Search results for "Non-destructive test"
showing 10 items of 29 documents
Laser Ultrasonics Inspection for Defect Evaluation on Train Wheel
2019
Abstract Passengers’ safety and in-service life of wheelset axles play an important role in railway vehicles. For this reason, periodic inspections are necessary. Among non-destructive techniques, ultrasonic ones are widely applied in this field. The main disadvantage of conventional ultrasonic techniques is that the overall inspection of wheels requires the train to be put out-of-service and disassembly each part, which is time-consuming and expensive. In this paper, a non-conventional non-contact laser ultrasonic inspection for train wheels is proposed. The proposed method uses a laser interferometer to receive the ultrasonic wave without contact. The receiving system allows choosing the …
Evaluation of Vertical Fatigue Cracks by Means of Flying Laser Thermography
2019
The present paper proposes a new procedure to analyze the temperature field distribution during Flying Laser Spot and Laser Line Thermographic scanning (FLST, FLLT) of metallic components, in order to detect vertical surface cracks. The methodology exploits the changes in the temperature field produced by a vertical crack, acting as a barrier towards heat diffusion, when the laser approaches the defect. A number of small regions of interests (ROIs) is placed nearby and around the laser source. The average temperature from each ROI is then monitored during the laser scanning. Vertical cracks can be detected by analyzing and comparing the temperature fluctuations from each ROI when the laser …
Autonomous ultrasonic inspection using Bayesian optimisation and robust outlier analysis
2020
The use of robotics is beginning to play a key role in automating the data collection process in Non Destructive Testing (NDT). Increasing the use of automation quickly leads to the gathering of large quantities of data, which makes it inefficient, perhaps even infeasible, for a human to parse the information contained in them. This paper presents a solution to this problem by making the process of NDT data acquisition an autonomous one as opposed to an automatic one. In order to achieve this, the robotic data acquisition task is treated as an optimisation problem, where one seeks to find locations with the highest indication of damage. The resulting algorithm combines damage detection tech…
Vision guided robotic inspection for parts in manufacturing and remanufacturing industry
2020
AbstractEnvironmental and commercial drivers are leading to a circular economy, where systems and components are routinely recycled or remanufactured. Unlike traditional manufacturing, where components typically have a high degree of tolerance, components in the remanufacturing process may have seen decades of wear, resulting in a wider variation of geometries. This makes it difficult to translate existing automation techniques to perform Non-Destructive Testing (NDT) for such components autonomously. The challenge of performing automated inspections, with off-line tool-paths developed from Computer Aided Design (CAD) models, typically arises from the fact that those paths do not have the r…
Assessing the accuracy of industrial robots through metrology for the enhancement of automated non-destructive testing
2016
This work presents the study of the accuracy of an industrial robot KR5 arc HW, used to perform quality inspections of components with complex shapes. Metrology techniques such as laser tracking and large volume photogrammetry were deployed to quantify both pose and dynamic path accuracies of the robot in accordance with ISO 9283:1998. The overall positioning pose inaccuracy of the robot is found to be almost 1 mm and path inaccuracy at 100% of the robot rated velocity is 4.5 mm. The maximum pose orientation inaccuracy is found to be 14 degrees and the maximum path orientation inaccuracy is 5 degrees. Despite of the significant maximum inaccuracies, uncertainty of a robotic scanning applica…
Non-destructive automatic determination of aspect ratio and cross-sectional properties of fibres
2015
A novel method for computerised estimation of the aspect ratio distribution and various cross-sectional geometrical properties of fibres in short-fibre reinforced composites is proposed. The method, based on X-ray micro-computed tomography, is non-destructive and does not require user intervention. Based on results on specially fabricated model material, the accuracy and precision of the method seems adequate. The method is applied in analysing a manufacturing process of wood fibre reinforced thermoplastic composite. The results indicate a significant decrease of the aspect ratio of fibres during the processing steps. Finally, the feasibility of the method is assessed by estimating paramete…
Global-Local model for guided wave scattering problems with application to defect characterization in built-up composite structures
2020
Abstract Predicting scattering of elastic guided waves in multi-layered solid plates with geometrical and/or material discontinuities is of great interest to many fields, including ultrasonic-based Non-Destructive Testing (NDT) and health monitoring of critical structural components (SHM). The problem is complicated by the multimode and dispersive behaviour of the guided waves. This paper describes a unified Global-Local (GL) approach that is computationally efficient in cases that can be very complex in terms of geometry and/or material properties. One example of this is a composite built-up structure. The proposed GL procedure discretizes the “local” region with the scattering discontinui…
Joint Investigation with Ground Penetrating Radar and Infrared Thermography as a Diagnostic Support for the Restoration of Two Wall Mosaics in the Ch…
2022
The church of S. Mary of the Admiral in Palermo, known as “La Martorana” and very famous for its Byzantine mosaics, has been a World Heritage site since 2015. The mosaic system of the church includes several groups of figures and scenes from the life of the Virgin Mary. From the western part of the ancient church only two mosaics survive, detached from their original position, and are now located in two internal chapels. On the occasion of several restoration works, these two mosaic panels were investigated with non-invasive techniques, in order to provide diagnostic support to the restoration and consolidation interventions. The investigations were aimed at detecting any air po…
Robotic path planning for non-destructive testing of complex shaped surfaces
2015
The requirement to increase inspection speeds for non-destructive testing (NDT) of composite aerospace parts is common to many manufacturers. The prevalence of complex curved surfaces in the industry provides significant motivation for the use of 6 axis robots for deployment of NDT probes in these inspections. A new system for robot deployed ultrasonic inspection of composite aerospace components is presented. The key novelty of the approach is through the accommodation of flexible robotic trajectory planning, coordinated with the NDT data acquisition. Using a flexible approach in MATLAB, the authors have developed a high level custom toolbox that utilizes external control of an industrial …
Comparison between GPR measurements and ultrasonic tomography with different inversion algorithms: an application to the base of an ancient Egyptian …
2011
By late 2008 one of the most important pieces of the ‘Museo delle Antichit`a Egizie’ of Turin, the sculpture of the Pharaoh with god Amun, was planned to be one of the masterpieces of a travelling exhibition in Japan. The ‘Fondazione Museo delle Antichit`a Egizie di Torino’, who manages the museum, was concerned with the integrity of the base of the statue which actually presents visible signs of restoration dating back to the early 19th century. It was required to estimate the persistence of the visible fractures, to search for unknown ones and to provide information about the overall mechanical strength of the base. To tackle the first question a GPR reflection survey along three sides of…