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Finite Element Analysis in Structural Mechanics

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en:example:dyn:3:1

Mode superposition, BEAM53D2

Problem

Mesh

element type nodes
1 53 1 2
2 53 2 3
3 53 3 4
4 53 4 5

Boundary conditions

$u=v=w=\varphi_x=\varphi_y=\varphi_z=0$ at node 1

Solution

In the mode superposition method we directly combine the eigenvectors neglecting the phase shift due to damping.

beam53d2.bat
rmd3 beam53d2.i1
rpd3 beam53d2.i2
srh3 beam53d2.i3
fefs beam53d2.i4
hmot beam53d2.iM
heig beam53d2.iE
hmod beam53d2.iD

Input

beam53d2.i1
;  NELEM NNOD ITED
IP   4     5   53
;  CRIT SCALE ...
RP 1.01   1   8*0
 ; default values of cross-sectional characteristics
 ; A    Ik              Wk                Ieta
   2e-4 6.6666666666e-9 6.666666666666e-7 1.66666666666e-9
 ; Weta             Izeta               Wzeta              Px Py Pz
   3.33333333333e-7 6.66666666666666e-9 6.666666666666e-7  0  1  0
XY N 1:5 X 5*0:1 Y 5*0 Z 5*0
EL E 1:4 N 1 2  2 3  3 4  4 5
EN
EN
beam53d2.i2
;  KREST
IP   1
         ; E    α ν   ρ
MP 1 T 1 V 2e11 0 0.3 7800
AS 1 /M 1 /B 0 N 1
EN
EN
beam53d2.i3
;  KREST
IP   1
EN
EN
beam53d2.i4
;  KREST
IP   1
EN
EN
beam53d2.iM
;  KDIAG KPRIN
IP   1     0
EN
EN
beam53d2.iE
;  KREST NROOT NITERX KTPR KEVP
IP   1     10     0     0    0
EN
EN
beam53d2.iD
;  KOUT KDUMP KPRIN KKIN
IP   3    0     0     1
;  TEND DT
RP   0   0

VC 1 T 1
  ; directional vector
  R 0 0 1 0 0 0 4*(6*0)
  ; amplitude
  R 0.001
  ; ang. frequency
  R 25.698761
  ; damping
  R 10*0.1

; use the first term of Fourier's series
RS 2 T 1 I 1 0

; direction, amplitude, frequency, damping
AS 3 T 1   I 1 3   I 2 5   I 3 6   I 4 8

EN
EN

Output

beam53d2.oD
;  KOUT KDUMP KPRIN KKIN                                                        
IP   3    0     0     1                                                         
;  TEND DT                                                                      
RP   0   0                                                                      
                                                                                
VC 1 T 1                                                                        
  ; directional vector                                                          
  R 0 0 1 0 0 0 4*(6*0)                                                         
  ; amplitude                                                                   
  R 0.001                                                                       
  ; ang. frequency                                                              
  R 25.698761                                                                   
  ; damping                                                                     
  R 10*0.1                                                                      
                                                                                
; use the first term of Fourier's series                                        
RS 2 T 1 I 1 0                                                                  
                                                                                
; direction, amplitude, frequency, damping                                      
AS 3 T 1   I 1 3   I 2 5   I 3 6   I 4 8                                        
                                                                                
EN                                                                              
EN                                                                              

                    RIGHT-HAND SIDE ASSIGNED
                    DAMPING INCLUDED


                            SUM OF REACTIONS
 -0.1353409505777549E-07  0.7209223447460681E-09 -0.1101235522045654E+01


                                REACTIONS
     1  -0.13534E-007   0.72092E-009  -0.11012E+001
     2   0.00000E+000   0.00000E+000   0.00000E+000
     3   0.00000E+000   0.00000E+000   0.00000E+000
     4   0.00000E+000   0.00000E+000   0.00000E+000
     5   0.00000E+000   0.00000E+000   0.00000E+000


                    AMPLITUDE OF THE STATIONARY SOLUTION


                    TIME T =  0.000000E+00 [s]

                    U [m]      V [m]      W [m] ALPHA [rad] BETA [rad]

                   DISPLACEMENT
     1   0.00000E+000   0.00000E+000   0.10000E-002
     2   0.84588E-016   0.11155E-015   0.10530E-002
     3   0.64241E-016  -0.26857E-016   0.11796E-002
     4  -0.35034E-016  -0.18142E-015   0.13409E-002
     5  -0.90682E-016  -0.34390E-015   0.15122E-002

                   VELOCITY
     1   0.00000E+000   0.00000E+000   0.25699E-001
     2   0.21738E-014   0.28667E-014   0.27061E-001
     3   0.16509E-014  -0.69020E-015   0.30314E-001
     4  -0.90034E-015  -0.46623E-014   0.34460E-001
     5  -0.23304E-014  -0.88379E-014   0.38863E-001

                   ACCELERATION
     1   0.00000E+000   0.00000E+000   0.66043E+000
     2   0.55864E-013   0.73671E-013   0.69544E+000
     3   0.42426E-013  -0.17737E-013   0.77904E+000
     4  -0.23138E-013  -0.11982E-012   0.88557E+000
     5  -0.59889E-013  -0.22712E-012   0.99873E+000

                                * END OF HMOD *
 TOTAL CPU: 00:00:00
en/example/dyn/3/1.txt · Last modified: 2022-03-15 08:29 by Petr Pařík