Lagrange’s Method in Physics/Mechanics: Stiffness Matrix

[kass...@gmail.com]

from sympy.physics.mechanics import *

provides:
LM = LagrangesMethod(L, [q1, q2])

and:
LM.mass_matrix

i.e. a matrix of some coefficients...

Why is there no:

LM.stiffness_matrix

i.e. a matrix of some other coefficients...?

Regards,
Sven 

[Jason Moore]

Sven,

A stiffness matrix is only relevant when you have a system that is described by linear differential equations. In the general, non-linear form of the equations of motion of a rigidbody system there is only one matrix that can be extracted, i.e. the matrix of coefficients for the accelerations, the mass matrix. You can always linearize you system of equations and then find the coefficients of the generalized speeds and coordinates to get the damping and stiffness matrices, respectively.

Jason
moorepants.info
+01 530-601-9791

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