Journal articles: 'Laminated plastics'

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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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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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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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Lin, Yan Yu, Mei-Chen Lin, Ching-Wen Lou, Yueh-Sheng Chen, and Jia-Horng Lin. "Thermoplastic Laminated Composites Applied to Impact Resistant Protective Gear: Structural Design and Development." Polymers 15, no. 2 (January 6, 2023): 292. http://dx.doi.org/10.3390/polym15020292.

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Laminated composites have been commonly applied to all fields. When made into laminated composites, Kevlar woven fabrics are able to provide the required functions. In this study, two types of TPU are incorporated to improve the intralayer features of Kevlar/TPU laminated composites. Hence, the Kevlar/TPU laminated composites consist of firmly bonded laminates while retaining flexibility of the fabrics. Being the interlayer of the laminated composites, the TPU layer provides adhesion while strengthening the tensile property, dynamic puncture resistance, and buffer strength of Kevlar/TPU laminated composites. The test results indicate that with a blending ratio of two types of TRU being 85/15 wt%, the Kevlar/TPU laminated composites exhibit a tensile strength of 18.08 MPa. When the stacking thickness is 1 mm, the tensile strength is improved to 357.73 N with the buffering strength reaching 4224.40 N. Notably, with a thickness being 1.2 mm, the laminated composites demonstrate a dynamic resistance being 672.15 N. In the meanwhile, functional Kevlar fabrics are allowed to keep the fiber morphology owing to the protection of TPU composite films. Considering the composition of protective gear, Kevlar/TPU laminated composites possess a powerful potential and are worthwhile exploring.

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Parhizgar, S. "Determination of Stiffness Properties of Multi-Ply Cord-Rubber Composites." Tire Science and Technology 17, no. 3 (July 1, 1989): 201–16. http://dx.doi.org/10.2346/1.2141685.

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Abstract The material properties of cord-rubber composites required for finite element analysis of tires are discussed. It is shown that the current experimental methods used in verification of the Laminated Plate Theory have not adequately included the coupling deformations existing in unsymmetrical laminated composites. The importance of these coupling deformations is demonstrated on a 0/90 laminated strip. A special grip system capable of decoupling loads and moments applied to a 0/90 laminated strip is introduced. A procedure for experimental determination of the stiffness constants of 0/90 laminate is given.

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Valot, E., P. Vannucci, and G. Verchery. "Complete In-plane Elastic Characterisation under Tensile Tests of Angle-Ply Laminates Composed of Polymer-Matrix Layers." Polymers and Polymer Composites 10, no. 7 (October 2002): 483–92. http://dx.doi.org/10.1177/096739110201000701.

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In this paper we present a new strategy to completely characterise the in-plane elastic properties of a large range of angle-ply laminates using only unidirectional tests. We consider laminates having the same number of identical plies in the α and – α directions. This new method uses some preceding results found by Verchery for orthotropic laminates, namely the conditions of existence of a specific direction ω, in which the shear-extension coupling is null. The characterisation of the laminate is then made using the results of three tensile tests: two in the orthotropy axes, and the third one in the ω direction, in order to have always a pure one-dimensional state of stress. We show that for the most common unidirectional fibre-reinforced materials, the angle ω is, in most cases, close to the α direction of the fibres. This result permits a complete experimental characterisation of the laminate, which then does not need any a priori knowledge of the elastic properties of the elementary layer. In addition, it provides a simple method to verify the predictions of the laminate behaviour obtained by the Classical Laminated Plate Theory (CLPT) when the elementary layer is completely known. The paper ends with numerical examples and with the results of some experimental tests.

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Huang, Zheng-Ming, X. C. Teng, and S. Ramakrishna. "Fatigue Behaviour of Multilayer Braided Fabric Reinforced Laminates." Polymers and Polymer Composites 13, no. 1 (January 2005): 73–81. http://dx.doi.org/10.1177/096739110501300106.

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In this paper, the fatigue behaviour of the laminated composites made from an epoxy matrix and four layers of flat regular braided carbon fiber fabrics of different braiding angles was investigated experimentally. Three laminate lay-ups were used. They are: [100/100/100/100], [280/100/100/280], and [280/280/280/280], where 100 within the bracket indicates that the single layer braid lamina had a braiding angle of 100 inclined with the longitudinal (loading) direction. The static tensile and tension-tension fatigue tests were conducted for those laminates, and detailed fatigue data are reported in the paper. Failure mechanisms of the tested laminates were also characterized. The stiffnesses and strengths (including static tensile and fatigue strengths) of the [100/100/100/100], [280/100/100/280], and [280/280/280/280] laminates were the highest, intermediate, and the lowest respectively. However, different failure mechanisms were recognized. It was found that under the uniaxial tensile or a high-level fatigue load, the [280/280/280/280] laminate failed catastrophically as a result of fiber breakage nearly across the cross section of the specimen. Delamination was seen only when a low-level fatigue load was applied to the laminate. In the case of the [100/100/100/100] laminate, a laminate longitudinal splitting was the main failure mode. No delamination accompanied the laminate failure. For the [280/100/100/280] laminate, significant delamination was found with any applied load (whether static or tensile fatigue of any load level). Splitting, both across the cross-sectional breakage and longitudinal, were involved in the failure of this combined laminate. These findings provide a useful insight into understanding the fatigue behaviour of braided fabric reinforced laminates.

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Evran, Savaş. "Experimental and statistical free vibration analyses of laminated composite beams with functionally graded fiber orientation angles." Polymers and Polymer Composites 28, no. 7 (June 27, 2020): 513–20. http://dx.doi.org/10.1177/0967391120938210.

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In this experimental and statistical study, free vibration behavior of laminated composite beams with functionally graded fiber orientation angles was investigated under clamped-free boundary conditions. The beams were manufactured using E-glass/epoxy. Fiber orientation angles of the beams were analyzed based on Taguchi’s L9 (33) orthogonal array. The effect of fiber orientation angles and beams with optimum levels were assessed using analysis of signal-to-noise ratio. Significant laminates of the beams and their percent contributions on the free vibration responses were obtained using analysis of variance. According to this study, the increase of fiber orientation angle from 0° to 80° causes a decrease in the fundamental frequency behavior of laminated composite beams. The most effective control factors were found to be the first and the second laminates symbolized as L1 with 85.86% contribution, the third and the fourth laminates symbolized as L2 with 12.29% contribution, the fifth and the sixth laminates symbolized as L3 with 1.84% contribution, respectively. This study can be used as a reference for free vibration analysis of cantilever laminated composite beams made of functionally graded fiber orientation angles as experimentally and statistically.

