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Journal articles on the topic 'Laminated'
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1
bin Yaakob, Mohd Yuhazri, T. T. T. Jennise, H. Sihombing, Qumrul Ahsan, S. T. W. Lau, and Mohd Imran bin Ghazali. "Gravity Effects on the Density of Laminated Composite due to the Differences in Angle Cured." Applied Mechanics and Materials 465-466 (December 2013): 81–85. http://dx.doi.org/10.4028/www.scientific.net/amm.465-466.81.
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This research is carried out to study the feasibility of the gravity effects on curing position of the laminated composite structures to enhance the curing space needed. Vertical cured laminate having almost similar properties with common horizontal cured laminate able to save much space in composite industry especially for developing Small and Medium Industry (SMI). Horizontal cured laminates filled up spaces in which SMI lack of. Polyesters and E-glass fibers were used as the raw material in this research. Vacuum bagging technique was used to suck out the excess resin during lay-up to avoid any voids and air inside laminate and cured at different angle position in room temperature for 24 hours. Seven samples of laminated composite were fabricated and cut into specific dimension in accordance to ASTM standard. The aim of the research was to investigate the density property of the thermosetting laminated composite by curing the laminate at different angle using vacuum bagging technique. From the testing, SN6 had the same density value with control sample, SN1 that had value of 1.46 g/cm3.
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Marzuki, Haslan Fadli Ahmad, Mawarni Mohamad, Engku Ahmadhilmi Engku Ubaidillah, Mohd Nasha’ain Nordin, Mohd Fadzlee Zainal Abidin, Norazlan Roslani, Yusli Mohamad Junos, Salleh Omar, and Mariatti Jaafar. "Effect of Anodizing on Strength of Carbon-Fibre Aluminium-Laminated Composites." Advanced Materials Research 748 (August 2013): 216–21. http://dx.doi.org/10.4028/www.scientific.net/amr.748.216.
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Fibre-metal-laminated composites that consist of aluminium and carbon fibre/epoxy was widely use in engineering fields such as in aerospace and civil application. An issue arise for this laminate systems is that aluminium surfaces must be treated to ensure the effectiveness of load transfer mechanism in the interfacial region. In this research, the effect of anodized layer on the aluminium surface towards strength of the carbon fibre-aluminium-laminated composites was studied. Aluminium 6061-T6 was anodized using phosphoric acid as electrolyte and different anodizing voltage to produce different surface morphology. The surface roughness and morphology were determined via Atomic Force Microscopy and its wettability was determined by Static Contact Angle. Then, anodized aluminium was laminated with carbon fibre/epoxy system via vacuum bagging techniques. It shows that the strength of laminated composite with anodized surface increases up to 26% compared to laminates without anodized surfaces. Furthermore, the failure mechanism of laminated composite with anodized surface resulted in partial adhered failure instead of adhesive failure. These show that anodized surfaces contributes to the effectiveness of load transfer mechanism in fibre-metal-laminates composites.
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Mujahid, Yasir, Nabihah Sallih, Mazli Mustapha, Mohamad Zaki Abdullah, and Faizal Mustapha. "Effects of Processing Parameters for Vacuum-Bagging-Only Method on Shape Conformation of Laminated Composites." Processes 8, no. 9 (September 14, 2020): 1147. http://dx.doi.org/10.3390/pr8091147.
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Complex composite structures manufactured using a low-pressure vacuum bag-only (VBO) method are more susceptible to defects than flat laminates because of the presence of complex compaction conditions at corners. This study investigates the contribution of multivariate processing parameters such as bagging techniques, curing profiles, and laminate structures on laminates’ shape conformation. Nine sets of laminates were produced with a concave corner and another nine sets with a convex corner, both with a 45° inclined structure. Three-way analysis of variance (ANOVA) was performed to quantify thickness variation and spring effect of laminated composites. The analysis for concave and convex corners showed that the bagging techniques is the main factor in controlling the laminate thickness for complex shape applications. The modified (single) vacuum-bag-only (MSVB) technique appeared to be superior when compared to other bagging techniques, exhibiting the least coefficients of variation of 0.015 and 0.016 in composites with concave and convex corners, respectively. Curing profiles and their interaction with bagging techniques showed no statistical significance in the contribution toward laminate thickness variation. The spring effect of laminated composites was investigated by calculating the coefficient of determination (R2) relative to that of the mold. The specimens exhibited a good agreement with R2 values ranging from 0.9824 to 0.9946, with no major data offset. This study provides guidelines to reduce thickness variations and spring effect in laminated composites with complex shapes by the optimum selection of processing parameters for prepreg processing.
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Mori, Ryota, Hiroshi Miyamura, Shiomi Kikuchi, Koji Tanaka, Nobuhiko Takeichi, Hideaki Tanaka, Nobuhiro Kuriyama, Tamotsu T. Ueda, and Makoto Tsukahara. "Hydrogenation Characteristics of Mg Based Alloy Prepared by Super Lamination Technique." Materials Science Forum 561-565 (October 2007): 1609–12. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.1609.
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In order to improve the hydrogenation property of Mg/Ti laminate composite, Ni was added as a third element. Hydrogen storage properties of the laminated Mg/Ti/Ni alloy films were studied. Laminated Mg/Ti/Ni multilayer alloy films were prepared by cold rolling of stacked Mg, Ti and Ni under ambient conditions. The stacked foils were subjected to repetition of rolling and stacking, resulting in super-laminated foils with the thickness less than 0.3mm, containing more than 15000 layers. Microstructures of the super-laminates were studied by scanning electron microscopy and X-ray diffractometry. Their hydrogenation behaviors were investigated by use of a Sieverts type apparatus. The hydrogen storage capacity (H/M) of the laminate with composition Mg/Ti/Ni=9.0/0.9/0.1 amounted H/M=1.6 at 573K, 0.4MPa. Initial activation property was improved by controlling the amount of Ni appropreately.
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Zhang, Guo Li, Fu You Wang, Jia Lu Li, Guang Wei Chen, and Li Chen. "The Effect of Splicing Shape and Interval Length on the Failure Mode of Laminated Composites under Tensile Condition." Applied Mechanics and Materials 44-47 (December 2010): 2922–25. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.2922.
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This paper presents an experimental investigation on the failure modes of glass fiber reinforced 2D woven fabric with ladder splicing laminate composites. On the basis of [0/0/+45/90/-45/90]s ply sequence, six kinds of laminated performs with different splicing interval lengths which were 4mm, 8mm, 12mm respectively and two different splicing shape which were ladder splicing and double vertical line splicing, and a kind of laminated perform with continuous laminates of 2D glass fiber woven fabric were made. By means of RTM molding technology, the technological parameters of RTM processing were designed as follows: injection temperature was 25°C, injection duration time was 180min and injection pressure was 0.4MPa, the epoxy resin based 2D glass fiber woven fabric RTM laminated specimen were prepared. According to the GB/T 1447-2005 and GB/T 1449-2005standard test method, the failure modes of 2D glass fiber woven fabric laminated RTM specimen were tested. Results show that the failure modes of laminate composites manifest as rapid damage in the form of line inlay mode and wedge shape mode at 4mm interval length condition, and accumulating failure in the form of inlay layer slippage - fiber pulled out mode and fiber fracture - splicing layer deboning mode at 12mm interval length. Otherwise, all fracture position of splicing laminates occurs at the site of splicing line because of the concentration of tensile stress.
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Kormanikova, Eva, Kamila Kotrasova, Jozef Melcer, and Veronika Valaskova. "Numerical Investigation of the Dynamic Responses of Fibre-Reinforced Polymer Composite Bridge Beam Subjected to Moving Vehicle." Polymers 14, no. 4 (February 20, 2022): 812. http://dx.doi.org/10.3390/polym14040812.
