Energy and Fatigue Damage Evolution of Sandstone under Different Cyclic Loading Frequencies

Abstract

To study the energy dissipation characteristics and damage evolution law of sandstone under cyclic loading, uniaxial cyclic loading tests are conducted on sandstone specimens under different frequencies with an MTS-815 rock testing machine. Furthermore, the characteristics of elastic modulus and energy evolution law during cyclic loading and unloading are explored. The results show that the loading and unloading moduli increase with the loading frequency. Under higher frequencies, the deformation resistance of the specimen is stronger, the elastic energy stored in a single cycle of loading is larger, the released energy is less, and it is less likely for the specimen to be damaged. At the beginning of loading, the energy dissipation ratio K decreases slowly with increasing loading cycles, and it then remains stable. When the specimen is close to failure, an inflection point of K appears, and K increases rapidly. Furthermore, the evolution equation of the damage variable is derived according to the strength characteristics and energy evolution law in the process of cyclic loading, and the reasons for the failure of sandstone specimens are explained from the perspectives of energy and fatigue damage.

Experimental Study on the Mechanical Properties of Rock–Concrete Composite Specimens under Cyclic Loading

“…Consequently, the damage variable started to increase more rapidly. The damage variable of dissipated energy [26], shown in Equation (11), and the damage variable of residual strain [27], shown in Equation (12), were used for a comparative analysis of the damage evolution of the composite specimen.…”

“…Figure 16 illustrates the calculated damage evolution of a composite specimen under a stress amplitude of 21.33 MPa in three different ways. It can be seen from Figure 16 that both the damage variable of cumulative energy dissipation and the damage variable of The damage variable of dissipated energy [26], shown in Equation (11), and the damage variable of residual strain [27], shown in Equation (12), were used for a comparative analysis of the damage evolution of the composite specimen.…”

“…With more in-depth research, many scholars have become concerned about fatigue damage [6][7][8] and the energy dissipation mechanism [9][10][11] of rock during cyclic loading. Sun et al [12] deduced a damage variable according to the strength characteristics and energy evolution law in the cyclic loading process. Meng et al [13] found that the energy density and hysteresis energy variation in different loading conditions show a decrease in the first few cycles and then start to increase up to failure.…”

Deformation Characteristics and Energy Evolution Rules of Siltstone under Stepwise Cyclic Loading and Unloading

“…In recent years, the study of rock damage has gained significant attention [24][25][26]. Scholars have developed various damage variable expressions based on the elastic modulus [27,28], residual strain [29,30], and energy principles [31,32]. However, the decay of the elastic modulus and the accumulation of residual deformation serve only as external indicators of damage and fail to quantitatively reflect the extent of damage.…”

Failure characteristic and acoustic emission spatio‐temporal evolution of coal under different cyclic loading rates

“…Peng et al 14 analyzed the energy dissipation and crack propagation modes of fractured sandstone with different cyclic gradient loading conditions. Sun and Yang 15 investigated the effect of cyclic frequencies on energy and damage characteristics of sandstone during the cyclic loading test. The crack opening stress was calculated under tension‐compression cyclic load 16 .…”