Author: Sai Bhargav Pottavathri
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 86
Book Description
The purpose of this study was to investigate the strength and effectiveness of certain composite materials when induced by 'in-plane fiber tow waviness' in a composite ply. Fiber waviness is usually induced by infusion processes and inherent in fabric architectures. Composite structural details like ply drops and ply joints can cause serious fiber misalignment. These are usually dependent on parameters such as ply thickness, percentage of plies dropped, and location of ply drop, the gap between the plies, mold geometry and pressure, and pressure of the resin which slides the dry fibers during the resin transfer molding process. Fiber disorientation due to fiber tow waviness in „in-plane‟ direction has been the subject of recent studies on wind turbine blade materials and other aerospace laminates with reports of compression strengths and failure strains that are borderline, depending upon the reinforcement architecture, matrix resin and environment. Waviness is expected to reduce compressive strength due to two primary factors. The fibers may be oriented in such a way that the geometry that results because of the orientation may exacerbate the basic fiber, strand, or layer buckling mode of failure. The waviness could also shift the fiber orientation of the axis of the ply longitudinal direction which eventually results in matrix dominated failures for plies normally orientated in the primary load direction (00). The longitudinal tension and compression behavior of unidirectional carbon fiber composite laminates of different materials (different grades of carbon, glass and Kevlar with different resins) were investigated using finite element analysis tool ABAQUS. Both global and local stress & strain values generated by the finite element model were validated by the traditional mechanical methods using ply/local stiffness matrix and global/reduced stiffness matrix. A precise geometry of waviness on different materials was modeled with different wave severity factor and a parametric study was conducted. Three different defects were modeled where the angle of misalignment ranged from 5 to 15 degrees with a wavelength ranged from 1 inch to 1.5 inches and amplitude which ranged from 0.05 inches to 0.1 inches. This revealed the effect of 'in-plane fiber tow waviness' on the stress distribution and loss of strength in carbon-reinforced composite materials. The results clearly show that the effect of 'in-plane fiber tow waviness' leads to resin rich areas which causes high stress concentrations and decrease in the strength ratio, leading to delamination's.
Effect of In-plane Fiber Tow Waviness in the Strength Characteristics of Different Fiber Reinforced Composites
Author: Sai Bhargav Pottavathri
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 86
Book Description
The purpose of this study was to investigate the strength and effectiveness of certain composite materials when induced by 'in-plane fiber tow waviness' in a composite ply. Fiber waviness is usually induced by infusion processes and inherent in fabric architectures. Composite structural details like ply drops and ply joints can cause serious fiber misalignment. These are usually dependent on parameters such as ply thickness, percentage of plies dropped, and location of ply drop, the gap between the plies, mold geometry and pressure, and pressure of the resin which slides the dry fibers during the resin transfer molding process. Fiber disorientation due to fiber tow waviness in „in-plane‟ direction has been the subject of recent studies on wind turbine blade materials and other aerospace laminates with reports of compression strengths and failure strains that are borderline, depending upon the reinforcement architecture, matrix resin and environment. Waviness is expected to reduce compressive strength due to two primary factors. The fibers may be oriented in such a way that the geometry that results because of the orientation may exacerbate the basic fiber, strand, or layer buckling mode of failure. The waviness could also shift the fiber orientation of the axis of the ply longitudinal direction which eventually results in matrix dominated failures for plies normally orientated in the primary load direction (00). The longitudinal tension and compression behavior of unidirectional carbon fiber composite laminates of different materials (different grades of carbon, glass and Kevlar with different resins) were investigated using finite element analysis tool ABAQUS. Both global and local stress & strain values generated by the finite element model were validated by the traditional mechanical methods using ply/local stiffness matrix and global/reduced stiffness matrix. A precise geometry of waviness on different materials was modeled with different wave severity factor and a parametric study was conducted. Three different defects were modeled where the angle of misalignment ranged from 5 to 15 degrees with a wavelength ranged from 1 inch to 1.5 inches and amplitude which ranged from 0.05 inches to 0.1 inches. This revealed the effect of 'in-plane fiber tow waviness' on the stress distribution and loss of strength in carbon-reinforced composite materials. The results clearly show that the effect of 'in-plane fiber tow waviness' leads to resin rich areas which causes high stress concentrations and decrease in the strength ratio, leading to delamination's.
