Low Velocity Impact Research Articles

Low-velocity impact behavior of woven fabric-reinforced natural rubber composites

Low-velocity impact behavior of woven fabric-reinforced natural rubber composites

Low-velocity impact of sandwich beams with fibre-metal laminate face-sheets considering local denting effect

Low-velocity impact of sandwich beams with fibre-metal laminate face-sheets considering local denting effect

Impact dynamic response of stiffened porous functionally graded materials sandwich doubly-curved shells with Arc-type auxetic core

The Arc-type auxetic core is based on the traditional concave hexagonal core and incorporates a bending configuration, facilitating a smooth transition of the cell elements. This modification proves highly effective in alleviating stress concentration. To extend its use in sandwich structures, the dynamic behavior of stiffened porous functionally graded materials (PFGMs) doubly-curved sandwich shell with Arc-type auxetic core under low-velocity impact is a concern that this research addresses. The material properties of external PFGM panels are controlled by two grading patterns (P-FGM and E-FGM) and has four different porosity distributions. The core layer is made of Arc-type auxetic core. A theoretical model that utilizes Hertzian elasticity theory and first-order shear deformation theory (FSDT) is proposed, and the equations of motions are derived using the Hamilton's principle. In addition, to simulate the contact force interaction in dynamic process, the spring-mass model is employed. The analytical solution is presented by using Duhamel's principle and Navier's method to anticipate the transverse displacement. The effectiveness of the obtained data is verified by comparing the findings with those of the existing literature and the numerical results established by the Abaqus commercial software. On this basis, efficient methods for optimizing the PFGM doubly-curved sandwich shell are presented by analyzing the effect of porosity, porosity distribution, gradient index, grading pattern, auxetic core inclined angle and circular arc radius on the energy absorption capability, wherein the sandwich shell of P-FGM reduces the transverse displacement by 24.5 % over E-FGM, and the corresponding gain effects for different porosity distributions are Type B > Type D > Type C > Type A.

Investigation of the Collapse Behavior of Aluminum Burr-Filled Cylindrical Energy Absorber Under Low-Velocity Impact

Investigation of the Collapse Behavior of Aluminum Burr-Filled Cylindrical Energy Absorber Under Low-Velocity Impact

Low-velocity impact behavior of two-way SFRC slabs strengthened with steel plate

Structural systems and structural elements can often suffer severe damage or even completely collapse under the effect of sudden dynamic impact loading, which is a different type of loading that is not considered during their design. Research on how structures behave under impact loading and how they can be strengthened to perform better against this type of loading has increased to avoid such undesirable severe damage. Within the scope of this study, it is aimed to improve the behavior and increase the performance of two-way steel fiber-reinforced concrete (SFRC) slabs, one of the leading structural elements that can be affected by impact loading, using steel fiber concrete (SFC) and placing steel plates on the surface of the RC slab. Within the scope of the study, the effects of placing FRC as layers in different positions within the slab and placing the steel plate on different surfaces of the slabs were examined. Impact loading was applied using a drop weight test setup designed by the authors, and the acceleration–time, displacement–time, and impact loading–time behaviors of the RC slabs were measured and interpreted. The use of fiber concrete in RC slabs and strengthened with steel plates increased the maximum acceleration values by an average of 3% and 113%, respectively. The use of fiber concrete in RC slabs reduced the maximum displacement and residual displacement values by an average of 2% and 25%, respectively. Placing steel plates on the slabs reduced the maximum displacement and residual displacement values by an average of 270% and 199%, respectively. In addition, the energy absorption capacities of RC slabs were calculated, and how they were affected by experimental variables was examined. Numerical analyses of the RC slabs tested in the study were also conducted using ABAQUS finite element software, and the results obtained were compared with the experimental ones.