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Go, Sun-Ho, Min-Sang Lee, Chang-Gi Hong, Lee-Ku Kwac, and Hong-Gun Kim. "Correlation between Drop Impact Energy and Residual Compressive Strength According to the Lamination of CFRP with EVA Sheets." Polymers 12, no. 1 (January 16, 2020): 224. http://dx.doi.org/10.3390/polym12010224.

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Carbon-fiber-reinforced plastic is an important building material; however, its application is limited because of its brittleness, leading to vulnerability under shock. Thus, the strength performance of carbon-fiber-reinforced plastics needs to be improved. Here, the drop impact test was conducted to analyze the impact energy and fracture characteristics of carbon-fiber-reinforced plastics and ethylene vinyl acetate sheets. The compression after impact test was performed to assess the residual compressive strength. The thermal energy generated was measured as change in temperature at the time of fracture to investigate the relationship between thermal and mechanical properties. The impact absorption efficiency of 100% was achieved when the carbon-fiber-reinforced plastics specimen was laminated with four or more sheets of ethylene vinyl acetate. The thermal energy generated during impact, the impact load, and the compression after impact test strength was reduced with the increasing number of laminated ethylene vinyl acetate layers. Our results showed that, by carefully selecting the optimal conditions of fabricating the carbon-fiber-reinforced plastic/ethylene vinyl acetate composites, carbon composite materials can be used for impact mitigation.

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Lee, Sang-Kwon, Sungil Bang, and Jiseon Back. "Effect of laminated angle of carbon fiber on interior noise on an enclosure under center point excitation." Journal of Reinforced Plastics and Composites 38, no. 3 (October 22, 2018): 117–32. http://dx.doi.org/10.1177/0731684418808091.

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This paper presents a novel method to control passively the interior noise of an enclosure such as car cabin by using the movement of the peak level and peak frequency according to the laminated angle of carbon fiber reinforced plastic composite plate. Recently, the use of carbon fiber reinforced plastic laminated plates in a car has been increased in order to reduce the weight of a car. For example, the metal plate roof has been replaced by the carbon fiber reinforced plastic plate roof for weight reduction of an electric vehicle. The characteristics of the interior noise inside of a car made of carbon fiber reinforced plastic plate roof can be changed according to the laminated angle of carbon fiber. In this paper, how this characteristic is changed was studied based on the effect of laminated angle of carbon fiber. In order to perform this study, a closed box with one flexible side wall and five acoustically rigid side walls was modelled as the interior compartment of a car. The flexible side wall of the closed box regards as the roof plate of a car. For the flexible side wall of the closed box, three carbon fiber reinforced plastic plates with different angle-ply (± θ) laminates each other were used. Therefore, three carbon fiber reinforced plastic plates with the fiber lamination angles of [−15/15/15/–15]s, [–30/30/30/–30]s, and [–75/75/75/–75]s were fabricated and used as the flexible side wall of the closed box. How the interior noise inside of the closed box was changed according to the laminated angle was studied by theoretical and numerical methods. For the validation of theoretical and numerical methods, the experimental work was performed. Finally, the carbon fiber reinforced plastic plate roof for a passenger car was numerically simulated, and the effect of the laminated angle on the interior noise was studied.

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Gurvich, Mark R. "On Multi-Scale Modeling of Elastomeric Laminated Composites for Structural Analysis." Rubber Chemistry and Technology 79, no. 2 (May 1, 2006): 217–32. http://dx.doi.org/10.5254/1.3547934.

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Abstract Analysis of complex structures is often based on multi-scale modeling, where effective properties of certain substructures are used instead of actual properties of smaller components. Laminated composites are usually considered as such sub-structures in components with laminated design. In case of elastomeric composites, well-known classical laminate theories could hardly be used due to significant non-linearity and incompressibility of material deformation. A convenient engineering variant of laminated model is proposed in this study for composites where neither physical nor geometrical non-linearity may be ignored. Possible material incompressibility is also taken into account. The model is primarily based on a previously developed constitutive approach to describe effective properties of anisotropic hyperelastic materials. Analytical and computational implementation of the model is considered in detail. Numerical examples illustrate accuracy and convenience of the model for representative cord/rubber composites.

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Taheri-Behrooz, Fathollah, and Nima Bakhshi. "Neuber’s rule accounting for the material nonlinearity influence on the stress concentration of the laminated composites." Journal of Reinforced Plastics and Composites 36, no. 3 (November 23, 2016): 214–25. http://dx.doi.org/10.1177/0731684416680302.

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Since holes comprise the necessary features of many structural components, a comprehensive understanding of the behavior of composite plates containing an open hole is a crucial step in their design process. In the present manuscript, an extensive numerical study has been conducted in order to investigate the effects of material nonlinearity on the stress distribution and stress concentration factors in unidirectional and laminated composite materials. To attain this objective, various models with different configurations were studied. In unidirectional composites, the maximum deviation of stress distribution around the hole (from the linear solution) happens in 45° lamina in which includes a high level of shear stress. However, the maximum difference in the stress concentration factor occurs in 15° lamina and is 15.1% at the onset of failure. In composite laminates, the maximum deviation of nonlinear stress concentration factor from the linear solution is reported 24.3% and it occurs in [+45/−45] s laminate. In the last section, Neuber’s rule is employed to find the stress concentration factors of the laminated composites, with a reasonable accuracy.

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Kablov, E. N., L. V. Semenova, V. A. Bogatov, I. V. Mekalina, A. G. Krynin, and M. K. Aizatulina. "New Electrically Heated and Bird-Strike-Resistant Polymer Glazing for Aircraft." International Polymer Science and Technology 45, no. 5 (May 2018): 231–36. http://dx.doi.org/10.1177/0307174x1804500510.

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The main stages in the development of a bird-strike-resistant heated curved organic laminate for aircraft glazing are described: the selection of the polymeric materials; the application of a heated coating to the polymeric material; the moulding of glazing elements; the application of leads to the conductive coating; autoclave pressing of the laminated polymer material.

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Li, Bo, Shu Nuan Liu, Xi Tian Tian, Fei Gao, and Zhen Ming Zhang. "Drilling Simulation on Carbon Fiber Reinforced Plastics and Aluminum Laminated Composite." Advanced Materials Research 490-495 (March 2012): 3281–85. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.3281.

