Effects of In-plane Fiber Waviness on the Static and Fatigue Strength of Fiberglass PDF Download

Author: Lei Wang
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 140

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Author: Mahmood M. Shokrieh
Publisher: Woodhead Publishing
ISBN: 0128188189
Category : Technology & Engineering
Languages : en
Pages : 504

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Book Description
The residual stress is a common phenomenon in composite materials. They can either add to or significantly reduce material strength. Because of the increasing demand for high-strength, lightweight materials such as composites and their wide range of applications; it is critical that the residual stresses of composite materials are understood and measured correctly. The first edition of this book consists of thirteen chapters divided into two parts. The first part reviews destructive and non-destructive testing (NDT) techniques for measuring residual stresses. There are also additional chapters on using mathematical (analytical and numerical) methods for the calculation of residual stresses in composite materials. These include the simulated hole drilling method, the slitting/crack compliance method, measuring residual stresses in homogeneous and composite glass materials using photoelastic techniques, and modeling residual stresses in composite materials. The second part of the book discusses measuring residual stresses in different types of composites including polymer and metal matrix composites. The addition of nanoparticles to the matrix of polymeric composites as a new technique for the reduction of residual stresses is also discussed. In the Second Edition of this book, each of the original chapters of the first edition has been fully updated, taking into account the latest research and new developments. There are also five new chapters on the theoretical and experimental studies of residual stresses in the composite integrated circuits; residual stresses in additive manufacturing of polymers and polymer matrix composites; residual stresses in metal matrix composites fabricated by additive manufacturing; the eigenstrain based method for the incremental hole-drilling technique; and the estimation of residual stresses in polymer matrix composites using the digital image correlation technique. Residual Stresses in Composite Materials, Second Edition, provides a unique and comprehensive overview of this important topic and is an invaluable reference text for both academics and professionals working in the mechanical engineering, civil engineering, aerospace, automotive, marine, and sporting industries. Presents the latest developments on theoretical and experimental studies of residual stresses in composites Reviews destructive and non-destructive testing (NDT) techniques for measuring residual stresses Discusses residual stresses in the polymer matrix, metal matrix, and ceramic matrix composites Considers the addition of nanoparticles to the matrix as a new technique for reduction of residual stresses in polymeric composites Introduces the latest advancements of research on the residual stresses in additive-manufactured polymer and metal matrix composites

Author: Sai Bhargav Pottavathri
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 86

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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.

Author: Hao-Ming Hsiao
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Michael William Lerman
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 212

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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.

Author: Rikard Benton Heslehurst
Publisher: CRC Press
ISBN: 146658047X
Category : Technology & Engineering
Languages : en
Pages : 216

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The advantages of composite materials include a high specific strength and stiffness, formability, and a comparative resistance to fatigue cracking and corrosion. However, not forsaking these advantages, composite materials are prone to a wide range of defects and damage that can significantly reduce the residual strength and stiffness of a structure or result in unfavorable load paths. Emphasizing defect identification and restitution, Defects and Damage in Composite Materials and Structures explains how defects and damage in composite materials and structures impact composite component performance. Providing ready access to an extensive, descriptive list of defects and damage types, this must-have reference: Examines defect criticality in composite structures Recommends repair actions to restore structural integrity Discusses failure modes and mechanisms of composites due to defects Reviews NDI processes for finding and identifying defects in composite materials Relating defect detection methods to defect type, the author merges his experience in the field of in-service activities for composite airframe maintenance and repair with indispensable reports and articles on defects and damage in advanced composite materials from the last 50 years.

Author: Forrest William Johnson
Publisher:
ISBN:
Category : Glass-reinforced plastics
Languages : en
Pages : 208

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Author: S. R. Reid
Publisher: Elsevier
ISBN: 1855738902
Category : Technology & Engineering
Languages : en
Pages : 318

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Book Description
This study covers impact response, damage tolerance and failure of fibre-reinforced composite materials and structures. Materials development, analysis and prediction of structural behaviour and cost-effective design all have a bearing on the impact response of composites and this book brings together for the first time the most comprehensive and up-to-date research work from leading international experts. State of the art analysis of impact response, damage tolerance and failure of FRC materials Distinguished contributors provide expert analysis of the most recent materials and structures Valuable tool for R&D engineers, materials scientists and designers

Author: Brian Esp
Publisher:
ISBN: 9780983245391
Category :
Languages : en
Pages :

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Author: Mahmood M. Shokrieh
Publisher: Woodhead Publishing
ISBN: 0857098594
Category : Technology & Engineering
Languages : en
Pages : 407

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Book Description
Residual stresses are a common phenomenon in composite materials. They can either add to or significantly reduce material strength. Because of the increasing demand for high-strength, light-weight materials such as composites and their wide range of applications in the aerospace and automotive industries, in civil infrastructure and in sporting applications, it is critical that the residual stresses of composite materials are understood and measured correctly. The first part of this important book reviews destructive and non-destructive testing (NDT) techniques for measuring residual stresses. Various mathematical (analytical and numerical) methods for calculation of residual stresses in composite materials are also presented. Chapters in the first section of the book discuss the simulated hole drilling method, the slitting/crack compliance method, measuring residual stresses in homogeneous and composite glass materials using photoelastic techniques, and modeling residual stresses in composite materials. The second part of the book discusses residual stresses in polymer matrix, metal-matrix and a range of other types of composites. Moreover, the addition of nanoparticles to the matrix of polymeric composites as a new technique for reduction of residual stresses is discussed. Residual stresses in composite materials provides a comprehensive overview of this important topic, and is an invaluable reference text for both academics and professionals working in the mechanical engineering, civil engineering, aerospace, automotive, marine and sporting industries. Reviews destructive and non-destructive testing (NDT) techniques for measuring residual stresses Discusses residual stresses in polymer matrix, metal-matrix and other types of composite Considers the addition of nanoparticles to the matrix of polymeric composites as a new technique for reduction of residual stresses