A numerical investigation of energy dissipation mechanism of visco-hyperelastic bimaterials subjected to low-velocity impact

Impact protection equipment typically relies on the material failure mechanism and is frequently discarded after the impact. A promising alternative emerges utilizing a foam-infilled lattice bimaterial with shape recovery trait and customizable impact protection capability. This study employs a numerical approach to elucidate the energy dissipation mechanism exhibited by the bimaterial under low-velocity impact condition. The experiment-based inverse method is used to characterize visco-hyperelastic models for two base materials. The investigation reveals that the interaction between the two base materials significantly amplifies the foam’s energy dissipation capability, resulting in an overall higher energy dissipation for the bimaterial. Besides, the study establishes a close correlation between the bimaterial’s effective viscoelastic properties and the enhancement in energy dissipation. Furthermore, the numerical design of experiments (DOE) analysis of base material properties indicates that there is an optimal region for selecting the critical foam material constants for a significant improvement of bimaterial energy dissipation. The results reveal that the combination effect of material interaction and material viscoelastic properties constitutes the fundamental elements of bimaterial energy dissipation mechanism. The insight derived from this study can inform the future design and material selection of a more complicated bimaterial across a wide range of impact protection applications.

An Experimental Study on the Low-Velocity Impact Behavior of Biopolymer-Coated Kenaf Fiber Reinforced Epoxy Nanocomposites: A Route to Sustainability

An Experimental Study on the Low-Velocity Impact Behavior of Biopolymer-Coated Kenaf Fiber Reinforced Epoxy Nanocomposites: A Route to Sustainability

Mechanical properties and low-velocity impact analysis of camel hair and hybrid camel hair/flax fibre-reinforced epoxy

Mechanical properties and low-velocity impact analysis of camel hair and hybrid camel hair/flax fibre-reinforced epoxy

Impact behavior of periodic, stochastic, and anisotropic minimal surface-lattice sandwich structures

Recent advancements in 3D printing technologies have made it possible to fabricate intricate lattice architectures with high precision. These lattices can now be utilized to design lightweight sandwich structures that serve multiple functions. To enhance the impact loading performance of these structures, it is crucial to understand how the lattice's topological properties, particularly those with minimal surface attributes like periodic or stochastic Primitive and Gyroid triply periodic minimal surfaces (TPMS) and spinodal-like stochastic cellular materials, associate with the mechanical properties of sandwich structures while keeping the skin thickness fixed. Thus, this paper explores the low-velocity impact behavior of various sheet/shell-based minimal surface-latticed cores of sandwich structures with woven composite skins. The elasto-plastic-damage numerical simulations consider lattice core periodicity, randomness, and anisotropy while keeping the relative density constant. Core lattice randomness and anisotropy are designed using the Gaussian Random Field (GRF) method for spinodal-based stochastic cellular materials and stochastic TPMS. The simulation results showed that the periodic Primitive-lattice core exhibits high out-of-plane shearing strength, enabling the sandwich structure to demonstrate the highest perforation limit. GRF spinodal-based core achieved the highest peak load due to its anisotropic mechanical properties. However, the post-yielding bending of the lattice sheet limited its ability to resist perforation, and absorb and dissipated energy. Interestingly, the stochastic Gyroid TPMS topology, with its inherent densely-distributed microstructure, showed high sensitivity to loading rate, resulting in enhanced energy absorption and dissipation of the sandwich structure. These findings offer valuable insights for optimizing multifunctional sandwich structures with superior impact performance and their design for additive manufacturing.

Experimental investigation on the effects of stainless-steel mesh reinforcing layers on low-velocity impact response of hybrid thermoplastic glass fiber composites

This study aims to assess the hybridization effect on the perforation threshold of Low-Velocity Impact (LVI) in thermoplastic glass composite laminates, incorporating layers of resin-impregnated stainless-steel mesh. Reinforcing methodologies such as hybridization are recently being adopted as a practical approach to increasing the energy-absorbing capacity of polymer composites. In the current paper, a multi-step hot press lamination method has been employed to fabricate the hybrid composite laminates strengthened with stainless-steel mesh layers. Several stacking sequences, metal mesh wire sizes, orientation and position relative to the impactor have been examined under various LVI energies. It was revealed that the LVI penetration energy was increased for the thermoplastic-based composite laminates reinforced with stainless-steel mesh layers. Furthermore, the LVI penetration energy threshold was significantly influenced by the metal mesh wire size, orientation and stacking sequence. Finally, the backlight method capability was assessed to detect the after-impact interlaminar damages.

