Showing papers on "Composite laminates published in 2010"
TL;DR: In this article, a three-dimensional reinforcement of woven advanced polymer-matrix composites using aligned carbon nanotubes (CNTs) is explored experimentally and theoretically.
382 citations
TL;DR: In this paper, a composite laminate may be designed as a permutation of several straight-fiber layers or as a matrix embracing fibers positioned in curvilinear paths.
354 citations
TL;DR: In this paper, a comprehensive review on the general methodologies on the damage constitutive modeling by continuum damage mechanics (CDM), the various failure criteria, the damage evolution law simulating the stiffness degradation, and the finite element implementation of progressive failure analysis in terms of the mechanical response for the variable-stiffness composite laminates arising from the continuous failure.
261 citations
TL;DR: Wang et al. as discussed by the authors examined the evolution of damage in graphite/epoxy composite laminates due to lightning strikes to clarify the influence of lightning parameters and specimen size.
Abstract: This study examines the evolution of damage in graphite/epoxy composite laminates due to lightning strikes To clarify the influence of lightning parameters and specimen size, artificial lightning testing was performed on a series of laminated composite specimens Damage was assessed using visual inspection, ultrasonic testing, micro X-ray inspection, and sectional observation The results showed that the damage modes can be categorized into fiber damage, resin deterioration, and internal delamination modes Damage progression is governed by the strong electrical orthotropic properties of the laminates, and the lightning parameters defining impulse waveform show strong relationship with certain damage modes, though specimen size and thickness variation barely affect damage size
254 citations
TL;DR: In this article, a comparative study on different drill point geometries and feed rate for composite laminates drilling is presented, showing that a cautious combination of the factors involved, like drill tip geometry or feed rate, can promote the reduction of delamination damage.
229 citations
TL;DR: In this paper, an anhydride-cured thermosetting epoxy polymer was modified by incorporating 10 wt.% of well-dispersed silica nanoparticles, which increased the fatigue life by about three to four times.
190 citations
TL;DR: Carbon fiber reinforced epoxy composite laminates, with strategically incorporated fluorine functionalized carbon nanotubes (f-CNTs) at 0.2, 0.3 and 0.5 weight percent (wt%), are studied for improvements in tensile strength and stiffness and durability under both tension-tension (R ǫ+0.1) and tension-compression (Rǫ −0. 1) cyclic loadings, and then compared to the neat (0.0) CNTs)-based composite laminate material as mentioned in this paper.
181 citations
TL;DR: In this paper, the authors presented a new methodology to measure the crack resistance curves associated with fiberdominated failure modes in polymer-matrix composites, which is based on the identification of the crack tip location using Digital Image Correlation and the calculation of the J-integral directly from the test data using a simple expression derived for cross-ply composite laminates.
175 citations
TL;DR: A thorough analysis of fatigue of composite laminates under multiaxial loading is presented in this article, where a large body of experimental data taken from the literature is examined to delineate the influence on the fatigue strength of factors such as biaxiaity ratios and off-axis and out-of-phase angles.
159 citations
TL;DR: In this paper, low-velocity impact characteristics and residual tensile strength of carbon fiber composite laminates are investigated by experimentally and numerically using finite element software, ABAQUS/Explicit.
149 citations
TL;DR: In this article, the impact resistance of composite laminate that has been interleaved by electrospun Nylon 66 nanofabric was evaluated and the impact velocit y, force, and energy were ranged from 2.0 to 4 m/s, 900 to 2,100 N and 0.46 to 1.8 J, respectively.
TL;DR: In this article, a composite plate is monitored for damage resulting from a low-velocity impact using a low profile piezoceramic transducer and a low frequency flexural modal excitation.
Abstract: The paper demonstrates the application of nonlinear acoustics for impact damage detection in composite laminates. A composite plate is monitored for damage resulting from a low-velocity impact. The plate is instrumented with bonded low-profile piezoceramic transducers. A high-frequency acoustic wave is introduced to one transducer and picked up by a different transducer. A low-frequency flexural modal excitation is introduced to the plate at the same time using an electromagnetic shaker. The damage induced by impact is exhibited in a power spectrum of the acoustic response by a pattern of sidebands around the main acoustic harmonic. The results show that the amplitude of sidebands is related to the severity of damage. The study investigates also the effect of boundary conditions on the results.
