CSWP - Certified Solidworks Professional Assembly Mass Properties Analysis Questions and Answers 1 — Questions and Answers
Question 1: An assembly includes a simplified model of a purchased electric motor. The motor's manufacturer has provided a specification sheet with the precise mass and center of mass location. To ensure the overall assembly's mass properties are accurate, what is the correct SOLIDWORKS procedure?
- Create a custom material with a density calculated to make the motor's mass match the specification sheet.
- In the motor's part file, use the 'Override Mass Properties' feature to manually input the mass and center of mass from the specification sheet. (Correct answer)
- Add a Point Mass feature to the assembly at the location of the motor's specified center of mass.
- In the main assembly, apply a 'Mass' property in the Custom Properties tab for the motor component.
Correct answer: In the motor's part file, use the 'Override Mass Properties' feature to manually input the mass and center of mass from the specification sheet.
The 'Override Mass Properties' feature is specifically designed for this scenario. It allows the user to manually enter the exact mass, center of mass, and moments of inertia for a component, which then overrides the values calculated from the model's geometry and material. This is the standard and most accurate method for incorporating data for purchased components where the model is a simplified representation.
Question 2: An engineer runs the Mass Properties command on an assembly. The report indicates a Center of Mass at X=150, Y=-50, Z=200. By default, what do these coordinates represent?
- The location of the assembly's balance point relative to the assembly's origin. (Correct answer)
- The geometric center of the assembly's bounding box.
- The average coordinate position of all vertices in the assembly.
- The location of the assembly's origin relative to the global coordinate system.
Correct answer: The location of the assembly's balance point relative to the assembly's origin.
The Mass Properties tool calculates the center of mass, which is the unique point where the object would balance perfectly. By default, SOLIDWORKS reports the coordinates for this point with respect to the assembly's primary origin (0,0,0).
Question 3: You are asked to determine an assembly's Center of Mass relative to a specific vertex on a component, which is not the assembly origin. What is the most efficient and accurate procedure using the Mass Properties tool?
- Temporarily move the entire assembly so that the desired vertex is coincident with the assembly origin before running the report.
- Manually calculate the difference between the reported Center of Mass and the vertex's coordinates.
- Create a new coordinate system at the desired vertex, then select this coordinate system in the 'Report coordinate values relative to' dropdown within the Mass Properties dialog box. (Correct answer)
- Use the Measure tool to find the distance and angles from the origin to the vertex and apply them to the Center of Mass report.
Correct answer: Create a new coordinate system at the desired vertex, then select this coordinate system in the 'Report coordinate values relative to' dropdown within the Mass Properties dialog box.
The Mass Properties dialog box includes a 'Report coordinate values relative to' option. The standard workflow for this task is to create a new reference coordinate system at the desired location (the vertex), and then select it from this dropdown menu. This prompts SOLIDWORKS to recalculate and display all relevant properties, including the Center of Mass, directly relative to that new reference.
Question 4: Which of the following is the MOST critical factor for ensuring an accurate mass properties calculation for a newly created assembly of manufactured parts?
- Setting the 'Image Quality' in Document Properties to the highest level.
- Ensuring all mates in the assembly are fully defined with no errors.
- Assigning the correct material to every component in the assembly. (Correct answer)
- Making sure all components are saved as the latest version of SOLIDWORKS.
Correct answer: Assigning the correct material to every component in the assembly.
The mass of a component is calculated using its volume (from the geometry) and the density of its assigned material (Mass = Volume × Density). If a material is not assigned, SOLIDWORKS uses a default density that is almost certainly incorrect. Therefore, assigning the correct material to each part is the most fundamental and critical step for an accurate result.
Question 5: In the Mass Properties report, what is the primary purpose of the values listed under 'Moments of inertia: (Taken at the center of mass and aligned with the output coordinate system.)'?
- To provide input for advanced engineering analysis, such as dynamic simulation or stress analysis involving rotation. (Correct answer)
- To determine the total surface area and volume of the assembly.
- To define the assembly's resistance to acceleration in a linear direction.
- To calculate the manufacturing cost of the assembly based on material complexity.
Correct answer: To provide input for advanced engineering analysis, such as dynamic simulation or stress analysis involving rotation.
Moments of inertia measure an object's resistance to a change in its rotational motion. These values (Ixx, Iyy, Izz, etc.) are critical inputs for engineering dynamics (Motion Analysis) and finite element analysis (FEA) software to accurately predict how an assembly will behave when subjected to torques or rotational forces.
Question 6: You are working with a very large top-level assembly that contains several instances of a complex sub-assembly. To significantly improve the performance and speed when calculating the mass properties of the top-level assembly, what is the best practice?
- Set the sub-assembly to 'Flexible' in its component properties.
- In the System Options, disable 'Update mass properties while saving document'.
- Open the Component Properties for the sub-assembly and configure it to use its own pre-calculated mass properties. (Correct answer)
- Ensure the sub-assembly is saved in the 'Resolved' state instead of 'Lightweight'.
Correct answer: Open the Component Properties for the sub-assembly and configure it to use its own pre-calculated mass properties.
Within the Component Properties dialog box for a sub-assembly, you can specify that the top-level assembly should use the sub-assembly's own cached mass properties. This prevents SOLIDWORKS from having to re-evaluate every single part within that sub-assembly each time the main calculation is run, leading to a significant performance improvement. Disabling the update-on-save option can also improve save performance but doesn't speed up the manual calculation itself.
CSWP - Certified Solidworks Professional Assembly Mass Properties Analysis Questions and Answers 1
An assembly includes a simplified model of a purchased electric motor.
The motor's manufacturer has provided a specification sheet with the precise mass and center of mass location.
To ensure the overall assembly's mass properties are accurate, what is the correct SOLIDWORKS procedure?