Dynamic Compressive Properties Research Articles

Improved Dynamic Compressive and Electro-Thermal Properties of Hybrid Nanocomposite Visa Physical Modification

The current work studied the physical modification effects of non-covalent surfactant on the carbon-particle-filled nanocomposite. The selected surfactant named Triton™ X-100 was able to introduce the steric repelling force between the epoxy matrix and carbon fillers with the help of beneficial functional groups, improving their dispersibility and while maintaining the intrinsic conductivity of carbon particles. Subsequent results further demonstrated that the physically modified carbon nanotubes, together with graphene nanoplates, constructed an effective particulate network within the epoxy matrix, which simultaneously provided mechanical reinforcement and conductive improvement to the hybrid nanocomposite system. For example, the hybrid nanocomposite showed maximum enhancements of ~75.1% and ~82.5% for the quasi-static mode-I critical-stress-intensity factor and dynamic compressive strength, respectively, as compared to the neat epoxy counterpart. Additionally, the fine dispersion of modified fillers as a double-edged sword adversely influenced the electrical conductivity of the hybrid nanocomposite because of the decreased contact probability among particles. Even so, by adjusting the modified filler ratio, the conductivity of the hybrid nanocomposite went up to the maximum level of ~10-1-100 S/cm, endowing itself with excellent electro-thermal behavior.

Experimental and theoretical study of dynamic mechanical behavior of concrete subjected to triaxial confining and impact loads

Confining stress is a key factor affecting the dynamic mechanical behaviour of concrete. To explore the mechanism of triaxial confining stress on the dynamic compressive properties of concrete, a series of static–dynamic combined compression experiments were performed using three–dimensional Split Hopkinson Pressure Bar equipment. The results show that there is an obvious strain rate effect of concrete under triaxial confining conditions, which is closely associated with the static triaxial confining stress and strain rate of impact loads. The confining stress significantly affects the dynamic response stress (strain) and dynamic stress (strain) along the loading direction. Moreover, the effects would decrease with an increase in the dynamic loading strain rate. Obvious fractures will occur on the concrete surface when the effective dissipated energy ratio exceeds 2.56 J/cm3, which proves that it is suitable to describe the fracture features of concrete under triaxial static–dynamic loads. In this study, a dynamic strength criterion of concrete was proposed for concrete under triaxial dynamic loads. The testing data and reference results matched well with suggested value of the proposed dynamic strength criterion. This can provide the theoretical guidance for concrete engineering construction.

High strain rate compressive behaviour of 6000-series aluminium alloy sheet under SHPB impact loading

High velocity forming technologies are widely used in manufacturing industries to improve the formability of the aluminum alloy sheets. In order to better control the high velocity forming technologies through numerical simulation, the dynamic compression properties of the thin 6000-series aluminum alloy sheet were investigated by SHPB experiments. The influence of strain rate on the mechanical properties is analyzed in detail. Results show the elastic modulus is independent of the strain rate. However, under high strain rate condition, the yield stress, ultimate compression strength and ductility enhance with the increased high strain rate. So this 6000-series aluminum alloy sheet has significant strain rate sensitivity. As a reference, the quasi-static uniaxial tension test is also carried out and the uniaxial compressive stress-strain data in the literature is also listed. However, it is found the quasi-static uniaxial tensile yield stress is larger than the uniaxial compressive yield stress, and the quasi-static uniaxial compressive yield stress is lower than that under dynamic compressive condition. Results prove the aluminum alloy has obvious tension-compression anisotropy. For the high velocity forming technologies that take stretching as the main deformation mode, the dynamic tensile behaviour, instead of the dynamic compressive behaviour, should be used for accurate simulation.

Dynamic mechanical properties and penetration behavior of reactive nano-inorganic cement-based composites