TL;DR: In this article, a global bolted joint model (GBJM) is proposed to capture effects such as bolt-hole clearance, bolt-torque, friction between laminates, secondary and tertiary bending in the laminate as well as the load distribution in multi-bolt joints.
Abstract: This paper presents the development and validation of a global bolted joint model (GBJM), a highly efficient modelling strategy for bolted composite joints. Shell elements are used to model the composite laminates and the bolt is represented by a combination of beam elements coupled to rigid contact surfaces. The GBJM can capture effects such as bolt–hole clearance, bolt-torque, friction between laminates, secondary and tertiary bending in the laminates as well as the load distribution in multi-bolt joints. The GBJM is validated using both three-dimensional finite element models and experiments on both single- and multi-bolt joints. The GBJM was found to be robust, accurate and highly efficient, with time savings of up to 97% realised over full three-dimensional finite element models.
TL;DR: In this paper, the damage characteristics of carbon fiber/toughened epoxy thin-ply laminates subjected to transverse loadings were investigated, and it was clarified that accumulated delamination position has a significant effect on the fiber fractures during the indentation.
TL;DR: In this paper, the authors present an experimental investigation of the mechanical response and the industrial manufacturability of CFRP-titanium hybrid laminates using the example of a spacecraft payload adaptor.
TL;DR: In this article, the application of cross-modulation vibro-acoustic technique for impact-damage detection in composite laminates is demonstrated, where a composite plate is monitored for damage resulting from a collision.
Abstract: The paper demonstrates the application of cross-modulation vibro-acoustic technique for impact-damage detection in composite laminates. A composite plate is monitored for damage resulting from a lo...
TL;DR: In this article, a substitute material model for describing the load response of globally flat corrugated sheets made from multidirectional laminates is proposed, and the analytical results are compared with those of finite-element models.
TL;DR: In this paper, a finite element approach using commercial ANSYS V11.0 software was developed to accurately predict the cured shape of bistable composites by including the influence of manufacturing imperfections, such as resin rich areas and ply-thickness variations.
TL;DR: In this paper, the authors present the results of a novel experimental investigation to map the surface profiles of a series of arbitrary layup laminates and conclude that while existing modelling techniques are successful in accurately predicting room-temperature shapes, the sensitivity of solutions to imperfections is significant.
TL;DR: In this article, two models were developed to characterize the Lamb wave propagation properties of orthotropic panels, and experiments were conducted to empirically characterize the wave propagation behavior in a manufactured laminate.
Abstract: Damage detection in composite laminated panels using Lamb waves is demonstrated with an innovative use of a sensor array and processing algorithm. Two models were developed to characterize the Lamb wave propagation properties of orthotropic panels. Predictions of the dispersion relations were made for a fiber-reinforced composite laminate. Experiments were conducted to empirically characterize the wave propagation behavior in a manufactured laminate. Piezoelectric patches were used as sensors and actuators in the experiments. Comparisons were made between analytical predictions and experimental results, which demonstrate that the higher order model captured essential wave propagation behavior at frequencies of interest. Sensor arrays and associated processing were used for wavenumber decomposition and filtering of the Lamb wave modes. Composite laminates were manufactured with an embedded defect to simulate inter-ply delamination. Experiments were conducted to detect the presence of delamination damage in...
TL;DR: In this paper, an experimental damage analysis of a 5-harness satin weave carbon-PPS (polyphenylene sulphide) composite under uni-axial static tensile load is presented.
TL;DR: In this article, a critical laminate energy parameter associated with formation of these cracks is defined and evaluated using experimental data for a reference cross-ply laminate, and a parametric study is conducted to evaluate effects of ply thickness and ply stacking sequence on damage evolution in [ 0 m / 90 n/ ∓ θ p ] s laminates.
TL;DR: In this paper, a finite element analysis (FEA) method was used to simulate the fatigue damage evolution in composite laminates and predict fatigue life of the laminate with different lay-up sequences on the basis of the fatigue characteristics of longitudinal, transverse and in-plane shear directions.
TL;DR: In this paper, the effects of bonding high strength carbon fibers to E-glass composite cores using a high temperature, inorganic matrix known as geopolymer were investigated, and the results indicated that hybrid composite plates manufactured using 3k unidirectional carbon tape exhibit an increase in flexural capacity of approximately 700% over those manufactured using Eglass fibers alone.
