CFVR4801 - UBC 97: Seismic Analysis (maximum spectrum) X-axis
Seismic Analysis on a 1 DOF beam according to UBC 97
This example compares spectrum accelerations given by CivilFEM to accelerations obtained when solving on a 1 DOF beam and to the correct UBC 97 spectum accelerations.
The model is 1 element beam with only 1 DOF, which direction the CivilFEM spectrum is set (the rest of the DOF are constrained). A different mass is applied at the free end of the beam for the beam period to be equal to the 20 CivilFEM spectrum points. After solving, the mass acceleration is obtained and compared to the CivilFEM spectrum acceleration and to the correct value. Therefore, this example checks the following results:
- CivilFEM spectrum is defined correctly by comparing to the correct value
- CivilFEM spectrum is applied correctly and response acceleration is equal to spectrum acceleration
Element types used in the model: BEAM4, MASS21 Needed CivilFEM Modules: |
|
| Model Statistics | |
| Number of elements | 1 |
| Number of nodes | 2 |
| Number of civil materials | 1 |
| Number of cross sections | 1 |
| Number of shell vertices | 0 |
Log file: CFVR4801.DAT
FINISH ~CFCLEAR,,1 NomFile='CFVR4801' /TITLE, %NomFile%, UBC 97: Seismic Analysis (maximum spectrum) X-axis ! ---------------------------------------------------------------------- ! Model definition ! ---------------------------------------------------------------------- ! CivilFEM Setup: Code & Units ~UNITS,,LENG,CM ~UNITS,,TIME,S ~UNITS,,FORC,KP ~CODESEL,,,,,UBC97 /PREP7 ! Preprocessor ! ---------------------------------------------------------------------- ! Materials: A-42 ~CFMP,1,LIB,STEEL,EA,A42 ! Modify density (Rho = 0) ~CFMP,1,USER ~CFMP,1,DatGen,RHO,,0 ! Element Types ET,1,BEAM4 ! Type 1: 3D Beam ET,2,MASS21 ! Type 2: Mass ! Sections ~SSECLIB,1,1,1,1 !IPE 80 ~BMSHPRO,1,BEAM,1,1,,,4,,0,, ! Nodes L = 10 ! L : Bar length N, 1 N,10,L ! Elements TYPE,1 MAT ,1 REAL,1 EN,1,1,10 EPLOT ! Parameters *GET,AR20,EX,1 ! Ex : Elastic Modulus ~CFGET,AR22,SECTION,1,MECHPROP,A,,2 ! Area : Bar area ~CFGET,AR23,SECTION,1,MECHPROP,IZZ,,2 ! Izz : Moment of inertia ~CFGET,AR24,SECTION,1,MECHPROP,IYY,,2 ! Iyy : Moment of inertia pi = 3.141592654 ! Seismic Spectrum ~DEFSPEC,ALL,1,A,MAXIMUM,A,7.5,2/3 ! ---------------------------------------------------------------------- ! DATA CHECK ! ---------------------------------------------------------------------- ! Data comparision number NComp = 40 NComp_ch = 0 ! Marix dim. *DIM,LABEL,CHAR,Ncomp,1 *DIM,LABEL_CH,CHAR,Ncomp_ch,1 *DIM,VALUE,,Ncomp,3 *DIM,VALUE_CH,CHAR,Ncomp_ch,3 *DIM,TOLER,,Ncomp,2 *DO,ARG1,1,20,1 /PREP7 ~CFGET,AR26,SEISM,,SPEC,TH,,ARG1,2 ! Period ! Labels LABEL(ARG1,1) = 'Sa(%ARG1%)x' LABEL(20+ARG1,1) = 'Sa(%ARG1%)x' AR25=AR20*AR22/L AR27=AR25*(AR26/(2*pi))**2 ! Mass applied at end R,2,AR27 TYPE,2 MAT, 1 REAL,2 EN,2,10 FINISH /SOLU ! Solution ! --------------------------------------------------------------------- ! Displacements D,1,,,,,,ALL D,10,,,,,,UY,UZ,ROTX,ROTY,ROTZ ~MODLSOL,1 ~CMBMOD,HORIZONT,NONE,NONE,0,0.0001 ! Query results *GET,ARG5,NODE,10,U,X ! Correct values VALUE(20-ARG1+1,1)=ARG5*AR25/AR27 ! Aceleration ! Obtained