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In modern industry, heavy traditional materials are being substituted with light and strong fibre-reinforced polymer composite materials. Bridges and railroads made of composite laminates are considerably affected by traffic loads. Therefore, it is very important to analyse this effect which would find practical applications in engineering designs. This paper explains the theoretical formulation that governs the dynamic response of a composite beam subjected to a moving load. The governing equations for the dynamic effect on the laminated composite bridge beam are explained here. The main theories in the micro–macro modelling of composite laminates are also described in the paper. Within the macro modelling, the Classical Laminate and Shear Deformation Laminate Theory of beams are presented. The symmetric cross-ply laminated bridge, made of boron/epoxy is under consideration. The computational two-dimensional model of the vehicle is adopted. The governing equations for the dynamic effect on the laminated composite bridge beam are explained. The calculation of the time response of the bridge for the characteristic speeds of the vehicle is performed in the environment of the MATLAB software. The maximum dynamic magnification factor for the dynamic analysis of a composite beam is found.
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Joshi, S. P., and N. G. R. Iyengar. "Optimal Design of Laminated Composite Plates Under Axial Compression." Transactions of the Canadian Society for Mechanical Engineering 9, no. 1 (March 1985): 45–50. http://dx.doi.org/10.1139/tcsme-1985-0007.
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The study is carried out for the optimum design of laminated fiber reinforced composite plates, subjected to multiple in-plane loadings. Angle-ply laminates with orthotropic laminae are considered. Thickness of plies and corresponding fiber orientations are incorporated as design variables. The constrained optimization problem is transformed into a series of unconstrained optimization problems, using an interior penalty function approach. The results have been obtained for different aspect ratios and uniform biaxial in-plane loading ratios. This study shows that the fiber orientations of the plies near mid-plane have little effect on the optimum design. There exists a particular fiber orientation angle for the over all thickness of laminate, which results in the optimum design for a plate of a given aspect ratio under a given set of loadings.
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Dibyajyoti, D., and B. Alfia. "Review on laminated composite plates." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 83–88. http://dx.doi.org/10.38208/acp.v1.477.
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A composite material is a combination of different material which can be assembled to provide required engineering properties like bending, buckling, stiffness etc. It can give better properties than those of individual components. A lamina is the building block of modern composite laminated structures. A lamina is also known as a ply, or a layer. A laminate has several layers of lamina, or laminae. Since the early years of engineering, various types of laminated composite materials have been used in various engineering fields, such as in aerospace, military and automotive industries that are subjected to high temperatures. Thermal stress caused due to change in temperature, increase in temperature causes the changes in material properties of a plate which in turn complicates the analysis and design and may affect the structure also. Therefore, the analysis of thermal stress in design of structure is very important. A critical review of available literature for the prediction of the behaviour of laminated composites under thermal conditions is carried out and summarized. This work attempts to review the studies carried out from 2000 on laminated composite plates by representing classification based on Classical laminate plate concept, First order shear deformation theory, Higher order shear deformation theory, Layerwise theory and Thermal stress on laminated plates.
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Huang, Zheng-Ming, K. Fujihara, and S. Ramakrishna. "Bending Failure Characterisation of Laminated Beams with Braided Fabric Reinforcement." Advanced Composites Letters 12, no. 3 (May 2003): 096369350301200. http://dx.doi.org/10.1177/096369350301200301.
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An experimental procedure has been performed in this work to characterise failure behaviour of braided fabric reinforced composite laminates subjected to flexural load. The material system used was carbon/epoxy. The laminated beams were made using eight layers of diamond braid reinforcement. Two braiding angles, i.e., 5° and 15°, were applied. Six beams with laminate arrangements of [5/5/5/5/5/5/5/5], [15/15/15/15/15/15/15/15], [5/5/15/15/15/15/5/5], [15/15/5/5/5/5/15/15], [5/5/15/15/5/5/15/15], and [15/15/5/5/15/15/5/5] were loaded under 4-point bending to their ultimate failure, where the braiding angle is measured with respect to the beam axis. Bending stiffnesses, ultimate bending strengths, and load-deflection curves of the tested beams were reported. It was found that all the bending failures of the laminated beams were initiated from their top surface inwards, as a consequence of an excessive compressive stress in the beam cross-section. Further evidence in failure mechanism was recognised through a matrix combustion and fabric peeling out technique. It was shown that after the bending test the only un-failed lamina in some of the laminates was its bottom surface ply. The evidence clearly indicates that the neutral plane in a laminated beam keeps shifting once a lamina in the laminate has failed. The failed lamina in the laminate can hardly sustain any additional load. Thus the present experiment confirms that a total stiffness discount should be adopted in the layer-by-layer progressive failure analysis of a laminated composite. Using this discount procedure, a simulation method is highlighted in the paper. The predicted load-deflection curves up to the third-ply failure agreed reasonably with the measured ones.
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bin Yaakob, Mohd Yuhazri, T. T. T. Jennise, H. Sihombing, N. Mohamad, S. H. Yahaya, and M. Y. A. Zalkis. "Water Absorption and Thickness Swelling of Laminated Composite after Cured at Different Angle." Applied Mechanics and Materials 465-466 (December 2013): 86–90. http://dx.doi.org/10.4028/www.scientific.net/amm.465-466.86.
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Moisture absorption is a very important factor in polymers and composite materials used for hull manufacture and stability in marine environment. High water absorption of the material will affects the mechanical properties and stability in composite. This research is carried out to study the feasibility of the gravity effects on curing position of the laminated composite structures to enhance the curing space needed. Vertical cured laminate having almost similar properties with common horizontal cured laminate able to save much space in composite industry. Horizontal cured laminates filled up spaces in which SMI lack of. Polyesters and E-glass fibers were used as the raw material in this research. Vacuum bagging technique was used to suck out the excess resin during lay-up to avoid any voids and air inside laminate and cured at different angle position in room temperature for 24 hours. Seven samples of laminated composite were fabricated and cut into specific dimension in accordance to ASTM standard. This paper will discuss about the investigation on the water absorption and thickness swelling of the thermosetting laminated composite by curing the laminate at different angle using vacuum bagging technique. From the testing, SN6 and SN7 shows to have good water resistant in physical properties.
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Gajbhiye, ParamD, Vishisht Bhaiya, and YuwarajM Ghugal. "Bending Analysis of Orthotropic Plate using 5th Order Shear Deformation Theory." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 89–94. http://dx.doi.org/10.38208/acp.v1.478.
Full textAbstract:
A composite material is a combination of different material which can be assembled to provide required engineering properties like bending, buckling, stiffness etc. It can give better properties than those of individual components. A lamina is the building block of modern composite laminated structures. A lamina is also known as a ply, or a layer. A laminate has several layers of lamina, or laminae. Since the early years of engineering, various types of laminated composite materials have been used in various engineering fields, such as in aerospace, military and automotive industries that are subjected to high temperatures. Thermal stress caused due to change in temperature, increase in temperature causes the changes in material properties of a plate which in turn complicates the analysis and design and may affect the structure also. Therefore, the analysis of thermal stress in design of structure is very important. A critical review of available literature for the prediction of the behaviour of laminated composites under thermal conditions is carried out and summarized. This work attempts to review the studies carried out from 2000 on laminated composite plates by representing classification based on Classical laminate plate concept, First order shear deformation theory, Higher order shear deformation theory, Layerwise theory and Thermal stress on laminated plates.
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Chen, Z., J. J. Mecholsky, and S. Hu. "Effect of interface design on high-temperature failure of laminated composites." Journal of Materials Research 11, no. 8 (August 1996): 2035–41. http://dx.doi.org/10.1557/jmr.1996.0256.
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The fracture strength and toughness of alumina can be increased by lamination with strategically placed nickel layers and with a modified Ni/Al2O3 interface through tape casting. In order to examine the potential of this type of laminated composite in high temperature applications, the laminates were tested at elevated temperatures. This paper describes how a modified tortuous interface, instead of a smooth interface, increases the creep resistance of the laminates. Interface modification can control high temperature laminate behavior and is critical to successful composite design.
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Sherman, D., and X. Gong. "Statistical behavior and misfit stresses in ceramic and metal laminated system." Journal of Materials Research 16, no. 3 (March 2001): 721–27. http://dx.doi.org/10.1557/jmr.2001.0106.
