نتایج جستجو برای: crack detection

تعداد نتایج: 589151  

2012
Zeng Jiexian Fu Xiang

In order to overcome the high computational complexity of beamlet tree-structure algorithm, the paper proposes an improved algorithm and applies it to pavement crack detection, thereby; solving the problem of pavement crack detection which has the disadvantages of poor noise immunity and inaccurate test results. First, the pavement crack image is rectified by multiplicative factors to eliminate...

2010
H Huang

Fatigue cracking is one of the most common failure modes of various load-bearing structures. Even though sensors of many different types have been developed for crack detection, very few can monitor crack growth with a high sensitivity. This paper presents an antenna sensor that is capable of monitoring the growth of fatigue cracks with a sub-millimeter resolution. According to microstrip patch...

Journal: :Infectious Diseases in Obstetrics and Gynecology 2008
Howard Minkoff Ye Zhong Howard D. Strickler D. Heather Watts Joel M. Palefsky Alexandra M. Levine Gypsyamber D'Souza Andrea A. Howard Michael Plankey L. Stewart Massad Robert Burk

OBJECTIVE Animal data suggest that cocaine has an immunosuppressive effect, but no human studies have been conducted to assess the relation of cocaine use with human papillomavirus (HPV) infection, the viral cause of cervical cancer. Since both cocaine use and HPV infection are common among HIV-positive women, we sought to determine whether use of cocaine and/or crack influences the natural his...

2007
Salil S. Kulkarni Jan D. Achenbach

Inspections play an essential role in the damage tolerance approach to control fatigue damage. In this paper a method is presented to optimize the cost-effectiveness of inspection scheduling for single and multiple inspections during the expected lifetime. Detailed results are given for a surface-breaking crack of depth a in a cyclic tension field. The original crack depth is treated as a rando...

2017
Bo Jin Weifang Zhang Meng Zhang Feifei Ren Wei Dai Yanrong Wang

In order to monitor the crack tip propagation of aluminum alloy, this study investigates the variation of the spectrum characteristics of a fiber Bragg grating (FBG), combined with an analysis of the spectrum simulation. The results identify the location of the subordinate peak as significantly associated with the strain distribution along the grating, corresponding to the different plastic zon...

Solar cell is known as a sustainable and environment friendly source of energy in nature. It converts sunlight directly into electricity with zero emission and also without side-effects on the environment. But, solar cells have optical and mechanical defects which include the type of micro crack, the size of crack, and the noise from electrical or electromechanical interference during the image...

2008
L. Doudet

Thermal fatigue in the mixing zones of pressurized water reactor pipings can potentially lead to the appearance of crack networks. Ultrasonic detection and characterization of a propagated defect in such a network is then a challenge. To study the influence of these secondary crack networks on the ultrasonic inspection of a propagated defect, a mock-up was produced. The innovative manufacturing...

2010
Shankar Sankararaman You Ling Sankaran Mahadevan

This paper presents a methodology for assessing the confidence and the predictive capability of prognosis models, using the application of fatigue crack growth analysis. Structures with complicated geometry and multi-axial variable amplitude loading conditions are considered. Several models – finite element model, crack growth model, retardation model, surrogate model, etc. – are efficiently co...

2003
D. L. Chopp N. Sukumar

A numerical technique for modeling fatigue crack propagation of multiple coplanar cracks is presented. The proposed method couples the extended finite element method (X-FEM) [Int. J. Numer. Meth. Engng. 48 (11) (2000) 1549] to the fast marching method (FMM) [Level Set Methods & Fast Marching Methods: Evolving Interfaces in Computational Geometry, Fluid Mechanics, Computer Vision, and Materials ...

2015
Yao Yao Branko Glisic

Reliable early-stage damage detection requires continuous monitoring over large areas of structure, and with sensors of high spatial resolution. Technologies based on Large Area Electronics (LAE) can enable direct sensing and can be scaled to the level required for Structural Health Monitoring (SHM) of civil structures and infrastructure. Sensing sheets based on LAE contain dense arrangements o...

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