Ansys Mechanical APDL lecture 9 by Haydar Alsalami from IRAQ - Hilla, studied in JNTUH - INDIA .

7/29/2019 Ansys Mechanical APDL lecture 9 by Haydar Alsalami from IRAQ - Hilla, studied in JNTUH - INDIA .

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1 | Haydar Alsalami \ JNTUH \ India mobile: 00919059070644Iraq mobile: 009647801518389 E-Mail: [email protected]

Harmonic and Transient motion:


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This is important thing we must

do, Changing Job Name is the

better way to save our work later

without any problems.

Enter the Job Name you want. And

PickYes for new Log error file thisis good for Session Editor.

Hint: Sometimes, some windows

disappear, so click on this icon


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Preprocessor:

Choosing structural to

update all mechanicaland physical properties

such as Loads, stresses ..

etc.


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Select element types, first we choose

Structure Mass3D mass 21

Then we choose Beam3D Finite

strain or2 node 188

Combination(SpringDamper) we add

this Element Type because we want apply

Harmonic orTransient according to the

Mass

(Spring Damper) element type

makes Natural Frequency and

frequently motion like pull and

push without any external force.


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From Mass Options select (2-D w/o rot iner),

this will make a mass give us 2D frequency.


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From COMBINATION Options

select (2-D longitudinal)


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Add Real Constant forMass :

enter the amount of mass let us

say (50 kg), then Apply.


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We must enterSpring Constant

according to any problem, we take it

here = 2500, also if there is Damping

Coefficient, this is OK, but here we

dont have. Also we have to set the

Real Constant Set No. as we wish,

here we take it = 2, because this will

help us in Mesh Attribute.

Real Constant for

Combination


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Add Material Properties forBeam


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EnterBEAM Section dimension according

to the problem, Note ID = 2 to make

compatibility between IDs.


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Draw keypoints and Lines according to the

problem.


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Mesh attribute for the Beam

Material forBeam

NO Real Constant forBeam select anything

Element Type is BEAM

Element Section forBeam


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NO Material forSpring select anything

Real Constant set forSpring is 2

Element Type is COMBINATION

NO Element Section forSpring


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Manual Mesh forSpring,

No of Division must be = 1

, to get suitable frequency


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Manual Mesh forBeam, No

of Division = 10


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Apply Mesh for this Keypoint,

because the Mass will affect

here, then OK

It will be like this,

activate Multi-Plots.


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Apply Mesh for All

Lines


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SolutionAnalysis Type

New Analysis, we already onStatic, then OK and go to click

Finish to enter to Modal.


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PickFinish


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Select Modal then OK


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Analysis Options : this window for setup motion of frequency like

up and down (all these options for choosing the shape of

frequency) and where it should affect .. select (Block Lanczos) if

there is no solution select (PCG Lanczos) they give same work.

Enter 10 for example, means the No. of Nodesthat expose to the extraction of Frequency

Enter 10, means the No. of Nodes

that expose to the expansion of

Frequency

Pick Yes

Pick OK

Frequency start from 0 unit

Frequency end at 10 units

Select To unity for better frequency as Dinesh said

Pick OK


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Apply Displacement Constraints

on Keypoints.


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IMPORTANT: we must pickFirst

Set before we go to Plot Results


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The deformation will be UP and

DOWN because of frequency.


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26 | Haydar Alsalami \ JNTUH \ India mobile: 00919059070644

Iraq mobile: 009647801518389 E-Mail: [email protected]

SelectNext Set of Nodes to see

the deformation on them.

NO deformation in theNext Set

of Nodes, again clickNext Set.


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Now you can see, since you click

Next Set you can see if there is

deformation on the Nodes or not, also

for better view activate Animation.


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We have got this from

picking Last Set.

ClickFinish, means end

ofModal study and

entering Harmonic study

(to see what happen with

respect to external force)


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Select Modal, then OK and

go forAnalysis Options.


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Select Full solution method

Select DOF format

Leave it Nobecause we dont have

sudden Mass occurs or falling.

If we use any assistant

program with ansys to solve

equations we can choose it.

Leave it 0

Pick Yes to activate

Prestress effect if desired.


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Go forSolution Printout Select Every substep means solutionfrom first Node to the last Node. OK


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Go for Freq and Substeps Frequency Range means Amplitude of

frequency.

Enter 10 as Range above (always

Select Stepped for steady load andRamped foe sudden load


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This is optional, if you wish to see

Boundary Conditions again

activate (All Applied Boundary

Conditions) or you can activate

anything from this window.


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Because of we study Harmonic,

there must be an external force

in addition to assigned mass


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See here the deformation for the First Set


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Activate Animation to see what happen

ClickFinish to go to

Transient study ( to see

what happen with

respect to Time)


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Time 0.0001 0.5 1.25 2 5

Incremental Time 1 0.1 0.1 0.2 0.5

Force 0 5000 -2000 5000 0

L.S File steps 1 2 3 4 5


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Select Transient

Select Full solution


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Select Soln Controls

Basic

Select Large to include large

deformation (reverse to small)

Pick it On

Given data input Time start with (0.0001)

On, to get continuous graph

Enter suitable No. for

amplitude of graph depending

on load steps and time

increments., in the given datanamed(incremental time), here

we start with (1).

Pick OK


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Delete Load from this keypoint because

forces in the given data start from zero.


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Pick OK


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Pick here

Write to L.S file means registering each

step that we made it and start with No.

(1) , then after completing all procedure

we can solve the problem (from L.S file)

not (Current L.S) as we used to.

Until now we finish step no. (1)

then repeat same procedure to

complete step no. (2) and so-on.


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Given data input second Time is (0.5)

Given data input second IncrementalTime is (0.1).

Basic


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PickTransient

Change from Stepped to Ramped because the

graph was in the zero point so the force was

uniform or horizontal, in current step the force

changed and the time changed to new peak so the

graph line is not horizontal as in the problem fig.

PickOK


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Add second force as the

given data table = 5000


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Pick OK


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Write L.S file

Step No. 2 complete

Repeat same procedure until

you finish all data in the table,

and you got many steps to

Usually we select (Current L S) to


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Solve (From L.S Files)

Usually we select (Current L.S) to

solve the problem only in one step,

But here we have many steps .

Solution start from Step 1

Until Step 5

Leave it

Pick OK


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Ansys Mechanical APDL lecture 9 by Haydar Alsalami from IRAQ - Hilla, studied in JNTUH - INDIA .

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Transcript of Ansys Mechanical APDL lecture 9 by Haydar Alsalami from IRAQ - Hilla, studied in JNTUH - INDIA .