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In order to study the process of drilling carbon fiber reinforced plastics and aluminum alloy laminated composite, a simulation on drilling is conducted by using FEM analysis software ABAQUS, the finite element model of carbon fiber composite material finite element model is established. The dynamic simulation of the drilling process of carbon fiber reinforced plastics is carry on, which based on the elastic-plastic theory of material deformation and the thermal coupling theory, obtaining continuous drilling force and torque data. The influence of material and parameters on drilling and drilling technology on drilling process are deeply analyzed, obtain relationship about material and feed rate and drilling force and torque. The result of the research provides the support for further study of high speed drilling mechanism of carbon fiber reinforced plastics.

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Vidinejevs, Sergejs, and Andrey Aniskevich. "The system of carbon fibre-reinforced plastics micro-tubes for self-healing of glass fibre-reinforced plastics laminates." Journal of Composite Materials 51, no. 12 (August 17, 2016): 1717–27. http://dx.doi.org/10.1177/0021998316665898.

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A system of pultruded carbon fibre-reinforced plastics micro-tubes is used for self-healing simulation in laminated polymer composite. The system consists of a package of micro-tubes, placed in the symmetry plane of the GFR/epoxy laminate stack. Healing agent is a mixture of the epoxy resin and hardener. The healing agent releases and penetrates into the cracks after the composite is damaged by the quasi-static indentation. The specimens are healed at 30℃ for 24 h. Rectangular specimens notched under ASTM D2733 have been subjected to tensile test to determine interlaminar shear strength. Shear strength of specimens has been compared in three states (virgin, damaged and healed) for various ways of healing. After the most effective self-healing, the interlaminar shear strength has been recovered to 70 ± 15% of those for virgin specimens that almost twice exceeds the residual strength of the damaged specimens.

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Luo, Guang-Min, Guang-Yen Liou, and Hong-Zhe Xiao. "Using a Fiber Bragg Grating Sensor to Measure Residual Strain in the Vacuum-Assisted Resin Transfer Molding Process." Polymers 14, no. 7 (April 1, 2022): 1446. http://dx.doi.org/10.3390/polym14071446.

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Vinyl ester (VE) resin has strong environmental tolerance and is the matrix commonly used in the composite materials of fiber-reinforced plastics (FRP). VE resin is often combined with glass fiber in different maritime structures, such as wind turbine blades, spinner cases, and nacelle cases. However, VE resin exhibits exothermic reactions and shrinkage during curing, which often generates residual strain in large structures and those with a high stacking number. This study explored the exothermic reaction and shrinkage of VE resin and glass fiber during the vacuum-assisted resin transfer molding process, as measured using a fiber Bragg grating sensor. The experiment results verified the relationship between the stacking number and residual strain shrinkage. In addition, the symmetric laminate method was used to prevent the bending–twisting coupling effect and subsequent warping deformation of the FRP laminated plate during curing. The experiment results also verified that the bottom layers of the FRP laminated plates produced using VE resin were closer to the mold, and exhibited more shrinkage as the stacking number increased. In addition, this study discovered that during the experiment, the symmetry layer of the FRP laminated plate had a higher exothermic temperature than the bottom layer as a result of the symmetry layer’s ineffective heat dissipation. Therefore, the curing shrinkage of the symmetry layer resin was measured. The experiment results indicated that if the stacking number was between 10 and 30, the residual strain shrinkage of the symmetry layer was greater than that of the surface layer. However, because of the symmetric laminate, the residual strain of the symmetry layer did not increase when the temperature increased. Therefore, the greatest residual strain occurred at the surface of the bottom layer of the laminated plate with a stacking number of 40.

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Froš, Denis, Karel Dušek, and Petr Veselý. "Investigation of Impacts on Printed Circuit Board Laminated Composites Caused by Surface Finish Application." Polymers 13, no. 19 (September 22, 2021): 3203. http://dx.doi.org/10.3390/polym13193203.

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The purpose of this study was to compare the strength of the bond between resin and glass cloth for various composites (laminates) and its dependence on utilized soldering pad surface finishes. Moreover, the impact of surface finish application on the thermomechanical properties of the composites was evaluated. Three different laminates with various thermal endurances were included in the study. Soldering pads were covered with OSP and HASL surface finishes. The strength of the cohesion of the resin upper layer was examined utilizing a newly established method designed for pulling tests. Experiments studying the bond strength were performed at a selection of laminate temperatures. Changes in thermomechanical behavior were observed by thermomechanical and dynamic mechanical analyses. The results confirmed the influence of the type of laminate and used surface finish on bond strength. In particular, permanent polymer degradation caused by thermal shock during HASL application was observed in the least thermally resistant laminate. A response to thermal shock was detected in thermomechanical properties of other laminates as well, but it does not seem to be permanent.

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Proietti, Alice, Leandro Iorio, Nicola Gallo, Marco Regi, Denise Bellisario, Fabrizio Quadrini, and Loredana Santo. "Recycling of Carbon Fiber Laminates by Thermo-mechanical Disassembly and Hybrid Panel Compression Molding." Materiale Plastice 59, no. 1 (April 5, 2022): 44–50. http://dx.doi.org/10.37358/mp.22.1.5558.

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An innovative recycling process for thermoset composite laminates is proposed by thermo-mechanical disassembly and further compression molding of hybrid thermoformable composite plates. Due to the thermo-mechanical process, single cured plies are extracted from the waste laminate. Subsequently re-lamination is performed by interposing thermoplastic films between the reclaimed composite plies. Final consolidation is carried out by compression molding. In order to show the feasibility of the novel recycling technology, carbon fiber reinforced composite plates by autoclave molding were thermo-mechanically disassembled in a manual roll bending machine after heating in oven. Reclaimed cured plies were laminated by alternating thermoplastic interlayers made of low density polyethylene. The hybrid laminate was consolidated at the temperature of 220�C and the holding pressure of 38.5 bar. Results from bending tests on virgin and recycled plates showed the very good agglomeration of the hybrid samples and the optimal preservation of performances of initial cured plies of the virgin material into the recycled plate.

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Ali, Hafiz Tauqeer, Roya Akrami, Sakineh Fotouhi, Farzad Pashmforoush, Cristiano Fragassa, and Mohammad Fotouhi. "EFFECT OF THE STACKING SEQUENCE ON THE IMPACT RESPONSE OF CARBON-GLASS/EPOXY HYBRID COMPOSITES." Facta Universitatis, Series: Mechanical Engineering 18, no. 1 (March 27, 2020): 069. http://dx.doi.org/10.22190/fume191119010a.

