Journal articles on the topic 'Fiber element method'
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1
Velloso, Raquel Q., Michéle D. T. Casagrande, Eurípedes A. V. Junior, and Nilo C. Consoli. "Simulation of the Mechanical Behavior of Fiber Reinforced Sand using the Discrete Element Method." Soils and Rocks 35, no. 2 (May 1, 2012): 201–6. http://dx.doi.org/10.28927/sr.352201.
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The general characteristics of granular soils reinforced with fibres have been reported in previous studies and have shown that fibre inclusion provides an increase in material strength and ductility and that the composite behaviour is governed by fibre content, as well as the mechanical and geometrical properties of the fibre. The present work presents a numerical procedure to incorporate fiber elements into an existing discrete element code (GeoDEM). The fiber elements are represented by linear elastic-plastic segments that connect two neighbor contacts where the fiber is located. These elements are characterized by an axial stiffness, tensile strength and length. The effect of the addition of fibers was evaluated numerically by comparing the stress-strain behavior of a pure sand with and without fibers. These simulations showed that the addition of fibers provides a significant increase in strength for the mixture in comparison with strength of the pure sand.
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Xiong, Xiaoshuang, Shirley Z. Shen, Lin Hua, Jefferson Z. Liu, Xiang Li, Xiaojin Wan, and Menghe Miao. "Finite element models of natural fibers and their composites: A review." Journal of Reinforced Plastics and Composites 37, no. 9 (February 6, 2018): 617–35. http://dx.doi.org/10.1177/0731684418755552.
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Finite element method has been widely applied in modeling natural fibers and natural fiber reinforced composites. This paper is a comprehensive review of finite element models of natural fibers and natural fiber reinforced composites, focusing on the micromechanical properties (strength, deformation, failure, and damage), thermal properties (thermal conductivity), and macro shape deformation (stress–strain and fracture). Representative volume element model is the most popular homogenization-based multi-scale constitutive method used in the finite element method to investigate the effect of microstructures on the mechanical and thermal properties of natural fibers and natural fiber reinforced composites. The representative volume element models of natural fibers and natural fiber reinforced composites at various length scales are discussed, including two types of geometrical modeling methods, the computer-based modeling method and the image-based modeling method. Their modeling efficiency and accuracy are also discussed.
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Gao, Jian Hong, and Xiao Xiang Yang. "Evaluation of 3D Embedded Element Technique in the Finite Element Analysis for the Composite." Key Engineering Materials 801 (May 2019): 65–70. http://dx.doi.org/10.4028/www.scientific.net/kem.801.65.
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RVE combined with finite element analysis (FEA) is a very popular method to predict the mechanical property of the composite reinforced by short fibers. In the conventional method, generally the “tie” approach is used. By this method, the FE model with high fiber aspect ratio can not be achieved and the non-convergence of the numerical calculation may appear because of the complex mesh. The embedded element techinique is considered to be a replaceable method . Using this method, the mechanical behavior of composite with high fiber aspect ratio would be simulated. Therefore, in this study, the 3D solid element was employed for the FE model with multi cylinder particles. The comparisions of the Mise stress and the displacement between the embedded and conventional method indicate that compared with the stress transfer, the simulated result of composite stiffness is more accurate. In addition, the effects of model size, fiber orientated angle, fiber volume fraction and fiber aspect ratio were investigated. The numerical results were compared with the Mori-Tanaka model and the good agreements verify the applicability of the embedded element technique we studied in this paper.
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Du, Zhao Qun, Ya Fen Luo, Yun Xu, Gang Zheng, and Wei Dong Yu. "Qualitative Characterization and Identification of Polylactic Fiber based on GC-MS, IR and Element Analysis." Advanced Materials Research 236-238 (May 2011): 1085–88. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.1085.
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Polylactic fiber is a new renewable and biodegradable polymer material for its better physical property and thermoplastic and biological properties, while there are no corresponding inspection method to characterize and identify polylactic fiber with other fibers. So, the present paper is to qualitative analyze the features of PLA fiber and identify it with general fibers, including Polyester, Polyamide, Polyacrylic, Diacetate, Cotton, Viscose and Silk fibers. Elementary analysis method is utilized to have the definite analysis of fiber purity degree and category by the corresoponding element contents of constructing elements. The experimental results show that there exist good accordance with the theoretical results, and is suitable for qualitative characterizaion and identification of fibers. Gas chromatography mass spectrum method is used to feature marker functional groups of these eight fibers, and to further have a qualitative analysis of each fiber. IR spectroscopy proves the qualitative identification on fiber category by the marker absorbing peaks of functional groups ranging from 650cm-1-2200cm-1. These results will be greatly helpful in the qualitative analysis and indectification of Polylactic fiber.
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Kimyong, Cha Yun, Sontipee Aimmanee, Vitoon Uthaisangsuk, and Wishsanuruk Wechsatol. "Micromechanics Damage Analysis in Fiber-Reinforced Composite Material Using Finite Element Method." Key Engineering Materials 525-526 (November 2012): 541–44. http://dx.doi.org/10.4028/www.scientific.net/kem.525-526.541.
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Fiber-reinforced composite materials (FRC) are used in a wide range of applications, since FRC exhibits higher strength-to-density ratio in comparison to traditional materials due to long fibers embedded in a matrix material. Failures occurred in FRC components are complicated because of the interaction of the constituents. The aim of this study is to investigate damage behavior in a unidirectional glass fiber-reinforced epoxy on both macro-and micro-levels by using finite element method. The Hashins criterion was applied to define the onset of macroscopic damage. The progression of the macroscopic damage was described using the Matzenmiller-Lubliner-Taylor model that was based on fracture energy dissipation of material. To examine the microscopic failure FE representative volume elements consisting of the glass fibers surrounded by epoxy matrix with defined volume fraction was considered. Elastic-brittle isotropic behaviour and the Coulomb-Mohr criterion were applied for both fiber and epoxy. The results of the macroscopic and microscopic analyses were correlated. As a result, damage initiation and damage development for the investigated FRC could be predicted.
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Breuer, Kevin, Axel Spickenheuer, and Markus Stommel. "Statistical Analysis of Mechanical Stressing in Short Fiber Reinforced Composites by Means of Statistical and Representative Volume Elements." Fibers 9, no. 5 (May 6, 2021): 32. http://dx.doi.org/10.3390/fib9050032.
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Analyzing representative volume elements with the finite element method is one method to calculate the local stress at the microscale of short fiber reinforced plastics. It can be shown with Monte-Carlo simulations that the stress distribution depends on the local arrangement of the fibers and is therefore unique for each fiber constellation. In this contribution the stress distribution and the effective composite properties are examined as a function of the considered volume of the representative volume elements. Moreover, the influence of locally varying fiber volume fraction is examined, using statistical volume elements. The results show that the average stress probability distribution is independent of the number of fibers and independent of local fluctuation of the fiber volume fraction. Furthermore, it is derived from the stress distributions that the statistical deviation of the effective composite properties should not be neglected in the case of injection molded components. A finite element analysis indicates that the macroscopic stresses and strains on component level are significantly influenced by local, statistical fluctuation of the composite properties.
