Application of shearography with thermal loading for structural inspection of Rembrandt’s Night Watch

The assessment of the structural condition of cultural heritage objects is important for conservation interventions and their long-term preservation. This investigation concerns The Night Watch (1642), a large-format 17^th-century canvas painting by Rembrandt van Rijn that is on display in the Rijksmuseum, Amsterdam. This painting,...

Shearography non-destructive testing of a composite ship hull section subjected to multiple impacts

The use of thick composites and sandwich structures is increasing rapidly in marine, aerospace, and wind energy industries [1–3]. For example in the marine sector, sandwich structures consisting of glassfiber laminate skins bonded to a foam core are attractive because of the advantages of being light-weight, resistant to corrosion and underwater...

Review of image segmentation techniques for layup defect detection in the Automated Fiber Placement process: A comprehensive study to improve AFP inspection

The aerospace industry has established the Automated Fiber Placement process as a common technique for manufacturing fibre reinforced components. In this process multiple composite tows are placed simultaneously onto a tool. Currently in such processes manual testing requires often up to 50% of the manufacturing duration. Moreover, the...

Synthetic image data augmentation for fibre layup inspection processes: Techniques to enhance the data set

In the aerospace industry, the Automated Fiber Placement process is an established method for producing composite parts. Nowadays the required visual inspection, subsequent to this process, typically takes up to 50% of the total manufacturing time and the inspection quality strongly depends on the inspector. A Deep Learning based...

Application of shearography and the percussion method for the structural inspection of wall paintings: A case study of St. Christopher in Maria Church, Nisse

Structural delamination in mural paintings is a complex phenomenon and is considered among the most frequent types of damage. In conservation practice, the most common technique to identify structural detachments is the percussion method. Full-field optical techniques based on interferometry, such as shearography, can provide a more...

Optical Material Characterisation of Prepreg CFRP for Improved Composite Inspection

Automated fibre layup techniques are often applied for the production of complex structural components. In order to ensure a sufficient component quality, a subsequent visual inspection is necessary, especially in the aerospace industry. The use of automated optical inspection systems can reduce the inspection effort by up to 50 %. Laser line...

Cross-evaluation of a parallel operating SVM – CNN classifier for reliable internal decision-making processes in composite inspection

In the aerospace industry, automated fibre laying processes are often applied for economical composite part fabrication. Unfortunately, the current mandatory visual quality assurance process takes up to 50% of the entire manufacturing time. An automised classification of manufacturing deviations using Neural Networks potentially improves the...

Explainability of deep learning classifier decisions for optical detection of manufacturing defects in the Automated Fiber Placement process

Automated fibre layup techniques are commonly used composite manufacturing processes in the aviation sector and require a manual visual inspection. Neural Network classification of defects has the potential to automate this visual inspection, however, the machine decision-making processes are hard to verify. Thus, we present an approach for...

Spatially modulated thermal excitations for shearography non-destructive inspection of thick composites

With the increasing application of thick composites in marine, wind energy and aerospace industries, the inspection of thick composites becomes more and more challenging when considering the variety of thick structures (e.g., laminate, sandwich, honeycomb structures). Shearography is a full-field and non-contact optical non-destructive...

Imaging sensor data modelling and evaluation based on optical composite characteristics: Investigation of data quality for inline inspection

Automated Fibre Placement is a common manufacturing technique for composite parts in the aero-space industry. Therefore, a visual part inspection is required which often covers up to 50% of the actual production time. Moreover, the inspection quality of this manual step fluctuates significantly. A camera-based automated inline inspection is...

Algorithm assessment for layup defect segmentation from laser line scan sensor based image data

The Automated Fiber Placement process is established in the aerospace industry for the production of composite components. This technique places several narrow material strips in parallel. Within current industrial Automated Fiber Placement processes the visual inspection takes typically up to 50% of overall production time. Furthermore,...

Incorporating Inductive Bias into Deep Learning: A Perspective from Automated Visual Inspection in Aircraft Maintenance

The near-term artificial intelligence, commonly referred as ‘weak AI’ in the last couple years was achieved thanks to the advances in machine learning (ML), particularly deep learning, which has currently the best in-class performance outperforming other machine learning algorithms. In the deep learning framework, many natural tasks such as...