Response based damage assessment using acoustic emission energy for plain concrete

Abstract

The aim of this study is to assess damage in the plain concrete using acoustic emission (AE) energy. During fracturing process of concrete, the AE energy evolves due to the expansion of multi-scale micro cracks developed in the fracture process zone (FPZ). The prediction of the AE energy capacity of a structural element is possible if the correlation coefficient between applied work and AE energy is known priori. This information is used in defining a response based damage variable for damage assessment. Three damage variables namely surface damage variable, acoustic emission (AE) energy damage variable and FPZ volume damage variable are defined and their inter relationship is established for a simplified triangular shaped FPZ. The actual FPZ is presumed to be of oval shape. The post-peak response curve is segmented piece-wise linearly. Volume of FPZ is approximated by relating its width with AE energy. An experimental program is conducted on three different sized plain concrete notched beams under three point flexure. Correlation between mechanical work for fracture and AE energy is established globally and locally to determine the correlation coefficients. The damage assessment approach is validated experimentally.