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The statistical behavior of ceramic and metal laminates was studied, and in particular the relationship between the failure distribution of the laminate and that of the ceramic layers that it comprises. An important result of this investigation is the ability to predict the misfit stresses due to thermal processing of the laminates. A finite different scheme that was capable of calculating the local stresses at each constituent and of considering the thermal residual stresses was developed. The laminated system was constructed from 380-μm-thick alumina alternating with nickel foil 25- or 50-μm thick.
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Toledano, A., and H. Murakami. "A Composite Plate Theory for Arbitrary Laminate Configurations." Journal of Applied Mechanics 54, no. 1 (March 1, 1987): 181–89. http://dx.doi.org/10.1115/1.3172955.
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In order to improve the accuracy of in-plane responses of shear deformable composite plate theories, a new laminated plate theory was developed for arbitrary laminate configurations based upon Reissner’s (1984) new mixed variational principle. To this end, across each individual layer, piecewise linear continuous displacements and quadratic transverse shear stress distributions were assumed. The accuracy of the present theory was examined by applying it to the cylindrical bending problem of laminated plates which had been solved exactly by Pagano (1969). A comparison with the exact solutions obtained for symmetric, antisymmetric, and arbitrary laminates indicates that the present theory accurately estimates in-plane responses, even for small span-to-thickness ratios.
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Marzuki, Haslan Fadli Ahmad, Engku Ahmadhilmi Engku Ubaidillah, Sivakumar A/l Sivarasa, Mohd Syamsul, and Mariatti Jaafar. "Study on Effect of Fiber Orientation on Flexural Properties of Glass Fiber Reinforced Epoxy Composite Laminates for Structural Applications." Solid State Phenomena 301 (March 2020): 227–37. http://dx.doi.org/10.4028/www.scientific.net/ssp.301.227.
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Composite laminate design is an important procedure in defining the mechanical properties of laminated composite structure to be used in multi-directional service loading application. Composite technologies or manufacturers who is lack of knowledge regarding the importance of laminate design, tend to develop a composite structure that will collapse or fail below the service requirement. The purpose of this study is to determine the effect of fiber orientation on flexural properties of the designed glass fiber reinforced epoxy laminated composite. Six sets of laminates with different fiber orientation and sequence were simulated using CompositeStar© software to determine its flexural properties. Samples were fabricated to verify the simulated data and were tested in accordance to ASTM D2344. Moreover, crack pattern within the samples after the flexural test is studied. From the simulated results, it shows that laminates which have fiber in tri-direction and quasi-direction display a higher flexural modulus and strength compared to laminates with fiber in uni-directional and bi-directional. In addition, data from tested fabricated laminates samples displayed the same modulus patterns against the simulated data, with variants from 8% to 35%. Additionally, it is found that samples with fiber in ±45 direction shows a transverse and shear cracking which prolonged the cracking propagation before the samples show a complete failure.
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Zhao, Wei, and Rakesh K. Kapania. "Buckling Analysis and Optimization of Stiffened Variable Angle Tow Laminates with a Cutout Considering Manufacturing Constraints." Journal of Composites Science 6, no. 3 (March 4, 2022): 80. http://dx.doi.org/10.3390/jcs6030080.
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Variable angle tow laminates (VAT) and stiffeners are known to redistribute the in-plane load distribution and tailor the buckling mode shapes, respectively, for improving structural performance. To leverage the benefits of using VAT laminates in the practical applications, in the present paper, we discuss buckling load maximization conducted for a stiffened VAT laminated plate with a central cutout considering VAT laminate manufacturing constraints. Three representative boundary conditions as seen in the aerospace structures are considered: in-plane axial displacement, in-plane pure shear, and in-plane pure bending displacements. Two common manufacturing constraints, the one on the automatic fiber placement (AFP) manufacturing head turning radius and the other on the tow gap/overlap, while fabricating VAT laminates are considered in the laminate design. These two manufacturing constraints are modeled by controlling the fiber path radius of curvature and tape parallelism in optimizing the fiber path orientations for the VAT laminates. Stiffener layout and fiber path angle for the VAT laminated plates are both considered in the buckling load maximization study. To avoid using a fine mesh in modeling the stiffened VAT laminates with a cutout when employing the finite element analysis during the optimization, the VAT laminated plate and the stiffeners are modeled independently. The displacement compatibility is enforced at the stiffener–plate interfaces to ensure that the stiffeners move with the plate. Particle swarm optimization is used as the optimization algorithm for the buckling load maximization study. Optimization results show that, without considering AFP manufacturing constraints, the VAT laminates can increase the buckling loads by 21.2% and 12.4%, respectively, comparing to the commonly used quasi-isotropic laminates and traditionally straight fiber path laminates for the structure under the in-plane axial displacement case, 19.7% and 12.5%, respectively, for the in-plane shear displacement case, and 62.1% and 26.6%, respectively, for the in-plane bending displacement case. The AFP manufacturing constraints are found to have different impacts on the buckling responses for the VAT laminates, which cause the maximum buckling load to be 9.3–10.1%, 3.0–3.2%, and 23.2–29.8% less than those obtained without considering AFP manufacturing constraints, respectively, for the present studied model under in-plane axial, shear, and bending displacements.
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Manoj Kumar Rath. "Condition Assessment of a Reinforced Concrete Residential Building using Non-destructive Testing Methods - A Case Study." Electronic Journal of Structural Engineering 21 (November 30, 2021): 18–33. http://dx.doi.org/10.56748/ejse.21288.
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The present study deals with both experimental and numerical investigation on buckling effects of laminated composite plates subjected to varying temperature and moisture. A simple laminated plate model is developed for the buckling of composite plates subjected to adverse hygrothermal loading. A computer program based on FEM in MATLAB environment is developed to perform all necessary computations. The woven fiber Glass/Epoxy specimens were hygrothermally conditioned in a humidity cabinet where theconditions were maintained at temperatures of 300K-425K and relative humidity (RH) ranging from 0-1% for moisture concentrations. All the investigations are made with a symmetric cross-ply laminates. The present study deals with both experimental and numerical investigation on buckling behavior of laminated composite plates subjected to varying temperature and moisture concentration. Quantitative results are presented to show the effects of geometry, material and lamination parameters of woven fiber laminate onbuckling of composite plates for different temperature and moisture concentrations with simply supported boundary conditions with different aspect and side-to-thickness ratios. Experimental results show that there is reduction in buckling loads in KN with the increase in temperature and moisture concentration for laminates with clamped-free-clamped-free boundary conditions
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Evran, Savaş. "Numerical and statistical buckling analysis of laminated composite plates with functionally graded fiber orientation angles." Polymers and Polymer Composites 28, no. 7 (June 26, 2020): 502–12. http://dx.doi.org/10.1177/0967391120936029.
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The aim of this numerical and statistical study was to investigate the buckling analysis of laminated composite plates containing functionally graded fiber orientation angles. The laminated composite plates had functionally graded fiber orientation angles based on Taguchi’s L18 (21 × 32) orthogonal array. The fiber orientation angles were considered to be control factors. Numerical analyses were performed using finite element software ANSYS. The optimum critical buckling load and the effects of fiber orientation angles for maximum data were determined using the analysis of the signal-to-noise ratio. The importance levels of laminates and their percent contribution on the buckling characteristics were calculated using analysis of variance. Regression analysis was employed to investigate the effects of control factors on buckling responses mathematically. The effects of laminate stacking sequence, mesh size, element type, mode number, and boundary condition were carried out using laminates with the optimum levels.
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Ramadhan, Redha Akbar, Muhamad Giri Suada, and Hendri Syamsudin. "A FINITE ELEMENT ANALYSIS OF CRITICAL BUCKLING LOAD OF COMPOSITE PLATE AFTER LOW VELOCITY IMPACT." Jurnal Teknologi Dirgantara 18, no. 2 (December 27, 2020): 195. http://dx.doi.org/10.30536/j.jtd.2020.v18.a3328.