Abstract: By far, carbon and glass fibers are the most popular fiber reinforcements for composites. Traditional carbon composites are relatively expensive since the manufacturing process requires significant heat and pressure, while the carbon fibers themselves are inherently expensive to produce. In addition, they are often flammable and their use is restricted when fire is a critical design parameter. Glass fabrics are approximately one order of magnitude less expensive than similar carbon fabrics. However, they lack the stiffness and the durability needed for many high performance applications. By combining these two types of fibers, hybrid composites can be fabricated that are strong, yet relatively inexpensive to produce. The primary objective of this study was to experimentally investigate the effects of bonding high strength carbon fibers to E-glass composite cores using a high temperature, inorganic matrix known as geopolymer. Carbon fibers were bonded to E-glass cores (i) on only the tension face, (ii) on both the tension and compression faces, or (iii) dispersed throughout the core in alternating layers to obtain a strong, yet economical, hybrid composite laminate. For each response measured (flexural capacity, stiffness, and ductility), at least one hybrid configuration displayed mechanical properties comparable to all carbon composite laminates. The results indicate that hybrid composite plates manufactured using 3k unidirectional carbon tape exhibit increases in flexural capacity of approximately 700% over those manufactured using E-glass fibers alone. In general, as the relative amount of carbon fibers increased, the likelihood of precipitating a compression failure also increased. For 92% of the specimens tested, the threshold for obtaining a compression failure was utilizing 30% carbon fibers. The results presented herein can dictate future studies to optimize hybrid performance and to achieve economical configurations for a given set of design requirements.
TL;DR: In this article, a finite element model for failure analysis of composite laminates with the phantom node method for matrix cracking and interface elements for delamination is presented, which allows for mesh-independent representation of straight intraply cracks in Laminates.
15 Jan 2010-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the effect of fiber orientation and stacking sequence on the progressive mixed mode delamination failure in composite laminates using fracture experiments and finite element (FE) simulations is investigated.
Abstract: This paper focuses on the effect of fiber orientation and stacking sequence on the progressive mixed mode delamination failure in composite laminates using fracture experiments and finite element (FE) simulations. Every laminate is modelled numerically combining damageable layers with defined fiber orientations and cohesive zone interface elements, subjected to mixed mode bending. The numerical simulations are then calibrated and validated through experiments, conducted following standardized mixed mode delamination tests. The numerical model is able to successfully capture the experimentally observed effects of fiber angle orientations and variable stacking sequences on the global load–displacement response and mixed mode inter-laminar fracture toughness of the various laminates. For better understanding of the failure mechanism, fracture surfaces of laminates with different stacking sequences are also studied using scanning electron microscopy (SEM).
TL;DR: In this paper, a new ultrasonic propagation system using macrofiber composite actuators and fiber Bragg grating (FBG) sensors was used to detect delamination damage in composite laminates.
Abstract: A new ultrasonic propagation system has been constructed using macrofiber composite (MFC) actuators and fiber Bragg grating (FBG) sensors. The MFCs and FBGs can be integrated into composite laminates because of their small size and high fracture strain. The developed system can send and receive broadband Lamb waves. In this research, this system was used to detect delamination damage in composite laminates. First, the multiple modes of Lamb waves in a carbon-fiber-reinforced plastic (CFRP) quasi-isotropic laminate were identified by transmitting and receiving the symmetric and antisymmetric modes separately. Then, the mode conversions at both tips of a delamination were investigated through an experiment and a two-dimensional finite element analysis (FEA). A new delamination detection method was proposed on the basis of the mode conversions, and experiments were carried out on laminates with an artificial delamination. When antisymmetric modes were excited, the frequency dispersion of the received A1 mode changed, depending on the delamination length owing to the mode conversion between the A1 mode and the S0 mode. This phenomenon was confirmed through the FEA and these results prove that this new method is effective in detecting a delamination in CFRP laminates.
TL;DR: In this article, a coupled mechanical and diffusion model is presented to better predict the final void size at the end of polymerization by considering the onset of pressure application and diffusive species concentration.
TL;DR: In this article, the initiation and propagation of edge delamination considering the effects of transverse cracks were investigated using quasi-isotropic carbon-fiber-reinforced plastic (CFRP) laminates with a stacking sequence of [45/0/−45/90] s.
Metz1
TL;DR: In this article, experimental investigations are carried out to determine the response of glass/epoxy cross ply laminates to repeated low-velocity impact, and the material response is evaluated in terms of damage progression with the number of impacts.