3. Considering a mesh of CST elements with the connectivity as defined on the following page, write each of the following structural stiffness sub-matrices (each 22 ) as a sum of the corresponding element stiffness sub-matrices: (a) K3,3 (b) K26,3 (c) K6,18 Note that this mesh and the corresponding connectivity table were generated in Abaqus, where CPS3 corresponds to the CST discussed in class. Each row of the connectivity table should be interpreted: Element No., Node 1 , Node 2 , Node 3 *Element,type=cPS31,1,2,132,13,12,13,2,3,144,14,13,25,3,4,156,15,14,37,4,5,168,16,15,49,5,6,1710,17,16,511,6,7,1812,18,17,613,7,8,1914,19,18,715,8,9,2016,20,19,817,9,10,2118,21,20,919,10,11,2220,22,21,1021,12,13,2422,24,23,1223,13,14,2524,25,24,1325,14,15,2626,26,25,1427,15,16,2728,27,26,1529,16,17,2830,28,27,1631,17,18,2932,29,28,1733,18,19,3034,30,29,1835,19,20,3136,31,30,1937,20,21,3238,32,31,2039,21,22,3340,33,32,21