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Composite is a material formed from two or more materials that macroscopically alloyed into one material. Nowadays, composite has been generally applied as lightweight structure of aircraft. This is due to the fact that composites having high strength-to-weight ratio. It means the composites have the capability to take on various loads, despite their lightweight property.Laminate composite is one type of composite that has been generally used in aircraft industries. This type of composite is susceptible to low-velocity impact induced damage. This type of damage can be happening in manufacture, operation, or even in maintenance. Low-velocity impact could cause delamination. Delamination happens when the plies of laminated composites separated at the interface of the plies. This type of damage is categorized as barely visible damage, means that the damage couldn’t be detected with visual inspection. Special method and tool would be needed to detect the damage. Delamination will decrease the strength of the laminated composite.Delamination can be predicted with numerical simulation analysis. With increasing capability of computer, it is possible to predict the delamination and buckling of laminated composite plate. This research presents the comparisons of buckling analysis results on laminated plate composite and damaged laminated plate composite. By the result of LVI simulation, it is shown that low velocity impact of 19.3 Joule causing 6398 mm2 C-Scan delamination area inside the laminated composite. The delamination causing structural instability that will affect buckling resistance of the plate. The result of analysis shows that the existence of delamination inside laminate composite will lower its critical buckling load up to 90% of undamaged laminate’s critical buckling load.Keywords : composite, laminate, delamination, buckling.
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Todoroki, Akira, Kazuomi Omagari, and Masahito Ueda. "Matrix Crack Detection of CFRP Laminates in Cryogenic Temperature Using Electrical Resistance Change Method." Key Engineering Materials 321-323 (October 2006): 873–76. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.873.
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For a cryogenic fuel tank of a next generation rocket, a Carbon Fiber Reinforced Plastic (CFRP) laminated composite tank is one of the key technologies. For the fuel tank made from the laminated composites, matrix cracks are significant problems that cause leak of the fuel. In the present paper, electrical resistance change method is adopted to monitor the matrix cracking of the CFRP laminate. Previous studies show that tension load in fiber direction causes electrical resistance increase due to the piezoresistivity of the carbon fibers, and fiber breakages also cause the electrical resistance increase of the CFRP laminates. In order to distinguish the electrical resistance changes due to matrix cracking from those due to the piezoresistivity and the fiber breakages, residual electrical resistance change under the complete unloading condition is employed in the present study. Experimental investigations were performed using cross-ply laminates in cryogenic temperature. As a result, it can be revealed that the residual electrical resistance change is a useful indicator for matrix crack monitoring of the cross-ply CFRP laminates.
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Vieira Carneiro, C. A., and M. A. Savi. "Modelling and simulation of the delamination in composite materials." Journal of Strain Analysis for Engineering Design 35, no. 6 (August 1, 2000): 479–92. http://dx.doi.org/10.1243/0309324001514242.
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Delamination is a phenomenon characterized by the loss of adhesion between two adjacent laminae. This is a damage process frequently observed in composite materials and it may cause either loss of structural stiffness or total failure of the laminate. This contribution presents a model to describe composite delamination. The proposed model considers a laminate with a finite thickness interlayer. Interlaminar stresses are evaluated from a modified lamination theory. This result is used as input in the constitutive adhesion model which describes the damage evolution of the interlayer. An iterative numerical procedure is developed, solving the model equations separately. This work considers numerical simulations of a laminated tube and a laminated bar as applications of the proposed general formulation. Numerical results are capable of capturing the general behaviour of experimental data.
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Kunčická, Lenka, Radim Kocich, Petr Kačor, Michal Jambor, and Martin Marek. "Characterising Correlations between Electric Conductivity and Structural Features in Rotary Swaged Al/Cu Laminated Conductors." Materials 15, no. 3 (January 27, 2022): 1003. http://dx.doi.org/10.3390/ma15031003.
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This study aims to characterize the correlations between electric characteristics and selected structural features of newly designed Al/Cu laminated conductors manufactured via room temperature rotary swaging. After swaging, the laminates with diameters of 15 mm were subjected to two different post-process annealing treatments. Structure analyses performed to evaluate the effects of thermomechanical processing were performed via scanning and transmission electron microscopies. Electric conductivity and resistivity of the laminates were experimentally measured and numerically simulated using models designed according to the real conditions. The results showed that the electric resistivity was affected by the grain size, bimodal grains’ distribution (where observed), the presence of twins, and, last but not least, dislocation density. Among the influencing factors were the area fractions of Al and Cu at the cross-sections of the of the laminated conductors, too. The results revealed that fabrication of the laminate via the technology of rotary swaging introduced more advantageous combinations of electric and mechanical properties than fabrication by conventional manufacturing techniques. The lowest specific electric resistivity of 20.6 Ωm × 10−9 was measured for the laminated conductor subjected to the post-process annealing treatment at 350 °C, which imparted significant structure restoration (confirmed by the presence of fine, equiaxed, randomly oriented grains).
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Luo, Shen-Yi, and Faruk Taban. "Deformation of Laminated Elastomer Composites." Rubber Chemistry and Technology 72, no. 1 (March 1, 1999): 212–24. http://dx.doi.org/10.5254/1.3538791.
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Abstract Flexible elastomer composites subjected to finite deformation are usually associated with significant fiber re-orientation and configuration change which cannot be described by classical composite lamination theory. Utilizing the Lagrangian description and a strain-energy density approach, this work presents a set of 2-D constitutive equations in terms of the overall deformation of laminated composites. This model includes both geometric and material nonlinearities of the laminate. Interlaminar shear deformation is addressed but not studied in this analysis. Theoretical predictions have been compared with the available experimental data about symmetric laminates with various fiber orientations in the finite deformation range. Also, a parametric study has been performed under various ratios of biaxial deformation.
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Magar, Ashok, and Achchhe Lal. "Progressive failure analysis of laminated plate containing elliptical cutout." International Journal of Structural Integrity 12, no. 4 (April 9, 2021): 569–88. http://dx.doi.org/10.1108/ijsi-10-2020-0092.
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PurposeThe prediction of accurate failure strength and a composite laminate failure load is of paramount importance for reliable design. The progressive failure analysis helps to predict the ultimate failure strength of the laminate, which is more than the first ply failure (FPF) strength. The presence of a hole in the laminate plate results in stress concentration, which affects the failure strength. The purpose of the current work is to analyze the stress variation and progressive failure of a symmetric laminated plate containing elliptical cutouts under in-plane tensile loading. The effect of various parameters on FPF and last ply failure (LPF) strength is studied.Design/methodology/approachThe ply-by-ply stresses around elliptical cutouts are obtained analytically using Muskhelishvili's complex variable formulation. To predict the progressive failure, Tsai–Hill (T-H) and Tsai–Wu (T-W) failure criteria are used, and depending on the mode of failure, lamina modulus is degraded.FindingsThe study has revealed that fiber orientation and stacking sequence for given loading have the most significant effect on the laminate's failure strength.Originality/valueComplex variable method and conformal mapping are simple and proficient for studying failure analysis of a laminated plate with elliptical cutout.
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Zhang, Guo Li, Fu You Wang, Jia Lu Li, Guang Wei Chen, and Li Chen. "Study on the Mechanical Performance of Glass Fiber 2D Woven Fabric Laminated Composites with Different Splicing Shape and Interval Length." Applied Mechanics and Materials 34-35 (October 2010): 1845–49. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.1845.
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In order to investigate the effect of splicing shape and splicing interval length of reinforced fabric on the mechanical performance for manufacturing composite parts in complicated shape with laminated 2D glass fiber woven fabric. On the basis of [0º/45º/90º/90º/0º] S ply sequence, six kinds of laminated performs with different splicing interval lengths which were 4mm, 8mm, 12mm respectively and two different splicing shape which were ladder splicing (LS) and double vertical line splicing (DLS), and a kind of laminated perform with continuous laminates (CL) of 2D glass fiber woven fabric were made. By means of RTM molding technology, the technological parameters of RTM processing were designed as follows: injection temperature was 25°C, injection duration time was 180min and injection pressure was 0.4MPa, the epoxy resin based 2D glass fiber woven fabric RTM laminated specimen were prepared. According to the GB/T 1447-2005 and GB/T 1449-2005standard test method, the tensile and flexural properties of the 2D glass fiber woven fabric laminated RTM specimen were tested. It was found that the tensile fracture position were all near the splicing line, the main reason of which was the concentration of tensile stress. The tensile and flexural test results show that the difference of the splicing shape and the splicing interval length will generate a significant effect on the mechanical performance of the laminate. All above experimental results could provide fundamental data to the optimal design complex structure laminated composite parts.