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 86
Book Description
The purpose of this study was to investigate the strength and effectiveness of certain composite materials when induced by 'in-plane fiber tow waviness' in a composite ply. Fiber waviness is usually induced by infusion processes and inherent in fabric architectures. Composite structural details like ply drops and ply joints can cause serious fiber misalignment. These are usually dependent on parameters such as ply thickness, percentage of plies dropped, and location of ply drop, the gap between the plies, mold geometry and pressure, and pressure of the resin which slides the dry fibers during the resin transfer molding process. Fiber disorientation due to fiber tow waviness in „in-plane‟ direction has been the subject of recent studies on wind turbine blade materials and other aerospace laminates with reports of compression strengths and failure strains that are borderline, depending upon the reinforcement architecture, matrix resin and environment. Waviness is expected to reduce compressive strength due to two primary factors. The fibers may be oriented in such a way that the geometry that results because of the orientation may exacerbate the basic fiber, strand, or layer buckling mode of failure. The waviness could also shift the fiber orientation of the axis of the ply longitudinal direction which eventually results in matrix dominated failures for plies normally orientated in the primary load direction (00). The longitudinal tension and compression behavior of unidirectional carbon fiber composite laminates of different materials (different grades of carbon, glass and Kevlar with different resins) were investigated using finite element analysis tool ABAQUS. Both global and local stress & strain values generated by the finite element model were validated by the traditional mechanical methods using ply/local stiffness matrix and global/reduced stiffness matrix. A precise geometry of waviness on different materials was modeled with different wave severity factor and a parametric study was conducted. Three different defects were modeled where the angle of misalignment ranged from 5 to 15 degrees with a wavelength ranged from 1 inch to 1.5 inches and amplitude which ranged from 0.05 inches to 0.1 inches. This revealed the effect of 'in-plane fiber tow waviness' on the stress distribution and loss of strength in carbon-reinforced composite materials. The results clearly show that the effect of 'in-plane fiber tow waviness' leads to resin rich areas which causes high stress concentrations and decrease in the strength ratio, leading to delamination's.
Effects of In-plane Fiber Waviness on the Static and Fatigue Strength of Fiberglass
Author: Lei Wang
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 140
Book Description
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 140
Book Description
Photochemical Behavior of Multicomponent Polymeric-based Materials
Author: Dan Rosu
Publisher: Springer
ISBN: 3319251961
Category : Technology & Engineering
Languages : en
Pages : 408
Book Description
This book offers in-depth insights into the photochemical behavior of multicomponent polymeric-based materials, with a particular emphasis on the photodegradation and photostabilization of these materials. Studying various classes of materials bases such as polysaccharides, wood, synthetic polymers, rubber blends, and nanocomposites, it offers a valuable reference source for graduate and postgraduate students, engineering students, research scholars and polymer engineers working in industry.
Publisher: Springer
ISBN: 3319251961
Category : Technology & Engineering
Languages : en
Pages : 408
Book Description
This book offers in-depth insights into the photochemical behavior of multicomponent polymeric-based materials, with a particular emphasis on the photodegradation and photostabilization of these materials. Studying various classes of materials bases such as polysaccharides, wood, synthetic polymers, rubber blends, and nanocomposites, it offers a valuable reference source for graduate and postgraduate students, engineering students, research scholars and polymer engineers working in industry.
Compression Strength Reduction in Composites with In-Plane Fiber Waviness
Author: PJ. Joyce
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 21
Book Description
The effect of fiber waviness, which develops during the processing and manufacture of fiber-reinforced composite structures, on compressive failure was investigated. Analytical and experimental evidence has shown that out-of-plane waviness (also referred to as layer or ply waviness) is a major contributing factor in compressive strength reduction; however, there is a paucity of data concerning the effects of in-plane waviness or wrinkling on the compressive response of composites. In this paper, we present data from a series of compression tests examining the effects of varying levels of in-plane fiber waviness. These tests used a novel combined shear/end loading compression test fixture (WTF combined loading compression test fixture) in order to ameliorate problems typically associated with pure end-loading (brooming and end-damage) and pure shear loading (tab debonding and high stress concentrations due to discontinuity stresses). The fixture performed adequately when testing wavy specimens, but we experienced repeated tab failures in the non-wavy specimens. The compression test results exhibit a distinct linear trend of decreasing compressive strength with increasing waviness severity as represented by the maximum off-axis angle of the wavy fibers. Optical microscopy revealed that kink bands, leading to catastrophic failure, initiate at the most severe fiber misorientation sites in the wavy regions.
