WORKSHOP 10A

MODAL ANALYSIS OF A CIRCUIT BOARDBOARD

WS10a-1NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

WS10a-2NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

MODAL ANALYSIS OF A CIRCUIT BOARD

Problem DescriptionThe purpose of this exercise is to prepare a Printed Circuit Board (PCB) for a Frequency Response Analysis. The user will import a MSC.Nastran Bulk Data file that contains the finite element definition of the PCB, assign the appropriate boundary conditions and submit the analysis for a Normal Modes Analysis.and submit the analysis for a Normal Modes Analysis.After the analysis is completed, user will use MSC.Patran to post-process the results. The main objective is to observe the natural frequencies of the PCB because they will be important at verifying the results from a Frequency Response Analysis.

WS10a-3NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

MODAL ANALYSIS OF A CIRCUIT BOARD

Problem Description (cont.)The following is a finite element representation of the Printed Circuit Board (PCB)

WS10a-4NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

MODAL ANALYSIS OF A CIRCUIT BOARD

Suggested Exercise Steps1. Import the model from a Nastran Input File.2. Create the boundary conditions.3. Submit the model to MSC.Nastran for analysis.4. Attach the .XDB results file.5. Post Process results – create a Deformation and Fringe Plot of the

eigenvectors of the normal modes.

WS10a-5NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

CREATE NEW DATABASE

a

d

Create a new database called ws10a.db.

a. File / New.

d

a. File / New.b. Enter ws10a as the file name.c. Click OK.d. Choose Default Tolerance.e. Select MSC.Nastran as the

A l i C d

b c

e

f

gAnalysis Code.

f. Select Structural as the Analysis Type.

g. Click OK.

WS10a-6NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

Step 1. File / Import

a

b

a

Import the model from a Nastran Input file.

a. File / Import.b. Select MSC.Nastran Input as cthe Source.c. Select pcb.bdf and click

Apply.d. Click OK when the Nastran

Input File Import Summary

c

p p yappears.

WS10a-7NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

Step 2. Loads/BCs: Create / Displacement / Nodal

Create the boundary condition. a. Loads/BCs: Create /

/Displacement / Nodal.b. Enter constraint for the

New Set Name.c. Click on the Input Data

button.

a

d

d. Enter <0,0,0> for Translations.

e. Click OK.f. Click on Select

Application Region.

g

pp gg. Change the Geometry

Filter to FEM.h. Select the 4 corner

nodes showed on the next page.

b

hi

p gi. Click Add, and click OK.j. Click Apply.

c

e

fi

WS10a-8NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

fj

i

Step 2. Loads/BCs: Create / Displacement / Nodal (Cont.)

WS10a-9NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

Step 3. Analysis: Analyze / Entire Model / Full Run

Submit the model for analysis. aa. Analysis: Analyze / Entire

Model / Full Run.b. Enter ws10a for the Job

Name.c. Click on Solution Type. yd. Select NORMAL MODES. e. Click on Solution

Parameter button.f. Enter 0.00259 for Wt-Mass

Conversion.

d

Conversion.g. Click OK.h. Click OK.i. Click Apply.

bf

ce

WS10a-10NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

hg i

Step 4. Analysis: Access Results / Attach XDB / Result Entities

Attach the XDB result file.aa. Analysis: Access

Results / Attach XDB / Result Entities.

b. Click on Select Result File.

a

c

c. Select ws10a.xdb.d. Click OK.e. Click Apply.

d

b

WS10a-11NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

e

Step 5. Results: Create / Quick Plot

Create a Deformation and F i l f h l

ba

Fringe plot of the normal modes.

a. Change the view to Iso View 3.

b. Results: Create /

c

Quick Plot.c. Select the Mode 1.d. Select Eigenvector,

Translational in both Result boxes.

de. Click Apply.f. Repeat the same

procedures for the remaining 9 normal modes.

d

d

WS10a-12NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

e

Summary

Summary of Frequencies and Modes for project _______________

Mode Freq (Hz)

Description

WS10a-13NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation

WS10a-14NAS122, Workshop 10a, January 2004Copyright© 2004 MSC.Software Corporation