Journal articles: 'Laminated plastics Testing'

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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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Song, Leilei, Jialu Li, Yufen Zhao, Xiaoming Chen, and Li Chen. "Improvement of interlaminar shear strength of 2.5D fabric laminated composites with short-cut web interlayer." Journal of Polymer Engineering 37, no. 3 (March 1, 2017): 261–69. http://dx.doi.org/10.1515/polyeng-2016-0029.

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Abstract In this study, the short-cut web interlayer and three-dimensional (3D) needle-punched technique were used to improve the interlaminar shear strength (ILSS) of 2.5D fabric laminated composites. The ILSS was measured by the short beam testing method, and the tensile and bending tests were carried out to investigate the in-plane mechanical properties. Observations on microstructure and crack propagation were carried out. The damage mechanisms of different 2.5D fabric laminated composites were analyzed. The results showed that the short-cut web interlayer and 3D needle-punched technique resulted in the improvement of ILSS, and they affected the tensile and bending properties of 2.5D fabric laminated composites.

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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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Taheri-Behrooz, F., M. Esmkhani, and A. Yaghoobi-Chatroodi. "Effect of testing procedure on the in-plane shear properties of CNF/glass/epoxy composites." Polymers and Polymer Composites 28, no. 3 (August 6, 2019): 159–69. http://dx.doi.org/10.1177/0967391119867200.

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Many investigations have demonstrated that the addition of nanoscale particles could affect in-plane shear properties of the laminated composites. Besides, a variety of testing procedures were introduced to evaluate the in-plane shear properties of the multiscale composite materials. In the current research, Iosipescu shear, double V-notched rail, and off-axis tensile testing methods were used to measure in-plane shear modulus and strength of the glass/epoxy and carbon nanofiber (CNF) as 0.25 wt% CNF/glass/epoxy laminated composites. In-plane shear properties of the CNF/glass/epoxy specimens were increased in comparison with the neat glass/epoxy specimens using all three testing procedures. However, the improvements were not identical for all the testing methods. The maximum improvements in the in-plane shear modulus and strength recorded using off-axis tensile test method were as 11% and 15.6%, respectively. In the off-axis tensile test method, all in-plane stress components are activated in the fracture plane parallel to the fiber orientation which are responsible for the failure initiation and propagation. Consequently, enhancing the resin’s mechanical property and interface bonding quality using CNF could remarkably enhance the in-plane shear property of the CNF/glass/epoxy specimens. On the other hand, the special fiber orientation of the specimens in Iosipescu shear and V-notched rail methods prevents the reinforcing effects of the CNF particles to be effectively revealed.

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Chang, Fu-Kuo, Jian Mao Tang, and Douglas G. Peterson. "The Effect of Testing Methods on the Shear Strength Distribution in Laminated Composites." Journal of Reinforced Plastics and Composites 6, no. 4 (October 1987): 304–18. http://dx.doi.org/10.1177/073168448700600401.

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Cadavid, M. Ospina, O. Al-Khudairi, H. Hadavinia, D. Goodwin, and G. H. Liaghat. "Experimental Studies of Stiffness Degradation and Dissipated Energy in Glass Fibre Reinforced Polymer Composite under Fatigue Loading." Polymers and Polymer Composites 25, no. 6 (July 2017): 435–46. http://dx.doi.org/10.1177/096739111702500602.

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In this work, tensile and compressive properties and fatigue performances of laminated glass fibre-reinforced polymer (GFRP) composite under constant amplitude sinusoidal load control at frequency of 5 Hz and at room temperature were investigated for three different types of loading: tension-tension at R=0.1 and 0.5, reverse loading tension-compression at R=-1 and compression-compression at R=2 and 10 in the fibre and normal-to-fibre directions. From these series of tests, the corresponding S-N diagrams were obtained. The dynamic stiffness during fatigue loading showed classical degradation of the GFRP laminates. It was observed that the dynamic modulus decreased with time, and the hysteresis loop area changed with some distortion according to the loading conditions. Finally hysteresis loops throughout fatigue testing were examined, and the variation of energy dissipated per cycle throughout the specimen lifetime was quantified. It was demonstrated that the dissipated energy during the fatigue lifetime is dependent on R-ratio and fibre orientation. However, in majority of the cases, the energy dissipated per cycle near the end of the fatigue lifetime increases as a result of an increase in the area captured by hysteresis loops.

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Arnautov, A. K. "Evaluation of the possibilities of using the method of asymmetric bending for shear testing laminated composites." Mechanics of Composite Materials 27, no. 4 (1992): 418–25. http://dx.doi.org/10.1007/bf00613570.

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El-Sagheer, Islam, Amr A. Abd-Elhady, Hossam El-Din M. Sallam, and Soheir A. R. Naga. "An Assessment of ASTM E1922 for Measuring the Translaminar Fracture Toughness of Laminated Polymer Matrix Composite Materials." Polymers 13, no. 18 (September 16, 2021): 3129. http://dx.doi.org/10.3390/polym13183129.

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The main objective of this work is to predict the exact value of the fracture toughness (KQ) of fiber-reinforced polymer (FRP). The drawback of the American Society for Testing Materials (ASTM) E1922 specimen is the lack of intact fibers behind the crack-tip as in the real case, i.e., through-thickness cracked (TTC) specimen. The novelty of this research is to overcome this deficiency by suggesting unprecedented cracked specimens, i.e., matrix cracked (MC) specimens. This MC exists in the matrix (epoxy) without cutting the glass fibers behind the crack-tip in the unidirectional laminated composite. Two different cracked specimen geometries according to ASTM E1922 and ASTM D3039 were tested. 3-D FEA was adopted to predict the damage failure and geometry correction factor of cracked specimens. The results of the TTC ASTM E1922 specimen showed that the crack initiated perpendicular to the fiber direction up to 1 mm. Failure then occurred due to crack propagation parallel to the fiber direction, i.e., notch insensitivity. As expected, the KQ of the MC ASTM D3039 specimen is higher than that of the TTC ASTM D3039 specimen. The KQ of the MC specimen with two layers is about 1.3 times that of the MC specimen with one layer.

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Kwon, Junbeom, Jaeyoung Choi, Hoon Huh, and Jungju Lee. "Evaluation of the effect of the strain rate on the tensile properties of carbon–epoxy composite laminates." Journal of Composite Materials 51, no. 22 (December 12, 2016): 3197–210. http://dx.doi.org/10.1177/0021998316683439.

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This paper is concerned with evaluation and prediction of the tensile properties of carbon fiber-reinforced plastics laminates considering the strain rate effect at intermediate strain rates. Uniaxial tensile tests of carbon fiber-reinforced plastics laminates were conducted at various strain rates ranging from 0.001 s–1 to 100 s–1 using Instron 8801 and a high speed material testing machine to measure the variation of the elastic modulus and the ultimate tensile strength. Tensile test specimens were designed based on the ASTM standards and stacked unidirectionally such as [0°], [90°] and [45°] to predict the elastic modulus of carbon fiber-reinforced plastics laminates with various stacking sequences. The axial strain was measured by the digital image correlation method using a high speed camera and ARAMIS software to enhance the accuracy of the strain measurement. A prediction model of the elastic modulus of carbon fiber-reinforced plastics laminates is newly proposed in consideration of the laminate theory and the tensile properties of unidirectional carbon fiber-reinforced plastics laminates. The prediction model was utilized to predict the tensile properties of [0°/90°]s laminates, [±45°]s laminates, and [0°/±45/90°]T laminates for validation of the model. The elastic moduli predicted were compared with the static and dynamic tensile test results to confirm the accuracy of the prediction model.

