Thanks, Lou. The issue is that no combination of any of the components is going to be constant. The material properties (AHEW and EEW) can be very different in magnitutude, e.g. AHEW1=40, AHEW2=200, EEW1=170, EEW2=250. A valid formulation for this would be (am1,am2,ep1,ep2) = (0.106, 0.213, 0.532, 0.149). Another valid formulation for this would be (am1,am2,ep1,ep2) = (0.139, 0.069, 0.347, 0.444). The only real constraint is the amine/epoxy balance ( sum( am_i/AHEW_i) = sum( ep_j/EEW_j) ). I've tried adding the two-constraints method(1) into the custom designer, but it gave a warning and an error message(2,3). (1) two-contraints, actual number used were the ones mentioned above. (1/AHEW1)*AM1 + (1/AHEW2)*AM2 + (-1/EEW1)*EP1 + (-1/EEW2)*EP2 >= 0 (1/AHEW1)*AM1 + (1/AHEW2)*AM2 + (-1/EEW1)*EP1 + (-1/EEW2)*EP2 <= 0 (2) A subset of the factor constraints is equivalent to an equality constraint. The resulting design may be singular if the model effects are not chosen carefully. (3) Optimal designer failed to converge.
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