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Kaushik, Nitish, Ch Sandeep, P. Jayaraman, J. Justin Maria Hillary, V. P. Srinivasan, and M. Abisha Meji. "Finite Element Method-Based Spherical Indentation Analysis of Jute/Sisal/Banana-Polypropylene Fiber-Reinforced Composites." Adsorption Science & Technology 2022 (September 20, 2022): 1–19. http://dx.doi.org/10.1155/2022/1668924.
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Material hardness of natural fiber composites depends upon the orientation of fibers, ratio of fiber to matrix, and their mechanical and physical properties. Experimentally finding the material hardness of composites is an involved task. The present work attempts to explore the deformation mechanism of natural fiber composites subjected to post-yield indentation by a spherical indenter through a two-dimensional finite element analysis. In the present work, jute-polypropylene, sisal-polypropylene, and banana-polypropylene composites are considered. The analysis is attempted by varying the properties of Young’s modulus of fiber and matrix, diameter of fiber, and horizontal and vertical center distance between the fibers. The analyses results showed that as the distance between the fiber’s center increases, the bearing load capacity of all composite increases nonlinearly. The jute fiber composite shows predominate load-carrying capacity compared to other composites at all L / D ratios and interference ratios. The influence of subsurface stress in lateral direction is minimal and gets reduced as the distance between the fiber centers increases. The variation in diameter of fiber influences significantly, i.e., beyond the L / D ratio of 1.0; for the same contact load ratio, the bearing area support is double for jute-polypropylene composite compared to sisal-polypropylene composite. Compared to the sisal-polypropylene composite, for the same interference ratio, the load-carrying capacity is two times high for banana-polypropylene composite, whereas four times high for jute-polypropylene composite, but this effect decreases as the L / D ratio decreases. In all the composites, the subsurface stress gets distributed as the L / D ratio increases. The ratio of fibers center distance to diameter of fiber influences marginally on the contact load and contact area and significantly on the contact stress for all the fiber-reinforced composites.
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Kvam, David J., Yi Yu Duan, Erica Donnelly, and Alicia Restrepo. "Finite Element Method and Analytical Studies on Fiber-Metal Laminates under Multiaxial Loadings." Advanced Engineering Forum 23 (July 2017): 63–71. http://dx.doi.org/10.4028/www.scientific.net/aef.23.63.
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Fiber-metal laminates (FMLs) are composites materials that are commonly used in areas such as aircraft industry. They are composed of ductile metal layers with high strength fiber reinforced polymer layers. So far, however, only uniaxial tests have been used to characterize the quasistatic mechanical properties, which cannot reflect the real loading situation of the FML applications. In this work biaxial tensile behavior of FMLs with glass and Kevlar fibers based on aluminum alloy is studied with finite element method simulation. The simulation is run to find the stress-strain relationship for FMLs at the off-axis angles of 0˚ and 45˚ for glass and Kevlar fibers. The “composites layups” are constructed for the 3D FML part. Two different elements C3D8R (8-node linear) and C3D20R (20-node quadratic) are used to carry out the simulation. The results show that C3D20R shows major advantages. Analytical solutions based on the classical laminate theory are obtained to compare with the finite element method (FEM) solutions. The results show good consistency.
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Kisała, Piotr, Waldemar Wójcik, Nurzhigit Smailov, Aliya Kalizhanova, and Damian Harasim. "Elongation determination using finite element and boundary element method." International Journal of Electronics and Telecommunications 61, no. 4 (December 1, 2015): 389–94. http://dx.doi.org/10.2478/eletel-2015-0051.
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AbstractThis paper presents an application of the finite element method and boundary element method to determine the distribution of the elongation. Computer simulations were performed using the computation of numerical algorithms according to a mathematical structure of the model and taking into account the values of all other elements of the fiber Bragg grating (FBG) sensor. Experimental studies were confirmed by elongation measurement system using one uniform FBG.
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Hejazi, Seyed Mahdi, Seyed Mahdi Abtahi, Mohammad Sheikhzadeh, and Amir Mostashfi. "Micromechanical analysis of loop-formed fiber-reinforced soil composite." Journal of Industrial Textiles 44, no. 3 (July 8, 2013): 418–33. http://dx.doi.org/10.1177/1528083713495251.
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In this research, loop-formed fiber is introduced as a novel reinforcement method of soil composites instead of using ordinary fibers. In order to investigate the materials' mechanical properties, the shear behavior of both fiber and looped-fiber-reinforced soil composites was analyzed by micromechanical method (finite element method) and a set of direct shear tests. The results indicate that the looped-fiber soil composite exhibits greater failure strain energy compared with fiber-reinforced soil composite at the same fiber orientation in the substrate. Furthermore, the proposed model demonstrated two major reinforcing components: “the fiber effect” and “the loop effect.” The latter effect is the key benefit and the main advantage of using looped fibers over ordinary fibers in soil reinforcement. Altogether, there is a close agreement between finite element method outputs and experimental results, suggestive of a novel technical textile material that could potentially be used in geotechnical engineering.
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Dimitrijevic, M. M., N. Tomic, B. Medjo, R. Jancic-Heinemann, M. Rakin, and T. Volkov-Husovic. "Modeling of the mechanical behavior of fiber-reinforced ceramic composites using finite element method (FEM)." Science of Sintering 46, no. 3 (2014): 385–90. http://dx.doi.org/10.2298/sos1403385d.
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Modeling of the mechanical behavior of fiber-reinforced ceramic matrix composites (CMC) is presented by the example of Al2O3 fibers in an alumina based matrix. The starting point of the modeling is a substructure (elementary cell) which includes on a micromechanical scale the statistical properties of the fiber, matrix and fiber-matrix interface and their interactions. The numerical evaluation of the model is accomplished by means of the finite element method. The numerical results of calculating the elastic modulus of the composite dependance on the quantity of the fibers added and porosity was compared to experimental values of specimens having the same composition.
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Katouzian, Mostafa, Sorin Vlase, and Maria Luminita Scutaru. "Finite Element Method-Based Simulation Creep Behavior of Viscoelastic Carbon-Fiber Composite." Polymers 13, no. 7 (March 25, 2021): 1017. http://dx.doi.org/10.3390/polym13071017.
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Usually, a polymer composite with a viscoelastic response matrix has a creep behavior. To predict this phenomenon, a good knowledge of the properties and mechanical constants of the material becomes important. Schapery’s equation represents a basic relation to study the nonlinear viscoelastic creep behavior of composite reinforced with carbon fiber (matrix made by polyethrtethrtketone (PEEK) and epoxy resin). The finite element method (FEM) is a classic, well known and powerful tool to determine the overall engineering constants. The method is applied to a fiber one-directional composite for two different applications: carbon fibers T800 reinforcing an epoxy matrix Fibredux 6376C and carbon fibers of the type IM6 reinforcing a thermoplastic material APC2. More cases have been considered. The experimental results provide a validation of the proposed method and a good agreement between theoretical and experimental results.
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Song, Leilei, Yufen Zhao, Li Chen, Yingdan Zhu, and Jialu Li. "Three-dimensional finite element models and tensile properties of carbon fiber needled felt reinforced composites." Journal of Industrial Textiles 50, no. 3 (February 4, 2019): 293–311. http://dx.doi.org/10.1177/1528083719827362.