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Subha, S., Battu Sai Krishna, Dalbir Singh, and R. Gokulnath. "Effect of Graphene Platelets/Fiber on Plastics Nanocomposites under Low-Velocity Impact Response." Applied Mechanics and Materials 852 (September 2016): 23–28. http://dx.doi.org/10.4028/www.scientific.net/amm.852.23.

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In this study, an attempt has made to explore the low-velocity impact response of a Carbon/epoxy laminate (CFRP) and E-Glass/epoxy laminates (GFRP). The composite was reinforced with Graphene Nanoplatelets (GnPs) and impact energy absorption capacity was studied. The plain GFRP and plain CFRP were served as a baseline for comparison. These composite laminate plates were fabricated using hand layup technique. The tests were carried out on the laminate plate as per ASTM D5628 FD. Impact tests were performed using a specially designed vertical drop-weight testing machine with an impactor mass of 1.926 kg. The result shows that laminate plate reinforced with GnPs reinforcement enhances the impact energy absorption capacity of the composites almost 4.5 % in the case Carbon/epoxy laminate and 3.5 % in the case of and E-glass/epoxy laminate. The enhanced impact resistance could be attributed to increased interlaminar fracture toughness of the fibres.

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Pîrvu, Cătălin, and Lorena Deleanu. "Failure Investigation of Layered LFT SB1plus Package after Ballistic Tests for Level IIA." Polymers 13, no. 17 (August 29, 2021): 2912. http://dx.doi.org/10.3390/polym13172912.

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The main objective of this study focuses on designing and testing body protection systems using advanced materials based on aramid fibers, for high impact speeds of up to 420 ± 10 m/s. Ballistic applications of aramid fiber-based composites mostly include soft body armors. The investigation of the failure mechanisms identifies issues of protective fabrics, major challenges and technological problems for efficient development of these systems. The authors present an investigation on the failure processes and destructive stages of a ballistic package made of successive layers of LFT SB1plus, a trade name for a multiaxial fabric by Twaron Laminated Fabric Technology (LFT), taking into account the particular test conditions from NIJ Standard-0101.06 Ballistic Resistance of Body Armor. The main parameter of interest was the backface signature (BFS), but also details of projectile arrest and SEM investigation could offer arguments for using this material for individual protection. For the reported tests, the maximum and minimum values for BFS were 12 mm and 24 mm, the mean value being 18.66 mm and the standard deviation being 3.8 mm.

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Xiong, Xiaoman, Tao Yang, Rajesh Mishra, Hiroyuki Kanai, and Jiri Militky. "Thermal and compression characteristics of aerogel-encapsulated textiles." Journal of Industrial Textiles 47, no. 8 (June 17, 2017): 1998–2013. http://dx.doi.org/10.1177/1528083717716167.

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In this work, a new approach to apply silica aerogel into textiles by laser treatment and laminating technique was used to fabricate aerogel-encapsulated textiles. Thermal insulation performance of the prepared multilayer aerogel-encapsulated laminated fabrics was characterized in terms of thermal conductivity, thermal resistance and thermal diffusivity by Alambeta instrument. Infrared thermography data were collected by FLIR ThermaCAM TVS300 thermal camera. The ORIENTEC STA-1225 Universal Testing Machine was employed for testing the compression properties like compression resistance, compression resilience and thickness loss. Results showed that the aerogel-encapsulated structure has significant effect on thermal insulation enhancement. A temperature gap of 1℃ to 1.5℃ was observed between aerogel-filled samples and regular ones. It is also found that nonwoven fabrics with aerogel-filled voids generally have lower compression resistance than regular nonwovens, samples with air-filled voids and aerogel-filled voids are observed to recover compression to a lower extent than regular samples. Nonwoven based aerogel-encapsulated composites exhibit lower thickness loss in comparison with untreated composites. The findings in this study can be used for further research in aerogel-encapsulated composites.

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Chen, Fengyan, Yong Peng, Xuanzhen Chen, Kui Wang, Zhixiang Liu, and Chao Chen. "Investigation of the Ballistic Performance of GFRP Laminate under 150 m/s High-Velocity Impact: Simulation and Experiment." Polymers 13, no. 4 (February 17, 2021): 604. http://dx.doi.org/10.3390/polym13040604.

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The ballistic resistance of GFRP laminates subjected to high-velocity impact was studied. Based on the damage situation of GFRP laminate observed from the single-stage gas gun testing, the three-dimensional (3D) model combining strain rate effect and Hashin failure criterion was established, and the result presented good agreement between the simulation and experiment. Three factors, including layer angle, stacking sequence and proportion of different layer angles, were taken into consideration in the models. An orthogonal test method was used for the analysis, which can reduce the number of simulations effectively without sacrificing the accuracy of the result. The result indicated a correlation between the ballistic resistance and layouts of GFRP laminates, on which the stacking sequence contributed stronger influence. What was more, the laminate with layer angles 0°/90° and ±45° presented greater ballistic resistance than the other angle pairs, and adopting an equal proportion of different layer angles is helpful for GFRP laminates to resist impact as well.

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Subramani, Mageshwaran, and Manoharan Ramamoorthy. "Vibration analysis of multiwalled carbon nanotube-reinforced composite shell: An experimental study." Polymers and Polymer Composites 28, no. 4 (August 22, 2019): 223–32. http://dx.doi.org/10.1177/0967391119870406.

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In the present study, the vibration analysis of a multiwalled carbon nanotubes (MWCNTs)-reinforced composite shell is performed to investigate the enhancement in natural frequencies and damping of polymer composite structure. Initially, the material characterization of MWCNT-reinforced polymer resin was performed using scanning electron microscope, transmission electron microscope, and energy-dispersive X-ray analysis to identify the bonding behavior of MWCNT with resin, structure of MWCNTs, structural integrity, and chemical purity of MWCNT. The mechanical characterization of MWCNT-reinforced polymer composites was performed using universal testing machine to identify the enhancement in tensile properties of the composites with MWCNT reinforcement. Laminated composite shell samples were then fabricated with the different weight fraction of the MWCNT to study the effect of weight percentage of MWCNT on the composite shells on enhancement of natural frequencies and damping. Significant increase in tensile characteristics of the composites could also be identified with the addition of MWCNT in polymer composites. It was also observed that the fundamental natural frequency and damping factor of the hybrid composite could be increased by 20% and 7%, respectively, with 1 wt% reinforcement of MWCNT in the polymer resin.

