Al-Ansari, Luay, Muhannad Al-Waily, and Ali Al-Hajjar. “Experimental and Numerical Study of Crack Effect on Frequency of Simple Supported Beam”. Al-Khwarizmi Engineering Journal 8, no. 2 (May 31, 2012): 30-41. Accessed August 16, 2021. https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/127.