Comsol for Dummies by B1J2u4

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									This man is not a dummy
Maximum power, minimum weight
Isaac Newton (1643 -1727)



                               F=m*a




Also known from the Da Vinci Code
Robert Hooke (1635 – 1703)

                   Force (F)

                               F=k*s



                       Extension (s)
Daniel Bernoulli (1700 -1782)




    ½rv2+rgh+p=constant
Joseph Fourier (1768-1830)


                     q=k(T-Tref)/L
Georg Ohm (1787 – 1854)



           V=I*R
James Maxwell (1831 – 1879)
Dmitri Mendelejev (1834 – 1907)
Science can be fun ... (1879-1955)




    ... and rewarding (1833-1896)
fun...      ...failure...




         ... and disaster...
This bridge should
have been modeled
             Why modeling?
• Suppose the laws of physics were unknown

• Every idea must be tested...
  ...and tested
          ... and tested

• Trial and error: very expensive
.....
                        Why modeling?
Save money by
  1 Describing the physics mathematically
  2 Solving the mathematical problem
     PHYSICS             IDEA BY      FORMULA        SOLUTION
      dynamics:          Newton:      F=m*a         -> a=F/m
     mechanics:          Hooke:       F=k*s         -> s=F/k
     gas/liquid flow     Bernoulli:   ½rv2+rgh+p=c -> v=2√ [(c-rgh-p)/r]
     heat:               Fourier:     q=k(T-Tref)/L    -> T=qL/k+Tref
     current             Ohm:         V=I*R          -> I=V/R
     electromagnetics    Maxwell:     Ask Magnus Olsson
..............
    Why modeling with software
• Simple geometry => Single equation
• Complex geometries => lots of equations



        F=k*s -> s=F/k

                                  s=???
               Why Comsol?
• Lots of physics, lots of software
  – Elasticity           – Abaqus, Ansys, Nastran etc
  – Air resistance       – Fluent, CFX etc
  – Electronics          – Ansoft, Maxwell
  – Heat transfer        – Flowterm
  – Chemical reactions   – Aspen


• COMSOL covers all
               Why Comsol?
• Do we need to model all physics?
  • Not always. But Comsol is very userfriendly
                Why Comsol?
• Many times physics influences other physics
        –Chemical reactions produce heat
        –Electronic get hot
        –Hot devices expand or melt
• Other softwares then need to be bundeled
        •expensive
        •lots of work to write interfaces

• Comsol is specifically written for this
                   Comsol!
• for all your research and development
  – Affordable
  – Powerfull
  – Userfriendly
  – Competative
       How does Comsol work?
• Geometry       -> create computerdrawing
• Physics        -> laws of nature (F=k*s etc.)
• Meshing        -> to handle complex geometry
                    together with the physics
• Solving         -> Mathematical operations
• Postprocessing -> Viewing the results
Graphical User Interface (GUI)
Meshing, solving and viewing
        More detailed example
                    F=k*s


sleft                                     sright



              Finternal=k*sinternal

           sinternal ?      Fexternal ?
Geom -> Physics -> Mesh -> Equations
Nodes
          Displacements

                S5
     S2
                 S7

                      S17
                                  S44
S1         S4    S9         S23         S49
                      S18

                S8

     S3
                                 Equations

                                    S5
                        S2
                                   F7=k7*S7+neighboring nodal influence

                                           S17
                                                                 S44
                 F1 = k1*S1          S9          S23
                                 S4                                       S49
                    + neighboring nodal influence
                    + external force       S18




                                                                                External force
External force




                                   F8=k8*S8+neighboring nodal influence

                        S3
     A large set of equations

F1=k1*S1+neighboring nodal influence + external force
        .
        .
        .
        .



F7=k7*S7 + neighboring nodal influence
F8=k8*S8 + neighboring nodal influence
        .
        .
        .
        .


F49=k49*S49+neighboring nodal influence + external force
    Fully write out all equations


• Neighboring nodal influence must be
  described mathematically
           Can be put in a matrix equation
 K11       K12         K13      K14                         K1 46     K1 48        K1 48     K1 49   s1   F1 
                                                            K 2 46    K 2 47       K 2 48             s  F 
                                                                                              K 2 49   2   2 
 K 21      K 22        K 23     K 24
                                               . . .
 K 31      K 32        K 33     K 34                        K 3 46    K 3 47       K 3 48    K 3 49   s3   F3 
                                                                                                         
 K 41      K 42        K 43     K 44                        K 4 46    K 4 47       K 4 48    K 4 49   s4   F4 
                   .                      .                                    .                       .   . 
                                                                                                         
                   .                            .                              .                      .    . 
                   .                                  .                        .                       .   . 
K         K 46 2       K 46 3    K 46 4                   K 46 46    K 46 48       K 46 48   K 46 49   s   F 
 46 1                                                                                                  46   46 
 K 47 1   K 47 2       K 47 3    K 47 4                   K 47 46    K 47 47       K 47 48   K 47 49   s   F 
K         K 48 2       K 48 3    K 48 4
                                               . . .
                                                           K 48 46    K 48 47       K 48 48             47   47 
                                                                                              K 48 49  s   F 
 48 1                                                                                                    48     48
 K 49 1   K 49 2       K 49 3    K 49 4                   K 49 46    K 49 47       K 49 48                
                                                                                              K 49 49  s
                                                                                                       49   F49 
  which can then be solved

Remember F=k*s => s=F/k => s=(1/k)*F



      K ] s  F 
s   F   1 * F 
        K ] K ]
  And finally.... viewing the results
• Results can be viewed
Even by animations
Comsol’s next topmodel?
Thank you for your attention

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