running many simulink at sametime using matlab but it keep failing what should i do ?

hey i hope you are fine i am trying to connect Simulink with fast nrel to run many simulation at the same time here is the code :

if true
  clc
clear all
j=1;
for i=5:5:100
perd(j) = i;
j=1+j;
end
a='A';
j=1;
for i=0.5:(0.5):4
amplitude(j) =i;
j=1+j;
end
for i=1:20
for p=1:8
   addpath('C:\Users\hmo\Desktop\fast\bin');
  FAST_InputFileName=sprintf('C:\Users\hmo\Desktop\fast\CertTest\singleturbine%c%d.fst',a,p);
  TMax= 2000;
  period=perd(i);
  amp=amplitude(p);
  sim('OpenLoop.mdl',[0,TMax]);
end
b = double(num2str(a));
b=b+1;
a= char(b);
end
end

what i am doing her is that i am running simulink modle but changing in the input files but what happens that it start running all of the simulation at the same time causing nothing to run at all .The simulink connects to FAST NREL and starts to running fast then when it finshes it sends back "simulation complete" in the command windows . I do not know what to do. is there something i need to do to stop it from looping .i mean to wait until the simulink finshes the first simulation before continuing loop ?i do not know what should i do ? is there a flag that simulink makes when it finshes the simulation ? any ideas ?

please help