Fatigue And Fracture Of Adhesively Bonded Composite Joints

It is commonly accepted that the majority of engineering failures happen due to fatigue or fracture phenomena. Adhesive bonding is a prevailing joining technique, widely used for critical connections in composite structures. However, the lack of knowledge regarding fatigue and fracture behaviour, and the shortage of tools for credible fatigue design, hinders the potential benefits of adhesively bonded joints. The demand for reliable and safe structures necessitates deep knowledge in this area in order to avoid catastrophic structural failures. This book reviews recent research in the field of fatigue and fracture of adhesively-bonded composite joints. The first part of the book discusses the experimental investigation of the reliability of adhesively-bonded composite joints, current research on understanding damage mechanisms, fatigue and fracture, durability and ageing as well as implications for design. The second part of the book covers the modelling of bond performance and failure mechanisms in different loading conditions. A detailed reference work for researchers in aerospace and engineering Expert coverage of different adhesively bonded composite joint structures An overview of joint failure

A lot of recent developments have been made about adhesively bonded joints modeling using various methods of analysis. The increasing application of adhesives in industry is partly due to the increased sophistication and reliability of adhesive joints modeling. The book proposed intends to provide the designer with the most advanced stress analyses techniques in adhesive joints to reinforce the use of this promising bonding technique.

The increased numbers of bonded composite components and bonded repairs of cracked structures make knowledge of adhesive bonding crucial to aircraft design and life extension. This report covers an effort which focused on using fracture mechanics to evaluate the Mode I fracture and fatigue properties of several adhesively bonded aerospace material systems. The research concentrated on bond line cracking rather than fatigue crack growth in composite or metal adherends. Particular attention was paid to the environmental durability of bonded systems in use or intended for use on transport, fighter, and supersonic aircraft. Analysis was performed using closed-form solutions as well as finite element analyses. Results were discussed with respect to their relevance and applicability to bonded joint design. Key results include the identification of significant degradation in some varieties of bonded joints subjected to long-term isothermal exposure under hot/wet conditions. The degradation was manifested by decreased fracture toughness and fatigue threshold levels. Finite element analyses were performed on specimens with dissimilar adherends having complex geometries and thermally induced stresses in the bond line. A case study in which finite element analyses were used to relate the experimental results from this program with those of an independent project is also included. The analyses highlight the importance of using tapered adherends to avoid fatigue failures and show that typical aircraft skin stresses are below experimentally obtained threshold values for the specimen geometries investigated. Results of this study emphasize that the environmental durability of adhesively bonded joints is a key issue which must be considered by aerospace design engineers.

"This book emphasizes the physical and practical aspects of fatigue and fracture. It covers mechanical properties of materials, differences between ductile and brittle fractures, fracture mechanics, the basics of fatigue, structural joints, high temperature failures, wear, environmentally-induced failures, and steps in the failure analysis process."--publishers website.

Adhesively-bonded joints provide many advantages over conventional mechanical fasteners and are increasingly receiving attention as an alternative to mechanical joints in engineering applications. The traditional fasteners usually result in the cutting of fibers and hence the introduction of stress concentrations, both of which reduce structural integrity. By contrast, bonded joints are more continuous and have potential advantages of strength-to-weight ratio, design flexibility, and ease of fabrication. This book provides an overview of available analytical methods as well as numerical methods.

This book explains the numerical method for fatigue life analysis of adhesive joints using the CZM technique. CZM is a robust approach that is widely used for failure analysis of adhesive joints exposed to various stress conditions including fatigue. In this book, various aspects of the numerical evaluation of adhesive bonds using CZM are discussed. First of all, it is explained how different load and environmental parameters influence the service life of adhesive connections. Various types of CZM shapes and their applications are then discussed. It was answered how different parameters of a CZM should be defined. It is also discussed which CZM form should be used for each condition. The book then describes how the CZM parameters should be degraded to simulate the cyclic loading behavior of bonded structures. Various CZM strategies for the fatigue life assessment of adhesive joints are discussed. The book presents various techniques that can be followed for the simulation of load cycles for both high-cycle and low-cycle fatigue regimes based on the concepts of the CZM. Details of numerical methods to be considered in the FE software for the fatigue life assessment of adhesives with CZM are also described in this book. Finally, some numerical examples using CZM are also provided.

Aircraft Sustainment and Repair is a one-stop-shop for practitioners and researchers in the field of aircraft sustainment, adhesively bonded aircraft joints, bonded composites repairs, and the application of cold spray to military and civil aircraft. Outlining the state-of-the-art in aircraft sustainment, this book covers the use of quantitative fractography to determine the in-service crack length versus flight hours curve, the effect of intergranular cracking on structural integrity and the structural significance of corrosion. The book additionally illustrates the potential of composite repairs and SPD applications to metallic airframes. Covers corrosion damage assessment and management in aircraft structures Includes a key chapter on U.S. developments in the emerging field of supersonic particle deposition (SPD) Shows how to design and assess the potential benefits of both bonded composite repairs and SPD repairs to metallic aircraft structures to meet the damage tolerance requirements inherent in FAA ac 20-107b and the U.S. Joint Services

