Low Velocity Impact Behavior Research Articles

Low-Velocity Impact Behaviour of Titanium-Based Carbon-Fibre/Epoxy Laminate

This study investigated the low-velocity impact response of titanium-based carbon-fibre/epoxy laminate (TI-CF FML). A comprehensive experimental study was carried out with impact energies ranging from 16.9 J to 91.9 J. Finite element analysis, performed using ABAQUS, was employed to elucidate the failure mechanisms of the laminate. Three distinct damage modes were identified based on the impact energy levels. The energy absorption characteristics of the TI-CF FML were analysed, revealing that maximum energy absorption is achieved and remains constant after penetration occurs. The relationship between impact force and displacement was also explored, showing that the laminate can withstand a peak force of 13.1 kN. The research on the impact resistance, damage mechanisms and energy absorption capacity of TI-CF FML provides an in-depth understanding of the impact behaviour of the laminate and its suitability for various industrial applications.

Recycled PET foam core sandwich panels with reinforced hybrid composite facesheets: A sustainable approach for enhanced impact resistance

This research explores the Low-Velocity Impact behavior of thermoplastic composite sandwich panels with 100% recycled Polyethylene Terephthalate (PET) foam sourced from post-consumer plastic water bottles. Being recognized as a reliable technique, hybridization using stainless-steel mesh layers was employed to reinforce the panels’ composite facesheets of sandwich panels accessible for modular housing, cold storage rooms and cargo trucks. Adequate impregnation of the reinforcement metallic mesh layer alongside proper skin-to-core adhesion was accomplished by optimizing a two-phase compression molding method. The effect of hybridization on impact response of sandwich panels with two different PET foam core thicknesses, and stacking sequence were evaluated. It was revealed that reinforcing the impacted surface of the composite sandwich panels significantly increased the perforation threshold. Moreover, analyzing the post-impact section view of the samples indicated that hybridization modified the damage propagation response of the PET foam core sandwich composites, through which the energy absorption capacity was improved.

Investigation into the Role of Z-Fiber Orientation in Low-Velocity Impact Behavior of Sandwich-Structured Composite: Numerical and Experimental Analysis

Investigation into the Role of Z-Fiber Orientation in Low-Velocity Impact Behavior of Sandwich-Structured Composite: Numerical and Experimental Analysis

Investigation of Low Velocity Impact Behavior of Aluminum Honeycomb Sandwich Structures with GFRP Face Sheets by Finite Element Method

The aim of this study is to examine the low velocity impact behavior of aluminum honeycomb sandwich structures with glass fiber reinforced plastic (GFRP) face sheets with the help of finite element method. In the study, low velocity impact tests were carried out in the LS DYNA finite element program to examine the effects of face sheets thickness, core number, wall thickness, impact location and impact velocity on maximum contact force, absorbed energy efficiency and damage mode. Progressive damage analysis based on the Hashin damage criterion and the combination of Cohesive Zone Model (CZM) and the bilinear traction-separation law was performed using the MAT-54 material model. At the end of the study, it was determined that the face sheets thickness in sandwich structures had a significant effect on the impact resistance up to a certain impact energy. It has been observed that as the impact velocity gradually increases, there is a decrease in the contact force after a certain threshold value. As the impactor velocity increases, the energy absorption efficiency also increases. It has been determined that the location of the impact is very effective on peak force and energy absorption efficiency. The effect of the number of core layers depends on the face sheets thickness. When the face sheets thickness was not damaged at first contact, the peak force value increased in parallel with the number of layers. It was determined that the dominant damage mode after impact was matrix damage. It has been observed that as the energy level of the impactor increases, damage also occurs on the back surfaces.

