Transfer Path Analysis (TPA) workflow

Transfer Path Analysis is performed in two parts:

• Part 1Compute the response of the model to unit force input at external load nodes and at connector elements.

• Part 2Compute the contribution of external applied loads across connector elements to acoustic and structural responses.

Part 1

Compute the response of the model to unit force input at external load nodes and at connector elements.

Step	Summary	Detailed help topic
1.	Create a FEM file.	Create a FEM using the Simcenter Nastran****FEM template. Set the Solver to Simcenter Nastran and set the Analysis Type to Vibro-Acoustic.	Create a new FEM file
2.	Mesh the structural model.	Mesh the structural model or import a structural mesh if desired.For each mesh collector, choose the appropriate material and physical properties for your analysis. Note: Your meshing and defeaturing steps will be different depending on whether you are performing an interior or exterior acoustic analysis.	Meshing for FEM acoustic analysis
3.	Define the fluid.	Create the 3D acoustic fluid mesh. In a vibro-acoustic analysis, the fluid and structural meshes can be dissimilar. For each mesh collector, choose the appropriate material and physical properties for your analysis. Note: Your meshing steps will be different depending on whether you are performing an interior or exterior acoustic analysis.	Meshing for FEM acoustic analysisFluid materials for acoustic analyses
4.	Create a Simulation file.	Create a Simulation file using the Simcenter Nastran Vibro-Acoustic simulation template. Select the solution as SOL108 Direct Frequency Response Functions.	Create a new Simulation file
5.	Create an AML (exterior acoustics).	Create an Automatically Matched Layer (AML) to define an artificial layer that absorbs returning waves regardless of frequency and angle of incidence.	Create Automatically Matched Layers
6.	Create microphone mesh.	Create a microphone mesh to measure sound inside or outside the fluid.	Create microphones
7.	Create structural or absorbent panels.	Create absorbent panels or acoustic absorber simulation objects on free faces of fluid elements.Or, you can use porous materials to model 3D acoustic absorbers.	Create a panelCreate an acoustic absorberPorous materials
8.	Create structural and acoustic constraints.	You can apply structural constraints only to structural nodes.You can apply acoustic constraints only to fluid nodes.	Create acoustic constraints
9.	Define forcing frequencies.	Add Forcing Frequencies to solution subcases, or at the solution level, to excite the model.	Specifying forcing frequencies for a frequency response analysis
10.	Create structural Unit Force loads.	Add Unit Forces to the connector elements and any external load nodes.	Defining acoustic sources and loadsModel and Load Pre-processing solution processUsing fields and expressions to define boundary conditions
11.	Request the types of results to output.	The Vibro-Acoustic Output Requests modeling object specifies the types of results to recover from the solution. For TPA the minimum output requests are Acoustic Pressure and Displacements. You can select nodes of interest to minimize output and solution time.	Requesting output for Simcenter Nastran analyses
12.	Solve the solution.	Solve the solution to generate the analysis results.	Solve the model
13.	Post-process results.	Use Scenario-based post-processing to examine the results.	Create and edit post-processing scenarios

Part 2

Compute the contribution of external applied loads across connector elements to acoustic and vibro-acoustic responses.

Step	Summary	Detailed help topic
1.	Create a new solution.	Create a new solution for Simcenter Nastran Vibro-Acoustic simulation template. Select the solution as SOL108 Direct Frequency Response.	Create a new solution
2.	Apply the AML (exterior acoustics).	Apply the Automatically Matched Layer (AML) to the acoustic fluid.Note: Use the same AML defined in Part 1.
2.	Create structural and acoustic constraints.	You can apply structural constraints only to structural nodes.You can apply acoustic constraints only to fluid nodes.	Create acoustic constraints
3.	Create structural loads.	You apply Forces or Moments to the external loading nodes where you applied Unit Forces.	Model and Load Pre-processing solution processUsing fields and expressions to define boundary conditions
4.	Define forcing frequencies.	Add Forcing Frequencies to solution subcases or at the solution level to excite the model. Note: Use the same Forcing Frequencies defined in Part 1.	Specifying forcing frequencies for a frequency response analysis
5.	Request the types of results to output.	The Vibro-Acoustic Output Requests modeling object specifies the types of results to recover from the solution. For TPA the minimum output requests are Applied Load and Force for the CBUSH connector elements. If you use CBUSH elements as connector elements, you must:Note: Select SORT2 as the output type.On the Bulk Data solution tab, Parameters, set PARAM, BSHFORCE, YESOn the Bulk Data solution tab select → Output Spring-Damper Forces in Absolute CSYS (BSHFORCE) YES	Requesting output for Simcenter Nastran analyses
6.	Define the vibro-acoustic solution parameters.	For vibro-acoustic solutions, in the Solution dialog box on the:Case Control page.Create a Fluid-Structure Interaction Control Parameters modeling object, where you can define parameters that control the fluid-structure interaction for the analysis.Specify the Eigenvalue solution method, number of desired modes, and the frequency range of interest.Specify the type of modal damping for fluid and structure (only for SOL 111).Bulk Data page.Create a Fluid-Structure Interface Modeling Parameters modeling object, where you can define parameters that control the fluid-structure interface (coupling) for the analysis.	Define fluid-structure interaction control parametersDefine fluid-structure interface modeling parameters
7.	Solve the solution.	Solve the solution.	Solve the model
8.	Post-process results.	Use Scenario-based post-processing to examine the results.	Transfer Path Analysis (TPA) scenario (Simcenter Nastran FEM acoustics)

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Transfer Path Analysis

Transfer Path Analysis (TPA) scenario (Simcenter Nastran FEM acoustics)

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Transfer Path Analysis (TPA) workflow, Simcenter 3D 2021.1 Series

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