Projectile Impact Tests Research Articles

Analysis and Comparison of the Projectile Impact Response of an Electron Beam Melt-Ti64 Body Centered Cubic Lattice-Cored Sandwich Plate

Abstract Background One potential application of additively fabricated lattice structures is in the blade containment rings of gas turbine engines. The blade containment rings are expected to be able to absorb the kinetic energy of a released blade (broken blade) in order to protect the engine parts from damaging. Metallic lattice-cored sandwich plates provide a gap (free space) between two face sheets, which helps to arrest the released blade and increases the energy absorption capability of containment rings. Objective The objective was to investigate numerically the projectile impact response of Body-Centered-Cubic (BCC) Electron-Beam-Melt (EBM) lattice-cored/Ti64 face sheet sandwich plates as compared with that of an equal-mass monolithic EBM-Ti64 plate. Methods The projectile impact simulations were implemented in LS-DYNA using the previously determined flow stress and damage models and a spherical steel impactor at the velocities ranging from 150 to 500 m s−1. The experimental projectile impact tests on the monolithic plate were performed at two different impact velocities and the results were used to confirm the validity of the used flow stress and damage models for the monolithic plate models. Results Lower impact stresses were found numerically in the sandwich plate as compared with the monolithic plate at the same impact velocity. The bending and multi-cracking of the struts over a wide area in the sandwich plate increased the energy absorption and resulted in the arrest of the projectile at relatively high velocities. While monolithic plate exhibited a local bent area, resulting in the development of high tensile stresses and the projectile perforations at lower velocities. Conclusions The numerical impact stresses in the sandwich plate were distributed over a wider area around the projectile, leading to the fracture and bending of many individual struts which significantly increased the resistance to the perforation. Hence, the investigated lattice cell topology and cell, strut, and face sheet sizes and the lattice-cored sandwich plate was shown potentially more successful in stopping the projectiles than the equal-mass monolithic plates.

Tough Monolayer Silver Nanowire-Reinforced Double-Layer Graphene.

Mixed-dimensional nanomaterials composed of one-dimensional (1D) and two-dimensional (2D) nanomaterials, such as graphene-silver nanowire (AgNW) composite sandwiched structures, are promising candidates as building blocks for multifunctional structures and materials. However, their mechanical behavior and failure mechanism have not yet been fully understood. In this work, we have performed integrated experimental, theoretical, and numerical studies to explore the performance and failure modes of graphene-AgNW composite under tensile and impact loading conditions. In situ tensile tests using a nanoindenter, implemented with a push-to-pull device and a laser-induced projectile impact test system, are used to shed light on load-bearing mechanisms in graphene-AgNW composites. Multiple failure modes have been observed in both experimental setups and analyzed with numerical and theoretical models. Results show that in the tensile loading the distribution of AgNW, as characterized by the effective free length, is the key parameter determining the failure mode. As for the impact failure scenarios, compared with failure modes observed in pure graphene cases, the mechanical reinforcing effect of AgNW will transform the failure mode from a scattered tensile fracture along radial directions to a shear failure that is constrained in a relatively local domain. Theoretical analysis using shear lag modeling, Timoshenko plate theory, molecular dynamics modeling, and finite element modeling approaches are adopted to further establish the failure modes.

Anomalous size effect of impact resistance in carbon nanotube film

Dynamic mechanical behavior and size-related impact resistance of CNT films are studied by employing laser-induced projectile impact test (LIPIT) and coarse-grained molecular dynamics (CGMD) simulation. The energy dissipation mechanisms of the CNT films are investigated via CGMD simulations. An evident anomalous thickness-dependent effect is directly observed in the experiment, consistent with simulation phenomena. The mechanisms underlying this anomalous thickness-dependent effect are investigated at the atomic scale. The disparities between experiments and simulations are discussed. Our analysis of energy dissipation modes, deformation behaviors during impact, and impact area reveals that kinetic energy change predominantly governs the deformation mode. Meanwhile, a plugging failure mode near the exit face of CNT film is identified at high impact velocity (∼160 m/s), leading to a deterioration in impact resistance and a corresponding reduction in SEA with increasing CNT film thickness. These findings provide a feasible strategy for the protection design of CNT film in broaden protective application scenarios.

