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How to extract the stiffness matrix K in multi-body dynamics (mbd) Transient simulation using MATLAB?
Posted Apr 1, 2026, 4:49 a.m. EDT LiveLink for MATLAB, Studies & Solvers, Structural Dynamics Version 6.3 1 Reply
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As the title indicates, when I attempted to use the mphmatrix function, I encountered an error: "The solution does not contain an active Variables node"
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After some time of trial and error, I figured out how to extract the matrix in the MBD simulation. Due to some reason, these matrices will not be automatically assembled. Before using the mphmatrix function, you need to add this statement: model.sol("sol1").feature("a1").set("K", true); Then it can be successfully extracted. Incidentally, this is something I obtained by copying the code of the "Assemble" node from the COMSOL software.
