The Experts below are selected from a list of 849 Experts worldwide ranked by ideXlab platform

Chun Hui Wang - One of the best experts on this subject based on the ideXlab platform.

  • Theory of Bonded Doublers and Bonded Joints
    Composite Repair, 2007
    Co-Authors: Cong N. Duong, Chun Hui Wang
    Abstract:

    This chapter presents various analytical models for determining stresses in Bonded joints and Doublers that are relevant to the repair geometries. Since a Bonded Doubler or joint represents a multiplayer structure involving two substrates and a thin adhesive layer, the stress states that exist at various levels in a Bonded Doubler or joint are very complex. This chapter presents theories that provide the same level of fidelity in the models for Bonded joints. These theories are applied to Doubler and joint configurations that are representative of a Bonded repair. They also include an elastic-plastic representation for the adhesive. The chapter presents all the analyses that are conducted for plane strain condition. The presented analytical models account for various important effects such as elastic-plastic adhesive, geometrically nonlinear deformation, triaxial stresses on plastic yielding, adherend stress concentration, and corner singularity at the termini of the adhesive layer.

Steven G. Russell - One of the best experts on this subject based on the ideXlab platform.

  • Nomenclature
    2016
    Co-Authors: Steven G. Russell
    Abstract:

    This paper presents a finite difference solution method that can be applied to calculation of shear and peel stresses in a general class of Bonded composite structural details. The method can be implemented with minimal computing capability, and it accurately calculates shear and peel stress gradients that contribute to out-of-plane failure modes observed in composite structures. Example analyses for a composite single-lap Bonded joint and a composite Bonded Doubler are provided to illustrate the application of the method

  • Finite Difference Calculation of Shear and Peel Stresses in Bonded Composite Structural Details
    50th AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference, 2009
    Co-Authors: Steven G. Russell
    Abstract:

    This paper presents a finite difference solution method that can be applied to calculation of shear and peel stresses in a general class of Bonded composite structural details. The method can be implemented with minimal computing capability, and it accurately calculates shear and peel stress gradients that contribute to out-of-plane failure modes observed in composite structures. Example analyses for a composite single-lap Bonded joint and a composite Bonded Doubler are provided to illustrate the application of the method.

W.z.l. Zhuang - One of the best experts on this subject based on the ideXlab platform.

  • Holographic measurement of the relative out-of-plane surface displacement in an adhesively Bonded Doubler
    Journal of Adhesion Science and Technology, 1997
    Co-Authors: L. Tong, W.z.l. Zhuang
    Abstract:

    It is relatively easy to demonstrate analytically the high gradient of peel stresses in an adhesive layer near the overlap ends of an adhesively Bonded lap joint. However, experimental validation of such a high peel stress gradient becomes quite difficult. One of the experimental methods is to measure the relative normal displacement between the two adherends Bonded together by an adhesive layer and then to calculate the stresses in the adhesive layer. In this study, a simple Doubler specimen was used to obtain an accurate measurement of the relative out-of-plane surface displacement using a holographic interferometry technique. Unlike a full Doubler specimen, the global rotation that occurred in the overlap was removed and the effects of the end misalignment were therefore reduced. It is shown that there is a good correlation between the relative out-of-plane surface displacement measured and that predicted using finite element analysis of the misaligned specimens.

Cong N. Duong - One of the best experts on this subject based on the ideXlab platform.

  • Theory of Bonded Doublers and Bonded Joints
    Composite Repair, 2007
    Co-Authors: Cong N. Duong, Chun Hui Wang
    Abstract:

    This chapter presents various analytical models for determining stresses in Bonded joints and Doublers that are relevant to the repair geometries. Since a Bonded Doubler or joint represents a multiplayer structure involving two substrates and a thin adhesive layer, the stress states that exist at various levels in a Bonded Doubler or joint are very complex. This chapter presents theories that provide the same level of fidelity in the models for Bonded joints. These theories are applied to Doubler and joint configurations that are representative of a Bonded repair. They also include an elastic-plastic representation for the adhesive. The chapter presents all the analyses that are conducted for plane strain condition. The presented analytical models account for various important effects such as elastic-plastic adhesive, geometrically nonlinear deformation, triaxial stresses on plastic yielding, adherend stress concentration, and corner singularity at the termini of the adhesive layer.

Blake, Steven Paul Lewis - One of the best experts on this subject based on the ideXlab platform.

  • Crack Propagation in Secondary Bonded FRP Composite Joints
    DigitalCommons@UMaine, 2010
    Co-Authors: Blake, Steven Paul Lewis
    Abstract:

    Structural composite materials are commonly used in large scale marine construction. Composite materials offer significant material advantages over more traditional materials such as steel; however, the design and production of high strength structural joints in composite structures is particularly difficult. Due to various limitations, many joints must be fabricated using secondary bonds, where additional material is cured onto an existing laminate. Secondary bonds result in planes of weakness, and as a result, composite structures commonly fail at secondary Bonded joints due to crack propagation at the bond line of the joint. Two types of joints are examined in this thesis, the Doubler plate joint and the tee joint. The fatigue performance is investigated for the double joint, and the static fracture response is investigated for the tee joint. The crack propagation response of secondary Bonded Doubler plate joints in fiber-reinforced polymer (FRP) composite panels was investigated due to variable amplitude fatigue produced by vessel design spectra loads. The Doubler plate joints were analyzed with respect to lifespan and failure criteria typically used for marine composites. The goal of the study is to characterize crack propagation in secondary Bonded Doubler plate joints under variable amplitude fatigue produced by design spectra loads for seaframes. The main contribution of the study to the marine industry is to improve current design methods for Doubler plate joints in vessels under service conditions. Furthermore, the study serves to gain a better understanding of fatigue life prediction in secondary Bonded joints for marine composites. Results have yielded insight into how crack propagation in secondary Bonded Doubler plate joints progresses under service conditions. A typical marine composite tee joint is investigated for fracture toughness. A 2D plane strain finite element model is used to predict failure using the virtual crack closure technique and fracture coupon data from a previous study. The numerical results of the model are considered with respect to the highly variable nature of the fracture toughness of woven fabric composite. Additionally, a detailed sensitivity study is conducted to determine the effect of nine geometric and material parameters on the strain energy release rate (SERR) and mixity of an assumed disbond at two likely crack locations. An innovative test method is used, such that the SERR and mixity can be set to the desired level by changing geometric parameters. The validity of the model is evaluated for deflections, strains, and SERR at failure. Additionally, the behavior of composite materials fabricated using woven fabrics are characterized for fracture toughness. Crack propagation behavior in woven fabric composites is investigated with respect to the periodic pattern produced as a result of the weave. Additionally, experimental methods for determining fracture toughness are investigated for woven fabric composites and a numerical technique to predict the location of crack onset is proposed. The ability to determine crack onset in any fracture test is critical to obtaining consistent and accurate results. Modifications to fracture toughness test methods are discussed. A case study encompassing is presented for a typical marine-grade E-glass fiber reinforced composite with a toughened vinyl ester resin matrix