Learning Forum

[Daeho Jang]

-cantilver beam with sinusoidal load(transient transient structural)

Im trying to export nodal force to make Forcer matrix to solve F=KX using matlab, and compare result from ansys solution.  I got stiffness matrix K_sparse using APDL, but i cant get force matrix. If i choose nodal force F, it only contain force at fixed nodes, which is useless. 

Are there any method to get nodal force for every nodes?

 Also, is the method I'm attempting to implement feasible?

 Thanks

 

[Chandra Sekaran]

Take a look at the APDL Math commands and examples like below ( https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v241/en/ans_apdl/apdlmathex.html?q=%5C*dmat ) . This example below shows how to read the stiffness matrix and the load vector (RHS).

Example 4.2: Read a Matrix and a Load Vector from a FULL File and Solve

! READ THE STIFFNESS MATRIX FROM THE FULL FILE
*SMAT,MatK,D,IMPORT,FULL,file.full,STIFF

! READ THE MAPPING TABLE: INTERNAL -> SOLV
*SMAT,Nod2Solv,D,IMPORT,FULL,file.full,NOD2SOLV

! READ THE LOAD VECTOR FROM THE FULL FILE
*DMAT,VecB,D,IMPORT,FULL,file.full,RHS

! ALLOCATE THE SOLUTION VECTOR IN SOLVER SPACE BY SIMPLY COPYING B
*DMAT,VecX,D,COPY,VecB			

! FACTORIZE A USING THE SPARSE SOLVER FUNCTIONS
*LSENGINE,DSP,MySolver,MatK
*LSFACTOR,MySolver
 
! SOLVE THE LINEAR SYSTEM
*LSBAC,MySolver,VecB,VecX 		

! CONVERT THE SOLUTION TO THE INTERNAL SPACE
*MULT,Nod2Solv,T,VecX,,XNod

! PRINT THE SOLUTION
*PRINT,XNod

! FREE ALL OBJECTS
*FREE,ALL