Assembly Mass Properties Analysis Flashcards

In a SolidWorks assembly, when you change the material of a subassembly component, what must you do to update the top-level assembly mass properties?

Answer: Run Mass Properties again from the Evaluate tab

Running Mass Properties again from the Evaluate tab recalculates based on the current material definitions of all components.

Which SolidWorks option allows you to override the density used in a mass properties calculation without changing the part's assigned material?

Answer: Override Mass Properties in the Mass Properties dialog

The 'Override Mass Properties' checkbox in the Mass Properties dialog lets you specify custom density, mass, or center of mass values.

When SolidWorks calculates the moment of inertia for an assembly, which reference frame is used by default?

Answer: The assembly origin

By default, the moment of inertia is reported relative to the assembly's origin coordinate system.

A SolidWorks assembly has components with no material assigned. How does this affect the Mass Properties result?

Answer: SolidWorks uses a default density and warns the user

SolidWorks applies a default density and displays a warning that some components lack assigned materials.

What is the primary difference between 'Assigned mass properties' and 'Computed mass properties' in SolidWorks?

Answer: Assigned values are manually entered overrides; computed values are geometry-based calculations

Assigned mass properties are user-defined overrides entered manually, while computed properties derive from the part's geometry and material density.

In which SolidWorks dialog can you select a custom coordinate system to report the center of mass relative to a user-defined reference frame?

Answer: Mass Properties dialog using the 'Report coordinate values relative to' dropdown

The Mass Properties dialog includes a dropdown to choose any user-created coordinate system as the reporting reference.

How does suppressing a component in a SolidWorks assembly affect the mass properties calculation?

Answer: The suppressed component is excluded from mass properties

Suppressed components are excluded from the assembly mass properties calculation as if they do not exist.

When using 'Include hidden bodies/components' in the Mass Properties dialog, what effect does this have?

Answer: It includes bodies hidden using Hide/Show in the calculation

Checking 'Include hidden bodies/components' ensures bodies that are visually hidden are still counted in the mass properties result.

For a CSWP exam scenario, if the assembly mass properties show the center of mass at X=15mm, Y=20mm, Z=10mm and you mirror the entire assembly about the YZ plane, what happens to the X coordinate of the center of mass?

Answer: It moves to X=-15mm

Mirroring about the YZ plane negates the X coordinate, so X=15mm becomes X=-15mm.

Which SolidWorks feature allows you to add a point mass to a location in an assembly without modeling the actual geometry?

Answer: Point Mass (under Insert > Assembly Feature)

The Point Mass feature (Insert > Assembly Feature > Point Mass) adds a lumped mass at a specified location in the assembly.

In a CSWP scenario, you need the moment of inertia about the center of mass rather than the origin. What does SolidWorks require you to use?

Answer: The 'Taken at the center of mass' option in Mass Properties

SolidWorks provides a 'Taken at the center of mass' option in the Mass Properties dialog to output inertia relative to the COM.

If a component in a SolidWorks assembly uses a configuration with a different geometry than the default, which configuration's mass is used in the assembly mass properties?

Answer: The configuration active in the assembly context

SolidWorks uses the configuration that is currently active within the assembly, which may differ from the part's default configuration.

What does the 'Ixx', 'Iyy', and 'Izz' values represent in a SolidWorks Mass Properties report?

Answer: Moment of inertia about the X, Y, and Z axes respectively

Ixx, Iyy, and Izz are the principal diagonal terms of the inertia tensor, representing moments of inertia about the X, Y, and Z axes.

In SolidWorks, what is the unit of moment of inertia in the default MMGS unit system?

Answer: g·mm²

In the MMGS (millimeter-gram-second) unit system, moment of inertia is expressed in g·mm².

When you save a SolidWorks Mass Properties report, what file format does SolidWorks use by default?

Answer: .txt

SolidWorks saves Mass Properties reports as plain text (.txt) files by default.

A CSWP question asks for the assembly's mass in grams, but the model uses the IPS unit system. What is the best approach?

Answer: Run Mass Properties and use the unit dropdown in the dialog to switch to grams

The Mass Properties dialog has a unit dropdown that allows you to display results in different units without changing the document's unit system.

Which product configuration technique in SolidWorks would allow you to quickly compare the mass of an assembly with and without a set of optional components?

Answer: Design tables with suppression states

Design tables can control the suppression state of components across configurations, enabling quick mass comparisons between variants.

In SolidWorks, the product of inertia terms (e.g., Ixy, Ixz, Iyz) in the mass properties report are zero when which condition is met?

Answer: The coordinate system is aligned with the principal axes of inertia

Products of inertia are zero when the reference coordinate system is aligned with the principal axes of inertia of the assembly.

When you access Mass Properties on a sub-assembly within a top-level assembly, which mass is reported?

Answer: The total mass of the subassembly and all of its child components

Mass Properties on a subassembly reports the total accumulated mass of the subassembly including all of its child components.

For the CSWP exam, if you need to find the center of mass of a selected subset of components in an assembly, what is the correct approach in SolidWorks?

Answer: Pre-select the desired components before opening Mass Properties

Pre-selecting specific components before running Mass Properties causes SolidWorks to calculate properties for only the selected items.