Elastic Strain Energy Release Research Articles

Comparing Earthquake Cycles on Normal and Reverse Faults Based on Simulations With a Dynamic Elasto‐Plastic Model

AbstractShear stress levels on reverse faults are anticipated to be several times higher than on normal faults with the same pore pressure ratio. In addition, ruptures on normal faults release gravitational potential energy, whereas earthquakes on reverse faults expend work in uplifting rocks. In this study, I investigate the significance of these differences for earthquake cycles and I question whether the source of energy driving earthquakes is the same on reverse and normal faults. Based on the assumption that normal and reverse faults have the same background frictional properties and pore pressure states, I use numerical simulations with a two‐dimensional dynamic elastic‐plastic model to show that due to stress differences, earthquakes on reverse faults tend to occur less frequently, produce more coseismic slip and stress drop and involve higher slip rates than ruptures on normal faults with equivalent dimensions. The analysis also shows differences in the energy changes associated with earthquake cycles on reverse and normal faults. However, the earthquakes on both fault types result from abrupt release of elastic strain energy, which proceed and essentially drive variations in gravitational potential energy. Thus, ruptures on both normal and reverse faults are consistent with elastic rebound theory.

Dynamic Simulation of Rock‐Avalanche Fragmentation

AbstractFragmentation is a common phenomenon in complex rock‐avalanches. The fragmentation intensity and process determines exceptional spreading of such mass movements. However, studies focusing on the simulation of fragmentation are still limited and no operational dynamic simulation model of fragmentation has been proposed yet. By enhancing the mechanically controlled landslide deformation model (Pudasaini & Mergili, 2024, https://doi.org/10.1029/2023jf007466), we propose a novel, unified dynamic simulation method for rock‐avalanche fragmentation. The model includes three important aspects: mechanically controlled rock mass deformation, momentum loss while the rock mass fiercely impacts the ground, and the energy transfer during fragmentation resulting in the generation of dispersive lateral pressure. We reveal that the dynamic fragmentation, resulting from the overcoming of the tensile strength by the impact on the ground, leads to enhanced spreading, thinning, run‐out and hypermobility of rock‐avalanches. Thereby, the elastic strain energy release caused by fragmentation becomes an important process. Energy conversion between the front and rear parts caused by the fragmentation results in the enhanced forward movement of the front and hindered motion of the rear of the rock‐avalanche. The new model describes this by amplifying the lateral pressure gradient in the opposite direction: enhanced for the frontal particles and reduced for the rear particles after the fragmentation. The main principle is the switching between the compressional stress and the tensile stress, and therefore from the controlled deformation to substantial spreading of the frontal part in the flow direction while backward stretching of the rear part of the rock mass. Laboratory experiments and field events support our simulation results.

Influence of an Engineered Notch on the Electromagnetic Radiation Performance of NiTi Shape Memory Alloy.

This work explores the influence of a pre-engineered notch on the electromagnetic radiation (EMR) parameters in NiTi shape memory alloy (SMA) during tensile tests. The test data showed that the EMR signal fluctuated between oscillatory and exponential, signifying that the specimen's viscosity damping coefficient changes during strain hardening. The EMR parameters, maximum EMR amplitude, and average EMR energy release rate remained constant initially but rose sharply with the plastic zone radius with progressive loading. It was postulated that new Frank-Read sources permit dislocation multiplication and increase the number of edge dislocations participating in EMR emissions, leading to a rise in the value of EMR parameters. The study of the correlation between EMR emission parameters and the plastic zone radius before the crack tip is a vital crack growth monitoring tool. An analysis of the interrelationship of the EMR energy release rate at fracture with the elastic strain energy release rate would help develop an innovative approach to assess fracture toughness, a critical parameter for the design and safety of metals. The microstructural analysis of tensile fractures and the interrelation between deformation behaviours concerning the EMR parameters offers a novel and real-time approach to improve the extant understanding of the behaviour of metallic materials.