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In this study, the three-dimensional finite element models of carbon fiber needled felt reinforced composites were built by using the embedded element technique and the virtual yarn method. Three sizes of samples for carbon fiber needled felt reinforced composites were designed and prepared. The tensile properties were investigated by experiments and theoretical methods, and the influences of sample size on tensile modulus were discussed. The results showed that, the longitudinal tensile moduli of carbon fiber needled felt reinforced composites decreased with the increase of sample size. Compared with the rule of mixtures and the inclusion theory, the longitudinal tensile moduli obtained by finite element method were closer to the experimental values. In addition, the transverse tensile moduli obtained by finite element method were greater than that obtained by the rule of mixtures and the inclusion theory. That was due to the orientation of some fibers had a proportion along the thickness. It was concluded that, these three-dimensional finite element models can be used to investigate the elastic properties of carbon fiber needled felt reinforced composites with different sizes.
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Bavan, D. Saravana, and G. C. Mohan Kumar. "Finite Element Analysis of a Natural Fiber (Maize) Composite Beam." Journal of Engineering 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/450381.
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Natural fiber composites are termed as biocomposites or green composites. These fibers are green, biodegradable, and recyclable and have good properties such as low density and low cost when compared to synthetic fibers. The present work is investigated on the finite element analysis of the natural fiber (maize) composite beam, processed by means of hand lay-up method. Composite beam material is composed of stalk-based fiber of maize and unsaturated polyester resin polymer as matrix with methyl ethyl ketone peroxide (MEKP) as a catalyst and Cobalt Octoate as a promoter. The material was modeled and resembled as a structural beam using suitable assumption and analyzed by means of finite element method using ANSYS software for determining the deflection and stress properties. Morphological analysis and X-ray diffraction (XRD) analysis for the fiber were examined by means of scanning electron microscope (SEM) and X-ray diffractometer. From the results, it has been found that the finite element values are acceptable with proper assumptions, and the prepared natural fiber composite beam material can be used for structural engineering applications.
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Antipas, I. R., and A. G. Dyachenko. "Using the Finite Element Method to Simulate a Carbon Fiber Reinforced Polymer Pressure Vessel." Advanced Engineering Research 22, no. 2 (July 9, 2022): 107–15. http://dx.doi.org/10.23947/2687-1653-2022-22-2-107-115.
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Introduction. Over the past decade, global demand for pressure vessels has increased significantly, specifically in such industries as aviation, space, chemical, and oil and gas. Being under the constant impact of high internal pressure, the walls of the tanks are under increased stress, which can cause their sudden destruction. To eliminate this probability and improve the strength characteristics, the tanks are made in the form of metal cylinders with an internal coating of composite material consisting of resin reinforced with carbon fibers. This article aimed at studying the effect of the angle of inclination of carbon fiber on cylindrical tanks and determining the maximum destructive pressure using the finite element method of ANSYS program.Materials and Methods. Using the ANSYS program, a finite element model of a tank was created. It has a central part, which is a metal cylinder with an internal coating of composite material consisting of polymer reinforced with carbon fibers. At the ends of the tank, spiral wound hemispheres were placed. In these studies, SHELL 99 was used to model the layered composite material. The Tsai-Wu theory was used to determine the pressure tank failure criterion.Results. The cylindrical tank model was calculated for two types of fiber winding paths: annular and spiral, at different angles of their inclination. The results of the pressure value analysis for different fiber inclination angles showed that, starting from the angle value of 0° and up to 45°, it increased, and then, up to the angle value of 65°, it began to decrease. The critical pressure value for a carbon fiber reinforced tank was 207 MPa, which was obtained at a fiber angle of 45º.Discussion and Conclusion. Analysis of the studies showed that at a fiber inclination angle of 45º, the value of the maximum stress turned out to be the smallest, and the maximum possible destructive pressure at the same angle was 207 MPa. It follows, that the optimal fiber orientation angle to provide safe operation of the high-pressure tank is ± 45º, and the carbon fiber tank, calculated at the same fiber winding angle, has the maximum strength value.
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Xie, Jun-bo, Chong Liu, Zhi Yang, Wei Jiao, Yi-fan Zhang, Xiao-ming Chen, and Li Chen. "Mechanical modeling of textile composites using fiber-reinforced voxel models." Journal of Composite Materials 54, no. 19 (January 9, 2020): 2529–38. http://dx.doi.org/10.1177/0021998319899134.
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The fiber-reinforced voxel modeling technique is proposed to analyze the stress field and predict stiffness properties of textile composites. The textile reinforcements and matrix materials are modeled by virtual fibers and 3D voxel elements separately. Then the virtual fibers are “inserted” into the background voxel elements to construct the fiber-reinforced voxel elements. Stiffness properties of each fiber-reinforced voxel element are determined using volume average method based on the volume fraction and orientation of the virtual fibers it occupies. Geometry modeling and meshing of the complex reinforcements and matrix regions are avoided. As the reinforcements are generated in quasi-fiber scale, contact interactions and compaction deformations of the yarns can be modeled with high fidelity. A composite model containing one crimped yarn is used to verify the proposed method by comparing the calculating results of the fiber-reinforced voxel and traditional meso-scale models. The effect of voxel meshing density and virtual fiber radius on the simulation accuracy is also analyzed. Mechanical modeling of a multiply plain weave composite is performed by this model. Influence of nesting and compaction of the plies on the stress field can be fully characterized.
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Cucinotta, A., S. Selleri, L. Vincetti, and M. Zoboli. "Holey fiber analysis through the finite-element method." IEEE Photonics Technology Letters 14, no. 11 (November 2002): 1530–32. http://dx.doi.org/10.1109/lpt.2002.803375.
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Pang, Yi Ling, and Duan Ming Dai. "XFEM for Crack Propagation in Fiber-Reinforced Materials." Advanced Materials Research 997 (August 2014): 450–53. http://dx.doi.org/10.4028/www.scientific.net/amr.997.450.
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This article describes the basic format of extended finite element method (XFEM), and simulation the crack propagation of fiber reinforced materials with extended finite element. Explore the number and elastic modulus of fibers influence the crack propagation by changing the elastic modulus and quantity of the fibers in matrix.
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Kim, Jin Woo, and Dong Gi Lee. "Comparison of Intensity Method and Counting Method in Measurement of Fiber Orientation Angle Distribution Using Image Processing." Materials Science Forum 544-545 (May 2007): 207–10. http://dx.doi.org/10.4028/www.scientific.net/msf.544-545.207.
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The fiber reinforced composites has high specific strength and stiffness than metallic material and are an anisotropic material whose mechanical properties, such as strength and elasticity, change with their fiber orientation state, the fiber length, the fiber aspect ratio, fiber mat structure, etc. Above all, the fiber orientation angle distribution state of fiber reinforced composite is fundamental element of mechanical properties. So, many researches on this element have been conducted by means of nondestructive method currently. The fiber distribution state is measured by intensity difference of pixel using image processing and these methods are intensity method by calculating of intensity value of pixel and counting method by calculating of fiber quantity. In this research, the fiber orientation simulation picture was constructed by plotter according to change of fiber’s diameter, length and orientation. The fiber orientation distribution state was measured by this intensity information. The fiber orientation angle distribution state measured by intensity method and counting method was compared with fiber orientation function calculation value.
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Soo Hwang, Hyung, and Joon Ho Cho. "Image Processing Algorithm for Calculating Uniformity of Carbon Surface Image Heating Element." International Journal of Engineering & Technology 7, no. 3.34 (September 1, 2018): 547. http://dx.doi.org/10.14419/ijet.v7i3.34.19378.