The dynamic compression, tensile, and penetration properties of a reactive nano-inorganic cement-based composite (RNICC) were tested using a split Hopkinson pressure bar (SHPB) and a light gas gun. The parameters of the Holmquist-Johnson-Cook (HJC) model suitable for describing the RNICC were determined according to experimental results and feed forward neural network, which provide a theoretical framework for the use of these materials in engineering applications. The stress–strain curves, strain rate effect, and dynamic compressive/tensile strength of the RNICC were obtained within the range 50–150 s−1. The penetration tests for the RNICC target were performed, and the penetration resistant properties were determined according to the penetration depth and radius of the RNICC based on a 270 g projectile within the impact velocity range 100–250 m/s. The comparison on DIF and anti-penetration performance between RNICC and other kinds of UHPCC was conducted. The DIF growth rate of RNICC is larger than that of other types of UHPCCs. The RNICC targets has excellent anti-penetration performance. The HJC model is employed to describe the dynamic mechanical properties of the RNICC. A feed forward neural network model was used to train samples and determine the strength parameters of the RNICC in the HJC model. Based on discussions on the damage of concrete influenced by the principal strain and the failure shear strain, this study analyzed the failure type of the HJC model that caused compression damage in the concrete. The parameters of the HJC constitutive model were verified and could be used to effectively predict the mechanical properties and penetration behavior of the RNICC.

The Dynamic Compressive Properties and Energy Dissipation Law of Sandstone Subjected to Freeze–Thaw Damage

To investigate the dynamic compressive properties and the law of energy dissipation of freeze–thaw-damaged sandstone, static and dynamic compressive experiments were conducted. The influences of the number of freeze–thaw cycles and strain rate on strength characteristics, energy dissipation rate and the fractal dimension characteristics of sandstone were evaluated. Based on the peak energy dissipation rate, a freeze–thaw damage variable was established. The results show that peak strength increases exponentially with strain rate, and there exists a strain rate threshold. When strain rate is below this threshold, the increasing rate of the DIF slows down with the increase in the number of freeze–thaw cycles; when strain rate is higher than this threshold, the increasing rate of the DIF increases with the increase in the number of freeze–thaw cycles. In addition, the fractal dimension increases with the number of freeze–thaw cycles as well as the strain rate. Based on the freeze–thaw damage variable established, the damage degree of sandstone under freeze–thaw cycling can be characterized.

Dynamic Behavior of a Novel High-Strength and Ductile Near-α Titanium Ti-Al-Mo-Zr-Fe-B Alloy

In this study, the dynamic compression properties of a new high-strength (>1000 MPa) and ductile (>15%) near-α titanium Ti-6Al-1Mo-2Zr-0.55Fe-0.1B alloy were investigated at high strain rates of 1620 s−1~2820 s−1 by a split Hopkinson pressure bar (SHPB). The microstructural evolution of the samples before and after the dynamic deformation was analyzed by electron backscatter diffraction (EBSD). The results indicated that the strength of the alloy enhanced significantly under the dynamic loading compared with the quasi-static compression and increased with the increase in the strain rate. An abundance of deformation twins released the dislocation pile-up and coordinated the plastic deformation of alloy during the dynamic loading. The dynamic plasticity constitutive equation of the alloy was obtained by fitting high strain rate experimental data at room temperature by the Johnson–Cook constitutive equation with the modified temperature term.

Dynamic Compression Mechanical Properties of Polyoxymethylene-Fiber-Reinforced Concrete.

The excellent overall performance of polyoxymethylene (POM) fiber enables it to show great potential for engineering applications. The effect of POM fibers on the dynamic compression mechanical properties of concrete is an important issue for its application in engineering structures such as airport pavement and bridges. It is necessary to investigate the dynamic compressive mechanical properties of POM-fiber-reinforced concrete (PFRC) under impact loading. The PFRC specimens with various POM fiber lengths (6, 8, 12, 16, and 24 mm) and ordinary-performance concrete (OPC) specimens were tested by utilizing the split Hopkinson pressure bar (SHPB). We studied the effect of fiber length and strain rate on the dynamic compression mechanical properties of PFRC and established a damage dynamic constitutive model for PFRC. The results indicate that the dynamic compressive strength, peak strain, ultimate strain, dynamic peak toughness, dynamic ultimate toughness, and dynamic increase factor (DIF) of the PFRC increased obviously with the increase in strain rate. POM fiber was found to be able to effectively improve the deformation ability and impact toughness of concrete. The dynamic compressive strength and impact toughness of PFRC with a fiber length of 8 mm was optimal at different strain rates. The POM fibers with 16 mm and 24 mm lengths negatively affected the dynamic compressive strength of the concrete. The fiber length variation had an insignificant effect on the DIF of PFRC. The established damage dynamic constitutive model for PFRC was fitted and analyzed, and it was found that the model is able to describe the dynamic characteristics of PFRC well. This study can extend POM fibers to engineering structures that may be subjected to impact loading and act as a reference for the design of PFRC under impact loading.