Biomimetic 3D printing: Cocoon-like silk reinforcements from discarded cocoons for hemispherical composite components

Silkworm cocoons serve as the primary raw material for silk fabric production. However, due to stringent quality requirements for silk products, only high-quality cocoons are selected, while defective ones such as spotted cocoons are relegated to low-value textile fillers or direct landfilling. To enhance the value of discarded cocoons, this study combines continuous fiber 3D printing technology with traditional molding techniques, using discarded cocoons as raw materials to create high-performance hemispherical composite materials that mimic the natural structure of silkworm cocoons, thereby achieving efficient resource reuse. Additionally, a novel random path algorithm for 3D printing was developed to address the issue of uneven fiber orientation in the manufacturing of curved composite materials. The vacuum bag molding method was utilized to combine silk-like hemispherical fiber-reinforced bodies with resin, producing hemispherical composites with a high fiber content. Extensive tensile testing on longitudinally and laterally cut cocoon fiber samples was conducted to explore the mechanical behavior in various directions, revealing unique anisotropic properties. Further tensile testing on homemade silk yarn confirmed the material's high strength and excellent toughness. Scanning Electron Microscopy (SEM) analysis demonstrated good interfacial bonding between the silk and bio-based epoxy resin within the composites. Compression tests indicated a maximum load capacity of 6717 N, showcasing exceptional impact resistance and superior energy absorption in projectile impact tests. Even under extreme loads, the hemispherical composites maintained a substantial intact area, highlighting their structural integrity advantages. This study not only breathes new life into industrial waste but also provides a new direction for the manufacturing sector to achieve a greener and more sustainable development path.

Impact and Adhesion Mechanics of Block Copolymers in Cold Spray: Effects of Rubbery Domain Content

The impact and adhesion mechanics of two-phase block copolymers during high-velocity impacts are studied experimentally and computationally to understand the effect of the rubbery phase on bonding behavior in cold spray additive manufacturing. Micron-scale (10-20 μm) spherical particles of polystyrene-block-polydimethylsiloxane with varying rubbery phases are impacted on a silicon substrate by using a laser-induced projectile impact test setup with impact velocities in the range of 50-600 m/s. Experiments indicate that the minimum impact velocity for polymer particles adhering to the substrate decreases with increasing rubbery phase content. A strain rate- and temperature-dependent constitutive model and cohesive zone model are calibrated for each material by comparing the deformed and computed deformed particle shapes and coefficient of restitution values of the rebounding particles. Computational results show that increasing the rubbery phase content in block copolymers increases plastic energy dissipation from 89 to 96% and the critical strain energy release rate from 1.87 to 9.3 J/m2 at 140 m/s, and thus contributes to the observed decrease in the minimum impact velocity required for block copolymers to adhere to substrates. The discovered direct relationship between soft phase content and critical strain energy release rate implies that increased soft-rubbery PDMS content in block copolymers enhances adhesion through improved chain mobility, better surface asperities coverage, and enhanced wetting, due to its lower surface energy and greater adiabatic heating.

Roentgenoscopy of laser-induced projectile impact testing.

Laser-induced projectile impact testing (LIPIT) based on synchrotron imaging is proposed and validated. This emerging high-velocity, high-strain microscale dynamic loading technique offers a unique perspective on the strain and energy dissipation behavior of materials subjected to high-speed microscale single-particle impacts. When combined with synchrotron radiation imaging techniques, LIPIT allows for in situ observation of particle infiltration. Two validation experiments were carried out, demonstrating the potential of LIPIT in the roentgenoscopy of the dynamic properties of various materials. With a spatial resolution of 10 µm and a temporal resolution of 33.4 µs, the system was successfully realized at the Beijing Synchrotron Radiation Facility 3W1 beamline. This innovative approach opens up new avenues for studying the dynamic properties of materials in situ.

Dynamic response of clamped metallic thin-walled cylindrical shells under lateral shock loading

A combined experimental and numerical study was carried out to explore the dynamic response of Q235 thin-walled cylindrical shells under lateral shock loading. The machined Q235 specimens were clamped on both sides and subjected to centered lateral simulated shock loading via foam projectile impact tests, with their dynamic deformation evolution, mid-point deflections, and final deformation modes experimentally measured. The mid-point deflections of the impact side are all positive (the direction of deformation is the same as the impact direction) while those of the rear side all exhibit negative values (the direction of deformation is opposite to the impact direction). To further explore this phenomenon, the method of finite element (FE) was employed to simulate the foam projectile impact, with good agreement against experimental measurements achieved. Using the validated numerical model, the effects of impact velocity, length-to-diameter ratio, and thickness-to-diameter ratio on the dynamic response of the thin-walled cylindrical shell were further analyzed. The direction of both side deflections and deformation modes are significantly affected by the impact level and the shell geometries. For the rear side, within the given range of impact momentum and geometric parameters, the numerically predicted deflection varies from −1.775 mm to 2.45 mm. Thereupon, the coupling of indentation and bulge deformation patterns are indicated, and their corresponding contribution changes are considered the main mechanism for determining the final deformation of the thin-walled cylindrical shell's rear side.