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Hwang, Po-Wen, An-Pang Chen, Ching-Wen Lou, and Jia-Horng Lin. "Electromagnetic shielding effectiveness and functions of stainless steel/bamboo charcoal conductive fabrics." Journal of Industrial Textiles 44, no. 3 (September 5, 2013): 477–94. http://dx.doi.org/10.1177/1528083713502995.

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Following technological advancements, there is a growing population of cellular phone and computer users. However, these electronic instruments cause electromagnetic waves, negatively influencing users’ health or precision instruments’ malfunction. Therefore, shielding electromagnetic wave becomes an important matter. In this study, stainless steel wires and bamboo charcoal roving are made into conductive yarn with 6 turns/cm by ring spinning machine. On a 14-gauge automatic horizontal knitting machine, the resulting yarn is then knitted into stainless steel/bamboo charcoal conductive fabrics and then evaluated for the electrical property and functions. According to experimental testing, electromagnetic shielding effectiveness (EMSE) of the fabrics increases with an increase in stainless steel content and number of lamination layers. In particular, when laminated at an angle of 0°/45°/90°/−45°/0°/45°, the fabrics have an EMSE of above 30 dB at an incident frequency between 2010 and 2445 MHz. The far infrared emissivity increases with bamboo charcoal content, reaching the maximum of 0.9 ɛ, when the fabric was made by one-cycle polyethylene terephthalate (PET)/stainless steel/bamboo charcoal plied yarn in the first feeder and four-cycle PET/bamboo charcoal plied yarn in the second feeder.

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Park, Je Woong, Kwang Hee Im, David K. Hsu, Sun Kyu Kim, and In Young Yang. "Feasibility and Application on Ultrasonic-Polarized Shear Wave of Fiber Orientation Detection in Orthotropic Composite Laminates." Key Engineering Materials 324-325 (November 2006): 911–14. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.911.

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It is very important to detect fiber orientation error in orthotropic composite laminates because the layup of a CFRP (carbon-fiber reinforced plastics) composite laminates affects the properties of the laminate, including stiffness, strength and thermal behavior. In this study, an investigation of shear wave ultrasonic technique was carried out in order to detect stacking orientation error for the orthotropic composite laminates. During testing, the most significant problem is that the couplant conditions do not remain the same because of changing the viscosity of the couplant. Therefore, the design and use of a shear wave transducers would greatly aid in alleviating the couplant problem. A pyramid with an isosceles triangle with two 45o was made of aluminum to generate shear waves using two longitudinal transducers based on ultrasonicpolarized mechanism. Also, the signal splitter was connected to the pulser jack on the pulser/receiver and to the longitudinal transducers which were mounted with mineral oil. The shear transducer was mounted on the bottom as a receiver with burnt honey. It is found that the shear wave was generated at a maximum and a minimum based on the ultrasonic-polarized mechanism. Finally, test results with model data were compared for a fiber orientation of the laminates.

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Mikalauskaite, Gerda, and Virginija Daukantiene. "Influence of the delamination loading velocity on textile bonds and sewn seams strength." International Journal of Clothing Science and Technology 29, no. 6 (November 6, 2017): 768–75. http://dx.doi.org/10.1108/ijcst-02-2017-0012.

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Purpose The purpose of this paper is to determine the influence of the loading velocity on textile bonds and sewn seam strength. Design/methodology/approach Commercially produced polyamide and polyester knitted fabric, and polyester woven fabrics as well as three commercially available monolayer urethane thermoplastic films were used in this research. Two layers of each fabric were laminated at 160°C temperature at 5.6 kPa for 20 seconds. Sewn specimens were joined applying (301) and (514) stiches for woven and knitted fabrics, respectively. The bond and sewn seam strength was investigated at different delamination loading velocities (50, 100, 150, 200, 300 mm/min). These values of velocities lies in the velocity interval which covers the different standard requirements for testing of the quality of textiles and their seams or were applied in the research works of previous scientists. As the influence of loading velocity was more significant for bond strength, the bond strength results were analyzed together with the analysis of bond rupture character. Findings The determined influence of the loading velocity on textile bonds strength has proved that the loading velocity in bond strength test is of high importance for the prediction of the behavior of clothing being in exploitation under different conditions. The opposite tendency was determined for the sewn seams, the strength of which was independent on loading velocity. Originality/value The influence of the loading velocity on textile bond and sewn seam strength was not analyzed in the previous research works published by other scientists. It was known that the standard velocity is 50 mm/min for seams and 100 mm/min for textiles strength testing. It was shown there that the real exploitation of a garment as a whole complicated heterogenic dynamic system could be simulated with changing loading velocities during their seam strength testing. It was also determined that the loading velocity makes different influence on bonded and sewn seams of textiles.

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Yang, In Young, Yong Jun Yang, Kil Sung Lee, David K. Hsu, and Kwang Hee Im. "Ultrasonic Nondestructive Approach on Fiber Orientation Inspection in CFRP Composite Laminates." Materials Science Forum 566 (November 2007): 261–66. http://dx.doi.org/10.4028/www.scientific.net/msf.566.261.

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Owing to the advantages associated with their very large strength-to-weight and stiffnessto- weight ratios, composite materials are attractive for a wide range of applications. Increasingly, high performance engineering structures are being built with critical structural components made from composite materials. In particular, the importance of carbon-fiber reinforced plastics (CFRP) has been generally recognized in both space and civil aircraft industries, and CFRP composite laminates are widely used. It is very important to detect fiber orientation error in orthotropic composite laminates because the layup of a CFRP composite laminates affects the properties of the laminate, including stiffness, strength and thermal behavior. In this study, a new approach was investigated on detection of fiber orientation with using two longitudinal and a shear wave ultrasonic transducers for the orthotropic composite laminates. During testing, the most significant problem is that the couplant conditions do not remain the same because of changing the viscosity of the couplant. Therefore, making a design for generating shear wave with longitudinal transducers would greatly aid in alleviating the couplant problem. A pyramid with an isosceles triangle was made of aluminum in order to generate shear waves using two longitudinal transducers based on ultrasonic-polarized mechanism. It is found that the shear wave was very sensitive to fiber of CFRP composite. Finally, a CFRP composite material was nondestructively characterized in order to measure fiber orientation error area using automated data acquisition C-scan system.

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Carbas, Ricardo J. C., Miguel P. Palmares, and Lucas F. M. da Silva. "Experimental and FE study of hybrid laminates aluminium carbon-fibre joints with different lay-up configurations." Manufacturing Review 7 (2020): 2. http://dx.doi.org/10.1051/mfreview/2019027.

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The use of composite materials in industry is growing due to various technological advances in composite materials accompanied by improvements in the structural adhesives used to bond them. Fibre metal laminates (FML's) are hybrid composite structures based on thin sheets of metal alloys and plies of fibre-reinforced polymeric materials. The fibre/metal composite technology combines the advantages of metallic materials and fibre-reinforced matrix systems. The aim of the present study is to use a concept similar to that used in FML to increase the peel strength of composite materials and increase the joint strength of hybrid laminates aluminium carbon-fibre adhesive joints. Carbon fibre-reinforced plastic (CFRP) composites were modified by including one or several aluminium sheets during the laminate manufacture to enhance the composite through the thickness properties. The objective was to identify the joint configuration that gives the best joint strength improvement in relation to the CFRP only reference joint. An adhesive developed for the aeronautical industry was used to manufacture single lap joints for tensile testing. Experimental and numerical studies were undertaken on modified CFRP joints to investigate the joint strength of different lay-up solutions to prevent delamination of adherends.

