I actually would disagree that Bond Graphs are the "underlying mechanism" in Modelica. The Modelica community and the Bond Graph community are a bit at odds in fact. My side of this story can be found at [1] and [2]. I disagree with the idea that Bond Graphs will give you an intuitive understanding of just about every system. What it will give you is an appreciation for the elegance of the Bond Graph formulation. But the analogies drawn there are, in my experience of 30 years of modeling in industry, extremely superficial. The analogies all break down once you get past passive, linear elements (e.g., why isn't there momentum in thermal systems, what if I have an compressible fluid, what is the analogy of a clutch in an electrical system, etc). Bond Graphs also aren't really acausal either, they are just a different causal formulation that is closer to the physics.

I'm sure Bond Graph fans will disagree. I am just sharing my personal, subjective opinion here.

[1]: https://www.linkedin.com/feed/update/urn:li:ugcPost:72725163... [2]: https://mbe.modelica.university/components/connectors/simple...