Experimental investigation on the deformation and damage of steel ribbon wound vessel for hydrogen storage under external impact and blast loading

Steel ribbon wound vessel is a preferred type for stationary storage of high-pressure hydrogen in refueling stations. However, it is under the threat of fragment impact and blast loads caused by accidental explosions of hydrogen or other vessels. For the first time, the fragment-simulating projectile (FSP) impact tests with impact kinetic energy range from 1.8 × 103 J–4.9 × 103 J and external blast loading tests with TNT equivalent range from 157 g–4 kg of industrial-grade 50 MPa steel ribbon wound vessel were carried out. The damage of vessel under FSP impact loading was studied. The effect of concentrated and distributed blast loads on the deformation and damage of gas-filled vessel was analyzed, and the explosion resistance of vessel under near-field blast loading was explored. It is revealed that: 1) the steel ribbon wound vessels generally have good resistances to external blast and impact loads, 2) the primary damage characteristics of vessel under contact/near-field blast loading was localized depression deformation, accompanied by steel ribbons warping as the shock wave impulse increases, 3) the saddle fails earlier than the vessel under the near-field blast loading. Further, the failure modes of vessel under extreme blast loads were revealed. Results can provide reference for the safe design and validation of dynamic damage/failure analysis models of steel ribbon wound vessels.

Development of a velocity measurement method for a microparticle projectile and high-speed impact testing of metallic materials for grain refinement

Since grain refinement, such as the nano-twinning and nano-crystallization of metallic materials, can improve mechanical properties, surface modification to generate nano-structures is an in-demand technology. This study aims to conduct ultrahigh velocity impact testing using microparticle projectiles to generate indentation craters via impact. Due to the resulting extreme plastic deformation with high strain rate, grain refinement is expected to occur. This study conducts the laser-induced particle impact test (LIPIT), in which laser ablation induces supersonic ejection of a microparticle, resulting in the generation of an impact crater. We first propose a method for measuring particle projectile velocity using a mechanoluminescent (ML) material. A particle collision against the ML material emits light as a result of the mechanical stimulus. The light is detected to determine the timing of particle arrival, thus, the particle projectile velocity is obtained. This measurement method is verified using a high-speed video camera. Next, LIPIT is applied to pure copper (Cu) and pure iron (Fe), thus producing nano-structures including twinning around the impact indentation craters. To clarify this mechanism, a molecular dynamics (MD) simulation is conducted to reveal the formation of nano-twinning around the impact craters. In addition, nano-indentation testing is conducted, indicating plastic hardening around the impact craters unlike the craters obtained using quasi-static indentation. This indicates that plastic deformation due to LIPIT improves mechanical properties, owing to the extreme plastic strain and strain rates involved. Therefore, our LIPIT has potential as a new surface modification technique to induce extreme plastic deformation with ultrahigh strain rates, resulting in grain refinement.

Impact and adhesion mechanics of block copolymer micro-particles with a silicon substrate

Deformation of a two-phase block copolymer (BCP) during high velocity impacts is studied experimentally and theoretically with an aim to use this material in cold spray (CS) additive manufacturing. Micron scale (10–20 μm) spherical particles of polystyrene-block-polydimethylsiloxane (PS-b-PDMS) are impacted on a silicon substrate by using a laser-induced projectile impact test (LIPIT) setup with impact velocities in the range of 50–600 m/s. Experiments indicate that polymer particles adhere to the substrate when their impact velocities fall within the range of 140–500 m/s. A constitutive model that accounts for the effects of both strain rate and temperature on the mechanical behavior of such materials is developed. A critical energy release rate function which depends on the surface temperature and rate of separation is formulated and used in a cohesive zone model (CZM) to model bonding of the BCPs on the substrate. The model parameters are calibrated by comparing the deformed and computed deformed particle shapes and coefficient of restitution values of the rebounding particles. Simulations show that the particles experience ultra-high strain rates (>104 s−1), large deformation, and temperature elevation due to plastic dissipation and interfacial friction. The outer rim of the contact interface is predicted to experience temperature levels above the glass transition temperature of the PS-domain of the BCP. Bonding is correlated with increase of contact area, plastic dissipation and temperature rise in the interface.

