Optimized spatial placement of structural bolts in connections for effective ultrasonic inspection

The layout of structural bolts used in infrastructures are determined based on the mechanical and design requirements. Minimum spacing is set to facilitate construction and control stress concentration, and maximum spacing is set to prevent the intrusion of water between plates and provide sufficiently equal force distribution to each bolt. Ultrasonic testing is one of the most widely used and rapid in-situ inspection methods to evaluate the status of bolted connections; however, scattering from hole boundaries may mask reflections from the cracked and corroded surfaces. In current practice, the ultrasonic-based inspectability of bolted connections for the presence of crack and corrosion as well as pretension loss is not a design criterion. In this paper, the inspectability is added as a design variable within the boundaries of design limits that control spacing as well as distribution of bolts at the connection. The ideal spatial distribution of different bolt groups is proposed to detect the critical crack length and area loss hidden between plates. The proposed bolt distribution is numerically tested to show the minimized influence of hole scatters to the ultrasonic inspectability of defects. The regression model is built to predict crack position and size.

[2]  Hwanjeong Cho,et al.  Structural health monitoring of fatigue crack growth in plate structures with ultrasonic guided waves , 2012 .

[3]  P. Fromme,et al.  Detection of cracks at rivet holes using guided waves. , 2002, Ultrasonics.

[4]  Gongkang Fu,et al.  Inspection and monitoring techniques for bridges and civil structures , 2005 .

[5]  Danilo Monarca,et al.  Ultrasonic waves for materials evaluation in fatigue, thermal and corrosion damage: A review , 2019, Mechanical Systems and Signal Processing.

[6]  D. Ozevin,et al.  Acoustoelastic Coefficients in Thick Steel Plates under Normal and Shear Stresses , 2016 .

[7]  Gangbing Song,et al.  Recent applications of fiber optic sensors to health monitoring in civil engineering , 2004 .

[8]  Adam Stawiarski,et al.  The crack detection and evaluation by elastic wave propagation in open hole structures for aerospace application , 2018, Aerospace Science and Technology.

[9]  Hamed Salem,et al.  Numerical investigation of collapse of the Minnesota I-35W bridge , 2014 .

[10]  Benjamin A. Graybeal,et al.  Visual Inspection of Highway Bridges , 2002 .

[11]  T. Arakawa,et al.  THE DETECTION OF WELD CRACKS USING ULTRASONIC TESTING , 1985 .

[12]  Claus-Peter Fritzen,et al.  Vibration-Based Structural Health Monitoring – Concepts and Applications , 2005 .

[13]  A. M. Wahl.  Finite deformations of an elastic solid: by Francis D. Murnaghan. 140 pages, 15 × 23 cm. New York, John Wiley & Sons, Inc., 1951. Price, $4.00 , 1952 .

[14]  Adam Stawiarski,et al.  Fatigue crack detection and identification by the elastic wave propagation method , 2017 .

[15]  Vistasp M. Karbhari,et al.  Structural health monitoring of civil infrastructure systems , 2009 .