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Li, Cuiyu, Jingyan Jia, Gaopan Wang, Rui Zhang, and Xueyu Li. "A study on the tensile properties of UHMWPE fiber weft-knitted structural composites." Journal of Reinforced Plastics and Composites 36, no. 6 (December 22, 2016): 435–42. http://dx.doi.org/10.1177/0731684416682854.

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This work presents a study of liquid oxidation modification effects on the tensile properties of UHMWPE fibers and UHMWPE fiber/epoxy composites. Three types of basic knitted structural composites were produced with 4, 6, and 8 layers. The shop-vacuum-assisted resin transfer molding (VARTM) process was used to laminate the composite. The tensile properties of the composite laminates were evaluated using a universal strength testing machine, and the tensile damage of the materials was analyzed. The results show that for the same number of layers of laminates, the tensile strength of the weft jersey structure was the highest, followed by those of the rib and cardigan structures. The tensile strength increased with the number of layers and increased with a nonlinear positive correlation. After modification, the stretching process did not result in yarn being pulled from the resin. The adhesion to the fabric and the resin increased, and the shear strength of the composite increased between the layers.

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Johnson, WS, JE Masters, DW Wilson, X. Huang, JW Gillespie, and RF Eduljee. "Matrix Cracking of High-Performance Composite Laminates with Variation of Laminate Stacking Sequence and Testing Temperature." Journal of Composites Technology and Research 19, no. 3 (1997): 142. http://dx.doi.org/10.1520/ctr10025j.

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Chen, Jiaju, Yanan Xu, and Yunkai Gao. "Topology Optimization of Metal and Carbon Fiber Reinforced Plastic (CFRP) Laminated Battery-Hanging Structure." Polymers 12, no. 11 (October 27, 2020): 2495. http://dx.doi.org/10.3390/polym12112495.

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This study addressed the topology optimization of a carbon fiber reinforced plastic (CFRP) laminated battery-hanging structure of an electric vehicle. To accommodate parameterization for thickness and orientation of CFRP materials, the discrete material and thickness optimization (DMTO) technique was adopted. To include metal material as a reinforcement structure into the optimization simultaneously, the DMTO technique was extended here to achieve concurrent optimization of CFRP thickness topology, CFRP orientation selection and the topology of the metal reinforcement plate. Manufacturing constraints were applied, including suppressing intermediate void across the thickness direction of the laminate, contiguity constraint and the symmetrical layers. Sensitivities of the objective function were derived with respect to design variables. To calculate analytical sensitivities, finite element analysis was conducted and strain vectors were exported from a commercial software (ABAQUS) into a mathematical analysis tool (MATLAB). The design objective was to minimize the local displacement subject to the constraints of manufacturing and mass fraction. The mechanical performance of the optimized CFRP structure was compared with the original steel structure. To validate the optimization results, a prototype of the CFRP battery-hanging structure was fabricated and experimental testing was conducted. The results show that the total mass of the CFRP battery-hanging structure was reduced by 34.3% when compared with the steel one, while the mechanical property was improved by 25.3%.

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Peterside, David T., Joseph E. Palaia, Andrew C. Schuerger, Melanie J. Correll, and Ray A. Bucklin. "Testing of Greenhouse Cladding Materials for Space Environments, Part 2: Laminates." Applied Engineering in Agriculture 34, no. 3 (2018): 575–80. http://dx.doi.org/10.13031/aea.12465.

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Abstract. Plants grown in greenhouse-type structures are potential sources of food, oxygen, clean water, fiber, and other resources needed for bioregenerative life support systems during long-term space missions. Identification of cladding materials with appropriate optical and physical properties that can withstand the high ultraviolet radiation, low pressure, and low temperature Martian environment is necessary for greenhouse design. The objective of this study was to evaluate the effects of simulated Mars environmental conditions on yield strength and light transmissivity of composites composed of a layer of 0.15 mm polyimide film (LaRC™CP1) attached to acrylic, polyvinyl chloride (PVC), or polycarbonate cladding materials. The University of Florida’s Mars Simulation Chamber (MSC) at Kennedy Space Center was utilized to expose material samples to simulated Mars environmental conditions. Changes in control versus exposed material sample transmissivities were measured using a spectroradiometer over the PAR range of wavelengths from 400 to 700 nm and material peak yield strengths were determined using an Instron universal testing machine. Keywords: LaRC™CP1, Mars greenhouse, PAR transmission, Plastics, Strength of materials, UV damage.The overall results comparing pre- and post-exposure of samples to simulated Martian conditions in the MSC showed that the addition of a layer of polyimide did not benefit either the transmissivity or strength of polycarbonate cladding materials, but did show benefits in retaining transmissivity for PVC and in maintaining strength for acrylics exposed to Mars simulated environment. However, transmissivities of the plastics were reduced by the addition of protective layers of polyimide. Keywords: LaRC™CP1, Mars greenhouse, PAR transmission, Plastics, Strength of materials, UV damage.

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Johnson, WS, JE Masters, DW Wilson, MV Hosur, CRL Murthy, and TS Ramurthy. "Compression After Impact Testing of Carbon Fiber Reinforced Plastic Laminates." Journal of Composites Technology and Research 21, no. 2 (1999): 51. http://dx.doi.org/10.1520/ctr10947j.

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Cheng, Jun, Cheng Yu, Shuai Xu, Jinhao Qiu, Toshiyuki Takagi, and Dezhang Xu. "Measurement of directionality in carbon fiber reinforced plastic composite with eddy current testing." International Journal of Applied Electromagnetics and Mechanics 64, no. 1-4 (December 10, 2020): 1207–15. http://dx.doi.org/10.3233/jae-209438.

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In carbon fiber reinforced plastic (CFRP) composite, the alignment of continuous carbon fibers guides the directional flow of eddy currents, which is beneficial to the structural and damage detection. In this study, for the purpose of impact damage repair, the transmitter-receiver (T-R) and the flat-tangent eddy current probes are used to determine the fiber orientations and stacking sequence in the CFRP laminate by surface scanning. Theoretical analysis shows that the T-R probe can flexibly pick up the magnetic field generated by the stretched eddy current in CFRP layers. In the meanwhile, the flat-tangent probe possesses layer selective characteristics. By calculating the fiber distribution images of individual directions based on two-dimensional fast Fourier transform (2D-FFT) and comparing the order of pixel intensity values of these images, the fiber orientation and the stacking sequence in the laminate plates can be obtained simultaneously, which provides guidance for damage detection and repair of the CFRP structures.

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Djukic, Luke P., Manudha T. Herath, Daniel C. Rodgers, Roderick Sweeting, and Honesto Buendia. "Analysis and testing of polymer matrix composites with thermoplastic liners having enhanced chemical resistance." Journal of Reinforced Plastics and Composites 36, no. 20 (May 26, 2017): 1487–502. http://dx.doi.org/10.1177/0731684417711027.