Tailoring flake size and chemistry to improve impact resistance of graphene oxide thin films

Multilayered graphene oxide (MLGO) possesses high elastic modulus and strength, as well as enhanced resistance to inter-layer sliding from functional groups. This makes it a promising candidate for impact-resistant thin films and nanocomposites. However, the effects functionalization and flake size on the physics of MLGO failure under high-strain rate impact remains to be fully understood. While laser induced projectile impact tests (LIPIT) have enabled microballistic characterization of MLGO, the dynamics of interlayer sliding processes cannot be accurately studied in physical experiments due to resolution challenges of existing techniques. Here we utilize systematically coarse-grained molecular dynamics to simulate MLGO under high-rate microballistic impact, explicitly accounting for functional group distributions while approaching micron-size specimen dimensions. In doing so, we evaluate the effects of oxidation level on the thin films’ ability to dissipate ballistic energy. We additionally explore effects of varying flake size on these systems, improving on studies that only consider infinite flake dimensions. The primary failure mechanism of these thin films (consisting of relatively small flakes) is found to be sliding of the GO flakes as no bonds were broken. We discover that elevated levels of oxidation increase the amount of energy required to penetrate the film, as do larger GO flake sizes as they increase energy dissipation via friction between sliding flakes. These findings illustrate the potential for MLGO films to be tailored for maximum ballistic energy dissipation, providing a starting point to design impact-resistant GO materials for diverse applications.

Projectile Impact Testing of a Concrete Coal Mine Seal Rated for 120 psi

Projectile Impact Testing of a Concrete Coal Mine Seal Rated for 120 psi

Orientation-dependent plasticity mechanisms control synergistic property improvement in dynamically deformed metals

We demonstrate the ability to synergistically enhance strength and toughness in metals by tailoring the dominant plasticity mechanisms from impact-induced heterogeneous nanostructures. Using a laser-induced projectile impact testing apparatus, we impact initially dislocation-free single crystal microcubes at high velocities to induce grain size and dislocation density gradients. These gradient nanostructures exhibit heterogeneous deformation under subsequent quasi-static loading leading to enhanced strength and toughness. Transmission Kikuchi diffraction (TKD) analyses show that the synergistic property improvement arises from the complimentary intragranular and intergranular plasticity mechanisms: the pronounced intragranular dislocation plasticity within coarse grained regions provides increased strain hardening and toughness while the nanograined regions with high dislocation densities provide high strength and supplemental toughness enhancement through cooperative grain rotation and grain boundary migration. These plasticity mechanisms are activated to different extents depending on the specific impact-induced nanostructures, which depend on the orientation of the single crystal upon impact. Controlled [100]-face, [110]-edge, and [111]-corner impact of single crystal microcubes, subsequent quasi-static mechanical testing, and pre- and post-compression nanostructural characterization provide a fundamental understanding of the comprehensive process-structure-property relations in heterogeneous nanostructured metals.

Influence of steel reinforcement on the performance of an RC structure subjected to a high-velocity large-caliber projectile

The reinforcement setting in reinforced concrete (RC) protective structure should be optimized to resist the impact of high-velocity large-caliber projectiles (LCPs), which is yet to be clearly understood. This study adopts a high-fidelity finite element analysis (FEA) approach to examine the influence of steel reinforcement setting, including the diameter/spacing/strength of reinforcement, the number/spacing/distribution depth of the mesh layer, and the reinforcement ratio, on the performance of RC structure against the large-caliber projectile impact. The FEA approach utilizes an improved dynamic constitutive model of concrete recently proposed by the authors to capture the responses of concrete, i.e., the penetration resistance, cratering, scabbing, and cracking failure, and the *CONSTRAINED_BEAM_IN_SOLID coupling method to consider the bond-slip relation between steel reinforcement and concrete. By simulating the 64 mm-diameter projectile impact tests on the plain concrete (PC) and RC targets, it validates the established FEA approach in contrast to that using the existing concrete models in LS-DYNA, i.e., the Holmquist-Johnson-Cook, Riedel-Thoma-Hiermaier, and Karagozian & Case concrete models, and the full coupling method, i.e., the *CONSTRAINED_LAGRANGE_IN_SOLID. The performance of the RC target struck by a 154 mm-diameter LCP is further numerically studied using the validated FEA approach. Based on more than fifty simulation cases, it derives the optimal reinforcement setting for the engineering design: (i) increasing the mesh layer number should be given priority to increasing the reinforcement ratio; (ii) the optimal rebar diameter and spacing are 1/15 and 1/2 of projectile diameter, respectively; (iii) uniform distribution of reinforcement layer along target thickness is suggested; (iv) normal strength reinforcement is preferred; (v) the practical highest reinforcement ratio is 4% to reduce structural thickness.

