Split Hopkinson Tension Bar Research Articles

Dynamic mechanical properties and uni-axial constitutive model of S30408 stainless steel

This paper investigates its mechanical properties at different strain rates and the uni-axial constitutive model of S30408 (S30408 known as 1.4301 in EN10088:1, 304 in ASTM standard) stainless steel. Firstly, the tensile and compressive mechanical properties of S30408 stainless steel were tested at four strain rates (0.001 s−1, 1000 s−1, 3000 s−1, 5000 s−1) by performing quasi-static tests as well as split Hopkinson tension bar (SHTB) and split Hopkinson pressure bar (SHPB) tests. Based on the tests, the stress-strain curves of S30408 stainless steel under tensile and compressive conditions at different strain rates were obtained. The results show that S30408 stainless steel revealed a significant strain rate strengthening effect, and there were some differences in the mechanical properties of S30408 stainless steel in tension and compression under different strain rates. Then based on these test results, a modified Johnson–Cook model was established under tensile and compression conditions. The accuracy of the proposed modified Johnson-Cook model was verified by the finite element software LS-DYNA. The modified model can provide a reference for the study of mechanical properties and computational simulation of S30408 stainless steel under high strain rate conditions such as impact and blast load.

Rate-Dependent Tensile Properties of Aluminum-Hydroxide-Enhanced Ethylene Propylene Diene Monomer Coatings for Solid Rocket Motors.

Quasi-static and dynamic tensile tests on aluminum-hydroxide-enhanced ethylene propylene diene monomer (EPDM) coatings were conducted using a universal testing machine and a Split Hopkinson Tension Bar (SHTB) over a strain rate range of 10-3 to 103 s-1. This comprehensive study explored the tensile performance of enhanced EPDM coatings in solid rocket motors. The results demonstrated a significant impact of strain rate on the mechanical properties of EPDM coatings. To capture the hyperelastic and viscoelastic characteristics of EPDM coatings at large strains, the Ogden hyperelastic model was used to replace the standard elastic component to develop an enhanced Zhu-Wang-Tang (ZWT) nonlinear viscoelastic constitutive model. The model parameters were fitted using a particle swarm optimization (PSO) algorithm. The improved constitutive model's predictions closely matched the experimental data, accurately capturing stress-strain responses and inflection points. It effectively predicts the tensile behavior of aluminum-hydroxide-enhanced EPDM coatings within a 20% strain range and a wide strain rate range.

Experimental and numerical study on the loading rate dependent tensile behavior of carbon fiber/epoxy interface

A series of experiments and simulations were performed to explore the effect of loading rate on the tensile behavior of carbon fiber/epoxy composite interface via the fiber bundle tensile method. Varying velocities were used to test the stress‒time and stress‒displacement curves of the samples, and a high-speed camera was used to study the in situ failure behavior of the carbon fiber/epoxy interface. Increasing the loading rate from 5 × 10−6 m/s to 12.0 m/s leds to an increase in the interfacial tensile strength from 6.1 ± 0.9 MPa to 16.4 ± 0.3 MPa, an increase in the interfacial stiffness from 1.58 ± 0.3 N/m to 17.4 ± 3.1 N/m, and a decrease in the fracture displacement from 0.23 ± 0.03 mm to 0.10 ± 0.01 mm. Optical microscopy analysis revealed rougher crack surfaces at higher loading rates. The fracture mode of interface transitioned from fiber breakage and pull-out to brittle matrix cracking with increasing loading rate. The finite element method was employed to verify the effectiveness of the fiber bundle tensile method with a split Hopkinson tension bar and study the failure behavior of the interface under dynamic loading. The simulation results showed that the calculated failure stress was 20 % lower than the actual value, and the cohesive layer was found to have greater stress at the edge region. This investigation deepens the understanding of the effects of the loading rate on the interfacial tensile behaviors of carbon fiber/epoxy composites.