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Polymer matrix composite tanks offer major advantages to the transport industry in terms of increased payload and corrosion resistance compared to conventional steel tanks. Chemical resistance and versatility can be enhanced through the addition of a thermoplastic liner. This paper presents the results of chemical conditioning, testing and analysis of a linear low-density polyethylene liner, on its own and supported by carbon fiber reinforced polymer. Results are compared to ADR (European Agreement Concerning the International Carriage of Dangerous Goods by Road) requirements. The linear low-density polyethylene liner was tested in combination with 12–15% sodium hypochlorite and 98% sulphuric acid. The results indicate that the liner is suitable for service in tanks transporting these two chemicals. Liners were conditioned at 50℃ for periods of 1000 or 2000 h. Shore D hardness tests and three-point bend tests were performed, compared to unconditioned benchmarks, and found to pass ADR requirements. Finite element models were validated and used to facilitate understanding of the failure of the laminates. Predictions indicate that failure load increases with increased liner modulus, yield stress, and thickness. The models also indicate that the laminate strength and modulus is not significantly changed during chemical conditioning for the stated chemicals.

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Kim, Dae-Young, Jung-Ho Kim, Seung-Woo Ra, Joung-An Jeong, and Ji-Hoon Kim. "Tightening Characteristics Research of M1.4 Subminiature Screw by Applying CFRP Laminates." Polymers and Polymer Composites 25, no. 1 (January 2017): 49–56. http://dx.doi.org/10.1177/096739111702500108.

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The recent core technologies developed in automobile and aerospace industries can be classified into two types, namely, advancement technology for safety and convenience and mechanical technology for eco-friendly and lightweight systems. Research in the field of composite materials has attracted significant attention. Carbon-fiber-reinforced plastics (CFRP) show high specific stiffness and specific strength compared with metallic materials. They exhibit mechanical properties with high damping characteristics and are lightweight. However, according to the direction of a laminate or its stacking sequence, the structural characteristics of CFRPs vary. It is hard to predict fracture under tensile and bending forces in CRFPs, when compared to metals. Threaded fasteners with easy assembly and disassembly are used widely in several fields. However, to maintain clamping force, proper torque force should be applied. As the size of the components decreases, the clamping force also decreases because the contact area between the component and other components decreases. In this study, CFRP specimens were subjected to tensile tests via a universal testing machine to estimate their mechanical properties with respect to the stacking angles of the laminates. The reverse screw torque and screw torque at each stacking angle were determined using a torque tester after tapping holes on the CFRP specimens. It was expected that both the epoxy attached to the screw surface and stacking direction of CFRP laminates affect the screw torque force of the composite material. In the case of woven composite specimens, there was no difference observed even when torque was applied to prevent loosening of the specimens with or without coating. The average results for the woven composite specimens were better than that for the other specimens.

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Daukantiene, Virginija, and Giedre Vadeike. "Evaluation of the air permeability of elastic knitted fabrics and their assemblies." International Journal of Clothing Science and Technology 30, no. 6 (November 5, 2018): 839–53. http://dx.doi.org/10.1108/ijcst-02-2018-0021.

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Purpose The purpose of this paper is to evaluate the air permeability of knitted fabrics containing elastane fibre and their seams applying both the new approach based on fabric thickness measurement at different pressures and standard method. Design/methodology/approach Investigations were performed with commercially available eight polyester knitted fabrics containing different elastane yarn proportion. Bonded seams were laminated applying the urethane thermoplastic adhesive film of 0.175 mm thickness. Bonds were laminated by heat at 5.6 kPa pressure applying pressing device GTK DEA 25 R at 140°C temperature for 40 s duration. Sewn seams were assembled with 607 covering chain stitch applying 5.0 stitches per cm density and 512 overedge chain stitch applying 5.0 stitches per cm density. Specimens without and with the seams were conditioned in standard atmosphere conditions according to the standard LST EN ISO 139 before air permeability testing according to the standard LST EN ISO 9237. Standard thickness of the investigated knitted fabric was determined according to the standard EN ISO 5084. It is known from literature that the porosity is dominant factor influencing the air permeability of knitted fabrics. Therefore, the assumption was made that due to fabric porosity knitted fabric thickness being measured at different pressures also may differ. Thus, the permeability property may also be related to the difference between fabric’s thicknesses being measured under different pressures which may be applied with different material thickness gauges. Findings There was shown that fabric assemblies make the significant influence on the textile permeability to air. The results obtained indicate that the air permeability of the investigated knitted fabrics depends not only on their structure parameters but also on the fabric seam type. Air permeability of the specimens with the seams was lower than one of specimens without the seams. The highest decrease in permeability which ranged from 19.9 per cent up to 60.0 per cent was determined for the bonds. Fabric specimens with 607 covering chain stitch seam were in the second place with regard to the previously considered parameter. And, their permeability was decreased from 0.6 per cent up to 52.6 per cent. Changes in the air permeability of the specimens with 512 overedge chain stitch seam were lowest in the range of investigated assemblies. Based on the determined results, it was concluded that the thickness difference of the specimens with and without seams measured at different pressures is related to fabric porosity which makes the significant influence on the air permeability. Practical implications The samples of investigated fabrics were taken from the two companies which manufactures leisure clothing and sportswear such as skiing or swimming costumes, etc. Thus, the obtained investigation results are significant not only for clothing science but also leads the improvement of clothing quality in fashion industry. Originality/value Assuring the comfort of the human body is one of the most important functions of clothing, especially of sportswear and leisure wear. Knitted fabrics should not only be elastic, but also have high air permeability for easily transmit of the perspiration from the skin to the atmosphere, thus making the wearer to feel comfortable. In this research, the air permeability of commercially available polyester knitted fabrics containing different amount of elastane was investigated and the influence of fabric assemblies on the air permeability property was evaluated. A new approach based on the fabric thickness measurement at different pressures and the standard methods for the evaluation of air permeability were used.

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Pauli, Alexander, Michael A. Kraus, and Geralt Siebert. "Experimental and numerical investigations on glass fragments: shear-frame testing and calibration of Mohr–Coulomb plasticity model." Glass Structures & Engineering 6, no. 1 (February 22, 2021): 65–87. http://dx.doi.org/10.1007/s40940-020-00143-5.

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AbstractThe numerical treatment of the residual load-bearing behavior of laminated glasses (LG) in the post-fractured state is highly topical. Nevertheless, currently only few numerical approaches for an accurate representation of the experimentally observed behavior are existent. In order to model the characteristics of the load-bearing behavior of glass laminates in the post-fractured state, the behavior of the interlayer, the behavior of the glass fragments as well as the bonding between glass and interlayer need to be characterized correctly. This paper focuses on the modeling of the frictional contacts between the glass fragments itself. In order to allow for the calibration of failure criteria for the fractured glass particles, framed shear tests which are a common experimental technique in geomechanical testing to determine the shear strength of soils, are performed on glass fragments of different thicknesses and levels of thermal pre-stress. The test results are subsequently used to calibrate non-associated Mohr–Coulomb criteria, which are widely applied to the description of failure and frictional sliding of soils, to the experimental data of four distinct kinds of glass fragments. The obtained parameters of the Mohr–Coulomb models are in magnitude similar to the parameters of standard soils such as sand or gravel. The experimental data further show, that the Mohr–Coulomb model in general can be used to approximate the stress failure plane of the glass fragments but lacks for capturing correctly the plastic volumetric strains (dilation) in Finite Element modelling. Numerical investigations by the Finite Element method showed, that it is possible to reproduce experimental data by using Mohr–Coulomb plasticity models and hence the numerical models are validated for further investigations.