Energy dissipation and fractal characteristics of basalt fiber reinforced concrete under impact loading

Basalt fiber reinforced concrete (BFRC) has been gradually used in buildings or structures to resist high-speed impact and explosion loading because of its good dynamic performance and energy absorption capacity. The dynamic compression experiments of BFRC with basalt fiber volume content of 0, 0.13 %, 0.26 % and 0.39 % were conducted using the Φ50 mm-diameter split Hopkinson pressure bar experimental system. The effects of different strain rates (80–220 s−1) on the dynamic compression property, dissipated energy (rate), fragmentation morphology and fractal dimension of BFRC were studied. Meanwhile, the SHPB impact numerical simulation of BFRC is carried out by LS-DYNA simulation platform. The results show that the peak stress and dissipated energy (rate) of BFRC increase with the increase of strain rate. However, the increase of the loading strain rate gradually decreases the fragmentation of BFRC, resulting in the continuous increase of the fractal dimension. The existence of basalt fiber as reinforcement in concrete increases the ability of concrete to resist impact cracking. BFRC with 0.26 % basalt fiber volume has higher dynamic compressive property and energy dissipation rate, but the fractal dimension of BFRC is the smallest compared with other contents. The stress–strain curves and damage evolution of BFRC under different loading rates are discussed by numerical simulation, which is further supplement to the experimental results.

Enhanced dynamic deformability and strengthening effect via twinning and microbanding in high density NiCoFeCrMoW high-entropy alloys

High density alloys with enhanced deformability and strength are urgently required in energy, military and nuclear industries, etc. In this work, we present a new kind of NiCoFeCrMoW high entropy alloys (HEAs) which possess higher densities and sound velocities than copper. We systematically investigate the phase structure, quasi-static tensile, dynamic compression and related deformation mechanism of these HEAs. It is shown that single FCC or FCC + μ dual phases were formed in the HEAs depending on Mo and W content and annealing temperature. Excellent quasi-static tensile and dynamic compression properties have been achieved for these HEAs, e. g. Ni30Co30Fe21Cr10W9 HEA annealed at 1573 K exhibited a yield and ultimate tensile strength and elongation of ∼364 MPa, ∼866 MPa and ∼32%, respectively, in quasi-static test; a yield strength of ∼710 MPa and no fracture under the dynamic strain rate of 4100 s−1. Superior strain rate sensitivity (SRS) of yield strength than that of previously reported FCC HEAs have been evidenced. The dynamic stress-strain constitutive relation can be described by the modified Johnson-Cook model. As for the dynamic deformation mechanism, it is envisaged that the regulation of stacking fault energy and Peierls barrier in current HEAs resulted in occurrences of abundant nanoscale deformation twins and microbands during high strain rate compression. The synergistic microbanding and twinning effectively contributes to the enhanced dynamic deformability and strengthening effect. Besides, the interactions of dislocations with precipitates, stacking faults (SFs) with twins, and between SFs also contribute to extraordinary work-hardening capacity.

Experimental study of dynamic biaxial compressive properties of full grade aggregate concrete after freeze thaw cycles

Most hydraulic concrete structures are in complex stress state, this study attempts to take some test of full grade aggregate concrete under biaxial compression after 0, 25, 50, 75, and 100 cycles of freeze-thaw. Five principle compression stress ratios of 1:0, 1:0.25, 1:0.5, 1:0.75 and 1:1 and four different strain rates of 10−5/s, 10−4/s, 10−3/s and 10−2/s were the main variables. The mass loss of concrete after freeze-thaw cycles has been studied. With the increase of freeze-thaw cycles, the quality loss is little. The failure pattern, ultimate strength, peak strain and stress-strain curve under different freeze-thaw cycles, stress ratios and strain rates were obtained. The dependence of ultimate strength on freeze-thaw cycles and ultimate strength, and the relationship between freeze-thaw cycles, stress ratio and strain rate were analyzed according to the testing data. The unified failure criterion of full grade aggregate concrete after freeze-thaw cycles under dynamic biaxial compressive stress state was established in principal stress space and octahedral stress space, respectively. The comparative analysis of experimental results of different types of concrete(large aggregate concrete, ordinary concrete, lightweight aggregate concrete, wet screened concrete) under biaxial compression after freeze-thaw cycles are made. With the increase of freeze-thaw cycles, the ultimate compressive strength of common concrete, wet screened concrete, lightweight aggregate concrete and large aggregate concrete gradually decreases. The results may serve as an experimental and theoretical reference for the design and maintenance of hydraulic structures.

