Sap2000 Steady State Ejemplo

Steady State Analysis Model for the Example in CSI Analysis Reference Manual

Rotating machinery is loading the tip of cantilever structure as shown in the above screen capture. he loading properties are as described in CSI  Analysis  Analysis Reference Manual! Manual! chapter "#re$uency %omain Analyses&! section "Steady'State Analysis (Example&. )se the

 factor of *.**+.

em

Steady State ime #unction #re$uency f entered in ,units

Steady state function value! calculated as / 0 1/ 2 f3/

%efinition of the Steady State 4oad Case

5ertical %isplacement of ip as a #unction of #re$uency for 6hase  Angle 0 *

Magnitude of 5ertical ip %isplacement as a #unction of #re$uency

7ote that the structure resonates for fre$uencies of modes / and 8 which are vertical modes.

Modal 6articipating Mass Ratios

Modes / and 8 are vertical modes.

Modal #re$uencies

#re$uency for the first vertical mode 1ie. mode /3 was used to setup time history analysis to verify the steady state results.

E$uivalent ime ,istory 4oad Cases ●

he results of the steady state analysis were verified by time history analyses for loading fre$uencies of + ,- and 9.:;9/ ,-

Calculate dynamic characteristics for f 0 9.:;9/ , f  =3.4832 Hz  = 2 

f  =21.8856 rad / sec

2

2

 = 478.9791 rad  / sec

T =1 / f  =0.2871

2

4oading Characteristics of the ",'per + ,-& ime ,istory 4oad Case 7ote< 1+3 Scale factor was set to em/ 0 1*.**+31=./;9+3/ 0 *.*9>:?; 1/3 ime factor was set to  0 +@f 0 + See previous page for calculation of intermediate values.

4oading Characteristics of the ",'per 9.:;// ,-& ime ,istory 4oad Case 7ote< 1+3 Scale factor was set to em/ 0 1*.**+31/+.;;8=3/ 0 *.:?> 1/3 ime factor was set to  0 +@f 0 *./;?+ See previous page for calculation of intermediate values.

%isplacement for f 0 + ,7ote that the time history displacement shown in the top screen capture matches the steady'state displacement shown in the bottom screen capture.

%isplacements for f 0 9.:;9/ ,7ote that the time history displacement shown in the top screen capture matches the steady'state displacement shown in the bottom screen capture.

6lot of the same displacement for transient time history analysis

7ote the gradual increase in amplitude due to resonance.