CFVR4905 - PS 92: Seismic Analysis (design spectrum) X-axis
Seismic Analysis on a 1 DOF beam according to PS 92
This example compares spectrum accelerations given by CivilFEM to accelerations obtained when solving on a 1 DOF beam and to the correct PS 92 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: CFVR4905.DAT
FINISH ~CFCLEAR,,1 NomFile='CFVR4905' /TITLE, %NomFile%, PS 92: Seismic Analysis (design spectrum) X-axis ! ---------------------------------------------------------------------- ! Model definition ! ---------------------------------------------------------------------- ! CivilFEM Setup: Code & Units ~UNITS,,LENG,CM ~UNITS,,TIME,S ~UNITS,,FORC,KP ~CODESEL,,,,,PS92 /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 ! Spectrum definition ~DEFSPEC,ALL,0.1*981,S0,DESIGN,1,5 pi = 3.141592654 ! ---------------------------------------------------------------------- ! DATA CHECK ! ---------------------------------------------------------------------- ! Data comparison number NComp = 40 NComp_ch = 0 ! Matrix 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 /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 ! Acceleration ! Obtained values ~CFGET,VALUE(20-ARG1+1,2),SEISM,,SPEC,SDH,,ARG1,2 ! Y components of design horizontal spectrum ~CFGET,VALUE(40-ARG1+1,2),SEISM,,SPEC,SDH,,ARG1,2 ! Y components of design 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) = 6.31937 VALUE(39,1) = 7.28055 VALUE(38,1) = 8.49901 VALUE(37,1) = 10.07990 VALUE(36,1) = 12.18995 VALUE(35,1) = 15.10731 VALUE(34,1) = 19.32710 VALUE(33,1) = 25.80753 VALUE(32,1) = 36.62556 VALUE(31,1) = 57.08818 VALUE(30,1) = 61.18004 VALUE(29,1) = 66.09377 VALUE(28,1) = 72.12987 VALUE(27,1) = 79.76396 VALUE(26,1) = 89.80155 VALUE(25,1) = 103.73756 VALUE(24,1) = 124.73837 VALUE(23,1) = 161.08066 VALUE(22,1) = 245.25000 VALUE(21,1) = 245.25000 ! 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 | 245.25 | 245.25 | 1.000 | 0.1 |
| Sa(2)x | 245.25 | 245.25 | 1.000 | 0.1 |
| Sa(3)x | 161.13 | 161.13 | 1.000 | 0.1 |
| Sa(4)x | 124.78 | 124.78 | 1.000 | 0.1 |
| Sa(5)x | 103.77 | 103.77 | 1.000 | 0.1 |
| Sa(6)x | 89.83 | 89.83 | 1.000 | 0.1 |
| Sa(7)x | 79.789 | 79.789 | 1.000 | 0.1 |
| Sa(8)x | 72.153 | 72.152 | 1.000 | 0.1 |
| Sa(9)x | 66.115 | 66.114 | 1.000 | 0.1 |
| Sa(10)x | 61.199 | 61.199 | 1.000 | 0.1 |
| Sa(11)x | 57.106 | 57.106 | 1.000 | 0.1 |
| Sa(12)x | 36.642 | 36.642 | 1.000 | 0.1 |
| Sa(13)x | 25.819 | 25.819 | 1.000 | 0.1 |
| Sa(14)x | 19.336 | 19.336 | 1.000 | 0.1 |
| Sa(15)x | 15.114 | 15.114 | 1.000 | 0.1 |
| Sa(16)x | 12.195 | 12.195 | 1.000 | 0.1 |
| Sa(17)x | 10.084 | 10.084 | 1.000 | 0.1 |
| Sa(18)x | 8.5028 | 8.5028 | 1.000 | 0.1 |
| Sa(19)x | 7.2838 | 7.2838 | 1.000 | 0.1 |
| Sa(20)x | 6.3222 | 6.3222 | 1.000 | 0.1 |
| Sa(1)x | 245.25 | 245.25 | 1.000 | 0.1 |
| Sa(2)x | 245.25 | 245.25 | 1.000 | 0.1 |
| Sa(3)x | 161.08 | 161.13 | 1.000 | 0.1 |
| Sa(4)x | 124.74 | 124.78 | 1.000 | 0.1 |
| Sa(5)x | 103.74 | 103.77 | 1.000 | 0.1 |
| Sa(6)x | 89.802 | 89.83 | 1.000 | 0.1 |
| Sa(7)x | 79.764 | 79.789 | 1.000 | 0.1 |
| Sa(8)x | 72.13 | 72.152 | 1.000 | 0.1 |
| Sa(9)x | 66.094 | 66.114 | 1.000 | 0.1 |
| Sa(10)x | 61.18 | 61.199 | 1.000 | 0.1 |
| Sa(11)x | 57.088 | 57.106 | 1.000 | 0.1 |
| Sa(12)x | 36.626 | 36.642 | 1.000 | 0.1 |
| Sa(13)x | 25.808 | 25.819 | 1.000 | 0.1 |
| Sa(14)x | 19.327 | 19.336 | 1.000 | 0.1 |
| Sa(15)x | 15.107 | 15.114 | 1.000 | 0.1 |
| Sa(16)x | 12.19 | 12.195 | 1.000 | 0.1 |
| Sa(17)x | 10.08 | 10.084 | 1.000 | 0.1 |
| Sa(18)x | 8.499 | 8.5028 | 1.000 | 0.1 |
| Sa(19)x | 7.2805 | 7.2838 | 1.000 | 0.1 |
| Sa(20)x | 6.3194 | 6.3222 | 1.000 | 0.1 |
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