Tensile properties at various strain rates of flexible carbon nanotube film densified by the combination of chlorosulfuric acid and uniaxial drawing

AbstractThe quasi‐static tensile properties of carbon nanotube (CNT) films have been extensively investigated, yet research on their impact tensile properties at high strain rates remains scarce. In this article, CNT films prepared by floating catalyst chemical vapor deposition (FCCVD) method were densely arranged by chlorosulfuric acid (CSA) under wet stretching. The Instron 3365 and miniaturized split Hopkinson tension bar (SHTB) were used to conduct tensile testing at different strain rates. The findings reveal that CSA wet‐stretching markedly enhances the density and orientation of CNT films, resulting in significant improvements in tensile properties with a notable strain rate effect. Specifically, when immersed for 60 s under a draft ratio of 40% and a strain rate of 1900 s−1, the densified CNT films exhibit maximum stress and energy absorption values of 777.44 MPa and 54.79 MJ/m3, respectively, achieving a 637.1% and 425.7% increase compared with the original film. This research provides a convenient and feasible strategy to prepare CNT films with high energy absorption tolerance across various strain rates, thus expanding the practical application potential of CNT films.Highlights The study innovates a posttreatment way to produce superior FCCVD CNT films. CSA treatment and wet stretching enhance CNT films' mechanical properties. Dynamic fracture strength boosts over 600% and energy absorption raises over 400%. CSA can purify FCCVD‐prepared CNT films, greatly improving their properties. The Prep can be effectively integrated with the direct spinning process.

Experimental study on dynamic direct tensile performances of steel fiber-reinforced RPC at high strain rates

Reactive power concrete (RPC) exhibits excellent mechanical properties, makes it great potential for applications. RPC has gained increasing attention in academic and engineering areas and has been used in fields such as anti-explosion engineering. The insufficient tensile strength of RPC is one of the critical reasons for its structural failure. Existing studies revealed that the strain rate effect of concrete under dynamic tension is stronger than that under dynamic compression. The existing research focuses either on dynamic splitting and spalling tests, or dynamic uniaxial tensile properties with a strain rate of 0–100/s, neither of which are representative of the effect of RPC subject to explosion. In addition, the study of the dynamic uniaxial tensile constitutive model of RPC has not been reported in the existing research. To solve the existing limitations, this study conducted dynamic direct tension tests on steel fiber-reinforced RPC with a predefined strain rate higher than 100 s−1 using a Split Hopkinson Tension Bar (SHTB) apparatus. RPC dumbbell-shaped samples, including plain RPC and steel fiber-reinforced RPC (SFRPC) with 1 % and 2 % fiber volumetric fractions, were tested at high strain rates of 98–528 s−1. Based on the test results of this study and those derived from existing publications, the relationship between dynamic direct tensile properties, steel fiber fraction, and strain rate was quantitatively analyzed, and corresponding empirical formulae were proposed. To meet the demand for numerical analysis on RPC structures subjected to explosive forces, a dynamic tensile stress-strain model for steel fiber-reinforced RPC considering steel fiber, strain rate, and dynamic toughness, was established.

Strain rate and temperature rate behavior of ultra-high-strength 1770 steel: Base for transverse impact analysis

The investigation was motivated by the widespread use of ultra-high-strength steels in cable-stayed bridges and armor steel plates. These structures are exposed to elevated risks from extreme loads, including vehicle impacts and blast loadings. The study aimed to investigate the mechanical properties of 1770 steel for applications in extreme conditions. The strain rates and temperatures ranged from 0.00095 s−1 to 1303 s−1 and 20 °C–900 °C, respectively. Tensile tests were conducted at various strain rates using a Split Hopkinson Tension Bar for dynamic testing and a universal testing machine for quasi-static testing at room temperature (20 °C). Quasi-static tension at elevated temperatures was carried out using an electromechanical testing machine coupled with a heating device. A uniform temperature distribution inside the specimens was ensured by a 30-min holding time. The results of the tensile test indicate that the 1770 steel displays notable thermal softening effects and strain rate hardening that differ from mild steel. The standard Johnson-Cook (J-C) model was found to be inadequate in accurately predicting the strain rate effects of this specimen. To address this issue, the strain rate parameter C in the standard model was adjusted to create the modified J-C model, which demonstrated good agreement with the experimental results. To further demonstrate the modified model and the identified parameters, drop hammer impact tests and corresponding numerical simulations were conducted. The impact test and numerical simulation results showed good agreement in terms of deformation and contact force. The mechanical properties and the constitutive models can serve as a design reference for the ultra-high-strength 1770 steel in extreme envirnments, as well as a theoretical basis for fitting material models of similar ultra-high-strength steels.

Tensile and Interfacial Mechanical Properties for Single Aramid III Fibers under Dynamic Loading.