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Background/Objectives: In this paper, numerical calculation method using image processing technology for percentage and uniformity of carbon fibers of planar heating element was proposed.Methods/Statistical analysis: The manufacturing method of the planar heating element is made by chopping the carbon fiber in small size and bonding it again via the dispersing agent. Filter the carbon fiber solution bound using a dispersant on the next nonwoven fabric. The last step is to obtain planar carbon fibers in the form of nonwoven fabrics for drying the filtered carbon fibers.Findings: n the planar heating element, electricity may be applied to the carbon fiber on the surface produced in this manner. Calculation of the ratio and uniformity of the planar heating element in this paper addressed four sample images (0.2 wt.%, 0.4 wt.%, 0.8 wt.%, 2.4 wt.%). In this method, the image of the planar heating element was divided into 5 × 5, converted into a binary image, and then the ratio and uniformity were numerically calculated.Improvements/Applications: The image analysis of the planar heating element proposed in this paper can be interpreted more accurately by combining it with the conventional method.
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T. V., Smitha, Madhura S, Shreya N, and Sahana Udupa. "Optical Waveguides and Terahertz Signal by Finite Element Method: A Survey." June 2021 3, no. 2 (June 3, 2021): 68–86. http://dx.doi.org/10.36548/jsws.2021.2.002.
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This paper examines the use of the Finite Element Method (FEM) in the field of optical waveguides and terahertz signals, with the main goal of explaining how this method aids in recent advances in this field. The basics of FEM are briefly reviewed, and the technique's application to waveguide discontinuity analysis is observed. Second-order and higher-order derivatives result from optical waveguide modeling, which is significant for information exchange and many other nonlinear phenomena. The use of FEM in the improvised design of hexagonal sort air hole porous core microstructure fibers, which produces hexagonal structure cladding and rectangular-shaped air holes in the fiber core for excellent terahertz signal transmission, was also observed. These modifications were intended to improve the fiber's properties in comparison to other structures. This approach verifies that the fiber has high birefringence, low material loss, a high-power fraction, and minimal dispersion varia-tion. The features of square-type microstructure fiber are investigated. A folded-shaped po-rous cladding design is recognized for sensing applications. This type of photonic crystal fiber is also known as FP-PCF since it features circular air holes. The most approximate findings of this application are obtained using FEM. In comparison to many other approach-es for various applications, it is evident that FEM is a powerful and numerically efficient tool. This work does a survey of optical waveguides and terahertz signals using the Finite Element Method. Terahertz signals can be used in conjunction with electromagnetic waves to identify viruses. Thus, Terahertz signals are employed in real-world applications such as fuel adulteration, liquid metal synthesis, and virus detection.
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Ahmadi, Majid, Seyed Hadi Seyedin, and Seyed Vahid Seyedin. "Investigation of the mechanical performance of fiber-modified ceramic composites using finite element method." Tehnički glasnik 13, no. 3 (September 24, 2019): 173–79. http://dx.doi.org/10.31803/tg-20181006143504.
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Ceramic materials are widely used in impact safekeeping systems. Ceramic is a heterogeneous material; its characteristics depend considerably both on specifications of its ingredients and the material structure completely. The finite element method (FEM) can be a useful tool for strength computation of these materials. In this paper, the mechanical properties of the ceramic composites are investigated, and the mechanical performance modeling of fiber-fortified ceramic matrix composites (CMC) is expressed by the instance of aluminum oxide fibers in a matrix composite based on alumina. The starting point of the modeling is an infrastructure (primary cell) that contains a micromechanical size, the statistical analysis characteristics of the matrix, fiber-matrix interface, fiber, and their reciprocal influences. The numeral assessment of the model is done using the FEM. The numerical results of composite elastic modulus were computed based on the amount of the added fibers and the porosity was evaluated for empirical data of samples with a similar composition. Various scanning electron microscope (SEM) images were used for each sample to specify the porosity. Also, the unit cell method presumed that the porous ceramic substance is manufactured from an array of fundamental units, each with the same composition, material characteristic, and cell geometry. The results showed that when the material consists of different pores and fibers, the amount of Young’s modulus reduces with the increment of porosity. The linear correlation model of elasticity versus porosity value from experimental data was derived by MATLAB curve fitting. The experimental data from the mechanical test and numerical values were in good agreement.
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Gao, Jian Hong, Xiao Xiang Yang, and Li Hong Huang. "Application of Embedded Element in the Short Fiber Reinforced Composite." Key Engineering Materials 774 (August 2018): 241–46. http://dx.doi.org/10.4028/www.scientific.net/kem.774.241.
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The finite element analysis (FEA) is a numerical method for predicting the mechanical property of short fiber reinforced composite usefully. However, as we know, there is always a “jamming” limit when generating fiber architecture expecially in the cases of high volume fraction and high aspect ratio of short fiber. Even if the volume fraction and aspect ratio in finite element model meet the practical requirements, the problem of mesh deformity will always occur which would lead to unconverge of numerical computation. In this work, embedded element technique which will help to reduce the probability of the above two problems is employed to establish the finite element model of short fiber reinforced composite. The effect of edge size, thickness and mesh density of FE models on the elastic modulus were investigated. Numerical results show that the value of elastic modulus mainly depend on the edge size and fiber amount of FE model while the effect of thickness can be neglected. The elastic modulus takes to converge for high element number. An inverse method is proposed to calculate volume fraction of short fibers, by which numerical results agree well with the calculation results of empirical formula based on Halpin-Tsai equation.
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Rofiq, H. I., Tavio, and D. Iranata. "Model validation of carbon-fiber and glass-fiber reinforced elastomeric isolators using finite element method." IOP Conference Series: Earth and Environmental Science 1116, no. 1 (December 1, 2022): 012001. http://dx.doi.org/10.1088/1755-1315/1116/1/012001.
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Abstract Fiber Reinforced Elastomeric Isolators (FREI) is a base isolation innovation for low-rise buildings suitable for developing countries with high earthquake intensity, for instance, Indonesia. The extension of the basic natural fundamental period by FREI will result into a reduction in floor acceleration when an earthquake occurs, thereby it will be reducing the inter-story drift movement in the superstructure. The FREI mass structure is lighter for low-rise buildings due its components consist of a layer of rubbers and a sheet of fibers. This study investigated numerically the use of fiber materials (glass and carbon fibers) for FREI reinforcement using ABAQUS program. The analysis results were evaluated based on mechanical characterization, including vertical and horizontal stiffness, effective horizontal stiffness, and damping ratio. The mechanical characterization in numeric research will be compared with experimental research as a research validation to ensure the input material variables are reliable and valid. Based on the analysis of numeric research results, CFREI and GFREI indicated that hysteresis curves and mechanical characterization were quite close to experimental research. Calculation of mechanical characterization in CFREI and GFREI refers to the regulations of BS_EN_1337:2005 and BS_EN_15129:2009. A deviation of mechanical characterization on numeric research of both specimens against the experimental research, including effective horizontal stiffness and damping ratio, indicated a fairly small deviation with less than 10%. The deviation between the maximum effective horizontal stiffness in CFREI and GFREI was 4.733% and 0.672% respectively, meanwhile the maximum damping ratio in CFREI and GFREI indicated the larger deviation that was 0.812% and 8.679% individually.