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Roy, Ajit K., and Stephen W. Tsai. "Three-Dimensional Effective Moduli of Orthotropic and Symmetric Laminates." Journal of Applied Mechanics 59, no. 1 (March 1, 1992): 39–47. http://dx.doi.org/10.1115/1.2899462.
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A simple and accurate method for estimating the three-dimensional effective moduli of symmetric and orthotropic laminated composites is presented. The method is based on obtaining the exact displacement field of three boundary value problems of laminated composites using the Airy stress function solution technique. The effective moduli are estimated by matching the boundary displacements of the equivalent homogeneous system with those of the laminated system. Among the estimated effective moduli, those associated with the interlaminar direction are of special interest. It is found that the effective interlaminar normal stiffness in extensional deformation is independent of laminae stacking sequence which is consistent with the finding of Pagano (1974). However, the laminate interlaminar shear stiffness is dependent on stacking sequence, and it is shown that the rule of mixtures can not predict the interlaminar shear stiffness accurately.
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Yazdani Sarvestani, Hamidreza, and Ali Naghashpour. "Investigation of Through-Thickness Stresses in Composite Laminates Using Layerwise Theory." International Journal of Engineering Mathematics 2013 (December 12, 2013): 1–11. http://dx.doi.org/10.1155/2013/676743.
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In this study, an analytical method is developed to exactly obtain the interlaminar stresses near the free edges of laminated composite plates under the bending moment based on the reduced form of elasticity displacement field for a long laminate. The analytical and numerical studies were performed based on the Reddy’s layerwise theory for the boundary layer stresses within cross-ply, symmetric, angle-ply, and general composite laminates. Finally, a variety of numerical results are presented for the interlaminar normal and shear stresses along the interfaces and through thickness of laminates near the free edges. The results showed high stress gradient of interlaminar normal and shear stresses near the edges of laminates.
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Ding, Guoping, Wenhao Song, Xiaoling Gao, and Hao Cao. "Damage Detection in Holed Carbon Fiber Composite Laminates Using Embedded Fiber Bragg Grating Sensors Based on Strain Information." Shock and Vibration 2020 (December 7, 2020): 1–11. http://dx.doi.org/10.1155/2020/8813213.
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Compared with metal materials, Carbon Fiber Reinforced Plastic (CFRP) is more excellent in performance, with high specific strength and high specific modulus. And among various CFRP structural elements, CFRP laminated plates have widespread applications. However, some indiscernible and hidden primary damage always appears on the CFRP laminated plate and will continuously evolve and expand after being loaded. This work starts with the analysis of the relationship between the changes of the strain distribution and damage expansion of CFRP laminated plates and proposes the damage recognition method of CFRP laminated plates based on strain information. Then, the CFRP laminate damage monitoring system based on Fiber Bragg Grating (FBG) sensor is established, and the CFRP laminate damage identification experiment based on FBG sensor is made to verify the accuracy of the CFRP laminate damage identification method. The results show that the maximum error between the load when the damage appears on the FBG sensor and that when the damage of CFRP laminated plates expands based on the simulated analysis does not exceed 16%. The accuracy of the damage recognition method of CFRP laminated plates is verified and the damage recognition of CFRP laminated plates and their expansion process is achieved.
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Wan Dalina, Wan Ahmad Dahalan, M. Mariatti, Radziana Ramlee, Zainal Arifin Mohd Ishak, and Abdul Rahman Mohamed. "Comparison on the Properties of Glass Fiber/MWCNT/Epoxy and Carbon Fiber/MWCNT/Epoxy Composites." Advanced Materials Research 858 (November 2013): 32–39. http://dx.doi.org/10.4028/www.scientific.net/amr.858.32.
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A hand lay-up and vacuum bagging method was used in this study to fabricate glass fiber/epoxy laminated composites and carbon fiber/epoxy composite laminates with multi-walled carbon nanotube (MWCNT). The density, flexural properties, and burning rate of the laminated composites incorporated with different concentration of MWCNT (0.5, 1.0, and 1.5 vol%) were investigated and analyzed. Trend in the density, flexural and burning rate of glass fiber composite laminates were compared to those of carbon fiber composite laminates. Effect of MWCNT concentration on glass fiber composites properties varies from carbon fiber composite laminates. Incorporation of 0.5vol% of MWCNT has increased flexural strength by 54.4% compared to 5-ply glass fiber composite laminates. Nonetheless addition of 1vol% of MWCNT has only increased flexural strength by 34% compared to 5-ply carbon fiber laminated composites. Incorporation of MWCNT has successfully reduced the burning rate of the glass fiber composites as well as the carbon fiber laminated composites.
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Colvin, G. E., and S. R. Swanson. "Mechanical Characterization of IM7/8551-7 Carbon/Epoxy Under Biaxial Stress." Journal of Engineering Materials and Technology 112, no. 1 (January 1, 1990): 61–67. http://dx.doi.org/10.1115/1.2903188.
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This paper presents the results of a detailed characterization of the relatively new IM7/8551-7 carbon/epoxy material system under conditions of multiaxial stresses applied to both laminae and laminates. IM7 is a high elongation, high strength carbon fiber, and the 8551-7 matrix is a high toughness epoxy resin. The lamina tests provided a failure envelope for combinations of transverse tension or compression and in-plane shear, and illustrated that the matrix dominated strength properties exhibit a strong dependence on the state of stress. The transverse strains at failure were found to be higher than for previous epoxy systems examined, and the shear stress-strain curves showed significant nonlinear behavior. These features apparently contribute to the “toughness” of the resin. Laminated specimens in a quasi-isotropic configuration were tested in tension-tension and tension-compression stress states. In previous work on other fiber/resin systems it has been shown that laminate ultimate failure could be correlated by means of fiber direction strain in a critical ply, independent of matrix cracking and the details of the laminate configuration and state of stress. However, different fiber strain values must be used for tension and compression. The behavior of quasi-isotropic IM7/8551-7 laminates appears to follow the observations noted above, with the important exception that laminate tension failure strain is lower than unidirectional coupon strain. The compression values are significantly higher than seen previously with AS4/3501-4 laminates, but as usual lower than the tension values. The results raise presently unresolved issues about the effect of the resin and possibly the processing variables on the delivered laminate strength.
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Loughlan, J. "The compressive buckling performance of anti-symmetric composite laminates and the effect on behaviour of membrane-flexural coupling." Aeronautical Journal 106, no. 1065 (November 2002): 595–606. http://dx.doi.org/10.1017/s000192400001825x.
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AbstractThe compressive stability of anti-symmetric angle-ply laminated plates with particular reference to the degrading influence of membrane-flexural coupling is reported in this paper. A specific configuration of anti-symmetric laminate is dealt with in the paper and this takes the form [θ/-θ]n whereby 2n is the total number of plies in the laminated stack. With regard to compressive buckling the paper gives an indication that anti-symmetric laminates with 8 plies or more will yield performance levels which are almost identical to their symmetric counterparts. The degree of membrane-flexural coupling in the laminated composite plates is varied, essentially, by changing the ply angle and also by altering the number of plies in the laminated stack, for a given composite material system. The coupled compressive buckling solutions are determined using the finite strip method of analysis. In order to provide an adequate level of flexibility in the analysis procedure and to ensure a high level of accuracy of solution, the buckling displacement fields of the strip formulation are those which are described in a multi-term form.Results are given for anti-symmetric angle-ply laminated plates subjected to uniaxial and biaxial compression and these have been obtained from fully converged finite strip structural models. Validation of the finite strip formulation is indicated in the paper through comparisons with exact solutions where appropriate. The natural half-wavelength of the compressive buckling mode of the composite plates is shown to be significantly influenced by variation in the ply angle. Increasing the number of plies in the laminated system is seen to reduce the degree of coupling and the critical stress levels are noted to tend towards the plate orthotropic solutions. The ply angle corresponding to the optimised, compressive buckling stress for any particular laminate is noted in the paper to be influenced by the support boundary conditions at the plates unloaded edges.