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This paper investigates low-velocity impact response of Quasi Isotropic (QI) hybrid carbon/glass fiber reinforced polymer composites with alternate stacking sequences. Cross-ply woven carbon and glass fibers were used as reinforcing materials to fabricate sandwiched and interlayer hybrid composites. For comparison, the laminates containing only-carbon and only-glass fibers were also studied. Drop weight test was used to impact the samples. The images captured by a normal camera demonstrated that localized damages (delamination) existed within plies. The hybrid laminates had smaller load drops, smaller maximum deflection, and higher maximum load compared to the single fiber laminates. In addition, carbon outside interlayer hybrid laminate showed the highest maximum load and energy absorption, showing the significant dependence of the impact performance on hybridization and stacking sequence. It was concluded that a hybrid composite would help improve impact performance of laminated composites compared to non-hybrid composites if they are properly designed.

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Kruklin'sh, A. A., and A. �. Pa�glitis. "Relative energy dissipation in laminated reinforced plastics." Mechanics of Composite Materials 24, no. 3 (1988): 332–39. http://dx.doi.org/10.1007/bf00606604.

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Ivanova, Angela. "Solving recycling challenges with sustainable polymers." Open Access Government 42, no. 1 (April 8, 2024): 378. http://dx.doi.org/10.56367/oag-042-11347.

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Solving recycling challenges with sustainable polymers [Angela Ivanova, CEO & Co-Founder, explains how her firm LAM’ON solves recycling challenges. A shift to sustainable polymers will reduce the environmental footprint of non-degradable packaging materials; we discover. Laminated flexible plastic packages play a vital role in protecting the quality and shelf-life of our favourite products. However, these widely used laminated paper containers, which consist of paper/cardboard, plastic, and metals like aluminium, pose significant recycling challenges. The pulp and paper sector stands as a significant pillar of the global economy. It also presents intricate waste management issues. The application of plastics as a barrier lining in paper-based packaging containers increases the overall recycling costs. The industry generates substantial volumes of diverse waste streams, presenting a distinct disposal challenge.

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Lukina, N. F., L. A. Dement’eva, and L. I. Anikhovskaya. "ADHESIVE PREPREGS FOR LAMINATED ALUMINUM GLASS PLASTICS (SIAL)." Proceedings of VIAM, no. 1 (January 2014): 5. http://dx.doi.org/10.18577/2307-6046-2014-0-1-5-5.

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Gurvich, Mark R. "On Effective Modeling of Laminated Cord-Rubber Composites." Rubber Chemistry and Technology 80, no. 4 (September 1, 2007): 608–20. http://dx.doi.org/10.5254/1.3548183.

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Abstract The major challenge in modeling of laminated cord-rubber composites (CRC) is to achieve desired predictive accuracy as well as maintain computational efficiency of corresponding numerical solutions. Existing modeling methods are primarily based on a) more traditional theories developed for fiber-reinforced polymer-matrix laminates and b) rebar- and shell based FEA approaches. Although mentality of these methods is widely used in rubber and tire engineering, these models often significantly simplify important issues of non-linearity and 3-D nature of interlaminar deformation. The objective of the paper, therefore, is to develop an efficient general modeling approach for typical laminated CRC capturing fundamental mechanisms of their deformation as well as providing relatively simple and cheap solutions. The approach uses advantages of previously developed methods (Gurvich) to quantify deformation of anisotropic elastomers. The present study is focused on 3D extension of the problem to account for crucially important interlaminar behavior of these composites. Several structural examples illustrate simplicity of implementation, demonstrate computational robustness, and show practical importance of obtained results. In particular, limitations of existing rebar-based models of CRC are shown and explained.

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Wang, Xing, Yu Jiang, Yonghui Huang, Yue Huang, and Fan Wang. "Finite Element Failure Analysis of GFRP Laminates in Plate-Cone Reticulated Shell." Advances in Polymer Technology 2020 (June 19, 2020): 1–12. http://dx.doi.org/10.1155/2020/2809302.

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Plate-cone reticulated shell is a new type of spatial structures with good mechanical behavior, technical economy, and architectural appearance. In this paper, using ANSYS software, the strength failure analysis model of composite laminates is established in cooperation with the Strength Criterion of Hoffman. The effects of layer number, laying direction, and thickness of laminates on the ultimate strength of laminates are studied by detailed parametric analysis, which provides a theoretical basis for the design of composite plate-cone reticulated shell and GFRP laminated plates. Some important conclusions are obtained and can be applied to engineering practice.

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Bernal-Carrillo, Johnatan Gabriel, Fernando Sebastián Chiwo-González, Ana del Carmen Susunaga-Notario, Mayra Del Ángel–Monroy, Hugo Arcos-Gutiérrez, and Isaías Emmanuel Garduño-Olvera. "Development and redesign of flexible packaging under sustainability criteria." REVISTA DE CIENCIAS TECNOLÓGICAS 7, no. 1 (January 18, 2024): e253. http://dx.doi.org/10.37636/recit.v7n1e253.

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The circular economy and sustainable development are critical issues today, given the growing environmental pollution caused by solid waste, especially plastics. Furthermore, plastic waste has raised significant social concerns and alerted plastic product designers. Therefore, developing or redesigning plastic products in the flexible packaging industry is imperative to ensure their recyclability at the end of their life cycle. It is necessary to ensure that the mechanical and barrier properties of the ecological plastic packaging remain intact for specific uses. The current study aims to redesign flexible packaging, focusing on providing the mechanical and barrier properties of the packaging suitable for food industry applications, thus offering a solution through new design proposals that allow the development of sustainable and flexible packaging, emphasizing material reduction and recyclability. This study assessed and compared the mechanical properties of the proposed packaging with those of existing products. The results demonstrated the feasibility of reducing plastic film thickness or eliminating layers in a tri-laminated structure and transitioning to a bi-laminated structure. This adjustment did not compromise the mechanical and barrier properties; the oxygen barrier remained at 35.39 cc/m2*day, and the humidity stood at 0.57 mg/m2*day. This investigation led to a 26.48% reduction in the raw material consumption of laminated coils and 12.68% in Doypack type packaging used in food applications. Consequently, the decreased material usage and adoption of monomaterial structures significantly minimized the environmental impact of plastic waste contamination due to the possibility of mechanically recycling the final product.

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Xu, Wei, Yunfeng Lu, Ruihu Zhu, Maciej Radzieński, Maosen Cao, and Wiesław Ostachowicz. "Shear Strain Singularity-Inspired Identification of Initial Delamination in CFRP Laminates: Multiscale Modulation Filter for Extraction of Damage Features." Polymers 14, no. 11 (June 6, 2022): 2305. http://dx.doi.org/10.3390/polym14112305.

