“…Unfortunately, the so-formed elements encounter the risk of shear and membrane lockings as their thickness becomes small. To alleviate lockings, a number of noteworthy techniques have been proposed including uniformly reduced integration, selectively reduced integration (Zienkiewicz, Taylor & Too 1971;Hughes, Cohen & Haroun 1978), heterosis elements , c-stabilization method (Belytschko, Ong, Liu & Kennedy 1984;Belytschko, Wong & Stolarski 1989), hybrid/mixed formulation (Lee & Pian 1978;Lee, Dai, & Yeom 1985;Rhiu & Lee 1987;Rhiu & Lee 1988;Rhiu, Russel & Lee 1990;Saleeb, Chang, Graf & Yingyeunyong 1990;Kim & Lee 1992;Basar, Ding & Kraetzig 1992;Sze 1994b;Guan & Tang 1995;Sze, Yi & Tay 1997), assumed strain methods (MacNeal 1978;Bathe & Dvorkin 1986;Huang & Hinton 1986;Park & Stanley 1986;Belytschko, Wong & Stolarski 1989, Flores, Onate & Zarate 1995, etc. Among them, the URI (uniformly reduced integrated) elements have an outstanding accuracy and computational ef®ciency.…”