Reza Babnadi - MSc,School of Railway Engineering, Iran University Science and Technology,
Parisa Hosseini Tehrani - Associate Professor, School of Railway Engineering, Iran University Science and Technology,
Amin Nazari - PhD Student, School of Railway Engineering, Iran University Science and Technology,
Mohsen Ghazanfari - PhD Student, School of Railway Engineering, Iran University Science and Technology,

To prevent damages, reduction of maintenance cost and improving the safety, defects detection is an essential issue. One of the most important defects is crack which may cause failure in structures. Owning knowledge about the cracks are important to predict and evaluation of time and position of failure and its consequences. Recently usingnondestructive tests (NDT) for cracks assessment has been common and one of the recent method is thermography. Heating the specimen and monitoring the result of temperature distribution by IR thermography camera would result a higher temperature gradient in crack surfaces. The cracks depth may detect by measurement equipment and correlate to temperature variation results. A relation between these temperature gradient and crack depth has been derived and compared to characterize cracks. The estimated model may be used in similar conditions by good accuracy

Crack detection, Nondestructive tests, Thermography