Experimental and Analytical Study on the Mechanical Behavior of Stitched Sandwich Composite Panel with a Foam Core

2008 ◽  
Vol 33-37 ◽  
pp. 477-482 ◽  
Author(s):  
Xi Tao Zheng ◽  
Jian Feng Zhang ◽  
Fan Yang ◽  
Ya Nan Chai ◽  
Ye Li
Keyword(s):  
Finite Element ◽  
Mechanical Behavior ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Foam Core ◽  
Compression Tests ◽  
Fiber Volume ◽  
Yarn Diameter

To quantify the effect of structural through-thickness reinforcement in foam core sandwich composite panels, an experimental study was carried out which included three-point bending tests, core shear tests, flatwise tensile and compression tests, as well as edgewise compression tests. Standard test procedures based on ASTM guidelines are followed to test the behavior of the stitched panels with reinforcement at 90 degree orientation with respect to the sandwich faces. The test specimens were manufactured by using polyurethane foam Rohacell 71 IG and carbon fiber reinforced composite facesheets. The dry perform facesheets and foam core were then assembled in a dry lay-up already stitched. Kevlar 29 yarn was used to stitch both sets of panels. The results showed a significant effect of the stitching on the in-plane Young’s modulus which was attributed to local displacements of the in-plane fibers and changes in the fiber volume fraction. Stitching of sandwich panels significantly increases the maximum failure loads under flexure, core shear, flatwise tensile, flatwise compression, and edgewise compression loading. A finite element based unit-cell model was developed to estimate the elastic constants of structurally stitched foam core sandwich composite panels taking into consideration the yarn diameter, the stitching pattern and direction as well as the load direction. Depending on these parameters, local changes of the fiber volume fraction as well as regions with undisturbed and disturbed fiber orientations within the laminate plies are taken into account. A good match between the finite element modeling and the experimental data was obtained. The present work should be considered as a step towards developing a more sophisticated numerical model capable of describing mechanical behavior of sandwich structures.

The Effects of Layer-by-Layer Thickness and Fiber Volume Fraction Variation on the Mechanical Performance of a Pressure Vessel

2018 ◽  
Author(s):  
Emre Özaslan ◽  
Ali Yetgin ◽  
Volkan Coşkun ◽  
Bülent Acar ◽  
Tarık Olğar
Keyword(s):  
Finite Element ◽  
Layer Thickness ◽  
Pressure Vessel ◽  
Fiber Volume Fraction ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Element Model ◽  
Layer By Layer ◽  
Fiber Volume ◽  
Filament Wound

Due to high stiffness/weight ratio, composite materials are widely used in aerospace applications such as motor case of rockets which can be regarded as a pressure vessel. The most commonly used method to manufacture the pressure vessels is the wet filament winding. However, the mechanical performance of a filament wound pressure vessel directly depends on the manufacturing process, manufacturing site environmental condition and material properties of matrix and fiber. The designed ideal pressure vessel may not be manufactured because of the mentioned issues. Therefore, manufacturing of filament wound composite structures are based on manufacturing experience and experiment. In this study, the effect of layer-by-layer thickness and fiber volume fraction variation due to manufacturing process on the mechanical performance was investigated for filament wound pressure vessel with unequal dome openings. First, the finite element model was created for designed thickness dimensions and constant material properties for all layers. Then, the model was updated. The updated finite element model considered the layer-by-layer thickness and fiber volume fraction variation. Effects of the thickness and fiber volume fraction on the stress distribution along the motor axial direction were shown. Also hydrostatic pressurization test was performed to verify finite element analysis in terms of fiber direction strain through the motor case outer surface. Important aspects of analyzing a filament wound pressure vessel were addressed for designers.

The Effects of Layer-by-Layer Thickness and Fiber Volume Fraction Variation on the Mechanical Performance of a Pressure Vessel

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Emre Özaslan ◽  
Ali Yetgin ◽  
Bülent Acar ◽  
Volkan Coşkun ◽  
Tarık Olğar
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Material Properties ◽  
Fiber Volume Fraction ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Element Model ◽  
Layer By Layer ◽  
Fiber Volume ◽  
Filament Wound

Abstract Due to high stiffness/weight ratio, composite materials are widely used in aerospace applications such as motor case of rockets which can be regarded as a pressure vessel. The most commonly used method to manufacture pressure vessels is the wet filament winding. However, the mechanical performance of a filament wound pressure vessel directly depends on the manufacturing process, manufacturing site environmental condition, and material properties of matrix and fiber. The designed pressure vessel may not be manufactured because of the mentioned issues. Therefore, manufacturing of filament wound composite structures are based on manufacturing experience and experiment. In this study, effects of layer-by-layer thickness and fiber volume fraction variation due to manufacturing process on the mechanical performance were investigated for filament wound pressure vessel with unequal dome openings. First, the finite element model was created for designed thickness dimensions and constant material properties for all layers. Then, the model was updated. The updated finite element model considered the thickness of each layer separately and variation of fiber volume fraction between the layers. Effects of the thickness and fiber volume fraction on the stress distribution along the motor axial direction were shown. Also hydrostatic pressurization tests were performed to verify finite element analysis in terms of fiber direction strain through the motor case outer surface. Important aspects of analyzing a filament wound pressure vessel were addressed for designers.