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Identification of initial delamination is crucial to ensure the safety of the fiber-reinforced laminated composite structures. Amongst the identification approaches based on mode shapes, the concept of multiscale shear-strain gradient (MSG) has an explicit physical sense of characterizing delamination-induced singularity of shear strains; moreover, it is robust against noise interference owing to the merits of multiscale analysis. However, the capacity of the MSG for identifying initial delamination is insufficient because the delamination-induced singularity peak can be largely obscured by the global component of the MSG. Addressing this problem, this study proposes an enhanced approach for identifying initial delamination in fiber-reinforced composite laminates. In particular, the multiscale modulation filter (MMF) is proposed to modulate the MSG with the aim of focusing on damage features, by which a new concept of enhanced MSG (EMSG) is formulated to extract damage features. By taking advantage of the MMF with the optimal frequency translation parameters, the EMSG is concentrated in a narrow wavenumber band, which is dominated by the damage-induced singularity peak. As a consequence, the delamination-induced singularity peak in the EMSG can be isolated from the global component. The capacity of the approach for identifying initial delamination is experimentally validated on a carbon fiber reinforced polymer (CFRP) laminate, whose mode shapes are acquired via non-contact laser measurement. The experimental results reveal that the EMSG-based approach is capable of graphically characterizing the presence, location, and size of initial delamination in CFRP laminates.

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Narkevich, Igor A., Stanislav V. Stepanov, Alla O. Volgusheva, Yuri Zvyagin Y. Zvyagin, Svetlana Vorobeva, Vladimir Perelygin, and Daria Dobrova. "Alexander Stepanovich Ardemasov: Party director of the Leningrad Pharmaceutical Institute in 1940-1942." Pharmacy Formulas 2, no. 3 (October 9, 2020): 116–21. http://dx.doi.org/10.17816/phf45993.

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Based on unpublished archival documents from the Central State Archive of Party Historical Documents, the article reconstructs the biography of A.S. Ardemasov, a party worker, the Director of the Leningrad Pharmaceutical Institute (now Saint Petersburg State Chemical and Pharmaceutical University) in the pre-war period, during the Great Patriotic War (WWII) and the post-war years. During his path of life, A.S. Ardemasov headed the leading chemical enterprises of the USSR: the Leningrad Laminated Plastics Plant (now the Laminated Plastics Plant, LLC, St. Petersburg), the State Institute of Applied Chemistry (now the Russian Scientific Center of Applied Chemistry).

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Martulli, Luca Michele, Riccardo Sala, Gennaro Rollo, Milutin Kostovic, Marino Lavorgna, Andrea Sorrentino, Emanuele Gruppioni, and Andrea Bernasconi. "Preliminary Stiffness-Driven Redesign of a Laminated Prosthetic Component Using Additive Manufacturing." Polymers 15, no. 2 (January 9, 2023): 346. http://dx.doi.org/10.3390/polym15020346.

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Three-dimensional printed polymers offer unprecedented advantages for prosthetic applications, namely in terms of affordability and customisation. This work thus investigates the possibility of designing an additively manufactured prosthetic foot using continuous fibre-reinforced polymers as an alternative to composite laminate ones. A numerical approach was thus proposed and validated as a possible design tool for additively manufactured composite feet. This approach was based on explicit separate simulations of the infill, aiming to capture its homogenised engineering constants. The approach was validated on simple sandwich specimens with a different infill geometry: stiffness predictions were within the experimental standard deviation for 3D simulations. Such an approach was thus applied to redesign a laminated component of a foot prosthesis inspired by a commercial one with new additive technology. The new component was about 83% thicker than the reference one, with 1.6 mm of glass fibre skins out of about 22 mm of the total thickness. Its stiffness was within 5% of the reference laminated one. Overall, this work showed how additive manufacturing could be used as a low-cost alternative to manufacturing affordable prosthetic feet.

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Ng, S. C., Napsiah Binti Ismail, Aidy Ali, and Barkawi Sahari. "Defect Reconstruction in Laminated Composites by Ultrasonic Imaging." Applied Mechanics and Materials 263-266 (December 2012): 371–77. http://dx.doi.org/10.4028/www.scientific.net/amm.263-266.371.

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Ultrasonic method for the investigation of multi-layered laminates such as glass fiber reinforced plastics (GFRP) has been a challenging task in industry due to their inherent nature as a combination of constituents and the respective fabrication process. The coarse-grain structure of the material, fiber orientation and stacking sequence of laminated composites generate undesirable echoes for the ultrasonic signals during the testing. These echoes distributed randomly in time affects the measurements of ultrasonic parameters. In this paper, the utilization of attenuation and time-of-flight (TOF) of ultrasound signals to reconstruct the internal structure of GFRP subsurface region were investigated. Comparisons of these two methods were conducted on two sets of GFRP with different structure condition. Analysis of C-scan images constructed by amplitude and TOF were conducted in a two dimensional region map of the scanning profile. Experimental results showed that attenuation of amplitude gave a better indication of damage and successfully improved the defect region detection in multi-layered reinforced composite materials.

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Gu, Huang. "Comparison between laminated and integrated glass fibre reinforced plastics." Materials & Design 21, no. 5 (October 2000): 461–64. http://dx.doi.org/10.1016/s0261-3069(00)00004-2.

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Ryska, J. "Deformation and strength of laminated quasiisotropic carbon-reinforced plastics." Mechanics of Composite Materials 21, no. 3 (1985): 300–305. http://dx.doi.org/10.1007/bf00611615.

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Magomedov, G. M., Z. R. Radzhabov, G. P. Mashinskaya, and A. B. Aivazov. "Anisotropy of the viscoelastic properties of laminated organometallic plastics." Mechanics of Composite Materials 25, no. 5 (1990): 559–63. http://dx.doi.org/10.1007/bf00612896.

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Naveen, J., M. Jawaid, ES Zainudin, Mohamed TH Sultan, and R. Yahaya. "Effect of graphene nanoplatelets on the ballistic performance of hybrid Kevlar/Cocos nucifera sheath-reinforced epoxy composites." Textile Research Journal 89, no. 21-22 (February 28, 2019): 4349–62. http://dx.doi.org/10.1177/0040517519833970.