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 21
Book Description
The effect of fiber waviness, which develops during the processing and manufacture of fiber-reinforced composite structures, on compressive failure was investigated. Analytical and experimental evidence has shown that out-of-plane waviness (also referred to as layer or ply waviness) is a major contributing factor in compressive strength reduction; however, there is a paucity of data concerning the effects of in-plane waviness or wrinkling on the compressive response of composites. In this paper, we present data from a series of compression tests examining the effects of varying levels of in-plane fiber waviness. These tests used a novel combined shear/end loading compression test fixture (WTF combined loading compression test fixture) in order to ameliorate problems typically associated with pure end-loading (brooming and end-damage) and pure shear loading (tab debonding and high stress concentrations due to discontinuity stresses). The fixture performed adequately when testing wavy specimens, but we experienced repeated tab failures in the non-wavy specimens. The compression test results exhibit a distinct linear trend of decreasing compressive strength with increasing waviness severity as represented by the maximum off-axis angle of the wavy fibers. Optical microscopy revealed that kink bands, leading to catastrophic failure, initiate at the most severe fiber misorientation sites in the wavy regions.
Modeling of the Impact Response of Fibre-Reinforced Composites
Author: Eng Sci Dept/U
Publisher: CRC Press
ISBN: 9780877628200
Category : Technology & Engineering
Languages : en
Pages : 142
Book Description
This book summarises the development of experimental techniques for determining the impact mechanical properties of fibre reinforced epoxy laminates, and the experimental results obtained for the tensile, compressive and interlaminar shear properties of various epoxy laminates.
Publisher: CRC Press
ISBN: 9780877628200
Category : Technology & Engineering
Languages : en
Pages : 142
Book Description
This book summarises the development of experimental techniques for determining the impact mechanical properties of fibre reinforced epoxy laminates, and the experimental results obtained for the tensile, compressive and interlaminar shear properties of various epoxy laminates.
Effect of Fiber Waviness on Tensile Properties of Sliver-Based Natural Fiber Composites
Author: Taweesak Piyatuchsananon
Publisher:
ISBN:
Category : Technology
Languages : en
Pages :
Book Description
Glass and carbon fiber-reinforced composite materials have been applied for the high demand in industrial use to date, because their advantages are light weight, high strength, and corrosion resistance. However, the disposal problem after the use of these materials has also surfaced as a serious environmental problem. As a measure to solve this problem, many researchers have tried to investigate the potential of plant-based natural fibers instead of artificial fibers. When we use natural fibers as a long fiber-reinforcement, the negative point is irregular fiber waviness inherent in a sliver form. This is because such fiber waviness often decreases the mechanical properties. The purpose of this study is thus to clarify the relation between irregular fiber waviness and the composite's tensile strength. The clarification was performed from two points of view: One is quantification of irregular fiber waviness, based on spatial analysis such as Local Moran's I and Geary's c. Result shows that quantified parameters were correlated well with tensile strengths of sliver-based natural fiber composites. Another is a 3-D finite element analysis in which the fiber waviness was treated as an orthotropic body. Finally, the relation of the tensile strengths with maximum stress and Tsai-Hill criterions was discussed.