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Li, Yujun, Zengzhi Yu, Stefanie Reese, and Jaan-Willem Simon. "Evaluation of the out-of-plane response of fiber networks with a representative volume element model." June 2018 17, no. 06 (July 1, 2018): 329–39. http://dx.doi.org/10.32964/tj17.06.329.
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Many natural and synthetic materials have fibrous microstructures, including nonwoven fabrics, paper, and fiberboard. Experimentally evaluating their out-of-plane mechanical behavior can be difficult because of the small thickness compared with the in-plane dimension. To properly predict such properties, network-scale models are required to obtain homogenized material mechanics by considering fiber-scale mechanisms. We demonstrate a three-dimensional representative volume element (RVE) for fiber networks using the finite element method. We first adopted the classical deposition procedure to generate fiber networks with random or preferential fiber orientations and then an artificial compression to achieve the practical fiber volume fraction. The hollow fibers, described with elastic-plastic brick elements, were joined by interface-based cohesive zone elements introduced in all fiber-fiber contact areas. Thereafter, the fiber networks were subjected to displacement boundary conditions, and their apparent mechanical response was evaluated by a homogenized stress. To determine the RVE dimension, we further conducted an RVE size convergence study for the out-of-plane compression and tension (varying specimen length while keeping the specimen thickness constant). Finally, we evaluated the apparent out-of-plane response of the obtained RVE for four loading cases: out-of-plane compression, tension, simple shear, and pure shear. The results show a quite different mechanical behavior of fiber networks between all these out-of-plane loading cases, particularly between tension and compression.
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Xu, Ding Jie, Hong Ru Song, Wei Wang, and Yue Fan. "The Optimization Research on Hollow-Core Photonic BandgapFiber CoreTransversal Radius." Advanced Materials Research 884-885 (January 2014): 370–73. http://dx.doi.org/10.4028/www.scientific.net/amr.884-885.370.
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In hollow-core optical fibers, surface mode is one most important reasons causes fiber loss. In order to suppress surface mode loss, simulations of the designed hollow-core optical fibers have been made numerically using full vector finite element method, and the light intensity distributions are in the different core transversal radius is obtained. Analysis results show that both the enlargement of core radius and using fusing transversal method lead into the core holeare more helpful to suppress surface mode loss. This conclusion may provide a basis for small duty cycle (f< 85%) hollow-core optical fibers fabrication the theoretically. Keywords:hollow-corephotonic band-gap fiber (HC-PBF),finite element method (FEM), surface mode loss, core transversal radius, core intersected method
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Wang, Zhen Qing, Xiao Qiang Wang, Ji Feng Zhang, and Song Zhou. "Parametric Modeling Method for Composite Microstructure Virtual Testing." Advanced Materials Research 97-101 (March 2010): 1661–64. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.1661.
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A method of parametric modeling composite microstructure is proposed. It can be used for composite microstructure virtual testing and optimization procedure. Considering the fiber random distribution features of composite microstructure and the flaw distribution in the fibers, a three dimensional parametric model has been built in this paper. Then, the sizes of the composite representative volume element (RVE) generated by the method are determined by moving-window function method. These models are close to reality and can be used for further virtual testing. Finally, numerical experiment is presented by the secondary development of the finite element packages (ABAQUS) via Python language programming to verify the proposed method. The following conclusions are obtained: (i) fiber volume fraction of the composite structure model reaches 65% by the modeling method, which meets the majority engineering demands; (ii) stress distribution feature of RVE generated by using moving-window function method coincides with general prediction.
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Liu, Y. J., N. Nishimura, Y. Otani, T. Takahashi, X. L. Chen, and H. Munakata. "A Fast Boundary Element Method for the Analysis of Fiber-Reinforced Composites Based on a Rigid-Inclusion Model." Journal of Applied Mechanics 72, no. 1 (January 1, 2005): 115–28. http://dx.doi.org/10.1115/1.1825436.
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A new boundary element method (BEM) is developed for three-dimensional analysis of fiber-reinforced composites based on a rigid-inclusion model. Elasticity equations are solved in an elastic domain containing inclusions which can be assumed much stiffer than the host elastic medium. Therefore the inclusions can be treated as rigid ones with only six rigid-body displacements. It is shown that the boundary integral equation (BIE) in this case can be simplified and only the integral with the weakly-singular displacement kernel is present. The BEM accelerated with the fast multipole method is used to solve the established BIE. The developed BEM code is validated with the analytical solution for a rigid sphere in an infinite elastic domain and excellent agreement is achieved. Numerical examples of fiber-reinforced composites, with the number of fibers considered reaching above 5800 and total degrees of freedom above 10 millions, are solved successfully by the developed BEM. Effective Young’s moduli of fiber-reinforced composites are evaluated for uniformly and “randomly” distributed fibers with two different aspect ratios and volume fractions. The developed fast multipole BEM is demonstrated to be very promising for large-scale analysis of fiber-reinforced composites, when the fibers can be assumed rigid relative to the matrix materials.
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Huang, Huan, and Xiu Chun Dong. "Application of Finite Element Method in Submarine Cable Fiber Excess Length Analysis." Applied Mechanics and Materials 138-139 (November 2011): 759–63. http://dx.doi.org/10.4028/www.scientific.net/amm.138-139.759.
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In this paper, finite element method is compared with analytic method in the analysis of submarine cable fiber excess length. And the limitations of using analytic method are analyzed. Then the feasibility and advantages of using finite element method is discussed. We can control and design fiber excess length more reasonably and produce cables in a more scientific way by using finite element method in the analysis of submarine cable fiber excess length.
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Marcalikova, Zuzana, and Oldrich Sucharda. "Modeling of Fiber-Reinforced Concrete and Finite Element Method." International Review of Civil Engineering (IRECE) 12, no. 1 (January 31, 2021): 11. http://dx.doi.org/10.15866/irece.v12i1.18636.
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Dehkordi, Javad Aminian, Seyed Saeid Hosseini, Prodip K. Kundu, and Nicolas R. Tan. "Mathematical Modeling of Natural Gas Separation Using Hollow Fiber Membrane Modules by Application of Finite Element Method through Statistical Analysis." Chemical Product and Process Modeling 11, no. 1 (March 1, 2016): 11–15. http://dx.doi.org/10.1515/cppm-2015-0052.
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Abstract Hollow fiber membrane permeators used in the separation industry are proven as preferred modules representing various benefits and advantages to gas separation processes. In the present study, a mathematical model is proposed to predict the separation performance of natural gas using hollow fiber membrane modules. The model is used to perform sensitivity analysis to distinguish which process parameters influence the most and are necessary to be assessed appropriately. In this model, SRK equation was used to justify the nonideal behavior of gas mixtures and Joule-Thomson equation was employed to take into account the changes in the temperature due to permeation. Also, the changes in temperature along shell side was calculated via thermodynamic principles. In the proposed mathematical model, the temperature dependence of membrane permeance is justified by the Arrhenius-type equation. Furthermore, a surface mole fraction parameter is introduced to consider the effect of accumulation of less permeable component adjacent to the membrane surface in the feed side. The model is validated using experimental data. Central Composite Designs are used to gain response surface model. For this, fiber inner diameter, active fiber length, module diameter and number of fibers in the module are taken as the input variables related to the physical geometries. Results show that the number as well as the length of the fibers have the most influence on the membrane performance. The maximum mole fraction of CO2 in the permeate stream is observed for low number of fibers and fibers having smaller active lengths. Also results indicate that at constant active fiber length, increasing the number of fibers decreases the permeate mole fraction of CO2. The findings demonstrate the importance of considering appropriate physical geometries for designing hollow fiber membrane permeators for practical gas separation applications.