Exploring the impact of varying notch-width ratios on electromagnetic radiation parameters at tensile fracture of C35000 brass

The paper discusses experimental research to analyze how the notch-width ratio (2a/w) impacts Electromagnetic Radiation (EMR) emission parameters at tensile fracture in C35000 brass. The EMR emission signals during tensile fracture were captured using a copper chip antenna and stored in an oscilloscope for further analysis. The EMR parameters and mechanical parameters at fracture showed a smooth correlation. Investigating the association between the EMR parameters and the plastic zone radius formed before the crack tip may help develop an innovative tool for crack growth monitoring. The interrelation between the EMR energy release rate and the Elastic strain energy release rate may help create an innovative method for assessing fracture toughness, a fundamental property of metallic materials. The EMR energy release rate exhibited a parabolic relationship with an analytical correlation of stacking fault energy. Field emission scanning electron microscopy (FESEM) examined the fractured specimen's microstructure. A thorough examination of the relationship between dislocations, EMR characteristics, and real-time applications could be a novel technique for understanding material behaviour in detail.

Design and Manufacturing of a Low-Cost Prosthetic Foot

Below-knee prosthetics are used to restore the functional activity and appearance of persons with lower limb amputation. This work attempted to design and manufacture a low-cost, novel, comfortable, lightweight, durable, and flexible smart below-knee foot prosthesis prototype. This prosthesis foot was designed according to the natural leg measurement of an adult male patient. The foot is composed of rigid PVC layers interspersed with elastic strips of PTFE, and the axis of the ankle joint is flexible and consists of metal layers and a composite of polymeric damping strips with different mechanical properties, making it flexible and allowing it to absorb shocks and store and release energy. The design, modeling, and simulation of the manufactured prosthetic foot were performed via the ANSYS 18.0 software and the finite element method (FEM), where a large number of parallel and oblique planes and sketches were created. This work included four adult patients weighing 50, 75, 90, and 120 kg with different walking cycles. The results show that the highest equivalent von Mises stress and total deformations for the prosthetic limb occur at the beginning of the walking step, while the highest equivalent elastic strains and strain energy release rates are observed at the end of the walking step, regardless of the weight. This prototype can satisfactorily perform the biomechanical functions of a natural human foot, and it can be produced in attractive sizes, models, and shapes to suit different levels of below-knee amputations for different ages and weights, especially for patients with limited income.

Stress-annealing induced quasistatic creep recovery in ZrCuAlNi metallic glass

The relationship between the structural relaxation of metallic glasses and their heterogeneous structure, characterized by a weakly bonded region and a strongly bonded region, remains ambiguous. Thus, our study aimed to explore the connection between the heterogeneous structure and structural relaxation by investigating the quasi-elastic and viscoelastic behavior of a Zr55Cu30Ni5Al10 metallic glass. Stress-annealing (SA) treatment was employed to retain elastic strain energy by subjecting the sample to constant stress and temperature. During the reheating of the SA-treated sample, we observed a unique shrinkage and elongation phenomenon in the glassy-solid region, known as creep recovery (CR). To qualitatively describe the mechanisms of elastic strain energy retention and release, we employed the Maxwell model, which accounts for the heterogeneous structure. The residual elastic strain energy was determined by the discrepancy in relaxation ability within the heterogeneous structure, and the shrinkage and elongation of the CR were associated with structural relaxation.

Acoustic Emission Sensor-Assisted Process Monitoring of Air Plasma-Sprayed Titanium Deposition

AbstractAcoustic emission is a sensing technique that offers the potential benefit for its use as an in situ monitoring tool for a wide range of manufacturing processes. This work attempts to highlight the robustness of using acoustic emission (AE) data for in-line process monitoring of the air plasma spray deposition technique. As part of this study, titanium powder was deposited under various conditions of robot speed, powder feed rates and the influence of these changes were investigated in the signature obtained from the AE analysis. The post-processed AE data showed sensitivity to these changes through variation in frequencies, power spectral densities and the cumulative energy that gets transmitted to the substrate during the spraying process. The AE signal sensitivity was found to be so robust that it picked up even the differences in the substrate conditions i.e., a substrate used for coating in an as received form vs a substrate that was grit blasted before spraying showed identifiable differences in the AE signature. An attempt to convert an AE signal to energy and then analyse the spraying process in light of the cumulative energy is an investigation first of its kind in this research, hitherto not seen in the literature. In light of the extensive experimental data gathered from the in-house deposition data, the influence of the release of elastic strain energy based on the particle states and the impact on the substrate has been discussed thoroughly. The interdependency of surface preparation, feed rate and the robotic gun scanning speed has been discussed in detail as well. Through the data presented in this study, we advocate the use of AE analysis to be a vital contributor and a welcome move towards digitalisation of the thermal spray process for in-process monitoring.