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This study investigated the effect of graphene nanoplatelets (GnPs) on the ballistic performance of Kevlar/ Cocos nucifera sheath-reinforced epoxy composites. GnPs with different wt. % (0%, 0.25%, 0.50%) were integrated into epoxy resin through ultra-sonication. Laminated composites were fabricated by incorporating Kevlar and Cocos nucifera sheath layers into the epoxy/GnP mixture by the hand lay-up method followed by hot pressing. Nine- and 12-layered laminates were fabricated with different numbers of Kevlar and Cocos nucifera sheath plies. Ballistic tests were conducted using a single-stage gas gun experimental setup with an 8 mm hemispherical stainless steel projectile. The results showed that the addition of GnPs improved the energy absorption by 8.5% (nine plies) and 12.88% (12 plies) and the ballistic limit by 4.28% (nine plies) and 6.17% (12 plies), respectively of Kevlar/epoxy/GnP composites at 0.25 wt. %. However, hybrid Kevlar/ Cocos nucifera sheath/epoxy/GnP composites and Cocos nucifera sheath/epoxy/GnP laminated composites decreased the energy absorption and ballistic limit after the addition of GnPs. This is because the addition of GnPs improved the interfacial interactions between the fiber and GnP modified epoxy matrix, which is inappropriate to absorb and dissipate the kinetic energy of the projectile. Statistical analysis was carried out using one-way analysis of variance and it was shown that there is a statistically significant difference between the obtained ballistic properties of the laminates.

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Ghavanini, Navid, Antonio Maria Caporale, Paolo Astori, Alessandro Airoldi, and Paolo Panichelli. "Impact Response of Monolithic and Laminated Polycarbonate Panels: An Experimental and Numerical Investigation." Polymers 15, no. 24 (December 11, 2023): 4677. http://dx.doi.org/10.3390/polym15244677.

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This study aimed to investigate the impact resistance of monolithic and laminated polycarbonate plates for windshields in motorsport applications through a coupled experimental–numerical study. Both low- and high-velocity impact tests were performed by using a drop tower and a gas gun, respectively, considering a sharp-edged projectile impacting on flat panels. The response of the polycarbonate plates was evaluated in terms of the failure mode, perforation velocity threshold, and energy absorption mechanism. The experiments allowed for the assessment and the generalization of a 3D finite element modeling approach originally developed for supersonic application based on different state-of-the-art constitutive theories, including temperature-dependent and rate-dependent von Mises plasticity coupled with ductile damage, Mie–Grüneisen equation of state, and temperature variation due to energy dissipation under adiabatic assumptions. The approach was completed with a cohesive zone model for a laminate plate and studies were performed to highlight the relevancy of different aspects of material characterization. The tests and numerical analyses performed at different velocity ranges highlight the importance of viscoplastic behavior in a polycarbonate windshield. The numerical approach showed its capability to model the different failure modes for monolithic and laminated panels and capture the perforation velocity thresholds with appreciable accuracy, which were actually found to be quite similar for the two types of panels in the test conditions considered. A numerical investigation suggests that the development of delaminations could lead to the improved energy absorption of laminated polycarbonate. To further assess the numerical model, it was used to successfully predict the penetration threshold velocity of a polycarbonate windshield subjected to a gas gun impact test.

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Bayati Chaleshtari, Mohammad Hossein, Mohammad Jafari, and Hadi Khoramishad. "Effect of cutout geometry on the failure strength of symmetric laminates under uniform heat flux." Journal of Reinforced Plastics and Composites 41, no. 3-4 (October 14, 2021): 81–98. http://dx.doi.org/10.1177/07316844211048772.

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The present work aims to investigate the thermal stress distribution in an infinite symmetrical laminated composite plate with a polygonal cutout to determine the laminate failure strength based on the first ply failure according to Hashin–Rotem and Tsai–Wu criteria. Lekhnitskii’s solution technique has been used to obtain the required potential functions. The extension of the technique used for the circular and elliptical cutouts into polygonal cutouts was performed using conformal mapping function in accordance with the procedure of complex variables. The main parameters such as cutout orientation, bluntness factor, the aspect ratio of the cutout, as well as stacking sequences in composite plates with symmetrical laminates made of glass/epoxy material containing triangular, square, pentagonal, and hexagonal cutouts have been examined. According to the research findings, it is possible to improve the failure strength of perforated plates by appropriate selection of cutout shapes along with the optimum values of the effective parameters. The unexpected result was that circular geometry was not always the best choice for the cutout because the selection of appropriate values for the parameters under consideration for a laminate with non-circular cutout leads to higher failure strength compared to the same plate with circular cutout.

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Mohammadi, Bjian, Milad Rohanifar, Davood Salimi-Majd, and Amin Farrokhabadi. "Micromechanical prediction of damage due to transverse ply cracking under fatigue loading in composite laminates." Journal of Reinforced Plastics and Composites 36, no. 5 (January 9, 2017): 377–95. http://dx.doi.org/10.1177/0731684416676635.

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To predict the matrix microcracking of laminated composites under fatigue loading, a novel energy based model is presented in the framework of micromechanics. For this purpose, strain energy release rate (SERR) of microcracks which had been derived previously for the whole laminate, is developed for a lamina, and then is calculated using a stress transfer-based stiffness reduction method. The advantages of the proposed method include its capability to predict the matrix cracking of general lay-ups based on the local stresses and stiffnesses of each plies separately and not being limited to a special stacking sequence. In order to predict micro-cracking propagation of composites under cyclic loading, the coefficients of the modified Paris law are extracted using the available experimental data of crack density–cycle curves. Then using multi-scale modelling and continuum damage mechanics concept, the proposed algorithm is implemented in ANSYS finite element software, as a new user defined material (Usermat). The static progress of failure on [45/−45]s laminate is simulated and the obtained results are compared with the existing experimental data in a good agreement. Finally, the results of implemented fatigue algorithm for different cross-ply laminates under different stress levels are obtained and compared with the available experimental data.

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Nabels-Sneiders, Martins, Oskars Platnieks, Liga Grase, and Sergejs Gaidukovs. "Lamination of Cast Hemp Paper with Bio-Based Plastics for Sustainable Packaging: Structure-Thermomechanical Properties Relationship and Biodegradation Studies." Journal of Composites Science 6, no. 9 (August 24, 2022): 246. http://dx.doi.org/10.3390/jcs6090246.

