Simcenter Testlab Transfer Path Analysis: Using Groupsets
The Groupset feature of Simcenter Testlab can be used for gaining more insights into results of a Transfer Path Analysis (TPA).
Consider the results of a powertrain noise transfer path analysis from a vehicle shown in Figure 1.
Figure 1: Each vertical bar represents the contribution of an individual path (left axis). The level of the path contribution is indicated by the color, while the operating condition is given in engine rpm (bottom axis).
Each colored vertical bar represents the contribution of one path. They include tailpipe noise, structural engine mounts, acoustic radiation from the engine, exhaust hangers, and more…
These sources are illustrated in Figure 2.
Figure 2: Powertrain noise sources.
Each group consists of several different individual paths. For example, the engine may have three different mounts connected to the vehicle body. The exhaust system could have four different exhaust hangers.
In the “TPA Results” worksheet of Simcenter Testlab Transfer Path Analysis, click on the “New Groupset” button located on the left side as shown in Figure 3.
Figure 3: To define a Groupset, click on the “New Groupset” button on the left side of the screen in the “TPA Results” workbook.
The other buttons next to the “New Groupset” button are used to edit existing Groupset or delete Groupsets.
In the “Group Set Definition” menu, enter an overall Groupset name at the top. Highlight the individual paths, and enter a sub group name as shown in Figure 4.
Figure 4: In the “Group set definition” menu, enter an overall Groupset name as well as a sub Group name.
In the “Group set definition” menu, the individual paths will be listed on the left side. Highlight the paths to be grouped (on the left side of the menu) and click on the “Create Group with Selected Paths” button (Figure 5).
Figure 5: Click on “Create Group with selected paths” button. The new group will appear on the right side of the screen and the individual paths will be removed from left.
The new sub group will be listed on the right side of the screen. The remaining paths will be on left.
The process can be repeated until all the desired groupings are defined as shown in Figure 6.
Figure 6: “Group set definition” menu after consolidating individual paths to five groups.
With the Groups defined, close out of the Groupset menu. It is not necessary that all individual paths are put into a group. Any individual path left over will be put in the “Ungrouped” set.
Now the Transfer Path Analysis results can be viewed using the Groupset information. In the “TPA Results” workbook, make sure the newly defined Groupset is selected and press the “Update Display” button as shown in Figure 7.
Figure 7: Make sure the new Groupset is selected (top of picture) and click on the “Update Display” button (bottom of picture).
Now instead of showing individual paths, the Transfer Path results display shows individual bars for each group as shown in Figure 8.
Figure 8: Using Groupsets, the individual path information is consolidated. In this case, the engine structure borne noise is clearly the highest contributor while the tailpipe noise is lowest.
In this result, the engine structure borne noise is the highest contributor while the airborne tailpipe noise is the lowest contributor. This is easier to understand than the original results shown in Figure 1.
The Groupset feature can be used to group data in several different ways. For example, data could be grouped by direction: lateral, fore-aft, vertical.
Enjoy the Groupset feature of Simcenter Testlab Transfer Path Analysis!