-1 is regarded as the static fracture toughness, the specific value of DI F f (the dynamic increase factor of fracture toughness) can be obtained at the other loading magnitudes from dynamic fracture tests. To describe the variation in DI F f from low to high loading rates, a new continuous model of DI F f was put forward to express the quantitative relation between the loading rate and rock dynamic fracture toughness. It is shown that the new DI F f model can accurately describe the loading rate effect on the dynamic fracture testing data for rock materials.