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Wang, J., Y. Xiao, M. Kawai, and K. Inoue. "Observation and modeling of loading–unloading hysteresis behavior of unidirectional composites in compression." Journal of Reinforced Plastics and Composites 37, no. 5 (November 29, 2017): 287–99. http://dx.doi.org/10.1177/0731684417743347.

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The loading–unloading hysteresis behavior of unidirectional HTS40/PA6 carbon/polyamide laminates under off-axis compression has been examined both experimentally and constitutively in the present study. Monotonic compressive tests are first performed on unidirectional laminates to identify the basic properties of off-axis deformation. Then, five cycles of compressive loading and unloading tests are carried out with a gradually increasing peak stress for each specimen, followed by testing to failure. Significant nonlinear unloading behavior is observed after the material has been loaded into the nonlinear deformation region, and apparent plastic strain is seen after full unloading. The reloading curve also exhibits nonlinearity and conduces to a slightly open hysteresis loop with unloading. An approach is developed to predict the nonlinear hysteresis behavior of unidirectional composites by assuming an anelastic strain component in the nonlinear compressive deformation. The assumption of anelastic strain is a modification of Sun–Chen’s one-parameter plasticity model that considers the nonlinear deformation completely as plastic strain from monotonic tests. The modified model has been validated by the off-axis loading–unloading test results on unidirectional laminates. Results verify that the model accurately captures not only the plastic strain but also the complex nonlinear hysteresis behavior in the observed off-axis loading–unloading stress–strain curves.

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TAI, Yoshimasa, Toshio SUGIBAYASHI, and Kozo IKEGAMI. "Method of interlaminar strength testing of a carbon cloth laminated plastic specimen with fillet." Transactions of the Japan Society of Mechanical Engineers Series A 53, no. 491 (1987): 1157–62. http://dx.doi.org/10.1299/kikaia.53.1157.

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Kosiński, P., and J. Osiński. "Laminated Windshield Breakage Modelling in the Context of Headform Impact Homologation Tests." International Journal of Applied Mechanics and Engineering 20, no. 1 (February 1, 2015): 87–96. http://dx.doi.org/10.1515/ijame-2015-0006.

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Abstract The purpose of modelling a laminated windshield using the FEM is to provide a critical look on the way the adult headform impact tests are conducted in the process of motor vehicle certification. The main aim of the study is to modify the design of a laminated windshield in the context of a vehicle collision with vulnerable road users. The initial phase of the work was to develop a model of the adult headform impactor. The validation consisted in conducting a series of FEM analyses of the impactor certification testing according to the Regulation (EC) 631/2009. Next, the impact of the headform model on a windshield was analysed. The FEM model of laminated glass is composed of two outer layers of glass and an inner layer of polyvinyl butyral. FEM analyses of the impaction were performed at five points of the windshield characterised by various dynamic responses of the impactor and various patterns of glass cracking. In modelling the layers of glass, the Abaqus environment “brittle cracking” model was used. The following material models of PVB resin were considered: elastic, elastic-plastic, hyperelastic, and low-density foam. Furthermore, the influence of the mesh type on the process of glass cracking in a laminated windshield was analysed.

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Watkins, Stetson, and James Bittner. "Resonance Bond Testing: Theory and Application." Materials Evaluation 79, no. 6 (June 1, 2021): 512–19. http://dx.doi.org/10.32548/2021.me-04225.

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Resonance bond testing is a nondestructive testing (NDT) technique that is used to detect disbonds, delaminations, and other voids in composite materials. The aerospace industry has seen an increase in the use of carbon fiber reinforced plastics (CFRP) for aircraft and spacecraft construction. Composite materials offer many advantages over traditional metallic structures, which include weight savings, increased strength, design for specific load paths, and the ability to easily construct geometrically complex structures. Resonance bond testing has many established uses for metallic structures as well, such as aluminum skin-to-skin and skin-to-core bonds. This bond testing technique has been around for many decades but is used by only a small portion of the NDT community. Ultrasonic testing (UT), specifically phased array ultrasonic testing (PAUT), using linear array techniques has proven to be a reliable method for the inspection of CFRP laminates. When composite structures do not permit the use of high-frequency sound waves due to rapid attenuation, resonance bond testing is a proven alternative. In this paper, the authors will discuss the theory behind resonance bond testing and how it has and continues to play an important role in the NDT industry.

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Bulavs, Felikss, Ivars Radinsh, and Normunds Tirans. "IMPROVEMENT OF CAPACITY IN BENDING BY THE USE OF FRP LAYERS ON RC BEAMS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 11, no. 3 (September 30, 2005): 169–74. http://dx.doi.org/10.3846/13923730.2005.9636347.

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Carbon‐filled plastic bands are more extensively used for strengthening the permanently exploited curved elements. As a result, the bending rigidity of the element is increased and the crack formation process is changed. Investigation of these problems is carried out basing on the model of laminated material, in which the mechanical properties of separate layers may have discreete different values depending on the external load volume. Practical calculations are made by numerical methods which make it possible to follow up the origin of the crack formation in the concrete, by taking into account its non‐linear deformation character. The work deals with the analysis of the beam strengthening specific character under unloaded and loaded conditions. Testing of the results is performed by using 2 m long reinforced concrete beams strengthened with carbon‐filled plastic bands.

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Chen, Yizhe, Yichun Wang, and Hui Wang. "Research Progress on Interlaminar Failure Behavior of Fiber Metal Laminates." Advances in Polymer Technology 2020 (March 10, 2020): 1–20. http://dx.doi.org/10.1155/2020/3097839.

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Fiber metal laminate (FML) is a kind of lightweight material with excellent mechanical properties combining advantages of metal laminates and fiber reinforced composites. It has been widely used in the aerospace and transportation fields and is especially used as structural material such as aircraft skins, wings, and tails. However, under complex service conditions, interlaminar failure in FMLs greatly reduced mechanical properties of the material, even leading to serious economic and safety disasters. The failure and destruction of important structural parts of aircraft and other manned transportation vehicles are extremely unsafe for people. Therefore, it is of great significance to summarize the interlaminar failure behavior of FMLs and find ways to avoid these defects. This review paper is a collection of various researches done by many groups, which systematically discuss the interlaminar failure behaviors and their control methods of FMLs. The application status of several common FMLs in aircraft structures was given. The common interlaminar failure modes of FMLs and the testing and evaluation methods of interlaminar properties were stated. The failure mechanisms and the corresponding control methods were analyzed. Finally, the future developments of FMLs were also discussed by the authors. Through this review article, readers can obtain new research progress about the control method, the mechanism and future development on the failure behavior of FMLs in a more efficient way.