In this study, the traditional mini split Hopkinson tension bar (SHTB) was enhanced for the dynamic mechanical performance testing of single fiber/resin interface of composites. Single Aramid III fibers were modified using a polyamine modification treatment. Quasi-static and dynamic tensile tests of modified single Aramid III fibers were conducted using an electronic tensile testing machine and mini SHTB. The test results indicated that the surface modification employing the Catechol-Tetraethylenepentamine (Cat-TEPA) approach had a negligible effect on the tensile mechanical properties of single Aramid III fibers. The microdroplet method was introduced to measure the dynamic interfacial shear strength (IFSS) of Aramid III fiber/waterborne polyurethane resin using a mini SHTB. The dynamic shear test results revealed an increase in the dynamic shear strength of the modified Aramid III fiber/resin interface from 36.16 MPa to 41.51 MPa. Furthermore, the Scanning Electron Microscope (SEM) photography of the modified single Aramid III fiber after debonding exhibited regular grid structures on the debonding area, which can prevent debonding between the single fiber and the microdroplet, thereby enhancing interfacial shear performance.

Mechanical properties and deformation mechanisms of C-doped interstitial high-entropy alloy CrMnFeCoNi: Effects of strain rate and C content

The effects of strain rate on mechanical properties, microstructural evolution and underlying deformation mechanisms of two kinds of interstitial CrMnFeCoNi high entropy alloys (HEAs), (CrMnFeCoNi)99.5C0.5 and (CrMnFeCoNi)99.0C1.0, are investigated under quasi-static and dynamic tension. Dynamic loading is carried out via a split Hopkinson tension bar system. The pre- and post-deformation microstructures are characterized with electron back scatter diffraction and transmission electron microscopy. Both yield strength and work hardening increase remarkably with increasing strain rate. Plastic deformation in both alloys under quasi-static and dynamic loading are dominated by dislocations, stacking faults, kink bands and deformation twins. Twinning is activated easier under dynamic loading, and twin density decreases with increasing carbon content due to the increased stacking fault energy. The Khan-Liu constitutive model can describe the experimental results for these two interstitial HEAs in a wide strain range.

The Effects of Strain Rate and Anisotropy on the Formability and Mechanical Behaviour of Aluminium Alloy 2024-T3

The present study focuses on the mechanical behaviour and formability of the aluminium alloy 2024-T3 in sheet form with a thickness of 0.8 mm. For this purpose, tensile tests at quasi-static and intermediate strain rates were performed using a universal testing machine, and high strain rate experiments were performed using a split Hopkinson tension bar (SHTB) facility. The material’s anisotropy was investigated by considering seven different specimen orientations relative to the rolling direction. Digital image correlation (DIC) was used to measure specimen deformation. Based on the true stress–strain curves, the alloy exhibited negative strain rate sensitivity (NSRS). Dynamic strain aging (DSA) was investigated as a possible cause. However, neither the strain distribution nor the stress–strain curves gave further indications of the occurrence of DSA. A higher deformation capacity was observed in the high strain rate experiments. The alloy displayed anisotropic mechanical properties. Values of the Lankford coefficient lower than 1, more specifically, varying between 0.45 and 0.87 depending on specimen orientations and strain rate, were found. The hardening exponent was not significantly dependent on specimen orientation and only moderately affected by strain rate. An average value of 0.183 was observed for specimens tested at a quasi-static strain rate. Scanning electron microscopy (SEM) revealed a typical ductile fracture morphology with fine dimples. Dimple sizes were hardly affected by specimen orientation and strain rate.

Dynamic mechanical properties and constitutive model establishment of QSTE420 steel

The uniaxial tensile tests of QSTE420 steel under different strain rates were carried out using an electronic universal material testing machine, a high-speed tensile testing machine and a split Hopkinson tension bar (SHTB) device, the engineering stress-strain curves of steel within the range of 0.001– 1000 s−1 were obtained and the mechanical properties of steel at different strain rates were analyzed. The results show that in the static strain rate range of 10−3– 10−2 s−1, the yield strength and tensile strength of QSTE420 steel exhibit minimal variation, fluctuating between 430– 434 MPa and 507– 515 MPa, respectively; while the uniform elongation and elongation at break remain approximately at 12% and 35%, respectively. In the high strain rate range of 10−1– 103 s−1, both yield strength and tensile strength exhibit a consistent increase in direct correlation with the tensile rate. Specifically, the yield strength increases from 444 to 607 MPa and the tensile strength increases from 523 to 640 MPa as the strain rate escalates from 10−1 to 103 s−1. Moreover, the elongation at break demonstrates a general increasing trend and reaches its peak value of 45.65% at 100 s−1. The morphology of fracture surfaces under different strain rates are observed by Scanning Electron Microscopy (SEM). The fracture appearance analysis reveals numerous dimples in the fracture, indicating a ductile fracture. Furthermore, the comparison demonstrates that steel exhibits enhanced plasticity at a strain rate of 100 s−1. Based on the experimental results, the Johnson-Cook constitutive model was established and modified. The modified Johnson-Cook model exhibits a higher determination coefficient (R2) compared to the original version, signifying an improved fitting accuracy.