Particularities on the Low-Velocity Impact Behavior of 3D-Printed Sandwich Panels with Re-Entrant and Honeycomb Core Topologies

This work describes, through experimental and numerical investigations, the mechanical behavior and energy absorption characteristics of 3D-printed sandwich panels with cellular cores subjected to low-velocity impact. Using fused deposition modeling techniques (FDM), three different sandwich panels, one with a regular hexagonal core and two with re-entrant cores at 0 and 90 degrees, were fabricated. The sandwich panels were subjected to low-velocity impact, at impact energies of 10 J and 15 J. A comprehensive investigation of the panels’ behavior through experimental testing and numerical simulation was conducted. The results indicate that the sandwich panel with a 90 degrees re-entrant core is stiffer and absorbs the largest amount of impact energy but, at the same time, suffers significant damage to the upper facesheet. The 0 degrees re-entrant core is compliant and provides both impact resistance and good energy absorption characteristics. Such a sandwich panel finds its application in the construction of personal protective equipment, where the aim is to minimize the forces transmitted during low-velocity impacts and maximize the total absorbed energy. Re-entrant core sandwich panels prove to be very good candidates for replacing the honeycomb core sandwich, depending on the desired engineering application.

Effect of Embedded Shape Memory Alloy (SMA) on the Low-velocity Impact Behaviour of Stringer Stiffened Composite Plates

Effect of Embedded Shape Memory Alloy (SMA) on the Low-velocity Impact Behaviour of Stringer Stiffened Composite Plates

Low-velocity impact behavior analysis on composite double curved-shell reinforced with graphene platelet

ABSTRACT This research investigates the low-velocity impact behavior of a spherical rigid body on a composite shell reinforced with graphene platelets (GPLs), in which GPL have been uniformly dispersed and randomly arranged within each individual layer. The weight proportion of GPL has been altered across the thickness. The modified Halpin Tsai model is employed to analyze the Young's modulus and the effective material characteristics of a composite reinforced with graphene platelets (GPLRC). The mass density and Poisson's ratio of the viscoelastic multilayer composite are determined using the rule of mixture. The material parameters of each layer are defined according to the Kelvin–Voigt model. The governing equations have been derived by applying the first order shear deformation shell theory, Hamilton's principle, and modifying the Hertz contact law. The PDE problems have been transformed into ODE equations through the utilization of the Galerkin method. Subsequently, the ordinary equations have been solved utilizing the Newmark method. A parametric study is conducted to examine the effects of various factors, such as fraction weight, GPL distribution pattern, impactor mass, radius, viscoelastic modulus, and initial velocity, on the low velocity impact response of a composite shell reinforced with GPL.

Probing uncertainty in low-velocity impact behaviour of hybrid functionally graded (FG)—sandwich plate and spherical shell structures

Probing uncertainty in low-velocity impact behaviour of hybrid functionally graded (FG)—sandwich plate and spherical shell structures

Low-velocity impact behavior and damage mechanisms of honeycomb sandwich structures with elastomeric interlayers in CFRP skins

Elastomers help improve the toughness of lightweight high-strength materials, offering significant potential for enhancing the mechanical properties. However, introducing elastomers into CFRP interlayers as skin for composite sandwich structures has not yet been explored regarding the impact responses of such novel structures. This paper, for the first time in literature studies the low-velocity impact behavior and damage mechanisms of this novel sandwich structure using a combined experimental and numerical approach. The experimental results of sandwich structures with and without elastomer layers under different impact energies are presented. Finite element models of the two sandwich structures are built and impact behaviors were compared. The differences in internal damage and energy distribution during the impact are investigated to explain the reasons for the differing impact responses of the two sandwich structures. The results reveal that elastomeric interlayers have a significant advantage in enhancing the damage resistance of composite sandwich structures, especially under high impact energy conditions. The key contributions of this paper include the experimental characterization of the impact behavior of composite sandwich structures with elastomeric interlayers, and the explanation of the reasons for the changes in impact responses caused by the elastomers from the perspectives of damage mechanisms and energy distribution.

A Review of Experimentation Numerical Simulation of Low-Velocity Impact Performances and Damages of Fiber-Reinforced Composites

Fiber-reinforced composites (FRCs) are extensively utilized in various industries due to their lightweight and high-strength properties, making the understanding of their response to low-velocity impact (LVI) crucial for ensuring structural integrity, performance and invisible internal damages that can compromise performance and safety. This paper critically examines the current state of research on the low-velocity impact behavior of FRCs, focusing on both experimental and numerical simulation approaches. The review comprehensively surveys on characterizing and modeling the response of FRCs to low-velocity impacts leading to damages. The effects of parameters including composites preparation; impact mechanics; testing methods; induced damages including assessment methods; different performance parameters including impact energy, force, load, impact resistance; post-impact damages and their resistance; performance and damage affecting different factors; numerical and simulation modeling are discussed. Current challenges and future prospects regarding the subject matter is highlighted. The comprehensive analysis presented in this review goals to consolidate current knowledge, identify research gaps, and guide future endeavors in enhancing the understanding of low-velocity impact (LVI) behavior in fiber-reinforced composites (FRCs).

