Learning Forum

[jtowns03]

Is there a straightforward way to calculate the global center of mass of a model in LS-PrePost?

I am working with a detailed human body model with distributed mass and all material densities explicitly defined (no *PART_INERTIA or lumped mass). I’m looking to compute the COM of the full model or a selected set of parts.

If LS-PrePost can’t do this directly, is exporting element masses and computing the COM externally using element centroids the recommended approach?

[Nanda]

Hello User,

Maybe the Mass Trim feature might match your requirements. LS-PrePost provides mass trimming and measurement functions that can report the current mass, centre of mass (CG), and inertia properties for visible entities in your model. This includes models where mass is distributed according to element densities, without the use of *PART_INERTIA or *ELEMENT_MASS cards. You can use the Mass Trim dialogue to compute and display the global centre of gravity (CG) coordinates (X, Y, Z) for the selected set of parts or the entire model.

Refer to section 6.1.15 in this document: 6.1. Mesh

Let us know how this goes.

Regards,

Nanda.

Introducing Ansys Assistant a 24/7 AI-powered virtual assistant for active Ansys academic customers.

Have a look at our public help documentation website: Ansys Help

For more exciting courses and certifications, hit this link: Ansys Innovation Courses | ANSYS Innovation Space

Guidelines for Posting on Ansys Learning Forum

[Nanda]

If you need more control or wish to perform custom calculations, LS-PrePost allows you to export element data, including masses and centroids. You can then compute the global centre of mass externally using the standard weighted average formula: sum(mass_i * centroid_i) / sum(mass_i)