Ws03_directtransient

8/6/2019 Ws03_directtransient

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WS3-1

WORKSHOP 3

DIRECT TRANSIENT ANALYSIS

NAS122, Workshop 3, August 2005Copyright 2005 MSC.Software Corporation


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WS3-2NAS122, Workshop 3, August 2005Copyright 2005 MSC.Software Corporation


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DIRECT TRANSIENT RESPONSE

Problem Description Using the direct method, determine the transient response of the

flat rectangular plate, created in Workshop 1a, subject to time-

varying excitation. This example structure is excited by 1 psi

pressure load over the total surface of the plate varying at 250 Hz.

In addition, a 50 lb force is applied at a corner of the tip also

varying for the duration of 0.008 seconds only. Use structuraldamping of g = 0.06 and convert this damping to equivalent viscous

damping at 250 Hz. Carry the analysis for 0.04 seconds.


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Problem Description (cont.) Below is a finite element representation of the flat plate. It also

contains the loads and boundary constraints.

1 p s i o ve r t h e t o ta l su r f a ce

50.00


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Suggested Exercise Steps1. Import the model from Workshop 1a.

2. Create a non-spatial field for the pressure load and the force load.

3. Create a time dependent load case.

4. Create the time dependent force load.

5. Create the time dependent pressure load.

6. Submit the model to MSC.Nastran for analysis.7. Attach the .XDB results file.

8. Post Process results create X vs Y graph of displacements.


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CREATE NEW DATABASE

Create a new database calledws3.db.

a. File / New.

b. Enterws3 as the file name.

c. Click OK.

d. Choose Default Tolerance.

e. Select MSC.Nastran as theAnalysis Code.

f. Select Structural as theAnalysis Type.

g. Click OK.

a

bc

d

e

f

g


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Step 1. File / Import

Import the model from Workshop 1a.

a. File / Import.

b. Select MSC.Patran DB as theSource.

c. Select ws1a.db.

d. Click Apply.

e. Click OK when the PatranDatabase Import Summaryappears.

a

bc

d


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Step 2. Field: Create / Non Spatial / Tabular Input

Create a Non Spatial field forthe pressure load.

a. Fields: Create / NonSpatial / TabularInput.

b. Enterpressure forthe Field Name.

c. Select Time (t) as theActive IndependentVariable.

d. Click Input Data.

e. Click Map Functionto Table.

f. Type in the function,sind(250*360*t) and

the values shown.g. Click Apply.

h. Click OK on the table.

i. Click Apply.

a

b

c

d

e

f

gh

i

Note the PCL Syntax:

Sind Sine function in degrees

t time is a Patran global variable


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Step 2. Field: Create / Non Spatial / Tabular Input (Cont.)

Create a Non Spatial field forthe force load.

a. Enterforce for theField Name.

b. Select Time (t) as theActive IndependentVariable.

c. Click Input Data.

d. Click Map Functionto Table.

e. Type in the function,-sind(250*360*t) andthe values shown.

f. Click Apply.

g. Click OK on the table.

h. Click Apply.

a

b

c

d

e

f

g

h


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Step 3. Load Cases: Create

Create a Time Dependent load case.

a. Load Cases: Create.

b. Enterdirect_transient for theLoad Case Name.

c. Select Time Dependent asthe Load Case Type.

d. Click Assign/Prioritize

Loads/ BCs.

e. Click on the Displ_constraint

in the Select IndividualLoads/BCS field.

f. Click OK.

g. Click Apply.

a

b

c

d

e

f

g


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Step 4. Loads/BCs: Create / Force / Nodal

Create the time dependentForce load.

a. Loads/BCs: Create /Force / Nodal.

b. Enter50lb for theNew Set Name.

c. Click on the InputData button.

d. Enter forForce, and selectForce for theTime/Freq.Dependent Field.

e. Click OK.

f. Click on SelectApplication Region.

g. Change the GeometryFilter to FEM.

h. Select the bottom

right corner node forthe application region.

i. Click Add, and clickOK.

j. Click Apply.

a

b

c

d

e

f

g

h

i

j

i


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Step 5. Loads/BCs: Create / Pressure / Element Uniform

Create the time dependentPressure load.

a. Loads/BCs: Create /Pressure / ElementUniform.

b. Enterpressure forthe New Set Name.

c. Change the TargetElement Type to 2D.

d. Click on the InputData button.

e. Enter-1 for Top SurfPressure, and selectPressure for theTime/Freq.Dependent Field.

f. Click OK.g. Click on Select

Application Region.

h. Select all theelements for theapplication region.

i. Click Add, and clickOK.

j. Click Apply.

a

b

c

d

e

f

g

h

i j

i


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Step 6. Analysis: Analyze / Entire Model / Full Run

Submit the model for analysis.

a. Analysis: Analyze /Entire Model / Full Run.

b. Click on Solution Type.

c. Select TransientResponse.

d. Change the Formulationto Direct.

e. Click on SolutionParameter.

f. Enter 0.00259 for Wt-Mass Conversion.

g. Enter0.06 for Struct.Damping Coefficientand 1570 for W3,Damping Factor.

h. Click OK.

i. Click OK.

a

b

c

d

e

f

g

h

i


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Step 6. Analysis: Analyze / Entire Model / Full Run (Cont.)

Submit the model for analysis(cont.).

a. Click on Subcases.

b. Select direct_transient

from the AvailableSubcases field.

c. Click on SubcaseParameters.

d. Click on DEFINE TIMESTEPS button.

e. Change Delta-T to0.0004. Click Enter.

f. Click OK.

g. Click OK.

h. Click Apply.i. Click Cancel.

a

c

b

d

e

f

g

h i


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Step 6. Analysis: Analyze / Entire Model / Full Run (Cont.)

Submit the model for analysis(cont.).

a. Click on SubcaseSelect.

b. Select direct_transient

and unselect Default.

c. Click OK.d. Click Apply.

a

b

c

d


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Step 7. Analysis: Access Results / Attach XDB / Result Entities

Attach the XDB result file.

a. Analysis: AccessResults / Attach XDB /Result Entities.

b. Click on Select ResultsFile.

c. Select ws3.xdb.d. Click OK.

e. Click Apply.

a

b

c

d

e


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Step 8. Results: Create / Graph / Y vs X

Create a X-Y graph ofdisplacement results.

a. Results: Create / Graph / Yvs X.

b. Click onSC1:DIRECT_TRANSIENT.

c. Select Global Variable asthe Filter Method.

d. Click Filter.

e. Click Apply.

f. Click Close.

a

b

c

d

e f


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Step 8. Results: Create / Graph / Y vs X (Cont.)

Create a X-Y graph ofdisplacement results (cont.).

a. Select Displacement,Translational for theSelect Y Result field.

b. Select Z Component asthe Quantity.

c. Click on the TargetEntities icon.

d. Change the TargetEntity Selection toNodes.

e. Select the upper right

node (node oppositewhere force is applied).

f. Click Apply.

b

a

c

d

e

f


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Step 8. Results: Create / Graph / Y vs X (Cont.)


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Documents

Ws03_directtransient