The growing use of composites over metals for structural applications has made a thorough understanding of the behaviour of composite joints in various applications essential for engineers, but has also presented them with a new set of problems. Composite joints and connections addresses these differences and explores the design, modelling and testing of bonded and bolted joints and connections. Part one discusses bolted joints whilst part two examines bonded joints. Chapters review reinforcement techniques and applications for composite bolted and bonded joints and investigate the causes and effects of fatigue and stress on both types of joint in various applications and environments. Topics in part one include metal hybridization, glass-reinforced aluminium (GLARE), hybrid fibre metal laminates (FML), glass fibre reinforced polymer (GFRP) and carbon fibre reinforced polymer (CFRP) composites. Topics in part two include calculation of strain energy release rates, simulating fracture and fatigue failure using cohesive zone models, marine and aerospace applications, advanced modelling, stress analysis of bonded patches and scarf repairs. Composite joints and connections is a valuable reference for composite manufacturers and composite component fabricators, the aerospace, automotive, shipbuilding and civil engineering industries and for anyone involved in the joining and repair of composite structures. Explores the design, modelling and testing of bonded and bolted joints and connections Reviews reinforcement techniques and applications for composite bolted and bonded joints Investigates the causes and effects of fatigue and stress on bolted and bonded joints in various applications and environments

This book gathers the proceedings of the International Symposium on Plastics Technology, which was held on March 10, 2020 in Aachen, Germany, and was organised by the Institute for Plastics Processing (IKV) in Industry and Craft at RWTH Aachen University. Peer-reviewed by an international scientific committee, the conference proceedings comprise the papers presented by the international speakers. Topics covered include - circular economy- extrusion- lightweight technologies- simulation and digitisation - injection moulding- hybrid materials and additive manufacturing. In these fields, key themes for plastics technologies have been identified that will shape the face of research and industry for the next decade. In their contributions, the authors present the latest scientific findings, and discuss topical issues in plastics technologies. The symposium offered an inspiring forum for the exchange on research and innovation, for discussing urgent questions and providing impulses for the future of plastics technology.

Composite material systems are the basis for much of the natural world around us and are rapidly becoming the basis for many modern engineering components. A controlling feature for the general use of such systems is their damage tolerance, durability and reliability. The present book is a comprehensive cross section of the state of the art in the field of the durability of polymer-based, composite, and adhesive systems. As such, it is of special value to researchers concerned with the frontier of the field, to students concerned with the substance of the subject, and to the applied community concerned with the finding methodologies that make it possible to design safe and durable engineering components using material systems.

Scientific background and practical methods for modeling adhered joints Tools for analyzing stress, fracture, fatigue crack propagation, thermal, diffusion and coupled thermal-stress/diffusion-stress, as well as life prediction of joints Book includes access to downloadable macrofiles for ANSYS This text investigates the mechanics of adhesively bonded composite and metallic joints using finite element analysis, and more specifically, ANSYS, the basics of which are presented. The book provides engineers and scientists with the technical know-how to simulate a variety of adhesively bonded joints using ANSYS. It explains how to model stress, fracture, fatigue crack propagation, thermal, diffusion and coupled field analysis of the following: single lap, double lap, lap strap/cracked lap shear, butt and cantilevered beam joints. Readers receive free digital access to a variety of input and program data, which can be downloaded as macrofiles for modeling with ANSYS.

This volume documents the proceedings of the International Symposium on Adhesive Joints: Formation, Characteristics and Testing held under the auspices of the Division of Polymer Mater ials:Science and Engineering of the American Chemical Society in Kansas City, MO, September 12-17, 1982. There is a myriad of applications (ranging from aerospace to surgery) where adhesives are used to join different materials, and concomitantly the understanding of the behavior of adhesive joints becomes very important. There are many factors which can influence the behavior of adhesive joints, e.g., substrate preparation, in terfacial aspects, joint design, mode of stress, external environ ment, etc., and in order to understand the joint behavior in a holistic manner, one must take due cognizance of all these germane factors. So this symposium was planned to address not only how to make acceptable bonds but their characterization, durability and testing were also accorded due consideration.

One of the most important and exciting areas of composites research is the development of modelling techniques to predict the response of composite materials to different types of stress. Predictive modelling provides the opportunity both to understand better how composites behave in different conditions and to develop materials with enhanced performance for particular industrial applications. Multi-scale modelling of composite material systems summarises the key research in this area and its implications for industry. The book covers modelling approaches ranging from the micron to the metre in scale, and from the single fibre to complete composite structures. Individual chapters discuss a variety of material types from laminates and fibre-reinforced composites to monolithic and sandwich composites. They also analyse a range of types of stress and stress response from fracture and impact to wear and fatigue. Authors also discuss the strengths and weaknesses of particular models. With its distinguished editors and international team of contributors, Multi-scale modelling of composite material systems is a standard reference for both academics and manufacturers in such areas as aerospace, automotive and civil engineering. Extensive coverage of this important and exciting area of composites research Understand how composites behave in different circumstances Compiled by an expert panel of authors and editors