Dynamic Response of Ductile Materials from Split Hopkinson Tension Bar Tests

Dynamic Response of Ductile Materials from Split Hopkinson Tension Bar Tests

Direct tensile mechanical properties and damage fracture mechanisms of thermally damaged coal measures sandstone under high strain rate loading

The direct tensile mechanical properties of highly thermally damaged rock under high strain rate loads are a key basic mechanical problem that must be solved for the stability and effective control of surrounding rock stability in the combustion control area of an underground coal gasification project. In this paper, a two-dimensional equivalent grain-based model (GBM) unit and Split Hopkinson Tension Bar (SHTB) numerical model for thermally damaged coal-measures sandstone were constructed using particle flow code (PFC). The comparison with the experimental results shows that the numerical method can accurately describe the dynamic direct tensile behavior of thermally damaged sandstone. The following conclusions are drawn: The dynamic tensile strength of thermally damaged sandstone shows a significant strain rate-strengthening effect. With the increase in thermal damage temperature, the dynamic tensile strength of sandstone increases first and then decreases. The generation and development of hot cracks in a high-temperature environment is the fundamental reason for the change in macroscopic mechanical properties. The dynamic tensile failure process of thermally damaged sandstone can be divided into four stages: the dynamic damage initiation, the dynamic damage development, the damage crack penetration, and the sample dynamic fracture. With the increase in impact velocity, the initial kinetic energy, elastic strain energy, dissipated energy, and elastic strain energy ratio in the failure process of thermally damaged sandstone gradually increase. In contrast, the dissipated energy ratio gradually decreases. As the heat treatment temperature increases, the elastic strain energy and the ratio of elastic strain energy increase first and then decrease.

Dynamic tensile mechanical properties of thermally damaged sandstone under impact loads and the influence mechanism of composition

The stability of surrounding rock in the combustion void is the key to continuous, safe, and efficient gas production in an underground coal gasification project. The key factors influencing the stability of surrounding rock in the combustion void are high temperature and impact dynamic load. At the same time, rock structure failure mainly depends on the rock materials’ tensile strength. Therefore, it is fundamental to study the dynamic tensile mechanical properties of thermally damaged rocks to control the surrounding rock stability of the combustion void in UCG projects. This paper used the coal measures as the research object. The dynamic direct tensile test of thermally damaged sandstone was carried out using a high-temperature load system and split Hopkinson tension bar (SHTB) test system. The test results showed that the dynamic tensile strength of sandstone increased linearly with the increase in strain rate. In contrast, it increased first and then decreased with temperature. In addition, the nonlinear regression method was applied to establish the prediction model of dynamic tensile properties of thermally damaged sandstone. XRD analyzed the composition and mass fractions of sandstone. From the standpoint of composition change, the change mechanism of the mechanical properties of thermally damaged coal measured in sandstone was illustrated.

Direct assessment of the shear behavior of strain-hardening cement-based composites under quasi-static and impact loading: Influence of shear span and notch depth

Strain-hardening cement-based composites (SHCC) represent a new frontier for improving the resistance of concrete structures against highly dynamic loading regimes, e.g., in the case of impact. A novel testing device was designed to characterize the shear behavior of such pseudo-ductile cementitious composites, whose dynamic response is extremely complex. The newly developed shear testing device was adapted to investigate the performance of fiber-reinforced, cementitious composites under both quasi-static and impact regimes. In the framework of setup validation and standardization, this article focuses on the investigation of the shear behavior of SHCC specimens and spotlights the influence of two main experimental shear parameters: shear span and notch depth. The purpose-specific shear device was integrated into a hydraulic testing machine and a gravity Split-Hopkinson tension bar (SHTB) for quasi-static and impact shear experiments, respectively. Shear spans of 2 mm and 5 mm were introduced by modifying the test setup. Furthermore, the specimens were shaped through sawn U-notches with varying depths of 3 mm, 5 mm, and 7 mm. The shear response of the SHCC specimens was monitored by means of Digital Image Correlation (DIC), which enabled the accurate derivation of strain fields, cracking behavior, and fracture modes on the specimen surface. The results showed that both shear span length and notch depth regulate the shear/tension fracture propagation. With an appropriate shear specimen shape, the desired dominant shear fracture could be obtained.