Temperature-dependent dynamic compressive properties and failure mechanisms of the additively manufactured CoCrFeMnNi high entropy alloy

CoCrFeMnNi high entropy alloy (HEA) parts were fabricated by laser powder bed fusion (LPBF), and their dynamic compressive properties at different temperatures as well as the resulting microstructures were analyzed. The HEAs showed an unprecedented strength-ductility combination, especially at a cryogenic temperature of 77 K and a high strain rate of 3000 s−1. Under this testing condition, the yield strength (YS) of the HEAs amounted to 665 MPa. Regardless of the testing temperature, the deformation mechanism of all investigated HEAs was dominated by a synergistic effect consisting of deformation twinning and dislocation pile-up around twins. The fraction of twin boundaries and dislocation density within the deformed microstructure of the HEA correlated with the test temperature. At 77 K, the formation of nanotwins together with dislocation slip prevailed and contributed to pronounced twin-twin and twin-dislocation interactions which effectively restricted the dislocation movement and, hence, contributed to a higher YS as well as strain hardening rate in comparison to that of the HEAs at room temperature of 298 K. The LPBF-fabricated HEAs showed unpronounced thermal softening even at a high testing temperature of 1073 K. Continuous dynamic recrystallization was restricted in the HEA because of its inherent sluggish dislocation kinetics and low stacking fault energy.

The dynamic compressive properties of B4C ceramic by plasma spraying multilayer Co/Ni–TiCN coatings

The Co/Ni–TiCN multilayer coatings with two layer, four layer and gradient structure were plasma sprayed on B4C ceramic matrix. The effect of the multilayer structure on the dynamic compressive properties of B4C matrix was investigated. The Co/Ni–TiCN coatings consisted of Co–Ni–Cr–Mo and TiC1-XNX (0 ≤ x ≤ 1) phases. At the strain rate of 700 s−1, the peak stress increased by ∼200% after B4C surface coated with multilayer Co/Ni–TiCN coatings, the energy reflectivity increased by 412% (2 layer), 850% (4 layer) and 847% (gradient), and the energy transmittance decreased by 55% (2 layer), 80% (4 layer) and 83% (gradient). At 1500 s−1, the energy reflectivity increased by 490% (2 layer), 705% (4 layer) and 750% (gradient), and the energy transmittance decreased by 57% (2 layer), 83% (4 layer) and 89% (gradient). Compared with 2 layer structure, the 4 layer and gradient structure exhibited enhanced compressive properties because of the more layer interfaces for the reflection and transmission of the stress waves.

Effects of deformation-induced martensitic transformation on quasi-static and dynamic compressive properties of metastable SiVCrMnFeCo high-entropy alloys

High-entropy alloys (HEAs) utilizing a deformation-induced martensitic transformation (DIMT) mechanism have been developed as they exhibit an excellent balance of strength, ductility, and toughness. Investigations on deformation behaviors under dynamic responses are essential for their wide and reliable cryogenic applications; however, the effects of DIMT on mechanical properties under dynamic and cryogenic environments have hardly been studied yet, especially in metastable HEAs. In this study, compressive properties of two SiVCrMnFeCo alloys having different initial microstructure and stability of face-centered-cubic (FCC) against the DIMT were investigated under both quasi-static and dynamic loadings and at room and cryogenic temperatures. Under dynamic loading, the extent of DIMT was reduced than that under quasi-static loading due to the increased adiabatic heating, which increased the stability of FCC and suppressed the DIMT behavior. Nevertheless, the activated DIMT with decreasing stability of FCC due to the increased Si content and the decreased test temperature enhanced overall compressive properties. However, the interrupted dynamic compressive test results showed that the shear localization and the formation of adiabatic shear band (ASB) were promoted as the martensite formed more by the DIMT, concurrently resulted in the deterioration of resistance to shear cracking. These findings suggest that the delicate control of stability of FCC would be significant in wide and effective applications of the metastable alloys toward cryogenic or dynamic environments.

Influence of Loading Directions on Dynamic Compressive Properties of Mill-Annealed Ti-6Al-4V Thick Plate.