On adiabatic shear instability in impacts of micron-scale Al-6061 particles with sapphire and Al-6061 substrates

Impact mechanics of micron-scale, Al-6061 particles on sapphire and Al-6061 substrates were investigated experimentally and through simulations. Particle impact experiments were carried out by using the laser induced projectile impact test (LIPIT) and the coefficient of restitution was evaluated for impact velocities in the range of 50–950 m/s. Bonding was observed only in Al-on-Al impacts with impact velocities over 810 m/s. A continuum model of the impacts was implemented by using commercially available finite element software. The bilinear Johnson–Cook model was implemented to model the material flow effects in the ultra-high strain rate (UHSR) regime. A cohesive zone model was used for the bonding along the particle–substrate contact interface. Heat generation due to plasticity and friction, and material damage were also included in the simulations. A quantitative measure of adiabatic shear instability (ASI) was implemented into the modeling framework to search for material points that experience drop of strength during loading. A small volume of the material internal to the particle was found to experience ASI in Al-on-sapphire impacts, but this was not observed in Al-on-Al impacts. However, if the flow rule is switched to one that neglects the effects of the UHSR-regime, ASI can be predicted in regions of the particle where the finite element mesh deforms excessively. It is recommended that any study searching for ASI in high-velocity impact simulations should assess the mesh distortion carefully and use a flow rule that includes UHSR effects.

Enhanced energy dissipation of graphene/Cu nanolaminates under extreme strain rate ballistic perforation

Dynamic deformations at extreme strain rates (>106/s) are frequently encountered by metallic structural materials. According to continuum theory, increasing the modulus and thus speed of sound in metallic materials could lead to enhanced impact resistance, while such goals are difficult to achieve via conventional alloying methods. On the other hand, recent researches have revealed that carbon materials such as graphene have far larger in-plane speed of sound than metals and therefore are intrinsically impact resistant. In this work, graphene/copper (Gr/Cu) nanolaminates were fabricated by incorporating graphene into copper matrix, and its ballistic performance at extreme strain rates (∼3 × 107 /s) was quantified via laser-induced projectile impact tests (LIPITs). The specific energy dissipation of Gr/Cu nanolaminates is found to be 54 % higher than Cu. Post-mortem analysis revealed that graphene nanoinclusions could cause additional coordinative deformation in regions surrounding the perforation zone in Gr/Cu, leading to enhanced ballistic performance of Gr/Cu nanolaminates.

Reliability Assessment of Steel-Lined and Prestressed FRC Slabs against Projectile Impact

A simulation-based probabilistic method is proposed for assessing the reliability of steel-lined and prestressed fiber-reinforced concrete (PFRC) slabs against the impact loads. The impact testing of several prestressed and non-prestressed FRC slabs of 800 × 800 × 100 mm in size was carried out. The experimental program involved projectile impact testing of prestressed and non-prestressed FRC slabs using a gas gun. Three parameters were varied for testing of slabs under the projectile impact, viz., a quantity of steel fibers in the concrete, steel lining on the backside of the slab, and the prestressing level. The probability-based reliability analysis of all the tested specimens was then performed to highlight the influence of steel lining, steel fibers, and prestress in enhancing the safety of RC (reinforced concrete) slabs against projectile impacts. Projectile impact velocity exceeding the slab’s ballistic limit was assumed to lead to the failure of the PFRC slab, i.e., the perforation failure of the slab. Study results indicate that when no steel fiber was present, slab reliability was low. Adding fibers to slabs increases slabs’ reliability significantly. Specimens with the highest steel fiber content (1.2%) showed the greatest increase in reliability. The steel lining on the back face makes the slab’s reliability almost doubled in comparison with those without lining. Additionally, steel lining makes the PFRC slabs as reliable as desired. It was further noticed that the prestressing helps in enhancing the slab safety against projectile impacts. Even a minimal amount of prestressing makes a noticeable improvement in the reliability of PFRC slabs.

