Home / Journals / SDHM / Vol.5, No.3, 2009
  • Open Access

    ARTICLE

    Generalized Stress Intensity Factors for Wedge-Shaped Defect in Human Tooth after Restored with Composite Resins

    Kyousuke Yamaguchi1, Nao-Aki Noda2, Ker-Kong Chen3, Kiyoshi Tajima3, Seiji Harada1, Xin Lan1
    Structural Durability & Health Monitoring, Vol.5, No.3, pp. 191-200, 2009, DOI:10.3970/sdhm.2009.005.191
    Abstract Wedge-shaped defects are frequently observed on the cervical region of the human tooth. Previously, most studies explained that improper tooth-brushing causes such defects. However, recent clinical observation suggested that the repeated stress due to occlusal force may induce the formation of these wedge-shaped defects. In this study, a two-dimensional human tooth model after a wedge-shaped defect is restored with the composite resin is analyzed by using the finite element method. To obtain the intensity of the singular stress accurately, a method of analysis is discussed for calculating generalized stress intensity factors, which control the singular stress around the corner of… More >

  • Open Access

    ARTICLE

    Residual Strength Evaluation of Unstiffened and Stiffened Panels under Fatigue Loading

    A. Rama Chandra Murthy1, G.S. Palani1, Nagesh R. Iyer1
    Structural Durability & Health Monitoring, Vol.5, No.3, pp. 201-226, 2009, DOI:10.3970/sdhm.2009.005.201
    Abstract This paper presents methodologies for residual strength evaluation of metallic structural components under fatigue loading. Structural components include plate panels of different crack configurations with and without stiffeners. For stiffened panels, stress intensity factor (SIF) has been computed by using parametric equations based on numerically integrated modified virtual crack closure integral (NI-MVCCI) technique. As a part of residual strength evaluation, remaining life has also been predicted by using standard crack growth models. Various methodologies for residual strength evaluation, namely, plastic collapse condition, fracture toughness criterion and remaining life approach have been described. From the studies, it has been observed that… More >

  • Open Access

    ARTICLE

    Unsupervised Time-series Fatigue Damage State Estimation of Complex Structure Using Ultrasound Based Narrowband and Broadband Active Sensing

    S.Mohanty1, A. Chattopadhyay2, J. Wei3, P. Peralta4
    Structural Durability & Health Monitoring, Vol.5, No.3, pp. 227-250, 2009, DOI:10.3970/sdhm.2009.005.227
    Abstract This paper proposes unsupervised system identification based methods to estimate time-series fatigue damage states in real-time. Ultrasound broadband input is used for active damage interrogation. Novel damage index estimation techniques based on dual sensor signals are proposed. The dual sensor configuration is used to remove electrical noise, as well as to improve spatial resolution in damage state estimation. The scalar damage index at any particular damage condition is evaluated using nonparametric system identification techniques, which includes an empirical transfer function estimation approach and a correlation analysis approach. In addition, the effectiveness of two sensor configurations (configuration 1: sensors placed near… More >

  • Open Access

    ARTICLE

    Structures with Surface-Bonded PZT Piezoelectric Patches: a BEM Investigation into the Strain-transfer Mechanism for SHM applications

    I. Benedetti1, A. Milazzo1, M.H. Aliabadi2
    Structural Durability & Health Monitoring, Vol.5, No.3, pp. 251-274, 2009, DOI:10.3970/sdhm.2009.005.251
    Abstract In this work a three-dimensional BEM model is used for the analysis of structures with cracks and surface bonded piezoelectric PZT patches used as strain sensors. The cracked structure is modelled by the dual boundary element method, which allows for accurate and reliable crack analysis, while the piezoelectric patch is analyzed by a finite element state-space approach, that embodies both the full electro-mechanical coupling and the suitable sensor's boundary conditions. The model is used to investigate the strain-transfer mechanism from an host elastic structure to the piezoelectric layer, taking into account the effect of the adhesive layer, as well as… More >

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