Experimental investigation on the low-velocity impact responses of fibre metal laminates with various internal and external factors

This paper aims to investigate the low-velocity impact (LVI) failure mechanism of fibre metal laminates (FMLs), and systematically explore the effects of internal factors (layup sequence and laminate configuration) and external factors (impact energy and environmental temperature) on the LVI responses. The drop-weight impact tester was utilised to conduct LVI tests at -30 ℃, 25 ℃, and 80 ℃ on FML-2/1 and FML-3/2 laminates. These laminates were made of S-class high-strength glass fibre and 2024 aluminium-alloy sheet with unidirectional, angle-ply, cross-ply and quasi-isotropic layup sequences. The characteristic curves including contact force-time, contact force-deflection, absorbed energy-time, and strain-time near the dent on the impacted and non-impacted specimen surfaces were obtained respectively. Furthermore, the dent depth of the impacted surface of the FMLs was measured. FML's damage was detected by ultrasonic C-scan, and its longitudinal and transverse sections were scanned by X-ray computed tomography (CT). The findings suggest that the layup sequence has a significant effect on the LVI response of FML-2/1, but has no obvious influence on FML-3/2. Moreover, FML-3/2 exhibits greater impact resistance compared to FML-2/1. The severity of LVI damage increases with the increase of impact energy. Notably, compared to the cases at 25 ℃, the LVI failure mechanisms of FMLs undergo significant changes at -30 ℃. The elevated temperature of 80 ℃ significantly affects the LVI damage of FML-2/1, while it has no significant effect on FML-3/2.

Low velocity impact response of Automated Fiber Placement Advanced Placed Ply composites

This study explores the influence of the internal architecture in the low-velocity impact response of Automated Fiber Placement Advanced Placed Ply laminates. AP-PLY laminates with different lay-up are subjected to low velocity impact and compression after impact experiments. Different performance in terms of damage tolerance is obtained as a function of their internal architecture. Triaxial and quasi-isotropic AP-PLY configurations presented a reduced extension of the delamination in comparison to cross-ply panels. As a result, the cross-ply configuration exhibited a drastic loss in residual strength of 49.1% when subjected to 50 J of impact energy. Numerical simulations were employed to provide insight into the deformation and failure mechanisms (e.g., matrix cracking of directly impacted yarns, delamination or tow debonding), and assess the performance of AP-PLY against conventional angle-ply laminates, predicting larger delamination for the latter, showing the potential of the AP-PLY architecture to produce laminates with improved low-velocity impact performance.

Dynamic response of ultra-high performance engineered cementitious composites (UHP-ECC) under low-velocity impact: effect of waste rubber incorporation and low temperatures

Dynamic response of ultra-high performance engineered cementitious composites (UHP-ECC) under low-velocity impact: effect of waste rubber incorporation and low temperatures

Numerical Analysis of Ultimate State of Reinforced Concrete Slabs under Low-Velocity Impact

Numerical Analysis of Ultimate State of Reinforced Concrete Slabs under Low-Velocity Impact

A constitutive model for shear thickening fluid (STF) impregnated Kevlar fabric subjected to impact loading

A constitutive model is presented herein to predict the response and failure of STF impregnated Kevlar fabric under impact loading on the basis of the progressive damage model for fibre reinforced plastic (FRP) laminates. In the constitutive model, the strain rate effect of shear strength is innovatively connected with the rheological property of STF. In order to verify the validity and accuracy of the model, numerical simulations of both ballistic and low-velocity impact experiments of STF impregnated Kevlar fabric are conducted. Furthermore, parametric study is carried out on the influences of impact velocity and rheological behavior of STF. It transpires that the numerical results using the constitutive model are in good agreement with the experimental data in terms of residual velocity, load-displacement curve, energy absorption, global deformation and failure patterns. It also transpires that, with the same impact energy, STF impregnated Kevlar fabric shows stronger resistance to lower velocity ballistic impact. In addition, the maximum viscosity and shear thickening interval of the STF have a significant effect on the ballistic performance of the STF impregnated Kevlar fabric.

Low-velocity Impact performance of 3D-printed PLA/Epoxy/Glass fibers of composite structures and latches

Low-velocity Impact performance of 3D-printed PLA/Epoxy/Glass fibers of composite structures and latches

Study on Dynamic Mechanical Properties of Sandwich Beam with Stepwise Gradient Polymethacrylimide (PMI) Foam Core under Low-Velocity Impact.