Flow behaviour of Ti-6Al-4V alloy in a wide range of strain rates and temperatures under tensile, compressive and flexural loads

The design and analysis of lightweight structures subjected to impact loads require detailed understanding of impact phenomena, and dynamic responses of the selected materials for their safety and reliability. Titanium alloys are in demand for such structures due to high strength to weight ratio, high toughness, and the ability to withstand extreme temperatures. Therefore, this paper investigates the flow behaviour of the titanium alloy Ti-6Al-4V under tensile, compressive and flexural loads at different strain rates and temperatures. Quasi-static tests are performed under tension and compression at strain rates 0.0001–0.1 s−1 while flexural (three-point bending) tests at crosshead speeds 1–100 mm/min are conducted for 90–150 mm span lengths with varying specimen orientations (flat and transverse) on electromechanical universal testing machine (UTM) at room temperature 25 °C. High temperature (300–700 °C) experiments are performed on this UTM under tensile strain rate 0.001s−1 where, the effects of soaking time (5–25 min) and heating rate (10–50 °C/min) are studied. Superplastic behaviour of the alloy is observed at temperature 700 °C with maximum engineering strain nearly 200%. High strain rate experiments on split Hopkinson tension bar (SHTB) and split Hopkinson pressure bar (SHPB) setups are conducted under tension with strain rates 850–1150 s−1, and compression with strain rates 1100–2300 s−1, respectively at room temperature. Ductility and toughness (energy dissipation) are determined at different loading rates. The dependency of the material properties is observed on specimen geometry. Fractography analysis is done for fractured tensile specimens by scanning electron microscope (SEM), and thereafter, existing Cowper-Symonds (CS) and Johnson-Cook (JC) material models are evaluated for the alloy based on the experimental data obtained at different loading conditions.

Thermal softening behavior up to fracture initiation during high-rate deformation

This work proposes an innovative method to analyze the softening behavior due to adiabatic heat up to the fracture onset during high-rate deformation of AISI4340 steel at room temperature. To derive the rate- and temperature-dependent constitutive equation considering the post-necking behavior, uniaxial (UT) and notched tension (NT) specimens were tested at three strain rates of 10-3/s, 100/s and 103/s. The full fields of strain and temperature were measured until fracture initiation with high-speed digital and thermal imaging cameras, respectively. In particular, this research focused on observing the abrupt localized temperature increase in the post-necking phase, which was achieved through the use of a newly configured split Hopkinson tension bar (SHTB) system. It enabled an experimental investigation of the effect of adiabatic heat on localized behavior up to fracture at high strain rates (103/s). As the strain rate increased, the strain-localization occurred more quickly, and a higher temperature was experimentally observed at the location where fracture initiated. The experimentally measured thermal field was newly utilized for inverse optimization, to determine the thermal softening effect of the constitutive model considering adiabatic heat up to the onset of fracture including post-necking. Finally, a hybrid experimental-numerical approach was used to investigate the physical quantities of local strain, strain rate, temperature inside the specimen where fracture actually began.

Effects of large strain reverse loading on the strain rate dependence and dynamic strain localization of ductile metallic rods

The dynamic necking of ductile metallic rods with large strain reverse loading history has received little attention in the published literature. A novel bespoke real time strain control setup is constructed to apply the reverse loading directly to the specimen gauge section up to a maximum strain level of ± 0.16. 304L stainless steel is used as a model material in this study. The subsequent tensile tests of the reverse loaded specimens are performed from quasi-static to high strain rates of 1000/s, using a Zwick 050 Machine, hydraulic Instron 8854, and a bespoke split Hopkinson tension bar with high speed photography equipment. The initial flow stress of the 304L rods shows similar strain rate dependence, regardless of the reverse loading history. The local strain rate during strain localization increases dramatically and eventually reaches one order of magnitude higher than the nominal strain rate. A higher strain reverse loading significantly influences the development of necking instabilities, with smaller strain to necking inception, higher local stress in the necking zone, and higher local strain rate up to failure. Instead of evaluating the impact energy absorption up to necking, an analysis of the local stress–strain relationship indicates that the reverse loaded 304L shows good impact energy absorption up to failure. This agrees with the ductile fracture surfaces of the 304L materials with reverse loading.