Energy Absorption Behavior of Carbon-Fiber-Reinforced Plastic Honeycombs under Low-Velocity Impact Considering Their Ply Characteristics.

Honeycomb structures made of carbon-fiber-reinforced plastic (CFRP) are increasingly used in the aerospace field due to their excellent energy absorption capability. Attention has been paid to CFRP structures in order to accurately simulate their progressive failure behavior and discuss their ply designability. In this study, the preparation process of a CFRP corrugated sheet (half of the honeycomb structure) and a CFRP honeycomb structure was illustrated. The developed finite element method was verified by a quasi-static test, which was then used to predict the low-velocity impact (LVI) behavior of the CFRP honeycomb, and ultimately, the influence of the ply angle and number on energy absorption was discussed. The results show that the developed finite element method (including the user-defined material subroutine VUMAT) can reproduce the progressive failure behavior of the CFRP corrugated sheet under quasi-static compression and also estimate the LVI behavior. The angle and number of plies of the honeycomb structure have an obvious influence on their energy absorption under LVI. Among them, energy absorption increases with the ply number, but the specific energy absorption is basically constant. The velocity drop ratios for the five different ply angles are 79.12%, 68.49%, 66.88%, 66.86%, and 60.02%, respectively. Therefore, the honeycomb structure with [0/90]s ply angle had the best energy absorption effect. The model proposed in this paper has the potential to significantly reduce experimental expenses, while the research findings can provide valuable technical support for design optimization in aerospace vehicle structures.

Low-velocity impact behavior of foam-based sandwich composite reinforced with warp-knitted spacer fabric; numerical and experimental study

The aim of this research is to investigate experimentally and numerically the low-velocity impact behavior of foam-based composites reinforced with warp-knitted spacer fabric (WKSF). To prepare different foam-based composites, the structural parameters of WKSFs including cell size, position, and Z-fiber height were considered. A drop weight impact test with an initial energy of 5J was carried out to examine the low-velocity impact behavior of composites, followed by experimental analyses of Mises, shear, and normal stress on various composite components. Thereafter, the impact behavior of the composites was simulated using ABAQUS/CAE software. The comparison between experimental and numerical results showed a maximum error of 9.79% in predicting the acceleration of impactor. In addition, the results revealed significant stress disparities among samples. Stress analysis showed complex patterns across samples, emphasizing structural parameter influence on stress tolerance and load-bearing capabilities. Notably, Z-fibers displayed substantial stress tolerance, while the matrix predominantly undergoes shear stress. Consequently, the ideal structure for low-velocity impact applications includes small cell size, high thickness, and non-facing hexagonal cells.

Effects of Rubber Core on the Mechanical Behaviour of the Carbon-Aramid Composite Materials Subjected to Low-Velocity Impact Loading Considering Water Absorption.

The large-scale use of composite materials reinforced with carbon-aramid hybrid fabric in various outdoor applications, which ensures increased mechanical resistance including in impact loadings, led to the need to investigate the effects of aggressive environmental factors (moisture absorption, temperature, thermal cycles, ultra-violet rays) on the variation of their mechanical properties. Since the literature is still lacking in research on this topic, this article aims to compare the low-velocity impact behaviour of two carbon-aramid hybrid composite materials (with and without rubber core) and to investigate the effects of water absorption on impact properties. The main objectives of this research were as follows: (i) the investigation of the mechanical behavior in tests for two impact energies of 25 J and 50 J; (ii) comparison of the results obtained in terms of the force, displacement, velocity, and energy related to the time; (iii) analysis of the water absorption data; (iii) low-velocity impact testing of wet specimens after saturation; (iv) comparison between the impact behaviour of the wet specimens with that of the dried ones. One of the main findings was that for the wet specimens without rubber core, absorbed impact energy was 16% less than the one recorded for dried specimens at an impact energy of 50 J. The failure modes of the dried specimens without rubber core are breakage for both carbon and aramid fibres, matrix cracks, and delamination at matrix-fibre interfaces. The degradation for the wet specimens with rubber core is much more pronounced because the decrease in the absorbed impact energy was 53.26% after 10,513 h of immersion in water and all the layers were broken.