3D spatial fracture behavior of sandstone containing a surface flaw under uniaxial compression

Surface defects are prevalent in natural rock masses, and the newborn cracks that initiate from these defects and significantly affect structural stability usually extend in a three-dimensional (3D) manner. Hence, in this research, a series of uniaxial compression tests were conducted on sandstone specimens containing a surface flaw to examine the effect of nondimensional flaw depth (0, 0.3, 0.5 and 0.75) on the fracture behavior. The crack propagation process was monitored by digital image correlation (DIC) technique, and postmortem microscopic fracture morphology was measured using scanning electron microscope (SEM) method. In addition, the fracture energy evolution and stress intensity factors (SIFs) along the semi-elliptical flaw perimeter were discussed in detail to theoretically interpret the experimental phenomena. The results indicate that the strength decreased by 2.70%, 10.90% and 11.91% for nondimensional surface flaw depths of 0.3, 0.5 and 0.75, respectively, and elastic modulus exhibited a reduction of 3.71%, 10.69% and 3.21%, respectively. Full-field deformation contours demonstrate that crack paths in the front surface of the specimen were totally different from those in the back surface, but the failure pattern tended to be similar to that of specimens containing a penetrated flaw with the increasing flaw depth. The micro appearance of a typical fracture further reveals the complicated stress state (mixed I-II-III mode) under uniaxial compression. For a larger flaw depth, the proportion of releasable elastic strain energy in total input strain energy was improved, while the percentage of dissipated energy was reduced. Based on fracture mechanics, SIFs along the flaw periphery uncover the magnitude of KI, KII and KIII and further the type of initiation crack type. Finally, parametric analysis was carried out to investigate the effects of flaw length and specimen thickness. The difference in crack pattern from surface and penetrated flaw was also discussed in detail.

Energy evolution characteristics of engineered cementitious composites (ECC) under tensile and compressive loading

To more truly reflect the failure law of engineered cementitious composites (ECC), this research investigates the multiple cracking and failure process of ECC from the perspective of energy and reveals the energy evolution characteristics of this process. The mechanical properties and energy evolution characteristics of ECC under different water-binder ratios were studied by uniaxial compression test. The effects of water-binder ratios, fiber volume fractions, and fiber aspect ratio on the tensile properties, energy evolution characteristics, and fracture energy of ECC were systematically investigated. It was found that the increase in the water-binder ratios decreases the compressive strength and elastic strain energy release rate, but increases the dissipated energy. The increase of fiber volume fraction and fiber aspect ratio can effectively improve the tensile properties, elastic strain energy, dissipated energy, and fracture energy. The abrupt change in the elastic energy consumption ratio can be used as a criterion for ECC failure.

Bursting Liability Criteria of Coal Mass Based on Energy Storage and Release Characteristics.

The bursting liability of coal, referring to the characteristic of coal to accumulate strain energy and produce impact damage, is an important factor influencing the occurrence and extent of rock burst disasters in coal mines. Two indicators-the elastic strain energy storage coefficient and energy release coefficient-are proposed based on the energy evolution characteristics of different stages during rock bursts. Twelve coal specimens from typical mines were selected for uniaxial compressive tests to analyze the damage characteristics of three types of typical coal specimens with different impact damage intensities in different loading stages. The initial kinetic energy of the coal specimens was obtained according to the principle of horizontal projectile motion. The bursting liability rating criteria according to the energy storage coefficient and energy release coefficient were determined based on the damage and motion characteristics of the coal mass, damage acoustic characteristics, and damage initial kinetic energy. The study demonstrated that the discrimination results based on the new criteria of coal mass bursting liability were consistent with the actual bursting liability level of the coal mass, thus providing a new method for determining coal mass bursting liability.

High-Throughput Screening and Prediction of High Modulus of Resilience Polymers Using Explainable Machine Learning.