Static and dynamic mechanical properties of carbon fiber reinforced polymer with different stacking sequences

With the wide application of carbon fiber reinforced polymer (CFRP) composites, dynamic loading cases are increasingly considered in structural design and analysis. Hence, it is necessary to investigate their dynamic mechanical properties. In this paper, the carbon/epoxy laminates with different stacking sequences prepared by vacuum assisted resin infusion process were studied by quasi-static tension and split Hopkinson tension bar experiments. The loading strain rate is ranged from 2.2 × 10−4 s−1 to 2200 s−1. The results indicate that the composites are strain rate dependent. Four stacking sequence laminates show different strain rate sensitivities, and their mechanical performance differences depend on the strain rate. As the strain rate increases, tensile strength and elastic modulus increase, but failure strain decreases. Therein, the elastic modulus is highly sensitive. The elastic modulus difference of unidirection/cross-ply or unidirection/quasi-isotropic decreases but that of unidirection/angle-ply increases with increasing strain rate. The failure strain difference of unidirection/angle-ply decreases significantly with increasing strain rate. These experimental data and research results could provide some insight for epoxy matrix CFRPs.

Influence of Strain History on Dynamic Strain Localization and Stress State During High-Rate Tensile Loading of Titanium Alloys: Experiments, Modeling, and Analytical Methods

Abstract The determination of the mechanical response of engineering materials subjected to high loading rates plays an important role in determining their performance and application. The high strain-rate tensile response of metals is usually investigated by means of the split-Hopkinson tension bar (SHTB) apparatus. The interpretation of the obtained results is, however, subjected to analogous stress and strain uniformity challenges present during quasi-static tensile experiments. Beyond the onset of necking, strains cease to be uniform along the gauge length and localize around the necking zone. Consequently, the nominal strain rate underestimates the effective strain rate experienced by the material. The analysis of the effective strain rate and stress state beyond the onset of necking has received considerable attention in the literature. Several research efforts have focused on the optimization of the geometry of specimens to be employed for the characterization of the dynamic tensile response using the SHTB. The present work investigates, systematically, the effects of strain history and adiabatic heating on the stress state during dynamic loading. A series of monotonic and various strain history experiments were conducted and analyzed. The diameter evolution, effective strain rate, and temperature histories were measured for all conducted experiments. Numerical simulations were carried out to examine the stress state during strain localization and to accurately reproduce engineering and local thermos-mechanical variables. The effectiveness of existing postnecking corrections for high-rate experiments is assessed. A modified postnecking correlation taking into account the effects of adiabatically induced thermal softening is proposed.

An experimental investigation on fatigue characteristics of granite under repeated dynamic tensions

Rock engineering is prone to fatigue failure under cyclic disturbances caused by repeated dynamic loadings such as earthquakes, blasting and impacts. These cyclic dynamic loadings could be tensile under repeated implosions , excavation induced unloading and reflection of compressive waves at free surfaces or interfaces. However, compared with cyclic dynamic compression, the rock fatigue characteristics under cyclic dynamic tension remain poorly understood. To investigate the dynamic tensile fatigue characteristics of rock, cyclic dynamic Brazilian tests and direct tension tests were conducted on granite using the split Hopkinson pressure bar and the split Hopkinson tension bar, respectively. The testing results showed that the peak stress of granite decreases, while the peak strain increases with increasing impact number under a given impact stress. The fatigue thresholds of granite in the cyclic dynamic Brazilian and direct tension tests are 0.71 and 0.49 times the critical impact stress, respectively, indicating that the rock is more prone to fatigue failure under dynamic direct tension. The total dissipated energy for fatigue failure of rock increases linearly with fatigue life. The damage accumulation features defined by energy dissipation and strain are distinct, and the damage calculated by strain can display nonlinear characteristics of damage evolution. In addition, with increasing impact stress, the failure surface roughness of the specimens in cyclic dynamic Brazilian tests increases, while that in direct tension tests decreases. The findings in this study could facilitate the understanding of rock fatigue characteristics and provide a basis for stability evaluation and disaster prevention in rock engineering.