On low-velocity impact behavior of flexible and stiff composites for better energy absorption

On low-velocity impact behavior of flexible and stiff composites for better energy absorption

Response of short jute fibre preform based epoxy composites subjected to low-velocity impact loadings

This work aimed to investigate the low velocity impact behaviour of short jute fibre non-woven preform epoxy matrix composites experimentally. Dry fibre preforms were developed using an optimised process and a laboratory made preforming device. The effects of alkali and poly vinyl alcohol (PVA binder) treatments on impact performances of jute composites were investigated and compared at 3 J and 6 J impact energy levels. To identify the failure modes of tested composites, the X-ray µCT tomography was employed. The results demonstrated that the developed untreated short jute fibre preform reinforced composites absorbed a higher impact energy, when they were compared to treated (alkali or PVA binder) composites. For untreated composites, maximum impact forces at 3 J and 6 J energies, were found as ⁓2478 N and ⁓2319 N, respectively; for the PVA treatment these values were measured as ⁓2457 N and ⁓2216 N, while, at same energy levels, alkali treated composites showed the lowest values as ⁓1683 N and ⁓1440 N, respectively. Untreated jute fibre contains natural matrices such as hemicellulose, lignin and waxes, which ensured a positive response to absorb more energy upon impact loading. In contrast, the alkali treatment facilitates a highly fibre packed composite structure, which accelerated the impact crack propagation in tested composites, resulting in lower resistance to impact energy. Although, PVA treated composites showed reduced impact properties compared to untreated composites due to the PVA polymer brittleness on the treated fibre surface during the impact incidents, this treatment demonstrated better impact responses over the alkali treatment. The application of PVA binder on alkali-treated fibres provided an extra support to fibres and a better fibre/matrix interface and hence, this combined treatment demonstrated a slightly better impact resistance (⁓2027 N and ⁓1874 N impact forces at 3 J and 6 J respectively) compared to only alkali treated fibre composites. The SEM fracture images and the X-ray µCT damage analysis revealed different impact damage modes, which supported the observed impact results. The obtained results from this investigation could be helpful for using short jute fibre composites in various load demanding applications where impact incidents are likely to be happened.

Experimental analysis of low-velocity impact behaviour on flax-balsa biobased sandwich

This article deals with a detailed experimental study dedicated to the evaluation of the overall mechanical behaviour of a bio-based composite structure used in transportation industries. The sandwich structure is designed to increase the lightening, vibration damping, and composite recyclability. The considered materials consist of a Flax/Elium® laminate composite for skins associated with a balsa core. The sandwich structure was obtained using a one-shot liquid resin infusion process. Low-velocity impact tests were carried out on different sandwich configurations with the aim of characterizing the effects of the stacking sequence and the density and thickness of the core. Furthermore, an experimental comparative analysis was conducted involving two composite laminate types: Glass/Elium and Flax/Elium to enhance the specific behaviour of flax fibre composite to be used as skins in the sandwich structures. The impact tests were carried out at low velocities and at different levels of impact energy using a drop-weight test bench. Notable damage mechanisms have been identified, and a chronological sequence of their development has been suggested. Ultrasonic analyses using C-Scan imaging were applied to the opposite side of the impacted specimen. The research proves the efficient energy-absorbing capability of the biobased sandwich structure during impact. Finally, this study enables a deeper understanding of various parameters that influence the behaviour of sandwiches during low-velocity impacts, thereby facilitating more informed material selection for practical applications.