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Composite laminate recycling and waste disposal routes remain a burden to existing systems, requiring special treatment and separation. The inclusion of a plastic layer is important for several key properties that are required for food safety, which in turn has made these products exceptionally hard to substitute in food packaging. Yet, the continued use of non-degradable commodity plastics is unsustainable. In this research, we compare the four most promising biodegradable and bio-based plastics that could replace non-degradable plastics in laminates. Polyhydroxyalkanoate (PHA), polylactic acid (PLA), polybutylene succinate (PBS), and polybutylene succinate adipate (PBSA) were applied as a direct melt coating on porous cast hemp papers, and the final composite was compressed under three different loads: 0.5 MT, 1.5 MT, and 3.0 MT. To promote sustainable agriculture waste management, we opted to use cast paper made from ground hemp stalks. The formation of the composite structure was examined with scanning electron microscopy (SEM), while surface wetting on the paper side of the laminate was performed to understand structural changes induced by polymer impregnation into the paper layer. Mechanical performance properties were investigated with tensile and peel tests, and suitability for an extended range of temperatures was examined with dynamical mechanical analysis. An increase in compression pressure yielded up to a two-fold improvement in elastic modulus and tensile strength, while thermomechanical analysis revealed that the polymer’s transition into a viscoelastic state significantly affected the laminate’s storage modulus values. Biodegradation was performed in a controlled compost at 58 °C, resulting in full degradation within 40 to 80 days, with PLA and PHA laminates showing 40 and 50 days, respectively. Produced bioplastic laminates have a tremendous potential to replace polyolefin laminates in packaging applications.

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Lake, G. J. "Application of Fracture Mechanics to Crack Growth in Rubber-Cord Laminates." Rubber Chemistry and Technology 74, no. 3 (July 1, 2001): 509–24. http://dx.doi.org/10.5254/1.3547649.

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Abstract The use of a fracture mechanics approach based on the strain energy release rate to assess failure due to the growth of fatigue cracks in rubber—cord laminated structures is discussed. The mechanics of crack propagation is considered for cracking either between the plies or around individual cords, and also for crack initiation and growth near cord ends. Energy release rates can be calculated approximately for each of these cases and enable the laminate results to be related to the independently measured crack growth characteristics of the rubber. Experimental energy release rate determinations, from compliance changes produced by propagating model inter-ply cracks by cutting, provide a check on the accuracy of the calculated energies. The approach identifies material properties relevant to laminate failure and indicates the effects of loading, design and construction parameters on the rate and nature of failure.

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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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Wei, C. Y., A. Miller, and A. G. Gibson. "Effects of Processing Variables on the Powder Impregnation Technique for Continuous Fibre Composite Materials." Polymers and Polymer Composites 5, no. 1 (January 1997): 41–48. http://dx.doi.org/10.1177/096739119700500105.

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Prepregs of continuous glass fibre reinforced thermoplastics were produced, applying different processing variables of the powder impregnation process. The investigation was concerned with the effects of tow tension, line speed and temperature. A recently developed process model was employed to interpret the effects of temperature and fibre volume fraction on void content. An equation was derived to calculate fibre volume fraction according to the width of a spread fibre tow. Experimental results demonstrate that the process variables greatly affect the fibre content and the void content of the prepregs. The unidirectional prepregs of polyphenylene sulphide were laminated by hot-pressing. The flexural and shear strengths of the laminates are disproportionate to the void content of the prepregs, and the laminates.

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MATSUSAKA, Kikuo. "Interaction between metal and resin on plastics laminated metal sheet." Journal of the Surface Finishing Society of Japan 42, no. 4 (1991): 394–99. http://dx.doi.org/10.4139/sfj.42.394.

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KANEKO, Masao, Minyoung JUN, and Akira YANAGISAWA. "Production of Conductive Plastics Using Laminated Coiled Sheet Shaving Method." Sen'i Kikai Gakkaishi (Journal of the Textile Machinery Society of Japan) 58, no. 10 (2005): T136—T141. http://dx.doi.org/10.4188/transjtmsj.58.t136.

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Gordeeva, M. I., and Yu A. Knyazeva. "The structure and properties of laminated aluminum-glass reinforced plastics." IOP Conference Series: Materials Science and Engineering 889 (August 11, 2020): 012015. http://dx.doi.org/10.1088/1757-899x/889/1/012015.

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Lin, Zikai, Changheng Shi, Xiaochu Huang, Can Tang, and Ye Yuan. "A Study on Damage of T800 Carbon Fiber/Epoxy Composites under In-Plane Shear Using Acoustic Emission and Digital Image Correlation." Polymers 15, no. 21 (November 3, 2023): 4319. http://dx.doi.org/10.3390/polym15214319.

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In addition to measuring the strain, stress, and Young’s modulus of materials through tension and compression, in-plane shear modulus measurement is also an important part of parameter testing of composites. Tensile testing of ±45° composite laminates is an economical and effective method for measuring in-plane shear strength. In this paper, the in-plane shear modulus of T800 carbon fiber/epoxy composites were measured through tensile tests of ±45° composite laminates, and acoustic emission (AE) was used to characterize the damage of laminates under in-plane shear loading. Factor analysis (FA) on acoustic emission parameters was performed and the reconstructed factor scores were clustered to obtain three damage patterns. Finally, the development and evolution of the three damage patterns were characterized based on the cumulative hits of acoustic emission. The maximum bearing capacity of the laminated plate is about 17.54 kN, and the average in-plane shear modulus is 5.42 GPa. The damage modes of laminates under in-plane shear behavior were divided into three types: matrix cracking, delamination and fiber/matrix interface debonding, and fiber fracture. The characteristic parameter analysis of AE showed that the damage energy under in-plane shear is relatively low, mostly below 2000 mV × ms, and the frequency is dispersed between 150–350 kHz.

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Fragoudakis, Roselita. "A numerical approach to determine fiber orientations around geometric discontinuities in designing against failure of GFRP laminates." International Journal of Structural Integrity 10, no. 3 (June 10, 2019): 371–79. http://dx.doi.org/10.1108/ijsi-10-2018-0064.