Experimental and Numerical Analysis of Impact Strength of Concrete Slabs

The topic of this paper is experimental and numerical analysis of the impact strength of unreinforced concrete slabs. Impact strength of concrete is significant in case of some accidental loads during exploitation. Impact strength can be determined experimentally, using Drop-weight test, Charpy test, Projectile impact test, Explosive test, etc. In this research, a numerical model for determining the impact strength of concrete slabs based on Finite element method (FEM) and high-end engineering software has been proposed. Modelling approach to this problem was applying the Explicit dynamics FEM analysis. Thereat, two different existing material models for concrete were enforced: Concrete damage plasticity model – CDP (implemented in ABAQUS/Explicit software), and the Riedel-Hiermaier-Thoma model – RHT (implemented in ANSYS Workbench software). Analysis parameters for both material models, necessary as input data, have been determined through a series of FEM analyses and validated by performed experiments, using drop-weight test. Results of the numerical analyses have been compared with the experimental ones, as well as mutually. Advantages and drawbacks of both material models are highlighted, as well as the reliability of the proposed numerical models. The proposed numerical FE models, confirmed by experiments, can be successfully used for determining impact strength of concrete slabs in further research.

Study of dynamic mechanical behavior of 1060-H112 aluminum alloy: Experimental and numerical simulation

1060-H112 aluminum alloy with high ductility is widely used in industrial engineering. The study of its dynamic mechanical behavior has theoretical and engineering application value. In this paper, quasi-static tensile tests from room temperature to 250°C and high strain rate compression tests were conducted using a universal material testing machine and a Hopkinson compression bar. By using a hybrid test-numerical simulation method, a modified Johnson-Cook (MJC) strength model and Cockcroft-Latham (C-L) fracture criterion parameters were calibrated. Subsequently, Taylor impact tests were performed on 1060-H112 aluminum alloy specimens with a diameter of 12.66 mm and a length of 50.64 mm in the range of 176.3–483.03 m/s. Upsetting and tensile tearing were observed in the tests. A 12.68 mm diameter blunt nosed projectile impact test on 2 mm 1060-H112 aluminum alloy plate was also conducted with a light gas gun system, and the speed related parameters and failure modes were obtained. Finally, a three-dimensional model corresponding to the test was established in ABAQUS/Explicit finite element simulation software, and the failure modes of the Taylor rod and the velocity parameters and failure modes of the target impact test were predicted. The results show that the MJC strength model and the C-L fracture criterion can predict the experimental results of the two tests accurately. It shows that the MJC strength model and C-L fracture criterion have high accuracy, and they will play an important role in the application of 1060-H112 aluminum alloy in industrial engineering.

Prediction of Ballistic Limit of Strengthened Reinforced Concrete Slabs Using Quasi-Static Punching Test

The formulas available in the literature for predicting the projectile impact response of reinforced concrete (RC) targets are generally developed based on the results of impact tests. Recently, however, in order to avoid performing involved and challenging projectile impact tests, the impact response of RC targets was predicted using the quasi-static punching response of RC slabs. In this paper, the concept is extended to concrete slabs strengthened with textile-reinforced mortar (TRM) or carbon fiber-reinforced polymer (CFRP) sheets externally bonded to the concrete surface. In 16 groups, 96 slabs of 600 × 600 × 90 mm size were cast and tested under quasi-static and impact loads. The slabs were reinforced with two types of reinforcement: ϕ8@100 mm and ϕ4@25 mm. The singly and doubly reinforced concrete slabs with rebar spacing of 100 mm were strengthened using externally bonded CFRP and TRM on the back side of the slab specimens. Two mixes of concrete, representing normal and high-strength concretes, were used. The results of the present study reveal that the CFRP and TRM strengthening of RC slabs enhanced the energy absorption in punching by 57–130% and 20–59%, respectively. The use of WWM in singly and doubly reinforced slabs also resulted in a 30–42% and 41–63% increase in energy absorption in punching, respectively. An earlier proposed model was modified to incorporate the influence of strengthening (CFRP and TRM) in the estimation of the projectile perforation energy of the strengthened RC slabs with the help of energy absorbed in their quasi-static punching. This perforation energy was then employed for predicting the ballistic limit of CFRP- and TRM-strengthened slabs. The predictions show good agreement with the experimentally observed ballistic limits.