The ability to store and release elastic strain energy, as well as mechanical strength, are crucial factors in both natural and man-made mechanical systems. The modulus of resilience (R) indicates a material's capacity to absorb and release elastic strain energy, with the yield strength (σy) and Young's modulus (E) as R = σy2/(2E) for linear elastic solids. To improve the R in linear elastic solids, a high σy and low E combination in materials is sought after. However, achieving this combination is a significant challenge as both properties typically increase together. To address this challenge, we propose a computational method to quickly identify polymers with a high modulus of resilience using machine learning (ML) and validate the predictions through high-fidelity molecular dynamics (MD) simulations. Our approach commences by training single-task ML models, multitask ML models, and Evidential Deep Learning models to forecast the mechanical properties of polymers based on experimentally reported values. Utilizing explainable ML models, we were able to determine the critical substructures that significantly impact the mechanical properties of polymers, such as E and σy. This information can be utilized to create and develop new polymers with improved mechanical characteristics. Our single-task and multitask ML models can predict the properties of 12 854 real polymers and 8 million hypothetical polyimides and uncover 10 new real polymers and 10 hypothetical polyimides with exceptional modulus of resilience. The improved modulus of resilience of these novel polymers was validated through MD simulations. Our method efficiently speeds up the discovery of high-performing polymers using ML predictions and MD validation and can be applied to other polymer material discovery challenges, such as polymer membranes, dielectric polymers, and more.

Study on the Effects of Different Water Content Rates on the Strength and Brittle Plasticity of Limestone

Water can deteriorate the compositional properties of rock through softening and dissolution. The water content rate of rock has a certain effect and can cause changes in rock properties caused by the water action. In this research, to study the effects of the water content rate on the strength and brittle plasticity of limestone, uniaxial compression tests with different water content rate states were conducted, and the form of limestone damage under different water content rate conditions was analyzed. The effects of the different water content rates on the modulus of elasticity, uniaxial compressive strength, brittleness index B value, and brittleness correction index BIM value (BIM: the ratio of dissipated strain energy to releasable elastic strain energy at the peak point of the specimen) of limestone were investigated. It was found that as the rate of water content in the limestone increased from 0% to 0.27%, the penetration shear surface on the limestone’s damaged surface decreased. The modulus of elasticity decreased from 8.85 to 6.76 GPa, the uniaxial compressive strength decreased from 74.11 to 57.60 MPa, the brittleness index B value decreased from 1.17 to 1.04, and the brittleness correction index BIM value increased from 0.09 to 0.26. As the rate of water content on the limestone increased, the rock’s modulus of elasticity and uniaxial compressive strength decreased. Additionally, the rock’s brittleness decreased, and the percentage of plastic deformation in the total deformation increased.

Latch Applicator for Efficient Delivery of Dissolving Microneedles Based on Rapid Release of Elastic Strain Energy by Thumb Force (Adv. Funct. Mater. 11/2023)

Latch Applicator In article number 2210805, Hyungil Jung and co-workers develop a novel applicator that enables efficient skin insertion of dissolving microneedle patches with optimized force and velocity. It is cost-competitive with simple components and easy to use with the thumb-force operation. Using a model antigen, they show that the microneedle and applicator system can produce significantly higher antibodies than intramuscular injection.

Simulation Research on Energy Evolution and Supply Law of Rock–Coal System under the Influence of Stiffness

The energy supply effect caused by the stiffness difference between roofs and sidewalls is an important factor that induces strain coal bursts. In order to quantitatively reveal the energy supply mechanism of strain coal bursts, this paper first establishes a coal burst energy model of the rock–coal system and proposes the calculation formula of coal burst kinetic energy considering supply energy and the stiffness ratio of rock to coal. Then the whole energy evolution law of the rock–coal system with different stiffness ratios is researched by using the numerical simulation method, and the whole process is divided into three stages. With the decrease in the stiffness ratio, the elastic strain energy of the coal changes little, while its kinetic energy is negatively correlated with the stiffness ratio in a power function. Meanwhile, the elastic strain energy and kinetic energy of the rock have power function relations with the stiffness ratio, too. When the rock–coal system is fractured, the kinetic energy of the coal comes from the release of elastic strain energy from the coal and the energy supplied from the rock. The energy supply rate is between 22% and 35% when the stiffness ratio changes from 3.0 to 0.5, and they show a linear relationship, while the supplied energy has a negative power function relationship with the stiffness ratio.

