“…This method was originally introduced by Brebbia and Nardini [18]. Interested readers can find more details in the following references: Ang et al [19], Divo and Kassab [20], Fahmy [21], Gaul et al [22], Partridge et al [23], Wrobel and Brebbia [24], Yun and Ang [25] and Zhang and Zhu [26].…”