The input assumes that a modal analysis has been done and expanded.n! After a modal analysis.npi=acos(-1)namplitude=20 ! pulse amplitude (20 g)nwidth=0.01 ! pulse width (10 milli-secs)n n*dim,acel,table,4,1nacel(1,0)=0.0, 0.5*width, width, 5.0*widthnacel(1,1)=0.0, amplitude, 0.0, 0.0n n/axlab,x,TIME n/axlab,y,ACEL (g)n*vplot,acel(1,0),acel(1,1) ! verify acceleration inputnThe table array, acel, can now be used as input to the RESP command in the time-history post-processor.n/post26nstore,alloc,10 ! allocate the number of frequencies to be solved fornvput,acel(1,0),1,0 ! variable 1 is time valuesnvput,acel(1,1),2,0 ! variable 2 is acceleration valuesndata,5,1,10,1,Frequncy ! variable 5 is frequency list (I love this old command!) n(10F5.1)n10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0n n! Use parameters for RESP command input to make more readablenSpec=6 ! variable to contain spectrum outputnFreq=5 ! variable with frequencies to be solved fornInp_Acel=2 ! variable with acceleration inputnOut_Type=3 ! create acceleration spectrumnDamp=0.05 ! damping (ratio to critical) to be usednTinc=0.0005 ! integration time step, 20 pts per cycle at 100 hznInp_Type=1 ! acceleration input, new at 14. Setting LOG 1 on /INPUT causes all commands read from the specified file to be recorded in the command log. A /INPUT (with a blank second field) switches back to the primary input file. A /EOF read from the terminal then switches back to the previous file. The time-history includes time after the shock load for the lower frequencies to reach their peak displacement value. For an interactive run, a /INPUT ,TERM switches to the terminal for the next input. In the input below the POST26 RESP command is used to compute the shock response spectrum for a 20g triangular acceleration of 10 milli-sec duration.
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