values ~CFGET,VALUE(20-ARG1+1,2),SEISM,,SPEC,SDH,,ARG1,2 ! Y components of maximum horizontal spectrum ~CFGET,VALUE(40-ARG1+1,2),SEISM,,SPEC,SDH,,ARG1,2 ! Y components of maximum horizontal spectrum ! CivilFEM gives the spectrum Normalized by gravity. ! To compare it must be changed to acceleration user units. VALUE(20-ARG1+1,2) = VALUE(20-ARG1+1,2)*981 VALUE(40-ARG1+1,2) = VALUE(40-ARG1+1,2)*981 /PREP7 EDELE,2 *ENDDO ! Correct values ! ---------------------------------------------------------------------- VALUE(40,1)= 77.759946 VALUE(39,1)= 85.346282 VALUE(38,1)= 94.572907 VALUE(37,1)= 106.036290 VALUE(36,1)= 120.661985 VALUE(35,1)= 139.967903 VALUE(34,1)= 166.628456 VALUE(33,1)= 205.835151 VALUE(32,1)= 269.169044 VALUE(31,1)= 388.799730 VALUE(30,1)= 388.799734 VALUE(29,1)= 365.471750 VALUE(28,1)= 342.143766 VALUE(27,1)= 318.815782 VALUE(26,1)= 295.487797 VALUE(25,1)= 272.159813 VALUE(24,1)= 248.831829 VALUE(23,1)= 225.503845 VALUE(22,1)= 202.175860 VALUE(21,1)= 178.847876 ! Warning and error tolerances ! ---------------------------------------------------------------------- *DO,II,1,NComp TOLER(II, 1)= 0.1 $ TOLER(II, 2)= 0.1 *ENDDO ! ---------------------------------------------------------------------- ! Results Comparison ! ---------------------------------------------------------------------- COMPARA.MAC |
Results
| Label | Target | CivilFEM | Ratio | Tolerance |
| Sa(1)x | 178.85 | 178.85 | 1.000 | 0.1 |
| Sa(2)x | 202.18 | 202.18 | 1.000 | 0.1 |
| Sa(3)x | 225.5 | 225.5 | 1.000 | 0.1 |
| Sa(4)x | 248.83 | 248.83 | 1.000 | 0.1 |
| Sa(5)x | 272.16 | 272.16 | 1.000 | 0.1 |
| Sa(6)x | 295.49 | 295.49 | 1.000 | 0.1 |
| Sa(7)x | 318.82 | 318.82 | 1.000 | 0.1 |
| Sa(8)x | 342.14 | 342.14 | 1.000 | 0.1 |
| Sa(9)x | 365.47 | 365.47 | 1.000 | 0.1 |
| Sa(10)x | 388.8 | 388.8 | 1.000 | 0.1 |
| Sa(11)x | 388.8 | 388.8 | 1.000 | 0.1 |
| Sa(12)x | 269.17 | 269.17 | 1.000 | 0.1 |
| Sa(13)x | 205.84 | 205.84 | 1.000 | 0.1 |
| Sa(14)x | 166.63 | 166.63 | 1.000 | 0.1 |
| Sa(15)x | 139.97 | 139.97 | 1.000 | 0.1 |
| Sa(16)x | 120.66 | 120.66 | 1.000 | 0.1 |
| Sa(17)x | 106.04 | 106.04 | 1.000 | 0.1 |
| Sa(18)x | 94.573 | 94.573 | 1.000 | 0.1 |
| Sa(19)x | 85.346 | 85.346 | 1.000 | 0.1 |
| Sa(20)x | 77.76 | 77.76 | 1.000 | 0.1 |
| Sa(1)x | 178.85 | 178.85 | 1.000 | 0.1 |
| Sa(2)x | 202.18 | 202.18 | 1.000 | 0.1 |
| Sa(3)x | 225.5 | 225.5 | 1.000 | 0.1 |
| Sa(4)x | 248.83 | 248.83 | 1.000 | 0.1 |
| Sa(5)x | 272.16 | 272.16 | 1.000 | 0.1 |
| Sa(6)x | 295.49 | 295.49 | 1.000 | 0.1 |
| Sa(7)x | 318.82 | 318.82 | 1.000 | 0.1 |
| Sa(8)x | 342.14 | 342.14 | 1.000 | 0.1 |
| Sa(9)x | 365.47 | 365.47 | 1.000 | 0.1 |
| Sa(10)x | 388.8 | 388.8 | 1.000 | 0.1 |
| Sa(11)x | 388.8 | 388.8 | 1.000 | 0.1 |
| Sa(12)x | 269.17 | 269.17 | 1.000 | 0.1 |
| Sa(13)x | 205.84 | 205.84 | 1.000 | 0.1 |
| Sa(14)x | 166.63 | 166.63 | 1.000 | 0.1 |
| Sa(15)x | 139.97 | 139.97 | 1.000 | 0.1 |
| Sa(16)x | 120.66 | 120.66 | 1.000 | 0.1 |
| Sa(17)x | 106.04 | 106.04 | 1.000 | 0.1 |
| Sa(18)x | 94.573 | 94.573 | 1.000 | 0.1 |
| Sa(19)x | 85.346 | 85.346 | 1.000 | 0.1 |
| Sa(20)x | 77.76 | 77.76 | 1.000 | 0.1 |
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