7.F3 Then w a2 w 2 2 4 3 2 2 -;;7 = all(12x - 12ax + 2a )(y - 2by + b y ) a 2 w - a 11 (x 4 - 2ax 3 + a 2 x 2 ) (12y 2 - 12by + 2b 2 ) a/ - First, determine the strain energy of one stiffener, then sum over all stiffeners. The strain energy of the deformed plate may then be computed and added to that of the stiffeners. 1 20 3 2 w 2 1 20 2 4 3 2 2 2 2 / EI [-;;7] dx = 2 / EI [all (12x 2 -12ax+2a ) (y -2ay +a y ) ] dx 1 2 4 3 2 2 2 20 2 2 2 2 EI all (y -2ay +a y) f (12x -12ax+2a) dx 0 1 2 4 3 2 2 2 20 4 3 2 2 3 4 2 EI a 11 (y -2ay +a y) f [144x -288ax +192a x -48a x+4a ]dx 0 In each 20m x 20m hull section there are 19 minor stiffeners evenly spaced running in each of the two principal directions. Summing Ustringx from y = 1 toy= 19 will give the strain energy of the stringers running in the x-direction. Assuming the deformation of the plate is symmetric, twice this sum will be the strain energy of all of the minor stiffeners supporting the plate. ~1 ....""""'"'"'·
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