How to place a Point mass on COMSOL

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Good morning everyone,

Im currently working on a Eigenfrequency Prestressed study.

I want to put a point mass at the top face of the lower flexure (see the image below)

I attached another image that show where i want the point mass (see the image with the blue arrow).

For referance I attach the mph.file for the system that is used for the simulation and a image of what it look like.

Before I put a point mass I use a cube with a very high density with interia and placed it where arrow is at but it won't be useful for long term research, and before I use a point load but it have no mass of interia.

An idea that I have is to use a added mass load but it only for boundary but I am not sure it a correct substitute for the point mass.

Any help or advice much appreciated thank you.



2 Replies Last Post May 15, 2024, 12:56 p.m. EDT
Henrik Sönnerlind COMSOL Employee

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Posted: 6 months ago May 15, 2024, 6:37 a.m. EDT
Updated: 6 months ago May 15, 2024, 6:45 a.m. EDT

There is no point mass feature in the Solid Mechanics interface. The reason is that a point mass causes a type of singularity, similar to a concentrated force. It is better to distribute the mass over some small boundary, using an Added Mass node.

You can also use a Rigid Connector with a Mass and Moment of Inertia subnode. Note that you can select a flexible formulation, if the constraints imposed by the rigid connector are too hard.

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Henrik Sönnerlind
COMSOL
There is no point mass feature in the Solid Mechanics interface. The reason is that a point mass causes a type of singularity, similar to a concentrated force. It is better to distribute the mass over some small boundary, using an **Added Mass** node. You can also use a **Rigid Connector** with a **Mass and Moment of Inertia** subnode. Note that you can select a flexible formulation, if the constraints imposed by the rigid connector are too hard.

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Posted: 6 months ago May 15, 2024, 12:56 p.m. EDT

got it i will use an added mass boundary thank you very much!

got it i will use an added mass boundary thank you very much!

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