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Loughlan, J. "The compressive buckling performance of anti-symmetric composite laminates and the effect on behaviour of membrane-flexural coupling." Aeronautical Journal 106, no. 1065 (November 2002): 595–606. http://dx.doi.org/10.1017/s000192400001160x.
Full textAbstract:
AbstractThe compressive stability of anti-symmetric angle-ply laminated plates with particular reference to the degrading influence of membrane-flexural coupling is reported in this paper. A specific configuration of anti-symmetric laminate is dealt with in the paper and this takes the form [θ/-θ]n whereby 2n is the total number of plies in the laminated stack. With regard to compressive buckling the paper gives an indication that anti-symmetric laminates with 8 plies or more will yield performance levels which are almost identical to their symmetric counterparts. The degree of membrane-flexural coupling in the laminated composite plates is varied, essentially, by changing the ply angle and also by altering the number of plies in the laminated stack, for a given composite material system. The coupled compressive buckling solutions are determined using the finite strip method of analysis. In order to provide an adequate level of flexibility in the analysis procedure and to ensure a high level of accuracy of solution, the buckling displacement fields of the strip formulation are those which are described in a multi-term form.Results are given for anti-symmetric angle-ply laminated plates subjected to uniaxial and biaxial compression and these have been obtained from fully converged finite strip structural models. Validation of the finite strip formulation is indicated in the paper through comparisons with exact solutions where appropriate. The natural half-wavelength of the compressive buckling mode of the composite plates is shown to be significantly influenced by variation in the ply angle. Increasing the number of plies in the laminated system is seen to reduce the degree of coupling and the critical stress levels are noted to tend towards the plate orthotropic solutions. The ply angle corresponding to the optimised, compressive buckling stress for any particular laminate is noted in the paper to be influenced by the support boundary conditions at the plates unloaded edges.
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Shin, Dong Ku, Zafer Gu¨rdal, and O. Hayden Griffin. "Minimum Weight Design of Laminated Composite Plates for Postbuckling Performance." Applied Mechanics Reviews 44, no. 11S (November 1, 1991): S219—S231. http://dx.doi.org/10.1115/1.3121359.
Full textAbstract:
Minimum-weight design of simply-supported, symmetrically laminated, thin, rectangular, specially orthotropic laminated plates for buckling and postbuckling strength is investigated. The postbuckling analysis is based on an Marguerre-type energy method extended to generally orthotropic plates with a special consideration of the mode change in the postbuckling load regime. The failure load of laminates is calculated by the maximum strain failure criterion based on the in-plane strains. Design variables are individual layer thicknesses with specified fiber orientations and assumed to take only discrete values corresponding to multiples of the lamina thickness. The optimization with discrete valued design is achieved by introducing additional penalty terms, in the form of a sine function, to the regular pseudo-objective function of sequential unconstrained minimization technique (SUMT). The proposed optimization technique is applied to the design of rectangular laminates made up of 0, ± 45, 90 degree laminae with various aspect ratios loaded by axial compressive loads.
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Azwan, Syed Mohd Saiful, Yahya Mohd Yazid, Ayob Amran, and Behzad Abdi. "Quasi-Static Flexural and Indentation Behaviour of Polymer-Metal Laminate." Advanced Materials Research 970 (June 2014): 88–90. http://dx.doi.org/10.4028/www.scientific.net/amr.970.88.
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Metal-polymer laminates were subjected to quasi-static flexural and indentation loading. The laminates were made of two aluminium skins heat-bonded (laminated) to a core made of polyethylene plastic material. The samples were trimmed into standard-sized beams and panels which were then tested in flexural and indentation using the Instron universal testing machine at loading rates of 1 mm/min, 10 mm/min and 100 mm/min. The load-displacement and energy absorption curves of the composite beams were recorded. It was found that the loading rate has a large effect on flexural and indentation behaviour of aluminium composite laminate.
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Groh, R. M. J., and P. M. Weaver. "Deleterious localized stress fields: the effects of boundaries and stiffness tailoring in anisotropic laminated plates." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 472, no. 2194 (October 2016): 20160391. http://dx.doi.org/10.1098/rspa.2016.0391.
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The safe design of primary load-bearing structures requires accurate prediction of stresses, especially in the vicinity of geometric discontinuities where deleterious three-dimensional stress fields can be induced. Even for thin-walled structures significant through-thickness stresses arise at edges and boundaries, and this is especially precarious for laminates of advanced fibre-reinforced composites because through-thickness stresses are the predominant drivers in delamination failure. Here, we use a higher-order equivalent single-layer model derived from the Hellinger–Reissner mixed variational principle to examine boundary layer effects in laminated plates comprising constant-stiffness and variable-stiffness laminae and deforming statically in cylindrical bending. The results show that zigzag deformations, which arise due to layerwise differences in the transverse shear moduli, drive boundary layers towards clamped edges and are therefore critically important in quantifying localized stress gradients. The relative significance of the boundary layer scales with the degree of layerwise anisotropy and the thickness to characteristic length ratio. Finally, we demonstrate that the phenomenon of alternating positive and negative transverse shearing deformation through the thickness of composite laminates, previously only observed at clamped boundaries, can also occur at other locations as a result of smoothly varying the material properties over the in-plane dimensions of the laminate.
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Abdullah, Shahrum, M. F. Abdullah, and W. N. M Jamil. "Ballistic performance of the steel-aluminium metal laminate panel for armoured vehicle." Journal of Mechanical Engineering and Sciences 14, no. 1 (March 23, 2020): 6452–60. http://dx.doi.org/10.15282/jmes.14.1.2020.20.0505.
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This paper presents the ballistic performance of the joining lightweight metal laminated panel consists of high strength steel and aluminium alloy for armoured vehicle application. Composite laminates trend in military industry present excellent performance in terms of lightweight material due to the improvement vehicle manoeuvrability, without sacrificing the performance and safety. The combination of aluminium plate and high strength steel offer the good potential for reducing the vehicle weight and improving the ballistic resistance. Ar500 and Al7075-T6 were chosen in designing laminated panel to achieve intended 20-30% weight reduction. Joining between these two materials have been investigated using both brazing method and adhesive bonding method. The adhesive bonding involved two types of material which is epoxy and polyurethane. Mechanical tests such as bending tests, drop weight tests and ballistic tests were performed to assess the strength of the laminated panel. Results showed that polyurethane bonded laminate panel through adhesion process exhibited 75% higher strength that that through the brazing process after performing impact test. Meanwhile, the penetration patterns found numerically are nearly similar to that from the ballistic tests and thus has validated the finite element models developed. The study on application of this laminated plate shall be extended using higher level of threat for hard armour vehicle panel.
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Huang, Zheng-Ming, X. C. Teng, and S. Ramakrishna. "Progressive Failure Analysis of Laminated Knitted Fabric Composites Under 3-Point Bending." Journal of Thermoplastic Composite Materials 14, no. 6 (November 2001): 499–522. http://dx.doi.org/10.1106/uw1g-83l2-91w9-g47y.
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The bending behavior of laminated beams reinforced with differently arranged plain-weft knitted fabrics has been investigated in this paper. Experiments were carried out to measure the bending stiffness and strength of six layers knitted fabric rein-forced epoxy composite laminates under 3-point bending. The laminate lay-ups of [0/0/0/0/0/0], [90/90/90/90/90/90] and [0/-45/45/45/-45/0] have been taken into account, where 0 denotes that the fabric wale direction is arranged along the beam axial direction. A simulation procedure is presented to analyze the bending property of the laminated beams based on the bridging micromechanics model and the classical lamination theory. It has been found that the use of a stress failure criterion only is no longer enough for estimating the ultimate bending strength of the laminate. An additional critical deflection condition is also required. By using only the constituent properties, which were measured using bulk material specimens independently, and the fabric knitting and lay-up parameters, the predicted stiffness and strength agree favorably with the experimental data.
