The following figure presents a finite element mesh for a plane strain configuration. All the constraints that appear are hinges apart from the ones in node 2 and node 4 which correspond to rollers (see also figure QB1). The numbers in brackets are the element numbering while the plain numbers are the global node numbering. The black dot represents the first local node for each constant strain triangle. 8.00 1 (b) (1) Construct: (a) (C) 85 (2) (9) (3) 28 Figure QB1. Finite Element mesh for a plane strain problem, using constant strain triangles. The ID matrix. The IEN matrix. (10) The LM matrix. (11) (5) 3 [6 Marks] [6 Marks] [8 Marks] (d) What would be the form of the ID, IEN and LM matrices if the configuration corresponded to plane stress problem? [5 Marks]