Finite Element Analysis of Interfacial Debonding Damage in Fiber-Reinforced Ceramic Matrix Composites

2007 ◽  
Vol 546-549 ◽  
pp. 1555-1558
Author(s):  
Chun Jun Liu ◽  
Yue Zhang ◽  
Da Hai Zhang ◽  
Zhong Ping Li
Keyword(s):  
Finite Element ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Interfacial Debonding ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Element Analysis

In this paper the composite fracture process has been simulated via the finite element method. A micromechanics model was developed to predict the stress-strain response of a SiO2f/ SiO2 composite explicitly accounting for the local damage mechanisms such as fiber fracture and interfacial debonding. The effects of interfacial strength and fiber volume fraction on the toughness of fiber-reinforced ceramic matrix composites were investigated. The results showed that the composite failure behaviors correlated with the interface strength, which could achieve an optimum value for the elevation of the composite toughness. The increase of fiber volume fraction can make more toughening contributions.

Parametric Generation of Random Distribution of Fibers in Long-Fiber Reinforced Composites and Micromechanical FE Analysis

2010 ◽  
Vol 452-453 ◽  
pp. 117-120
Author(s):  
Zhen Qing Wang ◽  
Xiao Qiang Wang ◽  
Ji Feng Zhang ◽  
Song Zhou
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Fiber Volume Fraction ◽  
Random Distribution ◽  
Volume Fraction ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Parametric Generation ◽  
High Fiber ◽  
Damage Initiation

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.

scholarly journals Pengaruh Penambahan Serat Batang Pisang Ketip dan Filler Dedak Padi Terhadap Density, Kekuatan Bending dan Tarik Kompositcore, Sandwich dengan Skin Plywood

MECHANICAL ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
Salman Salman ◽  
Ahmad Fadly
Keyword(s):  
Tensile Strength ◽  
Fiber Volume Fraction ◽  
Bending Strength ◽  
Volume Fraction ◽  
Sandwich Composite ◽  
Fiber Direction ◽  
Fiber Volume ◽  
Banana Fiber ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

Fiber-reinforced composite core banana stems with additional filler of husk powder is another way to obtain the expected mechanical behavior of the composite. The aim of this study was to analyze the effect of fiber volume fraction content to density, bending strength and tensile strength of sandwich composite.   Preparation of composite was done by hand lay-up method. Composite material used by banana ketip  fiber and addition of husk powder with variation of fiber volume fraction were 7, 10, and 13 % where husk was constant at 5% with random fiber direction. Tests were conducted by referring to the density est standard (ASTM C 271), bending est (ASTM C 393) and tensile test (ASTM D3039).  The result showed that the greater volume fraction of banana fiber, the lower the density value and the lower the bending strength. Whereas the tensile strength tended to increase as the volume fraction was higher.

Effect of Nanocomposite Microstructure on Stochastic Elastic Properties: An Finite Element Analysis Study

2019 ◽  
Vol 5 (3) ◽  
Author(s):  
Seyed Hamid Reza Sanei ◽  
Randall Doles ◽  
Tyler Ekaitis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Properties ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Microstructural Feature ◽  
Stochastic Response ◽  
Fiber Volume ◽  
Element Analysis ◽  
Analysis Study

This paper addresses the effect of microstructure uncertainties on elastic properties of nanocomposites using finite element analysis (FEA) simulations. Computer-simulated microstructures were generated to reflect the variability observed in nanocomposite microstructures. The effect of waviness, agglomeration, and orientation of carbon nanotubes (CNTs) were investigated. Generated microstructures were converted to image-based 2D FEA models. Two hundred different realizations of microstructures were generated for each microstructure type to capture the stochastic response. The results confirm previously reported findings and experimental results. The results show that for a given fiber volume fraction, CNTs orientation, waviness, and agglomeration result in different elastic properties. It was shown that while a given microstructural feature will improve the elastic property, it will increase the variability in the elastic properties.

Theoretical determination of the fiber volume fraction distribution for natural fiber fabric reinforced polymer composite

2017 ◽  
Vol 48 (5) ◽  
pp. 904-925
Author(s):  
Magdi El Messiry
Keyword(s):  
Polymer Composite ◽  
Fiber Volume Fraction ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Stress Transfer ◽  
Fiber Volume ◽  
Yarn Diameter ◽  
Reinforced Polymer ◽  
Spun Yarn ◽  
Fraction Distribution

The present work attempts to understand the inter-relation between the spun yarn fiber volume fraction and the fabric fiber volume fraction when adapted in the reinforced polymer composite. The yarn diameter of the natural fiber spun yarn has a great heterogeneity that affects the fiber volume fraction at the different basic units of the fabric. That in turn creates a rich fiber or rich polymer point in the final composite, resulting in the composite with varied reinforcement which has a crucial impact on the stress transfer between yarns and matrix and the composite fracture mechanism. The model was developed to express the effect of the lay out of the yarns in warp and weft directions with their real measured diameters. The fiber volume fraction of each basic weave unit was targeted to calculate the minimum, average, and maximum values of the fabric's fiber volume fraction distribution. The developed model predicts of the effect of yarn fiber volume fraction and warp and weft densities for weave fabric on its final fabric volume fraction, taking into consideration the actual variation of the yarn diameter along its length, to accomplish suitable structural performance for a composite material.

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