The need for high speed and cost efficient inspection in manufacturing lineshas led to a vast usage of camera-based vision systems The performance ofthese systems is sufficient to determine shape 

Enhanced image analysis, a tool for precision metrology in the micro and macro world

Ultrasonic time-of-flight diffraction (TOFD) is a non-destructive testing (NDT) technique for weld inspection that has gained popularity in the industry, due to its ability to detect, position, and size defects based on the time difference of the echo signal. Although the TOFD technique provides high-speed data, ultrasonic data interpretation is typically a manual and time-consuming process, thereby necessitating a trained expert. The main aim of this work is to develop a fully automated defect detection and data interpretation approach that enables predictive maintenance using signal and image processing. Through this research, the characterization of weld defects was achieved by identifying the region of interest from A-scan signals, followed by segmentation. The experimental results were compared with samples of known defect size for validation; it was found that this novel method is capable of automatically measuring the defect size with considerable accuracy. It is anticipated that using such a system will significantly increase inspection speed, cost, and safety.

https://www.mdpi.com/2075-1702/10/10/839/pdf?version=1666750560

Zero-Defect Manufacturing and Automated Defect Detection Using Time of Flight Diffraction (TOFD) Images

Based on the design concept of earthquake-resilient structure, a new-type of box-shaped steel piers with embedded energy-dissipating steel plates was proposed. Quasi-static tests of 6 box-shaped steel pier specimens under variable axial pressure and cyclic horizontal loading were carried out. By analyzing the failure mode, load-displacement hysteretic curve, skeleton curve, displacement ductility coefficient, stiffness degradation characteristics, strength degradation coefficient, and cumulative hysteretic energy, the effects of setting energy-dissipating steel plate, axial compression ratio, and thickness of energy dissipation steel plates on the seismic performance of new-type steel piers were discussed. Finite element models of steel bridge piers were established and compared with the test results. The analysis results using FEM agree well with the test results. Results show that the setting of energy-dissipating steel plates can effectively improve the ductility, deformation capacity, and energy-dissipating capacity of box-shaped steel piers, and effectively delay buckling deformation and cracking of wall plates. The steel plate near the bolt hole of the wall plate at the root of the new-type of box-shaped steel piers is easy to crack due to stress concentration, resulting in a rapid reduction of the maximum bearing capacity of the specimens. With the increase of axial compression ratio, the bearing capacity, energy-dissipating capacity, and earthquake-resilient capacity of the specimens increase. The smaller the thickness of the replaceable energy-dissipating steel plates, the smaller the bearing capacity and faster the stiffness degradation of the specimens become, while the ductility and energy-dissipating capacity of the specimens are improved. The axial compression ratio and the thickness of the energy-dissipating steel plate have relatively little effect on the strength degradation of the specimens. In order to facilitate the popularization and application of the new-type steel piers, formulas were also established to calculate the bearing capacity and displacement ductility factor of the new-type of box-shaped steel piers.

/pdf/seismic-behavior-of-box-steel-bridge-pier-with-built-in-14k22tb3.pdf

Seismic Behavior of Box Steel Bridge Pier with Built-In Energy Dissipation Steel Plates

A dual element time-of-flight diffraction (TOFD) transducer assembly (10) for use in detecting an anomaly (78) in a test piece (70), the transducer assembly (10) comprising: a first transducer element (35) a configured to transmit ultrasonic signals (85a) to the test piece (70), and a second transducer element (35b) configured to receive diffracted ultrasonic signals (85b) from the test piece, wherein the first and second transducer elements (35a, 35b) are housed within a common housing (15), the housing (15) also forming part of the transducer assembly (10).

A transducer assembly

To get more precise defect depth in parallel scanning of ultrasonic time-of-flight diffraction (TOFD) technique, a method for automatically measuring defect depth using defect image data is proposed in this paper. The method extracts defect image data from B-scan image through a series of image processing to fit a parabolic curve. Defect depth will be easily obtained by combining the quadratic coefficient of fitted parabolic curve with that of formula based on the principle of ultrasonic TOFD parallel scanning. Experiment result shows that the defect depth measuring error is less than 0.5 mm with this method and demonstrates strong practicability, high degree of automation and high measurement precision of the proposed method, reducing ultrasonic testing workload of the operator.

Defect depth automation measurement based on image processing for tofd parallel scanning

Curved multi-frame box-girder bridges with hinges are widely used in the United States due to the large spanning capacity, construction simplification and construction cost economy. This type of bridge frequently has the characteristics of column height asymmetry, adjacent bridge frames vibrating discrepancy. The combination of curved shape and random seismic excitation angles could aggravate the irregularity of the structural seismic response. In this study, an OpenSees model is established for an example bridge, and the hinge is taken as a key component to observe. The impacts of seismic excitation angles and column height layouts on fragility are investigated through the comparison of the fragility curves. The conclusions list the most unfavorable seismic excitation angles corresponding to the fragilities of bridge system, plug-type concrete elements in hinges, hinge restrainers, columns, abutment bearings as well as the secondary components, respectively. The symmetrical column height layout is proved to be beneficial to mitigate the damage risks of restrainers in intermediate hinges and reduce the fragility of the bridge system. This study can provide a reference for the rapid assessment of the fragile position and damage degree of bridges through structural configuration and shape, as well as the seismic excitation angle.

/pdf/seismic-fragility-of-a-multi-frame-box-girder-bridge-39iwmfmn.pdf

Shengchun Liu

Papers

Defect depth automation measurement based on image processing for tofd parallel scanning

Seismic Fragility of a Multi-Frame Box-Girder Bridge Influenced by Seismic Excitation Angles and Column Height Layouts