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Author: Christopher C. Pauly Publisher: ISBN: Category : Nature Languages : en Pages : 64
Book Description
The increasing acceptance and incorporation of fiber-reinforced polymer matrix composites (PMCs) as engineering construction materials have led many to look to the infrastructure as an application for these versatile materials. One such system is pultruded graphite fiber-reinforced epoxy (graphite/epoxy). Some PMC systems degrade when subjected to environmental conditions (e.g., moisture, stress, UV light, electrochemical polarization). These variables are typically studied either singularly or in series, but in real applications (e.g., aerospace, marine, infrastructure), these materials are subjected to many of these conditions simultaneously. To simulate field conditions, this study investigated the combined effects of an aqueous environment, electrochemical polarization, and applied bending stress on the durability of a pultruded graphite/epoxy composite. The findings indicate that graphite/epoxy composites cannot be assumed to be insensitive to degradation by environmental variables. Further, electrochemical polarization, as might occur with contact with a metal such as a fastener, can accelerate degradation. This damage requires the presence of moisture. Chloride and sulfate concentrations in rain are sufficient to establish an electrolyte within creviced regions, but deicing salts would overtake these as a contributor to conductivity. Further findings may be summarized as follows: 1.) Application of polarization in an aerated 0.6M NaCl environment led to breakdown of the fiber/matrix interface. The high pH environment created during the oxygen reduction reaction was necessary but not sufficient to create this breakdown, as the unpolarized specimen exposed to a pH 13 environment did not degrade. Cathodic polarization as would occur by coupling to steel or aluminum is required. 2.)Application of cathodic polarization did not significantly alter strength. Average measurements of shear strength, however, did decrease with the application of cathodic polarization for 70 and 90 days.
Author: Christopher C. Pauly Publisher: ISBN: Category : Nature Languages : en Pages : 64
Book Description
The increasing acceptance and incorporation of fiber-reinforced polymer matrix composites (PMCs) as engineering construction materials have led many to look to the infrastructure as an application for these versatile materials. One such system is pultruded graphite fiber-reinforced epoxy (graphite/epoxy). Some PMC systems degrade when subjected to environmental conditions (e.g., moisture, stress, UV light, electrochemical polarization). These variables are typically studied either singularly or in series, but in real applications (e.g., aerospace, marine, infrastructure), these materials are subjected to many of these conditions simultaneously. To simulate field conditions, this study investigated the combined effects of an aqueous environment, electrochemical polarization, and applied bending stress on the durability of a pultruded graphite/epoxy composite. The findings indicate that graphite/epoxy composites cannot be assumed to be insensitive to degradation by environmental variables. Further, electrochemical polarization, as might occur with contact with a metal such as a fastener, can accelerate degradation. This damage requires the presence of moisture. Chloride and sulfate concentrations in rain are sufficient to establish an electrolyte within creviced regions, but deicing salts would overtake these as a contributor to conductivity. Further findings may be summarized as follows: 1.) Application of polarization in an aerated 0.6M NaCl environment led to breakdown of the fiber/matrix interface. The high pH environment created during the oxygen reduction reaction was necessary but not sufficient to create this breakdown, as the unpolarized specimen exposed to a pH 13 environment did not degrade. Cathodic polarization as would occur by coupling to steel or aluminum is required. 2.)Application of cathodic polarization did not significantly alter strength. Average measurements of shear strength, however, did decrease with the application of cathodic polarization for 70 and 90 days.
Author: Peter Davies Publisher: Springer Science & Business Media ISBN: 9400774176 Category : Science Languages : en Pages : 264
Book Description
Composites are widely used in marine applications. There is considerable experience of glass reinforced resins in boats and ships but these are usually not highly loaded. However, for new areas such as offshore and ocean energy there is a need for highly loaded structures to survive harsh conditions for 20 years or more. High performance composites are therefore being proposed. This book provides an overview of the state of the art in predicting the long term durability of composite marine structures. The following points are covered: • Modelling water diffusion • Damage induced by water • Accelerated testing • Including durability in design • In-service experience. This is essential reading for all those involved with composites in the marine industry, from initial design and calculation through to manufacture and service exploitation. It also provides information unavailable elsewhere on the mechanisms involved in degradation and how to take account of them. Ensuring long term durability is not only necessary for safety reasons, but will also determine the economic viability of future marine structures.
Author: Rikard Benton Heslehurst Publisher: CRC Press ISBN: 146658047X Category : Technology & Engineering Languages : en Pages : 216
Book Description
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: Vistasp M. Karbhari Publisher: Elsevier ISBN: 1845693566 Category : Technology & Engineering Languages : en Pages : 381
Book Description
Given the increasing use of fibre-reinforced polymer (FRP) composites in structural civil engineering, there is a vital need for critical information related to the overall durability and performance of these new materials under harsh and changing conditions. Durability of composites for civil and structural applications provides a thorough overview of key aspects of the durability of FRP composites for designers and practising engineers.Part one discusses general aspects of composite durability. Chapters examine mechanisms of degradation such as moisture, aqueous solutions, UV radiation, temperature, fatigue and wear. Part two then discusses ways of using FRP composites, including strengthening and rehabilitating existing structures with FRP composites, and monitoring techniques such as structural health monitoring.Durability of composites for civil and structural applications provides practising engineers, decision makers and students with a useful and fundamental guide to the use of FRP composites within civil and structural engineering. - Provides a thorough overview of key aspects of the durability of composites - Examines mechanisms of degradation such as aqueous solutions, moisture, fatigue and wear - Discusses ways of using FRP composites, including strengthening and rehabilitating existing structures
Author: Geoffrey Pritchard Publisher: CRC Press ISBN: 9780849305474 Category : Technology & Engineering Languages : en Pages : 392
Book Description
Reinforced plastics are becoming widely adopted for long-term structural use-in everything from buildings and bridges to boats and swimming pools. However, the lifetimes being sought are far greater than the whole history of reinforced plastics production! Reinforced Plastics Durability explores the strength and weathering characteristics which make the material ideal for numerous applications, but also alerting the user of wear and corrosion-with studies of the processes and mechanisms which cause the deterioration. Written especially for first-time users of reinforced plastics-engineers, designers, and managers alike-Reinforced Plastics Durability offers substantial introductory information with key concepts. Subsequent chapters examine the long-term threats to the integrity of reinforced plastics: outdoor weathering, solvent/water attack, high temperatures, and repetitive stress. To maximize durability, contributors to the book report on experience with specific applications over time; the possibility of repair; and use of computer techniques to predict durability. Despite mentioning many possible threats to durability, Reinforced Plastics Durability emphasizes the fact that reinforced plastics composites have performed very well in most of the application areas. Readers will be able to take advantage of that success-and to possibly take steps toward the next phase of refinements and improvements.
Author: Christopher C. Pauly
Author: Christopher C. Pauly
Author: Christian JL.
Author: 
Author: Peter Davies
Author: Rikard Benton Heslehurst
Author: Vistasp M. Karbhari
Author: Thomas S. Gates
Author: 
Author: M. R. Louthan
Author: Geoffrey Pritchard