This paper investigates the influence of loading directions on mechanical performance, damage behavior and failure mechanisms of a mill-annealed Ti-6Al-4V (TC4) alloy thick plate at the strain rate of 2000/s. The plate possesses {11-20} texture and consists of globular α grain, fine equiaxial α grain, α laminate that is parallel to the normal direction (ND) of the plate and grain-boundary β laminate. The yield strength and the flow stress of the plate are not affected by the loading directions, while the fracture strain in ND is 38.2% and 32.2% higher than that in the rolling direction (RD) and the traverse direction (TD). As it is loaded in the RD and TD, the deformation mechanism of the alloy is dislocation slip. However, the deformation mechanisms in ND are dislocation slip and {10-12}<10-1-1> twinning. The activation of {10-12}<10-1-1> twinning could delay the formation of the adiabatic shearing band (ASB). Multiple adiabatic shearing bands (ASBs) form as the compression direction is in the RD and TD. In contrast, as the compression direction is in ND, only one ASB could be observed. The dramatic adiabatic shear could not result in the dynamic recrystallization of the mill-annealed TC4 alloy but could lead to the formation of nano-sized α laminate. The compressive fracture mechanism of the alloy plate is the crack propagation in the main ASB, which is not affected by the loading directions. Here we attribute the superior dynamic failure strain in the ND of the plate to the {10-12}<10-1-1> twinning induced by {11-20}α texture, cooperative deformation ability of the α laminate and higher shear strain within the ASB. The findings of our work are instructive for reducing foreign object damage to mill-annealed TC4 alloy fan blades.

Interfacial modification: The dynamic compression properties and enhancement mechanism of concrete added with micro-nano hierarchical carbon-based fiber

The modification of interfacial characteristics between carbon fiber and matrix (F/M) is one of the most pressing issues in the research related to carbon fiber reinforced concrete (CFRC). Herein, carbon nanotubes were grafted onto the surface of carbon fiber using an ultrasonic-assisted electrophoretic deposition technique to create a carbon-based fiber with micro-nano hierarchical structure (CNTs-CF) for concrete modification. The impact test of concrete (CCMC) added with micro-nano hierarchical carbon-based fiber was carried out by using split Hopkinson pressure bar (SHPB), and the effects of CNTs-CF and strain rate on the dynamic compression mechanical properties of concrete specimens were investigated. The microstructures and interfacial characteristics of CNTs-CF and CCMC were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results indicate that the CNTs-CF improves the internal F/M interface toughness due to its synergistic filling, bridging, and crack arresting effects, thus effectively relieving the local stress concentration and enhancing the dynamic compression properties of concrete. In the strain rate range of 50–120 s−1, as compared to CFRC, when the volume content of CNTs-CF is 0.3%, the dynamic compressive strength and peak strain of CCMC increase by 11.98% and 7.16%, respectively. When the volume content of CNTs-CF is 0.4%, the dynamic ultimate strain of CCMC increases by 5.52%.

Dynamic compressive properties of metaconcrete material

• It is the first experiment on dynamic compressive properties of metaconcrete. • Strain rate effect on dynamic compressive properties of metaconcrete is revealed. • Empirical formulae of DIF for dynamic compressive properties are proposed. Metaconcrete consisting of engineered aggregates is a newly manmade construction material possessing the ability to mitigate stress wave propagation and structural vibration. Several recent studies have investigated the responses of metaconcrete structures subjected to blast, impact and vibration loads and demonstrated their favourable performances. Metaconcrete materials, therefore, have great potential for application in the construction of engineering structures against multi-hazardous loads such as earthquake, impact and explosion. For the practical application of metaconcrete material in construction, the material properties need be defined for structural designs. A previous study by the authors tested the static properties of a few metaconcrete materials with different types of engineered aggregates. However, the dynamic properties of metaconcrete material have not been reported yet. This study investigated the dynamic properties of metaconcrete materials with three types of engineered aggregates, i.e., the conventional rubber-coated steel balls (RCSBs) and two types of enhanced RCSBs (ERCSB) (i.e., RCSBs with enhanced coating). Dynamic compression tests on the mortar-based and concrete-based metaconcrete materials were conducted by using the Split Hopkinson Pressure Bar (SHPB) system. Failure process, failure modes, dynamic compressive strength as well as energy absorption capacities at different strain rates of metaconcrete specimens were obtained. Dynamic increase factor (DIF) for compressive strength and energy absorption capacity of metaconcrete materials were derived and the corresponding empirical formulae were proposed. The results can be used to model the dynamic properties of metaconcrete materials in structural designs to resist dynamic loads.

