Getting Accurate Results from
When it comes to CAD software, users are mostly interested in functionality, ease-of-use and stability. However when it comes to Simulation, the requirements are different. The main focus would be:
With CAD, a user knows how the end results should be, and use the software to create it. With Simulation, they depend on the software to create the end results. SOLIDWORKS Simulation works on creating a simplified FEA solutions to achieve the reliability of a complex and comprehensive software solution.
For this blog article, I look at how one can verify the reliability of SOLIDWORKS Simulation.
For our case study, we would like to see the effect of gravity on a beam being fixed at its ends. The deflection of a beam being fixed on the ends and with a force applied has been thoroughly documented. With the basis of the Hooke’s Law and the integration method, we find that we can calculate the maximum deflection of the beam due to gravity as:
1. Fixed – Simply Supported Ends
2. Fixed – Free
In this case we chose to study the effect of deflection for both a circular profile as well as a square profile.
To simulate the fixtures of a Fixed – Simply supported ends, we would need to use a Beam mesh with the Immovable Boundary Fixture. This allows us to restrict on the 3 Transnational DOF, and not the Rotational DOF. For the other end, we will use Reference Geometry and restrict the 2 DOF across the end’s cross sectional face.
To simulate the fixtures of a Fixed – Simply supported ends, we again use a Beam mesh with the Immovable Boundary Fixture, and allow the other end to be free.
Apply Gravity under Loading Condition, assign the material and run the Simulation, and we will get the following results:
Fixed – Simply Supported
Fixed – Free End
The summary of the maximum deflection (mid-span) are tabulated below:
Fixture Type Beam Profile Manual Calculation SW Simulation Difference(%) Fixed – Simply Supported Circular 0.2 0.200mm 0 Square 1.44 0.150mm 4% Fixed – Free End Circular 1.92 1.920mm 0 Square 1.44 1.440mm 0
Here we can see that the manual calculation against the Simulation Results is highly similar.
So what is the advantage of using SOLIDWORKS Simulation if we could have just done hand calculation in the first?
On top of that SOLIDWORKS Simulation can run an analysis on assembly level, the other benefit is solving for the Second Moment of Area (I). To perform a hand calculation, we would need the I value which depends on the cross section of the beam, which becomes complex if the cross section is not symmetrical.
The beauty of SOLIDWORKS is that it calculates the I and uses it in Simulation automatically. How easy is that!
A benchmarking process is always important whenever you would like to run it on a full scale design. The important thing to remember is that in order to get accurate results, the input must also be accurate (like restricting the correct DOF). So always start on a smaller scale model in which you can verify the results, and once you become confident, move on to the full scale project.
On top of this, we have also done a study on the effect of thermal expansion together with the deflection due to gravity, and have achieved highly accurate results. If you would like to see the full study, or would like to know how you can start using SOLIDWORKS Simulation to perform highly accurate studies to improve your design, feel free to contact us at +65 6372 1416 or email firstname.lastname@example.org.