How to calculate equation system in Matlab, with some knowns

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SUMMARY

The discussion focuses on solving the equation system F=Ku in MATLAB, where K is a known 12x12 stiffness matrix, and some variables in the force vector F and displacement vector u are known. Participants emphasize the importance of linear algebra concepts such as Gaussian elimination and Cholesky decomposition for solving such systems. For MATLAB implementation, the solution can be computed using the syntax u = K \ F. Additionally, the context of finite element analysis (FEA) is highlighted, suggesting that further study of relevant textbooks may be beneficial for understanding the underlying principles.

PREREQUISITES
  • Linear algebra concepts, specifically Gaussian elimination and Cholesky decomposition
  • Understanding of finite element analysis (FEA) principles
  • Familiarity with MATLAB syntax and matrix operations
  • Knowledge of stiffness matrices and their applications in structural analysis
NEXT STEPS
  • Learn MATLAB matrix operations for solving linear equations
  • Study Gaussian elimination and Cholesky decomposition techniques
  • Explore finite element analysis textbooks for deeper insights
  • Investigate MATLAB's built-in functions for FEA applications
USEFUL FOR

Engineers, researchers, and students involved in finite element analysis, structural engineering, and anyone looking to solve linear equation systems in MATLAB.

berdan
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It's part of finite elements analysis.
All I need is to solve F=Ku,K is [12x12] matrix .
Some of the members of u are zeros ,some members of F are known forces . K is all known .
How do I solve F=Ku in that way ??

Thanks in advance.
 
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It's not clear if your K matrix is for a single structure or is the stiffness matrix for one element.

In any event, if you haven't studied linear algebra, particularly things like Gaussian elimination or Cholesky decomposition, now will be a good time.

If you are studying finite element analysis, there is usually part of the course which is devoted to solving the system of equations and understanding the various methods.
 
If this is just a Matlab question, then use u = K \ F. If it's a finite element question, you need to consult a few textbooks first.
 
SteamKing said:
It's not clear if your K matrix is for a single structure or is the stiffness matrix for one element.

In any event, if you haven't studied linear algebra, particularly things like Gaussian elimination or Cholesky decomposition, now will be a good time.

If you are studying finite element analysis, there is usually part of the course which is devoted to solving the system of equations and understanding the various methods.

I studied Linear Algebra ,and that's overcomplicating things .
All I am asking : How do I solve in Matlab something like this :
[A] [1 0 1 0][M]
[V] [0 1 2 0][N]
[0]=EA/L [0 1 2 0][Q]
[D] [0 4 5 4][L]

Where I know some of the variables in the first matrix ,and I know some variables in the last matrix (in a form of parameter,lets say Q is known and given) .
I need to find A,B,C,D,M,N and L .
How do I do this in Matlab ?
 

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