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Purpose Determining fiber orientations around geometric discontinuities is challenging and simultaneously crucial when designing laminates against failure. The purpose of this paper is to present an approach for selecting the fiber orientations in the vicinity of a geometric discontinuity; more specifically round holes with edge cracks. Maximum stresses in the discontinuity region are calculated using Classical Lamination Theory (CLT) and the stress concentration factor for the aforementioned condition. The minimum moment to cause failure in a lamina is estimated using the Tsai–Hill and Tsai–Wu failure theories for a symmetric general stacking laminate. Fiber orientations around the discontinuity are obtained using the Tsai–Hill failure theory. Design/methodology/approach The current research focuses on a general stacking sequence laminate under three-point bending conditions. The laminate material is S2 fiber glass/epoxy. The concepts of mode I stress intensity factor and plastic zone radius are applied to decide the radius of the plastic zone, and stress concentration factor that multiplies the CLT stress distribution in the vicinity of the discontinuity. The magnitude of the minimum moment to cause failure in each ply is then estimated using the Tsai–Hill and Tsai–Wu failure theories, under the aforementioned stress concentration. Findings The findings of the study are as follows: it confirms the conclusions of previous research that the size and shape of the discontinuity have a significant effect on determining such orientations; the dimensions of the laminate and laminae not only affect the CLT results, but also the effect of the discontinuity in these results; and each lamina depending on its position in the laminate will have a different minimum load to cause failure and consequently, a different fiber orientation around the geometric discontinuity. Originality/value This paper discusses an important topic for the manufacturing and design against failure of Glass Fiber Reinforced Plastic (GFRP) laminated structures. The topic of introducing geometric discontinuities in unidirectional GFRP laminates is still a challenging one. This paper addresses these issues under 3pt bending conditions, a load condition rarely approached in literature. Therefore, it presents a fairly simple approach to strengthen geometric discontinuity regions without discontinuing fibers.

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Han, Chaofeng, Baozhong Sun, and Bohong Gu. "Electric conductivity and surface potential distributions in carbon fiber reinforced composites with different ply orientations." Textile Research Journal 92, no. 7-8 (October 7, 2021): 1147–60. http://dx.doi.org/10.1177/00405175211048160.

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The electric conductivity and surface potential distributions of carbon fiber laminated panels with different ply orientations have been investigated. We found that the unidirectional (UD) lamina has higher conductivity along the carbon fiber direction than the perpendicular direction, and equipotential contours also show different gradients along the two directions. The cross-ply (CP) and quasi-isotropic (QI) laminates have the mixed effects of the UD lamina electric conductivity and ply orientations, while the surface potential distributions mostly depend on the surface lamina direction. The conductivity along the thickness direction depends on each lamina and inter-laminar bonding. A finite element analysis model was also developed to show the effect of ply orientation on potential distribution. The CP and QI laminates with 0° surface ply have uniform potential distributions and isotropic electricity behaviors. The results could be used to monitor damage locations and design electric composite materials.

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Galić, Josip, Lucija Stepinac, Antonia Bošnjak, and Ivana Zovko. "Influence of PVB Interlayer Mechanical Properties on Laminated Glass Elements Design in Dependence of Real Time-Temperature Changes." Polymers 14, no. 20 (October 18, 2022): 4402. http://dx.doi.org/10.3390/polym14204402.

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Most used laminated glass is composed of float glass plies bonded together with a viscoelastic Polyvinyl Butyral (PVB) interlayer. The shear stiffness of the polymeric interlayer is the key factor in the behavior of laminated glass. Structural engineers in the past were designing laminated glass regardless of the shear coupling of the plies. This approach with a high level of reliability led to expensive laminated glass structures due to insufficient knowledge of foil properties. Most of the current standards suggest methods that consider the shear coupling of the plies. This paper presents the experimental data from a static loading test performed on a laminated glass panel exposed to changing temperatures. The deformations were observed for 48 h. The measured results were compared with the known analytical design approaches and in addition with the finite element modeling (FEM) analysis in the available software for laminated glass design. A simplified design approach that simulates foil behavior in dependence on load duration and temperature change was adopted in this study. Design approaches that use effective thickness calculations are used with the Young and shear relaxation modulus provided by the foil producer. The imprecision of the Eurocode standards for glass design, and the propensity to change the approach to the calculation by introducing more precise parameters were expounded. The results when combining the time-temperature superposition (TTS) and the Wölfel–Bennison approach were found to be in very good agreement with the FEM analysis of 3D solid elements in Abaqus and measured data.

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Esfahani, Javad Moftakharian, Masoud Esfandeh, and Ali Reza Sabet. "Effect of Nanoclay on Quasi Static Perforation of Thin-walled Polymer Composite Laminates." Polymers and Polymer Composites 20, no. 8 (October 2012): 737–48. http://dx.doi.org/10.1177/096739111202000809.

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In this study, the penetration and perforation performance of nanoclay reinforced unsaturated polyester resin/fibreglass nanocomposite laminates have been investigated via quasi-static indentation tests using ahemispherical nose indenter. Unsaturated polyester resin (UP) was mixed with 1.5 and 3 wt.% nanoclay using a homogenizer stirrer to prepare a homogeneous mix. UP reinforced nanocomposite was then utilized to manufacture 150 × 150 mm2 laminated composite panels using 400 g/m2 glass fibre woven roving via a hand lay-up process. X-ray diffractometry, transmission electron microscopy analysis, energy-dispersive X-ray (EDXA) analysis and measurement of viscosity changes in the liquid state resin confirmed the exfoliation and the intercalation of the nanoclay by the unsaturated polyester resin system used. Quasi-static perforation tests were conducted using a surface-hardened steel indenter with a hemispherical tip at 5 and 500 mm/min load rates on nanocomposite laminated plates. Measurement of the quasi-static force as a function of indenter displacement for all the specimens showed four distinct regions, namely penetration, perforation, exit and residual frictional force. The results indicated a clear role being played by the nanoclay filler as a secondary reinforcement, in terms of higher energy absorption in all four regions.

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Deveci, H. Arda, and H. Seçil Artem. "On the estimation and optimization capabilities of the fatigue life prediction models in composite laminates." Journal of Reinforced Plastics and Composites 37, no. 21 (July 30, 2018): 1304–21. http://dx.doi.org/10.1177/0731684418791231.

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In this study, the estimation and optimization capabilities of the multiaxial fatigue life prediction models, namely, Failure Tensor Polynomial in Fatigue, Fawaz–Ellyin, Sims–Brogdon and Shokrieh–Taheri are investigated comparatively. Fatigue life predictions are obtained for multidirectional graphite/epoxy, glass/epoxy, carbon/epoxy and carbon/PEEK composite laminate data taken from the literature. The prediction study shows that the models can predict the fatigue behavior of the multidirectional laminates at different degrees of proximity. In the optimization, a hybrid algorithm combining particle swarm algorithm and generalized pattern search algorithm is used to search the optimum stacking sequence designs of the laminated composites for maximum fatigue life. The hybrid algorithm shows superior performance in terms of computational time and finding improved global optima compared to the best results presented in the literature. After the capability of the models and the reliability of the algorithm are revealed, several lay-up design problems involving different cyclic loading scenarios are solved. The results indicate that the reliability of the optimization may considerably change according to the used model even if the model may yield reasonable prediction results.

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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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Journal articles on the topic 'Laminated plastics'

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