“…In addition, Belytschko and Lasry (1988) have studied the behavior of a distorted element with a fractal patch test, which is also valid in the weak patch test sense. The patch test has been applied to many problem-types including, for example, mixed displacement-pressure finite element formulations Zienkiewicz et al, 1986;Razzaque, 1986;Wu and Chen, 1997;Zienkiewicz and Taylor, 1997), three-dimensional (3-D) solid elements (Loikkanen and Irons, 1984), plate bending elements (Samuelsson et al, 1987;Zienkiewicz and Lefebvre, 1988;Zhifei, 1993;Zienkiewicz et al, 1993;Auricchio and Taylor, 1993;Aricchio and Taylor, 1994;Martins and Sabino, 1997;Park and Choi, 1997), and shell elements (Herrmann, 1989). The patch test has also been used as a fundamental tool to create new elements or to improve existing ones (Ju and Sin, 1996;Cheung et al, 2002;Piltner and Taylor, 2000).…”