Obtaining Accurate Results with MSUP Transient - Lesson 3

The accuracy of the MSUP transient solution depends mainly on four factors. The first is mesh density, as higher the mesh density, more accurate the transient solution. The second factor to consider is the time step size used to solve the transient analysis; it should be small enough to accurately capture the transient response of the system. However, using fine mesh density and small time step size come at the cost of computational expense, which is why it is necessary to strike a balance between numerical accuracy and computational expense. The third key consideration for numerical accuracy is the number of modes included in the modal solution. A sufficient number of modes should be included in the modal solution to avoid mode truncation error, but despite including a high number of modes in some cases, it can still be difficult to capture a localized response. In such cases, residual vectors, can be used to help capture the accurate response despite including fewer modes. In this video lesson, we start with a short lecture and then get into a workshop example of a prestressed drum-head in Ansys Mechanical.

Alternate video link.

Video Highlights

00:21 Importance of numerical accuracy in transient response
01:38 Sufficient mesh density for accurate modes and mode shapes
02:10 Extraction of sufficient number of modes
02:15 Mode truncation error
03:33 - Time step size
04:46 -Rule to calculate time step size
06:16 - Residual vectors
10:15 - How to apply prestress in Ansys Mechanical
15:13 - Post-processing of transient results

Simulation Files

Download the accompanying geometry and archived files here. Ansys Student can be downloaded for free here.