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Chiasson, Matthew, and Jeremy Laliberté. "In situ measurement of vacuum consolidation of commingled thermoplastic composites using a non-contact displacement sensor." Journal of Reinforced Plastics and Composites 33, no. 22 (September 29, 2014): 2046–63. http://dx.doi.org/10.1177/0731684414553282.

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A vacuum consolidation process has been investigated for use with commingled thermoplastic composites. In particular, the vacuum consolidation behavior of commingled polypropylene/glass and commingled nylon/carbon precursors were studied. Laminates were consolidated in a convection oven under vacuum pressure and the thickness change of the laminates was measured by the use of a novel in situ non-contact eddy current displacement sensing technique. An empirical consolidation model was then fit to the measured experimental results to be used to predict future process cycles. The overall quality of the resulting laminates was assessed using cross-sectional analysis and mechanical strength and stiffness testing. Dynamic mechanical analysis and differential scanning calorimetry were also used to measure the physical properties of laminates produced using differing consolidation cycles to further assess the quality of the resulting laminates. The use of a non-contact in situ consolidation measurement technique was shown to be a useful tool for assessing the consolidation behavior of commingled thermoplastic laminates.

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Johnson, WS, JE Masters, DW Wilson, JS Welsh, and DF Adams. "Unidirectional Composite Compression Strengths Obtained by Testing Cross-Ply Laminates." Journal of Composites Technology and Research 18, no. 4 (1996): 241. http://dx.doi.org/10.1520/ctr10109j.

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Chekhonin, P., B. Beausir, J. Scharnweber, C. G. Oertel, J. Jaschinski, Tina Hausöl, Heinz Werner Höppel, Heinz Günter Brokmeier, and Werner Skrotzki. "Mechanical Anisotropy of Aluminium Laminates Produced by ARB." Materials Science Forum 702-703 (December 2011): 151–56. http://dx.doi.org/10.4028/www.scientific.net/msf.702-703.151.

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The plastic anisotropy was studied on aluminium sheets with layers of different purity (A: 5N and B: 2N+) produced by accumulative roll bonding (ARB). Both material layers show a contrasting recrystallization behavior where A and B are discontinuously and continuously recrystallized, respectively. Global textures were measured by neutron diffraction. The mechanical anisotropy was measured by tensile testing after different numbers of ARB cycles. The planar anisotropy decreases with the number of ARB cycles while the normal anisotropy reaches a plateau after 4 cycles. Simulations of the Lankford parameters were carried out with the help of the viscoplastic self-consistent scheme (based on the global texture) and compared with the experimental data. Deviations of the simulated values from those of experiment are discussed with regard to through-thickness texture and material heterogeneities.

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Naik, H. Rama Murthy, J. Jerald, and N. Rajesh Mathivanan. "Impact Damage Detection in GFRP Laminates through Ultrasonic Imaging." Advanced Materials Research 585 (November 2012): 337–41. http://dx.doi.org/10.4028/www.scientific.net/amr.585.337.

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Composite materials are increasingly used in aerospace, naval and automotive vehicles due to their high specific strength and stiffness. In the area of Non destructive testing, ultrasonic C-scans are used frequently to detect defects in composite components caused during fabrication and damage resulting from service conditions. Ultrasonic testing uses transmission of high frequency sound waves into a material to detect imperfections or to locate changes in material properties. The most commonly used ultrasonic testing technique is pulse echo and through transmission wherein sound is introduced into a test object and reflections (echoes) are returned to a receiver from internal imperfections. Under low-velocity impact loading delaminating is observed to be a major failure mode. This report presents the use of above two techniques to detect the damage in glass fiber reinforced plastic (GFRP) laminates. Pulse echo is used to locate the exact position of damage and through transmission is used to know the magnitude of damage in composite. This paper work will be carried out on two different thicknesses and at impact energy levels varying from 7 to 53J. The ensuring delamination damage will be determined by ultrasonic C-scans using the pulse-echo immersion method for through transmission. Delamination areas were quantified accurately by processing the raw image data using a digital image processing technique. Based on the data obtained, correlation will be established between the delamination area and the impact energy.

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Boychuk, A. S., I. A. Dikov, A. S. Generalov, and S. I. Yakovleva. "THE FEATURES OF NON-DESTRUCTIVE INSPECTION OF CARBON FIBER REINFORCED PLASTIC SOLID LAMINATE SAMPLES DURING LOW-CYCLIC FATIGUE TESTING." Proceedings of VIAM, no. 12 (2020): 108–15. http://dx.doi.org/10.18577/2307-6046-2020-0-12-108-115.

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The results of CFRP samples ultrasonic inspection during low-cyclic fatigue testing are given in this article. It is established that for ultrasonic pulse-echo inspection during cycling mechanical testing and after the special correction of flaw detector’s gain and inspection’s sensitivity concerning back-wall echo decreasing in compare with testing specimen is necessary.

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Cao, Yang, Siyuan Zhao, Limin Sun, Wenbin He, and Jun Ma. "Experimental and simulated research on the ballistic performance of Ti/Al3Ti laminate composites." Advanced Composites Letters 29 (January 1, 2020): 2633366X2092088. http://dx.doi.org/10.1177/2633366x20920884.

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The metal-intermetallic laminate composite Ti/Al3Ti can be used as protective armor in aerospace and military applications, due to its low density, high strength, and superior impact-resistant performance. The ballistic performance of the laminate composite was studied by ballistic testing and finite element technology. The failure modes, such as radical cracks, layer delamination, and plastic deformation, have been found after the ballistic test, and the specific energy absorption was used to evaluate the ballistic capacity of the material. The finite element model of the Ti/Al3Ti impacted by the projectile was established by considering the interface, which was simulated by the solid elements with zero thickness. The simulation results demonstrate the failure process of the interface during penetration. The interfacial failure allowed for layer detachment with its labor layers. The simulation results agree well with that of the experiment, and the practicality and credibility of the model is verified.

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Chen, Xiaoping, Lihua Zhan, Yongwei Pu, Minghui Huang, Xintong Wu, Guiming Liu, and Zijun Lin. "Effect of cure pressure on microstructure and interlaminar shear strength properties of carbon fiber–reinforced plastics with microwave curing." High Performance Polymers 30, no. 9 (November 9, 2017): 1084–93. http://dx.doi.org/10.1177/0954008317739679.

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Under a given microwave curing process, different curing pressures were applied to the carbon fiber–reinforced epoxy resin pre-impregnated laminates. Nondestructive testing and microscopic analysis were used to assess the effect of curing pressure on the interlaminar shear strength (ILSS) of the carbon fiber–reinforced plastic (CFRP) laminates. Results showed that in the low curing pressure stage (below 0.4 MPa), the porosity and ILSS of the components were reduced substantially as the curing pressure increased. In the high curing pressure stage (above 0.4 MPa), the ILSS only increased by 2.2% or so and the porosity and ILSS were no longer sensitive to the pressure, which indicated there was a threshold value (0.4 MPa) of mechanical property for forming the CFRP by the microwave curing. Above the threshold value, the curing pressure should be sufficient to allow the volatile gases to dissolve in the resin, thereby eliminating the generation of voids fundamentally, and the effect of curing pressure on the quality of composites was becoming small. These results could give process engineers some basic references for eliminating the voids in the CFRP component, so that they could reach a balance between preserving the mechanical properties and reducing the curing pressure in a cost-effective way.