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Liu, Jen-Chieh, Robert J. Moon, Alan Rudie, and Jeffrey P. Youngblood. "Mechanical performance of cellulose nanofibril film-wood flake laminate." Holzforschung 68, no. 3 (April 1, 2014): 283–90. http://dx.doi.org/10.1515/hf-2013-0071.
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Abstract Homogeneous and transparent CNF films, fabricated from the (2,2,6,6- tetramethylpiperidin-1-yl) oxyl (TEMPO)-modified CNF suspension, were laminated onto wood flakes (WF) based on phenol-formaldehyde (PF) resin and the reinforcement potential of the material has been investigated. The focus was on the influence of CNF film lamination, relative humidity (RH), heat treatment, and anisotropic properties of WF on the CNF-WF laminate tensile properties (elastic modulus, ultimate tensile strength, strain to failure). Results demonstrated that CNF-WF laminates had improved mechanical performance as compared to the neat WF. In the WF transverse direction, there were gains of nearly 200% in Young’s modulus and 300% in ultimate tensile strength. However, in the WF axial direction, the reinforcement effect was minor after PF modification of the wood and the presence of the CNF layers. The effective elastic moduli of the CNF-WF laminates were calculated based on the laminated plate theory, and the calculation in both axial and transverse directions were in agreement with the experimental results.
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Çınar, Okan, Merve Erdal, and Altan Kayran. "Accurate equivalent models of sandwich laminates with honeycomb core and composite face sheets via optimization involving modal behavior." Journal of Sandwich Structures & Materials 19, no. 2 (August 3, 2016): 139–66. http://dx.doi.org/10.1177/1099636215613934.
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An approach is introduced for determining accurate two-dimensional equivalent laminated models of sandwich laminates with honeycomb core and composite facesheets by optimization involving modal behavior. The approach relies on minimizing the objective function which is defined as the sum of the square of the differences between the natural frequencies of the honeycomb sandwich laminate estimated by the finite element analysis of the 3D detailed model with the actual honeycomb core geometry and by the 2D equivalent laminated model with the honeycomb core replaced by the equivalent 2D orthotropic material model. Equivalent elastic constants of the 2D orthotropic model of the honeycomb core are defined as the design variables of the optimization problem, and a finite element solver and genetic algorithm-based optimizer are coupled to perform the optimization task. Results show that with the optimization-based approach, very accurate 2D equivalent models of honeycomb sandwich laminates are obtained compared to equivalent models obtained by replacing the honeycomb core with elastic constants of the 2D orthotropic material model obtained utilizing analytical models available in the literature.
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Freddi, Francesco, and Lorenzo Mingazzi. "Phase Field Simulation of Laminated Glass Beam." Materials 13, no. 14 (July 20, 2020): 3218. http://dx.doi.org/10.3390/ma13143218.
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The complex failure mechanisms of glass laminates under in-plane loading conditions is modelled within the framework of phase-field strategy. Laminated glass is widely used for structural purposes due to its safe post-glass-breakage response. In fact, the combination of several glass plies bonded together with polymeric interlayers allows overcoming the brittleness of the glass and to reach a pseudo-ductile response. Moreover, the post-breakage behaviour of the laminate is strictly correlated by the mechanical properties of the constituents. Ruptures may appear as cracks within the layers or delamination of the bonding interface. The global response of a glass laminate, validated against experimental results taken from the literature, is carried out by investigating a simplified layup of two glass plies connected by cohesive interfaces through an interlayer. Delamination of the adhesive interface is described, and crack patterns within the materials are fully described. Finally, the proposed approach put the basis for future comparisons with results of experimental campaign and real-life applications.
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Peng, L. X. "Free Vibration Analysis of Symmetrically Laminated Folded Plate Structures Using an Element-Free Galerkin Method." Mathematical Problems in Engineering 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/124296.
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An element-free Galerkin method for the solution of free vibration of symmetrically laminated folded plate structures is introduced. Employing the mature meshfree folded plate model proposed by the author, a folded laminated plate is simulated as a composite structure of symmetric laminates that lie in different planes. Based on the first-order shear deformation theory (FSDT) and the moving least-squares (MLS) approximation, the stiffness and mass matrices of the laminates are derived and supposed to obtain the stiffness and mass matrices of the entire folded laminated plate. The equation governing the free vibration behaviors of the folded laminated plate is thus established. Because of the meshfree characteristics of the proposed method, no mesh is involved to determine the stiffness and mass matrices of the laminates. Therefore, the troublesome remeshing can be avoided completely from the study of such problems as the large deformation of folded laminated plates. The calculation of several numerical examples shows that the solutions given by the proposed method are very close to those given by ANSYS, using shell elements, which proves the validity of the proposed method.
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Ramful, Raviduth. "EVALUATION OF THE MECHANICAL PROPERTIES OF BAMBUSA BAMBOO LAMINATES THROUGH DESTRUCTIVE TESTING." Journal of Green Building 13, no. 4 (September 2018): 1–18. http://dx.doi.org/10.3992/1943-4618.13.4.1.
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In this research study, Bambusa ssp, the utilized species of bamboo, was rendered into a more versatile construction material in the form of laminates. The laminated specimens were manufactured using simplified processing methods according to the ASTM D3039 and ASTM D143 standards. Polyvinyl acetate was the adhesive used between the 2-ply laminate. The mechanical properties of the specimens were evaluated through tensile, compressive and bending strength tests according to set standards on the Testometric M500-50AT Universal Testing Machine. The tensile strength of laminated bamboo was comparable to that of redwood, spruce, cedar and pine. The ratio of compressive strength of parallel to perpendicular fibers in compressive tests was in a close range to that of poplar, fir and pine. The correlation in compressive strength values between bamboo and wood confirmed the inherent anisotropic nature of both plant materials.
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Ashaari, Z., S. H. Lee, F. L. Nabil, E. S. Bakar, A. Ghani, and M. R. Rais. "Physico-mechanical properties of laminates made from Sematan bamboo and Sesenduk wood derived from Malaysia's secondary forest." International Forestry Review 19, no. 3 (December 1, 2017): 1–8. http://dx.doi.org/10.1505/146554817828562323.
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A study was conducted to evaluate the performance of laminated composite made from phenolic resin-treated wood and bamboo strips. Sesenduk (Endospermum diadenum) wood and Sematan bamboo (Gigantochloa scortechinii) strips were impregnated using 30% phenol formaldehyde (PF) resin and assembled in different configurations and orientations prior to compreg nation. The assembled samples were then compressed in a hot press at 150 ± 2 °C for 60 minutes. Dimensional stability, hardness, bending, shear and compression strength of the products were assessed. The results revealed that the properties of the compreg laminates were significantly affected by the treatment variables. Laminated compreg wood had inferior mechanical properties compared to laminated compreg bamboo and bamboo/wood hybrid. However, the dimensional stability of laminated compreg wood is the best among the three types of laminates. Samples assembled parallelly possessed better properties. Mixed application of wood and bamboo had imparted respective advantages to the compreg laminates.
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Kam, Chee Zhou, and Ahmad Beng Hong Kueh. "Bending Response of Cross-Ply Laminated Composite Plates with Diagonally Perturbed Localized Interfacial Degeneration." Scientific World Journal 2013 (2013): 1–13. http://dx.doi.org/10.1155/2013/350890.
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A laminated composite plate element with an interface description is developed using the finite element approach to investigate the bending performance of two-layer cross-ply laminated composite plates in presence of a diagonally perturbed localized interfacial degeneration between laminae. The stiffness of the laminate is expressed through the assembly of the stiffnesses of lamina sub-elements and interface element, the latter of which is formulated adopting the well-defined virtually zero-thickness concept. To account for the extent of both shear and axial weak bonding, a degeneration ratio is introduced in the interface formulation. The model has the advantage of simulating a localized weak bonding at arbitrary locations, with various degeneration areas and intensities, under the influence of numerous boundary conditions since the interfacial description is expressed discretely. Numerical results show that the bending behavior of laminate is significantly affected by the aforementioned parameters, the greatest effect of which is experienced by those with a localized total interface degeneration, representing the case of local delamination.