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TANG, C., M. A. SHEIKH, and D. R. HAYHURST. "FINITE ELEMENT MODELING OF TRANSVERSE DEFORMATION IN REPRESENTATIVE VOLUME ELEMENTS OF CERAMIC MATRIX COMPOSITES (CMCs)." Journal of Multiscale Modelling 02, no. 01n02 (March 2010): 107–26. http://dx.doi.org/10.1142/s1756973710000308.
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The paper reports the use of the finite element method to model longitudinal and transverse deformation of representative volume elements (RVE) of ceramic matrix composites subjected to uniaxial loading parallel to fibers. Cohesive elements have been used to model two forms of damage: fracture initiation and propagation both within the matrix, and along the fiber–matrix interface. From the knowledge of the constituent materials behavior, the FE technique has been used to predict the stress–strain behavior and the variation of Poisson's ratio of the RVE due to these two damage forms; but the model does not cater for fiber failure. The RVE predictions have been benchmarked against experimental results for Nicalon-CAS material and good agreement has been obtained. Comparison of the predicted behavior of the single Nicalon-CAS RVE with experimental data for unidirectional tows indicates that the stress–strain curve is predominantly controlled by the Weibull distribution of fiber failure stress, while the degradation of Poisson's ratio is determined by the Weibull distribution of interfacial strength. The same approach has been used for a HITCO C/C material for which transverse deformation behavior is unknown. The results for the HITCO C/C material, as for the Nicalon-CAS, show that the fiber behavior determines the ultimate failure of the RVE, and that interface debonding is the controlling mechanism for the variation of the Poisson ratio with axial strain.
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Yang and Li. "Development of a Refined Analysis Method for Earthquake-Induced Pounding between Adjacent RC Frame Structures." Sustainability 11, no. 18 (September 9, 2019): 4928. http://dx.doi.org/10.3390/su11184928.
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Pounding of two adjacent structures is one of the factors that cause damage and hinder sustainable use of reinforced concrete (RC) frame structures under strong ground motion excitations. This study developed a pounding analysis method with a refined beam-column element in order to solve the pounding problem between two RC frame structures. The analysis method combines the fiber beam-column element model with the element sections discretized into concrete and longitudinal rebar fibers, the Hertz-damp contact element model to describe the pounding between beam-column elements, and the method to integrate the pounding force into the system dynamic equilibrium equation. The pounding can be considered either at the level between the story slab to slab or at the level between story slab to mid-column. The application of the proposed method in pounding analyses to provide a rational seismic separation gap between two adjacent RC frame structures is finally conducted to increase their safety and sustainability under strong earthquakes.
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Caglar, Fazil Abdulkadir, and Tuba Tatar. "Calibration of RC Columns Using Fiber Elements." Academic Perspective Procedia 4, no. 2 (November 6, 2021): 205–13. http://dx.doi.org/10.33793/acperpro.04.02.52.
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Although experimental studies have proven as the most effective method, its high cost has provoked researchers to seek alternative approaches. The increase in computational power in the 21st century provides the opportunity to numerically model experimental studies with various programs. This study examines the comparison of force-based element and displacement-based element in columns using nonlinear fiber elements. Within the scope of the study, OpenSees program is employed for columns selected from the PEER (Structural Performance Database) site. The aim is to compare the employment of the FB element and DB elements in RC columns in terms of number of elements and integration points, to simulate the global behavior of the columns numerically, and to optimize the parameters that affect the results.
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Wang, Zhen Qing, Xiao Qiang Wang, Ji Feng Zhang, and Song Zhou. "Parametric Generation of Random Distribution of Fibers in Long-Fiber Reinforced Composites and Micromechanical FE Analysis." Key Engineering Materials 452-453 (November 2010): 117–20. http://dx.doi.org/10.4028/www.scientific.net/kem.452-453.117.
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A method for the parametric generation of the transversal cross-section microstructure model of unidirectional long-fiber reinforced composite (LFRC) is presented in this paper. Meanwhile, both the random distribution of the fibers and high fiber volume fraction are considered in the algorithm. The fiber distribution in the cross-section is generated through random movements of the fibers from their initial regular square arrangement. Furthermore, cohesive zone element is introduced into modeling the interphase between the fiber and the matrix. All these processes are carried out by the secondary development of the finite element codes (ABAQUS) via Python language programming. Based on the model generated, micromechanical finite element analysis (FEA) is performed to predict the damage initiation and subsequent evolution of the composites. The results show that this technique is capable of capturing the random distribution nature of these composites even for high fiber volume fraction. Moreover, the results prove that a good agreement with the experimental results is found.
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Park, Jang Min, and Seong Jin Park. "Modeling and Simulation of Fiber Orientation in Injection Molding of Polymer Composites." Mathematical Problems in Engineering 2011 (2011): 1–14. http://dx.doi.org/10.1155/2011/105637.
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We review the fundamental modeling and numerical simulation for a prediction of fiber orientation during injection molding process of polymer composite. In general, the simulation of fiber orientation involves coupled analysis of flow, temperature, moving free surface, and fiber kinematics. For the governing equation of the flow, Hele-Shaw flow model along with the generalized Newtonian constitutive model has been widely used. The kinematics of a group of fibers is described in terms of the second-order fiber orientation tensor. Folgar-Tucker model and recent fiber kinematics models such as a slow orientation model are discussed. Also various closure approximations are reviewed. Therefore, the coupled numerical methods are needed due to the above complex problems. We review several well-established methods such as a finite-element/finite-different hybrid scheme for Hele-Shaw flow model and a finite element method for a general three-dimensional flow model.
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Liao, Tianyi, Sabit Adanur, and Jean-Yves Drean. "Predicting the Mechanical Properties of Nonwoven Geotextiles with the Finite Element Method." Textile Research Journal 67, no. 10 (October 1997): 753–60. http://dx.doi.org/10.1177/004051759706701008.
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A new computer model is developed to predict the tensile behavior of nonwoven fabrics from the stress-strain behavior of their constituent fibers and distributions of fiber orientation angles. The finite element method is used to calculate the numerical solution of stress and strain distribution in different regions of the samples during tensile deformation. Stress-strain curves of fabrics are simulated. Tensile testing is done on several nonwoven fabrics to verify the simulated results, which are in a good agreement with those obtained from tensile experiments.
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Ghasemi, Ahmad Reza, Mohammad Mohammadi Fesharaki, and Masood Mohandes. "Three-phase micromechanical analysis of residual stresses in reinforced fiber by carbon nanotubes." Journal of Composite Materials 51, no. 12 (September 20, 2016): 1783–94. http://dx.doi.org/10.1177/0021998316669854.