Effects of microwave radiation on dynamic compressive properties of basalt

The dynamic mechanical properties of basalt affected by microwave were investigated by performing dynamic compressive tests using the SHPB system. Meanwhile, the thermal damage of the treated basalt was characterized by ultrasonic non-destructive testing and nuclear magnetic resonance technology. The results show that with the increase of microwave power and exposure time, the P-wave velocity, dynamic compressive strength and elastic modulus decrease continuously, and the dynamic failure mode tends to be a more complex fracturing. The increase in microwave power and exposure time can enhance the temperature difference and transfer coefficient among minerals, hence intensifying the rock damage induced by thermal shock.

Dynamic response and adiabatic shear behavior of β-type Ti–Mo alloys with different deformation modes

This study examined the dynamic compressive properties and adiabatic shear behavior of β-type Ti–10Mo, Ti–15Mo, and Ti–22.5Mo alloys whose deformation modes are stress-induced α''-martensitic transformation combined with {332}<113> twinning, {332}<113> twinning, and dislocation slip under quasi-static loading, respectively. Based on the characterization of deformation microstructures, the deformation modes did not undergo significant change regardless of quasi-static and dynamic conditions. Their yield strength increased remarkably when the strain rate rose from 10−3 s−1 to 103 s−1, thus exhibiting the strain rate strengthening effect. The impact absorbed energy showed an increasing trend with a rise in strain rate, and the highest value (319.2 J/cm3) was observed in the Ti–15Mo alloy at a strain rate of 3956 s−1. The {332}<113> twinning deformation led to a high capacity for strain hardening, which delayed the formation of adiabatic shear bands, comprising the ultra-fine β-matrix and nano-scale ω-phase. Moreover, the deformed twins provided a tortuous and bifurcated path to enhance the propagation resistance of adiabatic shear bands, thereby further consuming the impact energy.

Compressive Mechanical Properties and Shock-Induced Reaction Behavior of Zr/PTFE and Ti/PTFE Reactive Materials.

Existing research on PTFE-based reactive materials (RMs) mostly focuses on Al/PTFE RMs. To explore further possibilities of formulation, the reactive metal components in the RMs can be replaced. In this paper, Zr/PTFE and Ti/PTFE RMs were prepared by cold isostatic pressing and vacuum sintering. The static and dynamic compressive mechanical properties of Zr/PTFE and Ti/PTFE RMs were investigated at different strain rates. The results show that the introduction of zirconium powder and titanium powder can increase the strength of the material under dynamic loading. Meanwhile, a modified J-C model considering strain and strain rate coupling was proposed. The parameters of the modified J-C model of Zr/PTFE and Ti/PTFE RMs were determined, which can describe and predict plastic flow stress. To characterize the impact-induced reaction behavior of Zr/PTFE and Ti/PTFE RMs, a quasi-sealed test chamber was used to measure the over-pressure induced by the exothermic reaction. The energy release characteristics of both materials were more intense under the higher impact.

Perforation studies of concrete panel under high velocity projectile impact based on an improved dynamic constitutive model

The finite-depth concrete panels have been widely applied in the protective structures, and its impact resistance and dynamic fracture failures, especially the scabbing/perforation limits, under high velocity projectile impact, are mainly concerned by protective engineers, which are numerically studied based on an improved dynamic concrete model in this study. Firstly, based on the framework of the KCC (Karagozian & Case concrete) model, a dynamic concrete model is proposed which considers an independent tensile damage model and a continued transition between dynamic tensile and compressive properties. Secondly, the strength surface, equation of state and damage parameters of the proposed model are comprehensively calibrated by a triaxial compressive test with high confinement pressure, the rationality of which is further verified based on the single element tests, e.g., uniaxial and triaxial compression as well as uniaxial, biaxial and triaxial tension. Thirdly, a series of projectile high velocity impact tests on thin and thick concrete panels are simulated, which indicates that the projectile residual velocity and dynamic fracture failures are reproduced satisfactorily, while the KCC model underestimates both the spalling and scabbing dimensions severely. Finally, based on the validated concrete model and finite element analyses approach, the validations of the existing five empirical formulae are evaluated, in terms of the depth of penetration (DOP) and scabbing/perforation limits of concrete panel. Both the Army corps of engineers (ACE) and modified National Defense Research Committee (NDRC) formulae are recommended in the design of the protective structure to avoid scabbing failure.