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Wang, Xianzhong, Yingying Zuo, and Yongshui Lin. "Structural-Acoustic Modeling and Analysis of Carbon/Glass Fiber Hybrid Composite Laminates." International Journal of Structural Stability and Dynamics 20, no. 04 (April 2020): 2050048. http://dx.doi.org/10.1142/s0219455420500480.
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The vibration and acoustic behaviors of both glass fiber laminated plates and carbon/glass fiber hybrid laminated plates are investigated by numerical simulation. The free vibration, forced vibration and acoustic radiation of laminated plates including glass fiber laminates and carbon/glass fiber hybrid laminates in air and water are calculated by the coupled finite element and boundary element method and compared with the corresponding test results. It was demonstrated that results obtained by the coupled finite element and boundary element method are in good agreement with the experimental ones. The effects of dispersion, outer fiber types and fiber hybrid ratio on the vibration and sound radiation of the laminates plates are also discussed.
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Aizat, G., A. Zaidon, S. H. Lee, S. B. Edi, and B. Paiman. "A comparison between the properties of low and medium molecular weight phenol formaldehyde resin-treated laminated compreg oil palm wood." International Forestry Review 19, no. 3 (December 1, 2017): 1–11. http://dx.doi.org/10.1505/146554817828562305.
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In order to improve the inherently poor properties of oil palm wood (OPW), this study examines the effects of resin molecular weight, diffusion time and compression ratio on the properties of laminated compreg OPW. Treating solutions used were medium molecular weight phenol formaldehyde (MmwPF) and low molecular weight phenol formaldehyde (LmwPF). OPW strips were soaked in the treating solutions for 24 h before wrapping in a plastic bag and leaving them for diffusion for 2, 4 and 6 days, respectively. Then, three-layer laminated compreg OPW were fabricated and compressed in hot press at 150°C for 20 minutes to achieve compression ratios of 55%, 70% and 80%. Results indicated that dimensional stability and mechanical properties of the phenolic resin treated laminated compreg OPW were significantly better than the untreated laminates. MmwPF-treated laminates exhibited inferior properties in comparison to that of LmwPF-treated laminates. Nevertheless, MmwPF-treated laminated compreg OPW emitted significantly lesser formaldehyde.
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Srinivasa, C. V., Y. J. Suresh, and W. P. Prema Kumar. "Experimental and Finite Element Studies on Free Vibration of Skew Plates." International Journal of Applied Mechanics and Engineering 19, no. 2 (May 1, 2014): 365–77. http://dx.doi.org/10.2478/ijame-2014-0024.
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Abstract The present paper deals with the experimental studies carried out on free vibration of isotropic and laminated composite skew plates. The natural frequencies were also determined using QUAD8 finite element of MSC/NASTRAN and a comparison was made between the experimental values and the finite element solution. The effects of the skew angle and aspect ratio on the natural frequencies of isotropic skew plates were studied. The effects of the skew angle, aspect ratio, fiber orientation angle and laminate sequence (keeping the number of layers constant) on the natural frequencies of antisymmetric composite laminates were also studied. The experimental values of natural frequencies are in good agreement with the FE solutions. The natural frequencies are found to increase with an increase in the skew angle. The variation of natural frequencies with the aspect ratio is small and negligible both for isotropic and laminated composite skew plates.
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Tasdemir, Burcu, and Demirkan Coker. "Fatigue and static damage in curved woven fabric carbon fiber reinforced polymer laminates." Journal of Composite Materials 56, no. 11 (March 25, 2022): 1693–708. http://dx.doi.org/10.1177/00219983221078787.
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Failure mechanisms of curved cross-ply laminates under static and fatigue loading have been studied extensively, but the examination of fabric laminates which are the most commonly used ply type in curved supports in airplane wing structures is lacking. In this study, unidirectional (UD) and fabric carbon fiber reinforced polymer (CFRP) laminates are examined to elucidate the failure initiation mechanisms of laminated composites under fatigue and static loading. The crucial point of the research is applying the analyses using fabric laminate with a currently used stacking sequence in commercial airplanes. In addition to the fabric laminate, UD laminate is also included in the research to compare the real complex stacking with the simplest stacking. In the experiments, it is observed that both static and fatigue failures initiate roughly at the maximum radial stress location (approximately 35% of the thickness from the inner radius). For UD laminates, there is no visible difference between the failure mechanisms under static and fatigue loadings. However, for fabric laminates, fatigue failure is observed to occur as a single major crack at the maximum radial stress location as in UD laminates, whereas static failure is observed to occur as multiple diffusive cracks at the maximum radial stress location. Additionally, cracks grow mostly as intralaminar cracks connected with regions of occasional interlaminar cracks.
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Zulkifli, M. A. A., Z. I. A. Halim, N. A. S. Norbani, and J. Mahmud. "Failure Analysis of Boron/Epoxy Composite Laminates with Square Cutouts in Various Size under Uniaxial Tension." Journal of Physics: Conference Series 2051, no. 1 (October 1, 2021): 012062. http://dx.doi.org/10.1088/1742-6596/2051/1/012062.
Full textAbstract:
Abstract Composite laminates have received much interest in precise engineering fields such as aerospace and automotive industries. Understanding the failure behaviour of laminated composites is important when designing modern structures, but many studies only focus on laminates without cutouts. In practice, the structures are design with cutouts to accommodate the space for fasteners, such as rivets, screws and bolts. This study analyses the failure behaviour of Boron/Epoxy composite laminates with square cutout of various sizes under uniaxial tension. In this study, failure analysis was performed using a Finite Element Analysis (FEA) software, ANSYS, for laminated composite plates with square cutout. The laminas were arranged in the sequence of [θ4/04/-θ4]s where the fibre angle, θ ranges from 0˚ to 90˚. The failure load was predicted based Maximum stress theory. For better visualisation, failure curves are plotted and analysed. Prior to that, the numerical validation procedure has proved the accuracy of the simulation as the results obtained from analytical approach (Matlab) and simulation (ANSYS) are in close agreement. The failure curves show that the Boron/Epoxy composite laminate has weaken seven times due to the square cutout. Such information is vital when designing a structure. Even though more rigorous research should be conducted, it could not be denied that the current study has contributed significant fundamental knowledge. The novelty of this work is that a new set of failure envelopes for Boron/Epoxy laminates with various cutout sizes was developed.
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Mühlstädt, Mike, Wolfgang Seifert, Matthias ML Arras, Stefan Maenz, Klaus D. Jandt, and Jörg Bossert. "An advanced geometrical model for laminated woven fabrics using Lamé exponents with enhanced accuracy." Journal of Composite Materials 52, no. 11 (August 23, 2017): 1443–55. http://dx.doi.org/10.1177/0021998317725570.
Full textAbstract:
Three-dimensional stiffness tensors of laminated woven fabrics used in high-performance composites need precise prediction. To enhance the accuracy in three-dimensional stiffness tensor prediction, the fabric’s architecture must be precisely modeled. We tested the hypotheses that: (i) an advanced geometrical model describes the meso-level structure of different fabrics with a precision higher than established models, (ii) the deviation between predicted and experimentally determined mean fiber-volume fraction ( cf) of laminates is below 5%. Laminates of different cf and fabrics were manufactured by resin transfer molding. The laminates’ meso-level structure was determined by analyzing scanning electron microscopy images. The prediction of the laminates’ cf was improved by up to 5.1 vol% ([Formula: see text]%) compared to established models. The effect of the advanced geometrical model on the prediction of the laminate’s in-plane stiffness was shown by applying a simple mechanical model. Applying an advanced geometrical model may lead to more accurate simulations of parts for example in automotive and aircraft.