Transverse low-velocity impact behaviors of pultruded carbon-fiber-reinforced polymer rods with tensile preloads: Experiment and simulation

Extensive research has been conducted on the replacement of steel cables with carbon-fiber-reinforced polymer (CFRP) cables to eliminate steel corrosion and self-weight problems in cable-supported bridges. The potential low-velocity impact (e.g., vehicle collision) may cause CFRP cables to experience catastrophic failure. However, little attention has been paid to the low-velocity impact on a pultruded composite rod. This article focused on understanding and modeling the transverse impact behaviors of the pultruded CFRP rod with tensile preloads (0–0.58 preload ratios). Two damage models were proposed for predicting these behaviors: one combining the fiber/matrix damage model with a cohesive zone model (Model A), and the other employing only the fiber/matrix damage model (Model B). The short-beam shear test method was proposed to identify the intended interlaminar debonding location when employing a cohesive zone model. Both proposed models were validated against the experimental results, and their applicability was given. It was found that the tensile preloading presented a ‘stiffening effect’ and changed the rod from shear stress-dominated failure to tensile stress-dominated failure.

Experimental investigation on axial quasi-static compression and low-velocity impact behaviors of perforated thermoplastic composite cylindrical shells

Perforation in cylindrical shells is commonly a typical technique to fulfill relevant functional requirements. However, how the perforation influence the mechanical performance of thermoplastic composite cylindrical shells (TPCCS) is incompletely understood. Hence, a systematic investigation through quasi-static compression and low-velocity impact (LVI) experiments was carried out in this paper. The full-field strain distributions of TPCCS intact tubes (IT) and perforated tubes (PT) were monitored by using 3D-DIC, and the residual properties were also characterized by compression-after-impact (CAI) tests. The results show that under quasi-static compression, the structural stiffness decreases significantly with increasing perforation diameter. The perforation reduces the interference of internal random defects on the structural deformation mode, which leads to a significant strain concentration in PT. The peak force and initial stiffness under LVI are smaller than those under quasi-static compression, with IT displaying higher sensitivity to dynamic loading compared to PT. At the impact energy of 100 J, IT and PT exhibit “S”- and “X”-shaped deformation modes, respectively. CAI tests indicate that although PT has a poorer residual load-carrying capacity than IT, it retains good structural integrity and secondary energy absorption capacity. This study provides a valuable reference for the assessment and application of perforated TPCCS.

Influence of Reinforcement Architecture on Behavior of Flax/PLA Green Composites under Low-Velocity Impact.

The main goal of this study is the comparison of different reinforcement architectures on the low-velocity impact behavior of green composites. The study includes the comparison of unidirectional, basket weave, and twill weave flax/PLA composites, they are subjected to unidirectional tensile tests, drop-weight impact tests, and after-impact compression tests. Results show that the unidirectional composite demonstrates superior tensile strength and initial modulus due to reduced fiber crimp, while basket weave exhibits the highest energy absorption capability and strain capacity attributed to its higher fiber-weight ratio and fiber crimp. Unidirectional composite also shows a larger impacted damage area compared to basket weave and twill weave, attributed to its internal architecture. Residual compressive strength across all composites decreased by 40% compared to the reference sample. However, the reduction in stiffness after impact was different, UD/PLA composite stiffness was reduced by 30% while the reduction in BW/PLA and T/PLA composites was about 20%.

Inter-layer failure and toughening mechanisms of carbon/aramid hybrid fiber composites interleaved with micro/nano pulps under low-velocity impact load

Hybrid fiber-reinforced polymer (HFRP) composites are widely used in aerospace structures because of their excellent overall performance. However, it is still challenging to address the issue of high sensitivity to delamination between dissimilar material interlayers in HFRP composites. This study combines experimental and numerical simulation to analyze the low-velocity impact behavior and interlaminar damage of two types of HFRP. Based on a micromechanical model, an equivalent aramid pulp (eAP) toughening laminate model is developed. The impact behavior of the HFRP toughen by eAP only in dissimilar material interlayers is simulated based on the model. The effect of eAP areal density on the impact behavior and evolution of interlaminar damage is analyzed. Results show that the maximum force and impact stiffness of eAP-toughened HFRP increase initially with the increase in eAP areal density, and then decrease slowly. The area and extent of damage of dissimilar material interlayers in eAP toughened laminates is significantly reduced. Finally, the interlaminar toughening and failure mechanisms by eAP-toughening only in dissimilar material interlayers of the HFRP composites are systematically revealed from fiber bridging and damage transfer perspectives.