Latch Applicator for Efficient Delivery of Dissolving Microneedles Based on Rapid Release of Elastic Strain Energy by Thumb Force

AbstractDissolving microneedle (DMN) is an attractive alternative to parenteral and enteral drug administration owing to its painless self‐administration and safety due to non‐generation of medical waste. For reproducible and efficient DMN administration, various DMN application methods, such as weights, springs, and electromagnetic devices, have been studied. However, these applicators have complex structures that are complicated to use and high production costs. In this study, a latch applicator that consists of only simple plastic parts and operates via thumb force without any external complex device is developed. Protrusion‐shaped latches and impact distances are designed to accumulate thumb force energy through elastic deformation and to control impact velocity. The optimized latch applicator with a pressing force of 25 N and an impact velocity of 5.9 m s−1 fully inserts the drug‐loaded tip of the two‐layered DMN into the skin. In an ovalbumin immunization test, DMN with the latch applicator shows a significantly higher IgG antibody production rate than that of intramuscular injection. The latch applicator, which provides effective DMN insertion and a competitive price compared with conventional syringes, has great potential to improve delivery of drugs, including vaccines.

Mechanical properties and damage constitutive model of coal specimen with different moisture under uniaxial loading

The moisture content has an important influence on the strength and stability of coal pillar dams in underground reservoirs. In this paper, the uniaxial compression test was performed on coal samples with three different moisture contents, to study the mechanical properties of them under water intrusion condition. The results show that, water has a significant damaging and softening effect on the mechanical properties of the samples. As the moisture content grows of coal samples, the peak strength and elastic modulus fall exponentially while the peak strain increases exponentially. In addition, the energy characteristics of coal samples with different moisture contents under uniaxial compression were analyzed. The releasable elastic strain energy, dissipated energy and total input energy all experience a decline with water content, and the proportion of the releasable strain energy in the total energy drops. The capacities of energy storage and strain energy release of coal samples both fall under influence of moisture, and more energy was transformed. Given this result, the damage variable on the basis of energy dissipation was introduced to explore the influence of moisture contents on the damage variable of coal samples and the damage evolution equations of coal samples with three different moisture contents were calculated from the results of uniaxial loading tests. Finally, the compaction coefficient considering the influence of immersion time was proposed to describe the compaction degree and being used to amend the damage constitutive model obtained, and the fitted results of the models were compared to experimental data. Results show that the values of damage variables increase exponentially with strains, and the modified damage constitutive equation can give a more accurate description of the compressive deformation of coal samples that contain varying contents of moisture.

On the fracture behavior of cortical bone microstructure: The effects of morphology and material characteristics of bone structural components

Bone encompasses a complex arrangement of materials at different length scales, which endows it with a range of mechanical, chemical, and biological capabilities. Changes in the microstructure and characteristics of the material, as well as the accumulation of microcracks, affect the bone fracture properties. In this study, two-dimensional finite element models of the microstructure of cortical bone were considered. The eXtended Finite Element Method (XFEM) developed by Abaqus software was used for the analysis of the microcrack propagation in the model as well as for local sensitivity analysis. The stress–strain behavior obtained for the different introduced models was substantially different, confirming the importance of bone tissue microstructure for its failure behavior. Considering the role of interfaces, the results highlighted the effect of cement lines on the crack deflection path and global fracture behavior of the bone microstructure. Furthermore, bone micromorphology and areal fraction of cortical bone tissue components such as osteons, cement lines, and pores affected the bone fracture behavior; specifically, pores altered the crack propagation path since increasing porosity reduced the maximum stress needed to start crack propagation. Therefore, cement line structure, mineralization, and areal fraction are important parameters in bone fracture.The parameter-wise sensitivity analysis demonstrated that areal fraction and strain energy release rate had the greatest and the lowest effect on ultimate strength, respectively. Furthermore, the component-wise sensitivity analysis revealed that for the areal fraction parameter, pores had the greatest effect on ultimate strength, whereas for the other parameters such as elastic modulus and strain energy release rate, cement lines had the most important effect on the ultimate strength. In conclusion, the finding of the current study can help to predict the fracture mechanisms in bone by taking the morphological and material properties of its microstructure into account.