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In this study, circular disk model and cylinder theory for two dimension (2D) and three dimension (3D), respectively, have been used to determine residual stresses in three-phase representative volume element. The representative volume element is consisting of three phases: carbon fiber, carbon nanotubes, and polymer matrix, that carbon fiber is reinforced by carbon nanotube using electrophoresis method. Initially, the residual stresses analysis of two-phase representative volume element has been implemented. The two-phase representative volume element has been divided to carbon fiber and matrix phases with different volume fractions. In the three-phase representative volume element, although the volume fraction of carbon fiber is constant and equal to 60%, the volume fractions of carbon nanotubes for various cases are different as 0%, 1%, 2%, 3%, 4%, and 5%. Also, there are two different methods to reinforce the fiber according to different coefficients of thermal expansion of the carbon fiber and carbon nanotube in two longitudinal and transverse directions; carbon nanotubes are placed on carbon fiber either parallel or around it like a ring. Subsequently, finite element method and circular disk model have been used for analyzing micromechanic of the residual stresses for 2D and then the results of stress invariant obtained by the finite element method have been compared with the circular disk model. Moreover, for 3D model, the finite element method and cylinder theory have been utilized for micromechanical analysis of the residual stresses and the results of stress invariant obtained by them, have been compared with each other. Results of the finite element method and analytical model have good agreement in 2D and 3D models.
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Shokreih, Mahmoud, and Ahmad Parsaee. "Measuring the Optimum Fiber Content Ratio of E-Glass/Epoxy Composite through Microbuckling." Advanced Materials Research 548 (July 2012): 7–11. http://dx.doi.org/10.4028/www.scientific.net/amr.548.7.
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When fiber-reinforced composites (FRC) are subjected to compressive load parallel to the fiber direction, they fail as a result of fiber buckling and/or transverse failure of the resin. Compressive loading brings about two buckling modes to fibers. The first mode is shear buckling, and the other is transverse buckling. Recent studies support the hypothesis that fiber buckling causes compressive rupture. In this study, finite element modeling software was employed to examine the behavior of a resin-embedded single fiber in terms of fiber content ratio. The performed modeling procedures illustrated that the single fiber experiences three discrete failure modes depending on fiber content ratio; and then a corrected equation was proposed for each mode. Fiber content ratio of the composite is one of effective parameters to determine the compressive strength value. Optimum fiber content ratio has been measured using finite element method. Numerical results are compared to experimental ones to analyze the obtained results. The optimum fiber content ratio calculated by the finite element modeling was measured 40% in this paper.
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Kim, Jeong Soo, and Moon Kyum Kim. "Finite Element Analysis of Steel-Shotcrete Composite Using the Fiber Beam-Column Element." Applied Mechanics and Materials 275-277 (January 2013): 1359–63. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.1359.
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Owing to strong nonlinearity of shotcrete and difficulty of determining the equivalent material properties of steel-shotcrete composites for numerical analysis, methods are required to estimate nonlinear behavior of steel-shotcrete composite in the computational aspect efficiently. In this study, the behavior of steel-shotcrete composites, main primary supports in the NATM tunnel, are estimated by finite element method using the fiber beam-column element. The numerical results are compared with results of uniaxial and flexural test. Results of comparison show that finite element analysis of using fiber beam-column element can be an efficient tool of estimating the steel-shotcrete composite as the primary support in the NATM tunnel.
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Furukawa, Takao, Tomofumi Okamoto, Yoshio Shimizu, and Kazuya Sasaki. "Modal Analysis of Anisotropic Elastic Body Like Woven Fabrics Using Finite Element Method." Sen'i Gakkaishi 54, no. 2 (1998): 108–14. http://dx.doi.org/10.2115/fiber.54.2_108.
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Hu, Juan, and Fenghui Dong. "Finite Element of Nanoscale Carbon Fiber-Reinforced Concrete Bridge Engineering Monitoring Based on Data Mining Technology." Advances in Materials Science and Engineering 2022 (August 23, 2022): 1–13. http://dx.doi.org/10.1155/2022/9666911.
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The finite element method divides the existing solid structure into a finite number of elements. It integrates and analyzes the divided elements according to preset criteria, and then solves the equilibrium equation of the overall structure according to the corresponding boundary conditions. The problem is analyzed through a finite element model. A large amount of data from the experiment are derived, and then data mining technique is used to find out the data that are useful for the experiment. The purpose of this paper is to test bridge engineering through data mining technology, and then simulate different fiber-reinforced concrete models through finite element method. In this paper, three kinds of nanofibers, carbon fiber (CFRP), glass fiber (GFRP), and aramid fiber (AFRP) are used to make concrete bridges. Loading experiments are also carried out with different degrees of load on the bridge and 100 experiments on the error interval. The experimental results show that the displacement is proportional to the load to a certain extent. The carbon fiber concrete has a stronger positive correlation than the other two materials. Its finite element simulation experimental data have 78% error difference between 0 and 10, while the other two are around 40%.
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Gun, Halit, and Gorkem Kose. "Prediction of longitudinal modulus of aligned discontinuous fiber-reinforced composites using boundary element method." Science and Engineering of Composite Materials 21, no. 2 (March 1, 2014): 219–21. http://dx.doi.org/10.1515/secm-2013-0055.
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AbstractIn this study, the boundary element method is presented for the prediction of longitudinal modulus of aligned discontinuous fiber-reinforced composites. The details of the boundary element formulation model covering infinite friction (stick) contact conditions are given. Both fiber and matrix materials are assumed to display linear elastic material behavior. The formulation is applied to boron/epoxy discontinuous fiber-reinforced composites. The computed results show a very good agreement with the modified Cox model and the finite element analysis with experimental data.
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Higuchi, Rie, and Yoshinori Kanno. "Proposal of Various Connecting Methods of Fiber Strands and Finite Element Method Analysis of Strength." Key Engineering Materials 340-341 (June 2007): 143–48. http://dx.doi.org/10.4028/www.scientific.net/kem.340-341.143.
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The main purpose of this study was to investigate the strength and performance of CFRP by using simple fiber-reinforced methods. It shows that the Reef knot has the highest strength in all by an uni-axial loading test. It is confirmed that the outer shape of the CFRP is important to fabricate the strongest structure. It is also attributed that the CFRP joining methods with a smooth contour will improve the connection strength between fiber strands and knot.
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Mueller, Dieter H., and Markus Kochmann. "Numerical Modeling of Thermobonded Nonwovens." International Nonwovens Journal os-13, no. 1 (March 2004): 1558925004os—13. http://dx.doi.org/10.1177/1558925004os-1300114.
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In thermobonded nonwovens, the design of the bond point geometry is of major importance to the desired mechanical behavior. Despite the geometry's significance the selection is subject to a trial and error approach. This paper describes a numerical method for the prediction of the nonwovens tensile behavior depending on the bond point geometry and process parameters. The tensile behavior of thermobonded nonwovens is modeled in a numerical model using the Finite Element Method (FEM). The approach covers the influence of the shape and size of the bonded area as well as the properties of the non-woven. The influence of the technological parameters during the bonding process such as process temperature and pressure, are also covered. The solidified area within the bond point is represented using solid elements. The connection between the bonded areas is modeled using link elements, representing the connecting fibers. This approach covers the nonlinear behavior caused by the fiber material properties and geometry. Sets of fibers are combined into fiber bundles in order to reduce the numerical effort. The fiber orientation within the nonwoven is taken into account in order to represent the different fiber distributions caused by the nonwovens production techniques. The mechanical properties of fibers and fiber bundles are taken from experimental data and are mapped onto the model. The model is verified using experimental data from tensile testing.
