A fractal image analysis methodology for heat damage inspection in carbon fiber reinforced composites

• Main Authors: Murukeshan, V. M., Haridas, Aswin, Crivoi, Alexandru, Prabhathan, P., Chan, Kelvin
• Other Authors: Asundi, Anand K.
• Format: Conference or Workshop Item
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Mechanical engineering; Image Processing; Fractal Dimension
• Online Access: https://hdl.handle.net/10356/102524; http://hdl.handle.net/10220/47254
• Institution: Nanyang Technological University

The use of carbon fiber-reinforced polymer (CFRP) composite materials in the aerospace industry have far improved the load carrying properties and the design flexibility of aircraft structures. A high strength to weight ratio, low thermal conductivity, and a low thermal expansion coefficient gives it an edge for applications demanding stringent loading conditions. Specifically, this paper focuses on the behavior of CFRP composites under stringent thermal loads. The properties of composites are largely affected by external thermal loads, especially when the loads are beyond the glass temperature, Tg, of the composite. Beyond this, the composites are subject to prominent changes in mechanical and thermal properties which may further lead to material decomposition. Furthermore, thermal damage formation being chaotic, a strict dimension cannot be associated with the formed damage. In this context, this paper focuses on comparing multiple speckle image analysis algorithms to effectively characterize the formed thermal damages on the CFRP specimen. This would provide us with a fast method for quantifying the extent of heat damage in carbon composites, thus reducing the required time for inspection. The image analysis methods used for the comparison include fractal dimensional analysis of the formed speckle pattern and analysis of number and size of various connecting elements in the binary image.