The relationship between storage-dissipation-release of coal energy and intensity of induced charge

Using uniaxial compression experiments, the evolution characteristics between energy and induced charge in each stage of coal deformation and failure are studied. Further, the relationship of energy conversion in the process of coal failure is analyzed. The calculation methods of energy storage, dissipation, and release of coal are proposed. The relationships between induced charge intensity and factors, including storage of elastic strain energy, increment of elastic strain energy, increment of dissipated energy, released energy, accumulated dissipated-released energy, are studied. A theoretical model of induced charge based on dissipated energy and released energy is established. The monitoring test of induced charge under the mine is conduced. The results show that the induced charge intensity is not related to the accumulation of elastic strain energy, but positively correlated to the dissipation and release of elastic strain energy. The induced charge intensity is not significantly correlated with the cumulative dissipated-released energy, but is significantly correlated with the slope of the cumulative dissipated-released energy curve and its variations. Especially when the escalation effect shows, the induced charge intensity accordingly increases in an abrupt manner. When the increment of dissipated energy rises to a certain degree, the intensity of induced charge suddenly increases. When the released energy suddenly increases, if the major part converts into the kinetic energy of coal chips and particles, a violent ejection phenomenon occurs, the induced charge intensity suddenly increases. The induced charge intensity is positively correlated with the increment of dissipated energy and the sudden increase of released energy. The higher the stress concentration degree and the greater the influence of mining for coal-rock, the larger amount of energy is dissipated and released, and thus the greater intensity of induced charge is monitored. The study can provide a theoretical basis for the monitoring and early warning of coal-rock dynamic disaster.

Muscle preactivation and the limits of muscle power output during jumping in the Cuban tree frog Osteopilus septentrionalis.

Previous studies of jumping in frogs have found power outputs in excess of what is possible from direct application of muscle power and concluded that jumping requires the storage and release of elastic strain energy. Of course, the muscles must produce the work required and their power output should be consistent with known muscle properties if the total duration of muscle activity is known. Using the Cuban tree frog, Osteopilus septentrionalis, I measured jumping performance from kinematics and used EMG measurements of three major jumping muscles to determine the duration of muscle activity. Using the total mass of all the hindlimb muscles, muscle mass-specific work output up to 60 J kg-1 was recorded. Distributed over the duration of the jump, both average and peak muscle mass-specific power output increased approximately linearly with the work done, reaching values of over 750 and 2000 W kg-1, respectively. However, the muscles were activated before the jump started. Both preactivation duration and EMG amplitude increased with increasing amounts of work performed. Assuming the muscles could produce work from EMG onset until toe-off, the average muscle mass-specific power over this longer interval also increased with work done, but only up to a work output of 36 J kg-1. The mean power above this value of work was 281 W kg-1, which is approximately 65% of the estimated maximum isotonic power. Several reasons are put forward for suggesting this power output, although within the known properties of the muscles, is nevertheless an impressive achievement.

Experimental and Numerical Investigation of Energy Evolution Characteristic of Granite considering the Loading Rate Effect

In order to investigate the loading rate effect of energy evolution in granite, the indoor physical simulation test of single face fast unloading-three directions and five faces stress-vertical continuous loading under different loading rates was conducted using a new true triaxial rockbursttest system. The energy accumulation-dissipation-release characteristics in the process of rock deformation and failure were revealed. Based on the three-dimensional discrete element theory and the polycrystalline modeling technique (randomly generated Voronoi mineral grains), the entire process of rockburst inoculation-occurrence-development, as well as the energy evolution characteristics under true triaxial single face unloading conditions, were studied. The test results indicate that the energy transport and conversion of rock samples under different loading rates exhibit distinct stage characteristics. It can be divided into the initial energy accumulation stage, steady energy accumulation stage, rapid energy dissipation stage, and rapid energy release stage. With a rise in loading rate, the specimen in the process of energy accumulation is accompanied by energy dissipation, more external input energy, and elastic strain energy release amount into the kinetic energy of fragments, resulting in the rockburst phenomenon. As the loading rate increases, the elastic strain energy conversion rate (Ue/U) falls, while the dissipative energy conversion rate (Ud/U) increases. The higher the elastic strain energy conversion rate and the lower the dissipative energy conversion rate, the more serious the rockburst occurs. Numerical simulation results show that the entire process of rockburst inoculation-occurrence-development is successfully simulated using the crystal scale fine model (CSFM) considering the grain mineral composition. The ejection failure process can be divided into four stages, including grains ejection, rock spalling into plates, rock shearing into fragments, and rock fragments ejection. The relationships between the peak strength, elastic strain energy of rock samples, and loading rates are obtained, which is consistent with the laboratory test results. The high rate linear growth of kinetic energy evolution between the two inflection points can provide precursor information for rockburst prediction.