Publisher:
ISBN:
Category : Technology
Languages : en
Pages :
Book Description
Glass and carbon fiber-reinforced composite materials have been applied for the high demand in industrial use to date, because their advantages are light weight, high strength, and corrosion resistance. However, the disposal problem after the use of these materials has also surfaced as a serious environmental problem. As a measure to solve this problem, many researchers have tried to investigate the potential of plant-based natural fibers instead of artificial fibers. When we use natural fibers as a long fiber-reinforcement, the negative point is irregular fiber waviness inherent in a sliver form. This is because such fiber waviness often decreases the mechanical properties. The purpose of this study is thus to clarify the relation between irregular fiber waviness and the composite's tensile strength. The clarification was performed from two points of view: One is quantification of irregular fiber waviness, based on spatial analysis such as Local Moran's I and Geary's c. Result shows that quantified parameters were correlated well with tensile strengths of sliver-based natural fiber composites. Another is a 3-D finite element analysis in which the fiber waviness was treated as an orthotropic body. Finally, the relation of the tensile strengths with maximum stress and Tsai-Hill criterions was discussed.
Applied Mechanics Reviews
Modeling of the Impact Response of Fibre-Reinforced Composites
Author: Eng Sci Dept/U
Publisher: CRC Press
ISBN: 1000117308
Category : Technology & Engineering
Languages : en
Pages : 139
Book Description
This book summarises the development of experimental techniques for determining the impact mechanical properties of fibre reinforced epoxy laminates, and the experimental results obtained for the tensile, compressive and interlaminar shear properties of various epoxy laminates.
Publisher: CRC Press
ISBN: 1000117308
Category : Technology & Engineering
Languages : en
Pages : 139
Book Description
This book summarises the development of experimental techniques for determining the impact mechanical properties of fibre reinforced epoxy laminates, and the experimental results obtained for the tensile, compressive and interlaminar shear properties of various epoxy laminates.
Investigation of the Effect of In-plane Fiber Waviness in Composite Materials Through Multiple Scales of Testing and Finite Element Modeling
Author: Michael William Lerman
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 212
Book Description
Defects in materials can reduce strengths and lifetimes of manufactured parts. The number of possible defects increase with the complexity inherent in composite materials. The wind industry uses composite wind turbine blades in which the manufacturing process induces a number of defects. In order for the wind industry to continue sustainable expansion, the effects of defects must be better understood. In-plane (IP) fiber waviness is the focus of this work. The three main parts of this work include testing on the coupon level, modeling on the coupon level, and testing of beams in four-point bending (with and without defects). The coupon level testing includes partial IP waves, similar to those in manufactured parts, rather than full width IP waves. This allows investigation into complex interactions and varying failure mechanisms caused by the fiber misalignment gradient. Partial waves are also modeled to both validate testing as well as to increase robustness of a previously developed progressive damage modeling method. Lastly, a sandwich beam test specimen for testing in 4-point bending is developed to investigate the effects of fiber waviness in both tension and compression when loaded in flexure.
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 212
Book Description
Defects in materials can reduce strengths and lifetimes of manufactured parts. The number of possible defects increase with the complexity inherent in composite materials. The wind industry uses composite wind turbine blades in which the manufacturing process induces a number of defects. In order for the wind industry to continue sustainable expansion, the effects of defects must be better understood. In-plane (IP) fiber waviness is the focus of this work. The three main parts of this work include testing on the coupon level, modeling on the coupon level, and testing of beams in four-point bending (with and without defects). The coupon level testing includes partial IP waves, similar to those in manufactured parts, rather than full width IP waves. This allows investigation into complex interactions and varying failure mechanisms caused by the fiber misalignment gradient. Partial waves are also modeled to both validate testing as well as to increase robustness of a previously developed progressive damage modeling method. Lastly, a sandwich beam test specimen for testing in 4-point bending is developed to investigate the effects of fiber waviness in both tension and compression when loaded in flexure.
Modeling of the Impact Response of Fibre-Reinforced Composites
Author: Eng Sci Dept/U
Publisher: CRC Press
ISBN: 1000160173
Category : Technology & Engineering
Languages : en
Pages : 140
Book Description
This book summarises the development of experimental techniques for determining the impact mechanical properties of fibre reinforced epoxy laminates, and the experimental results obtained for the tensile, compressive and interlaminar shear properties of various epoxy laminates.
Publisher: CRC Press
ISBN: 1000160173
Category : Technology & Engineering
Languages : en
Pages : 140
Book Description
This book summarises the development of experimental techniques for determining the impact mechanical properties of fibre reinforced epoxy laminates, and the experimental results obtained for the tensile, compressive and interlaminar shear properties of various epoxy laminates.