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KARATON, Muhammmet, and İsra YILMAZ. "An Investigation of Torsional Behaviour of Reinforced Concrete Buildings by using Fiber Element Method." Deu Muhendislik Fakultesi Fen ve Muhendislik 24, no. 72 (September 19, 2022): 773–85. http://dx.doi.org/10.21205/deufmd.2022247208.
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Bu çalışmada, 15×15 m boyutlarına sahip 24 katlı betonarme üç tip yüksek binanın (Tip-1, Tip-2, Tip-3) zaman tanım alanında doğrusal olmayan analizleri yapılmıştır. Perdeler, Tip-1 binasında çekirdekte, Tip-2 binasında köşelerde ve Tip-3 binasında ise dış kenarların ortalarında konumlandırılmıştır. Tüm binalarda dört farklı perde alanı seçilmiştir. Betonarme taşıyıcı elemanların kesitleri Kuvvete Dayalı Fiber Eleman Yöntemi ile modellenmiştir. Dinamik analizlerde her katın döşemesi rijit diyafram kabul edilmiştir. Deprem yükü için TBDY-2018’ e göre yapay olarak üretilmiş 11 adet ivme kaydı kullanılmış olup bu ivme kayıtları tüm binaların her iki doğrultusunda etki ettirilmiştir. Karşılaştırmalar, binalardaki hasar bölgesi, bina tepesinin burulma açısı, açısal hız ve açısal ivme tepkilerinin mutlak maksimumlarının maksimum değerleri için yapılmıştır. Kolon ve perde elemanların farklı hasar bölgelerine geçen oranları karşılaştırıldığında en az hasara sahip olan binanın Tip-2 olduğu belirlenmiştir. Aynı zamanda, burulma açısı, açısal hız ve açısal ivme tepkilerinin mutlak maksimumlarının maksimum değerleri dikkate alındığında en düşük değerleri veren bina tipinin Tip-2 olduğu görülmüştür. Sonuç olarak burulma davranışı açısından en uygun bina tipinin Tip-2 olduğu belirlenmiştir.
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Kemeny, Steven Frank, and Alisa Morss Clyne. "A Simplified Implementation of Edge Detection in MATLAB is Faster and More Sensitive than Fast Fourier Transform for Actin Fiber Alignment Quantification." Microscopy and Microanalysis 17, no. 2 (March 9, 2011): 156–66. http://dx.doi.org/10.1017/s143192761100002x.
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AbstractFiber alignment plays a critical role in the structure and function of cells and tissues. While fiber alignment quantification is important to experimental analysis and several different methods for quantifying fiber alignment exist, many studies focus on qualitative rather than quantitative analysis perhaps due to the complexity of current fiber alignment methods. Speed and sensitivity were compared in edge detection and fast Fourier transform (FFT) for measuring actin fiber alignment in cells exposed to shear stress. While edge detection using matrix multiplication was consistently more sensitive than FFT, image processing time was significantly longer. However, when MATLAB functions were used to implement edge detection, MATLAB's efficient element-by-element calculations and fast filtering techniques reduced computation cost 100 times compared to the matrix multiplication edge detection method. The new computation time was comparable to the FFT method, and MATLAB edge detection produced well-distributed fiber angle distributions that statistically distinguished aligned and unaligned fibers in half as many sample images. When the FFT sensitivity was improved by dividing images into smaller subsections, processing time grew larger than the time required for MATLAB edge detection. Implementation of edge detection in MATLAB is simpler, faster, and more sensitive than FFT for fiber alignment quantification.
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Liu, Y. J., N. Xu, and J. F. Luo. "Modeling of Interphases in Fiber-Reinforced Composites Under Transverse Loading Using the Boundary Element Method." Journal of Applied Mechanics 67, no. 1 (September 23, 1999): 41–49. http://dx.doi.org/10.1115/1.321150.
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In this paper, interphases in unidirectional fiber-reinforced composites under transverse loading are modeled by an advanced boundary element method based on the elasticity theory. The interphases are regarded as elastic layers between the fiber and matrix, as opposed to the spring-like models in the boundary element method literature. Both cylinder and square unit cell models of the fiber-interphase-matrix systems are considered. The effects of varying the modulus and thickness (including nonuniform thickness) of the interphases with different fiber volume fractions are investigated. Numerical results demonstrate that the developed boundary element method is very accurate and efficient in determining interface stresses and effective elastic moduli of fiber-reinforced composites with the presence of interphases of arbitrarily small thickness. Results also show that the interphase properties have significant effect on the micromechanical behaviors of the fiber-reinforced composites when the fiber volume fractions are large. [S0021-8936(00)02501-0]
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Zhou, Xiong, Yingjie Wei, Yuyou Yang, and Pengfei Xu. "Numerical Study of the Optimum Fiber Content of Sealing Grease Using Discrete Element Method." Materials 15, no. 10 (May 12, 2022): 3485. http://dx.doi.org/10.3390/ma15103485.
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A sealing grease plays a crucial role in the sealing of shield tails. Its pumpability and pressure sealing resistant sealing performance are greatly affected by the fiber content. In this study, discrete element method models were used to simulate the pressure-resistant tests of sealing grease in order to investigate the influence of viscosity grade and fiber’s aspect ratio on the optimum fiber content of sealing grease. Meanwhile, the rationality of the optimum fiber number determined based on the sealing performance was verified with the unbalanced force and fiber area proportion obtained in the simulation, of which the variation curves with the increasing fiber number were practically identical. The simulation results elucidated that the viscosity of grease had little effect on the optimum fiber content for sealing grease. However, the increase in viscosity can improve the sealing effect, and increasing the fiber’s aspect ratio can reduce the fiber number to reach a specific seal state. Based on the analysis of the total number of fiber spheres for the models with different fiber’s respect ratios, it can be concluded that the sealing grease sample made of the same fiber material and quality can reach the same seal state and seal effect, independent on fiber’s aspect ratio.
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Karakoc, Alp, Mindaugas Bulota, Michael Hummel, Simona Sriubaitė, Mark Hughes, Herbert Sixta, and Jouni Paltakari. "Effect of single-fiber properties and fiber volume fraction on the mechanical properties of Ioncell fiber composites." Journal of Reinforced Plastics and Composites 40, no. 19-20 (March 26, 2021): 741–48. http://dx.doi.org/10.1177/07316844211005393.
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The present study concentrates on a series of experiments and numerical analyses for understanding the effects of fiber volume fraction ( VF) and draw ratio ( DR) on the effective elastic properties of unidirectional composites made from an epoxy resin matrix with a continuous fiber reinforcement. Lyocell-type regenerated cellulose filaments (Ioncell) spun with DRs of 3, 6, and 9 were used. In accordance with the specimens in situ, the fibers were modeled as slender solid elements, for which the ratio between the diameter and length was taken to be much less than unity and deposited inside the matrix with the random sequential adsorption algorithm. The embedded element method was thereafter used in the numerical framework due to its computational advantages and reasonable predictions for continuous fiber reinforced composites. Experiments and numerical investigations were carried out, the results of which were compared, and positive trends for both fiber VFs and DRs on the effective properties were observed. The presented experimental and numerical results and models herein are believed to advance the state of the art in the mechanical characterization of composites with continuous fiber reinforcement.