Different PMI foam materials of 52, 110, and 200 kg/m3 were used to design stepwise gradient cores to improve the impact resistance of the sandwich beam. The stepwise gradient core consists of three layers arranged in positive gradient, negative gradient, and sandwich-core (e.g., 200/52/200). These sandwich beams were subjected to the impact of a steel projectile under impact momentum of 10 to 20 kg·m/s, corresponding to impact energy in the range of 12.5 to 50 J. During the test, the impact force was recorded by an accelerometer, and the different failure modes were also obtained. Subsequently, the influence of the layer arrangement on the energy absorption and load transfer mechanism between the different layers was analyzed. The results showed that the top layer with a large density can improve the impact force, but the middle/bottom layer with a low density promoted specific energy absorption. Thus, based on these two points, the negative gradient core (200/110/52) had an excellent specific energy absorption because it can transfer and expand the area to bear the load layer by layer, which improved the energy absorption in each layer. Combined with the failure modes, the load transfer and deformation mechanisms between the layers were also discussed. The present work provided a valuable method to design an efficient lightweight sandwich structure in the protection field.

Experimental and Numerical Investigation of Dynamic Damage and Load Transfer of PBX Substitute Material under Low Velocity Impact.

The accidental initiation of explosives under mechanical loads has caused numerous catastrophic events. Therefore, the dynamic damage behavior of confined polymer-bonded explosives (PBXs) must be assessed to improve their practical applicability. In this study, polymer-bonded sugar (PBS) materials were prepared using a novel agglomerate to develop a PBX substitute material with enhanced experimental safety. The mechanical properties of the PBS shell were evaluated using a dynamic compression test, which revealed that the compression response of the shell was affected by the strain rate. A low-velocity impact experiment was performed to investigate the dynamic damage and load transfer characteristics of the PBX substitute. A constitutive model was developed to characterize the mechanical response of PBS subjected to high strain rates, and implementing this model in ABAQUS ensured successful prediction of the damage evolution process associated with PBS. Simulation results indicated that the PBS specimen was primarily damaged around its center while sliding friction was dominant near the center during pressure application. Notably, different stress states result in distinct crack growth velocity histories along the axial direction, with the damage ratio progressively decreasing toward regions closer to the impact surface.

Research on the influence of foaming silica gel-filled on low-velocity impact performance of M-type GFRP foldcore sandwich structure

The M-type GFRP foldcore was prepared by thermal pressing method, and was bonded with the panel to obtain the complete foldcore sandwich structure and filled the core with foaming silica gel. The influence of filling foam, impact energy and impact position on the damage mode and impact dynamic response under the low-velocity impact of GFRP M-type foldcore sandwich structure is studied through low-velocity experiment. The results show that the impact resistance of Node-impact is better than the Base-impact under low energy impact, while the Node-impact is worse than the Base-impact under high energy impact. Filling foam could effectively improve the impact properties of the foldcore sandwich plate and decrease the damage degree of the sandwich plate. In addition, filling foam could absorb about 16–26% more energy than the empty core sandwich plate.

A comprehensive analysis of low velocity impact response of [0/±45/90]s thin woven GFRP composites at room temperature

This study is motivated by the need to explore the low-velocity impact behavior of angle-ply thin woven GFRP composites with stacking sequence of [0/±45/90]s, especially the lack of literature concerning damage analysis correlation with a comprehensive range of measurements. The damage diameter, area, and perimeter length are characterized in this study by a novel AutoCAD image processing technique. The test results revealed that specimens subjected to impact energies in the range of 2–30 J are free from edge delamination compared to those tested at 40–50 J. Decreasing the contact duration at impact energy of 60 J is due to perforation accompanied with damage propagation toward the specimen edges and thus, the contact force is sharply dropped from its maximum value of about 4.48kN to 1.3kN. Consequently, both rebound speed and coefficient of restitution dropped to zero. The direct measurement of the energy threshold is increased in the following order: energy threshold at Fmax (2.3–14.9 J), first penetration (load drop) after peak load (23.9–25.6 J), penetration energy threshold (37.9 J), perforation energy threshold (31.1 J), and perforation and crack propagation energies (43.3 J). The perimeter length represents a novel damage parameter, exhibiting a strong correlation with impact energy, as evidenced by a high coefficient of determination of 0.97.