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Youssef, Y., S. Labonté, C. Roy, and D. Lefebvre. "Specimen design, manufacturing and testing procedures for flat carbon fiber reinforced plastic laminates under biaxial loading." Polymer Composites 19, no. 3 (June 1998): 257–63. http://dx.doi.org/10.1002/pc.10098.

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Mizukami, Koichi, Yudai Watanabe, and Keiji Ogi. "Eddy current testing for estimation of anisotropic electrical conductivity of multidirectional carbon fiber reinforced plastic laminates." Composites Part A: Applied Science and Manufacturing 143 (April 2021): 106274. http://dx.doi.org/10.1016/j.compositesa.2021.106274.

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Noroozi, Siamak, John Vinney, Philip Sewell, and Rasoul Khandan. "An Empirical Model of Ribbed Cylindrical Glass Reinforced Plastic Tanks." Applied Mechanics and Materials 232 (November 2012): 51–56. http://dx.doi.org/10.4028/www.scientific.net/amm.232.51.

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Ribbed cylindrical Glass Reinforced Plastic (GRP) tanks are currently designed using simplified theory the results of which are then verified by extensive destructive testing. This approach is expensive and can only generate non-optimal design solutions. In addition, there is often a high degree of discrepancy between theoretical and experimental results which necessitates the use of undesirably high factors of safety, which in turn results in the excessive use of material with the concomitant increase in cost, weight and manufacturing time. The primary aim of this investigative research was to develop a more deterministic and accurate design method of predicting the structural integrity and performance of underground cylindrical GRP tanks using non-destructive testing. Linear and non-linear Finite Element Analysis (FEA) techniques, validated against experimental results, were used to analyze a large number of underground ribbed cylindrical GRP tanks. The outcome of which was then expressed in the form of an empirical ‘Design Formula’ which provides a comprehensive solution to ribbed cylindrical GRP tank design for a wide range of tank sizes, laminate lay-ups and material properties. It is intended that the application of this method will eliminate the need for the expensive field tests that are currently required by design codes and standards.

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Tsai, Jung-Ting, Joshua S. Dustin, and Jan-Anders Mansson. "Distributed optical sensing for monitoring strain evolution during mechanical testing of composite laminates." Polymer Testing 96 (April 2021): 107076. http://dx.doi.org/10.1016/j.polymertesting.2021.107076.

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van Bogaert, P., and S. van Bogaert. "Mechanics of Bend-Over-Sheave (Shoeshine) Fatigue Testing of Cord-Rubber Laminates." Tire Science and Technology 39, no. 3 (September 1, 2011): 168–92. http://dx.doi.org/10.2346/1.3637742.

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Abstract The Bend-Over-Sheave test is used for screening reinforcement cords used in tires, especially on fatigue interply delamination as well as rubber-fabric and rubber-cord adhesion degradation. The typical cyclic load of tension-tension of the sidewalls or tension-compression of the belt can be achieved by the proper definition of two-ply laminates bent over a sheave. The objective of this paper is to define relevant fatigue test conditions that can predict the performance of new materials. A finite element model of the Bend-Over-Sheave test configuration is presented and shows that, for the test arrangements studied in this paper, flanged wheels should be used to prevent lateral buckling in the compressed cords. Besides, a simplified model enables us to determine the different factors that have significant effect on the strain levels in the cords. The material of the cords, the rubber hardness (“Shore”), and the sample manufacturing process are shown to have an influence on the specimen strain levels. The test conditions, i.e., the sheave radius, the traction force, and the contact angle between the sheave and the sample, also affect the behavior specimen strain levels. On the other hand, if the sample length is higher than a certain value, it is shown not to have a significant effect on the results.

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Habeger, C. C. "An Ultrasonic Technique for Testing the Orthotropic Symmetry of Polymeric Sheets by Measuring Their Elastic Shear Coupling Coefficients." Journal of Engineering Materials and Technology 112, no. 3 (July 1, 1990): 366–71. http://dx.doi.org/10.1115/1.2903340.

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An ultrasonic method, which allows the determination of the in-plane elastic stiffnesses of thin polymeric sheets, is described. The determination is complete, as it includes the shear coupling coefficients. Sheets are often assumed to display orthotropic symmetry, which means that the shear coupling coefficients are zero along the principal axes. With this technique, the shear coupling coefficients can be independently calculated, and the validity of the orthotropic assumption can be tested. A quantity called the nonorthotropic angle is presented as a coordinate-independent measure of the lack of orthotropic response. Results from a polyester sheet demonstrate that significant nonorthotropic behavior is encountered in commercial plastic sheets. Stiffnesses, calculated from tests conducted on laminated sheets, are shown to be in good agreement with stiffnesses predicted from measurements on individual plies. The technique is argued to be self-consistent and an attempt is made to convince the reader that this is a legitimate way to characterize all the in-plane elastic stiffnesses of thin sheets.

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Saenz-Castillo, Diego, María I. Martín, Vanessa García-Martínez, Abhiram Ramesh, Mark Battley, and Alfredo Güemes. "A comparison of mechanical properties and X-ray tomography analysis of different out-of-autoclave manufactured thermoplastic composites." Journal of Reinforced Plastics and Composites 39, no. 19-20 (May 7, 2020): 703–20. http://dx.doi.org/10.1177/0731684420924081.

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Three different out-of-autoclave manufacturing processes of CF/poly-ether-ether-ketone thermoplastic composites were characterized, including innovative laser-assisted automated fibre placement with in situ consolidation. Characterization techniques included differential scanning calorimetry, ultrasonic non-destructive testing and matrix digestion, in addition to 3D X-ray microcomputed tomography to investigate the void distribution, size and shape. The results revealed that in situ consolidation process can lead to the accumulation of large voids between the upper layers. Interlaminar shear, in-plane shear, tensile and flexure testing were used for mechanical evaluation. A reduction in the mechanical properties was observed for in situ consolidation laminates when compared to the other out-of-autoclave methods. The drop in mechanical properties of in situ consolidation laminates was mainly attributed to the differences found in void distribution and size. Optimization of processing parameters along with higher quality prepreg raw material could be of assistance for the improvement of mechanical properties of in situ consolidation structures.

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NOWAK-GRZEBYTA, JAGODA, FRANS MEIJER, and EWA STACHOWSKA. "Non-destructive holographic vibrometric testing of the adhesive joint in metal-polymer laminates." Polimery 65, no. 07/08 (July 2020): 572–77. http://dx.doi.org/10.14314/polimery.2020.7.11.

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Journal articles on the topic 'Laminated plastics Testing'

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