Crack length measurement during the wedge-splitting test using digital image correlation

• Grant number: 14/03594-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2014
• End date: February 11, 2017
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Rodrigo Bresciani Canto
• Grantee: Rafael Vargas Maginador
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated scholarship(s): 15/11104-7 - Identification of stress intensity factor by digital image correlation combined with finite element method, BE.EP.IC

Abstract

Refractory ceramics can maintain its mechanical properties under extremes conditions, including high temperatures or corrosive environment. This characteristic implies a high technological importance, especially for basic industries. The extreme conditions of work and its variations can damage the material with cracks. An interesting study for this effect is analyzing the material R-curve, that provides its crack growth resistance. One issue on plotting the R-curve, with the information obtained in a stable crack growth test, is the acknowledgment of the crack length during the test. Even though different methods do exist, they generally need some complex calculation or are limited to only be useable in some cases. As such, this project propose a new methodology for crack length measurement, using the Digital Image Correlation (DIC) technique. This methodology would dispense conventional methods, and its limitations and calculations needed to obtain the crack length. For this study, mechanical cracking tests will be performed with stable crack growth (the same used to measure fracture energy), along with the DIC technique. The results will be compared with a microscopic analysis of the specimen made after the test, to achieve the crack tip position more accurately. The perspective of this project is to obtain the crack length during the mechanical test directly by DIC technique. If successful, plotting a R-curve for different materials would become simpler and by the curves comparison, easier to determine which material would be better used in a particular application.