Finite-Element ProjectABAQUS Tutorial

Mohith Manjunath

July 30, 2009

1

Contents

1 Introduction 3

2 Problem Description 3

3 Pre-processing 43.1 Part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.1.1 Ceramic . . . . . . . . . . . . . . . . . . . . . . . . . . 53.1.2 Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63.1.3 Solder . . . . . . . . . . . . . . . . . . . . . . . . . . . 103.1.4 Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.1.5 PC Board . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.2 Property . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193.2.1 Assign Sections . . . . . . . . . . . . . . . . . . . . . . 20

3.3 Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213.4 Step . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223.5 Interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243.6 Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243.7 Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.7.1 Partitioning . . . . . . . . . . . . . . . . . . . . . . . . 263.7.2 Meshing . . . . . . . . . . . . . . . . . . . . . . . . . . 37

3.8 Job . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4 Postprocessing 454.1 Visualization . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.1.1 Selecting the field output to display . . . . . . . . . . . 454.1.2 Plotting . . . . . . . . . . . . . . . . . . . . . . . . . . 45

2

1 Introduction

ABAQUS is a finite-element analysis software. Abaqus/CAE provides a pre-processing and postprocessing environment for the analysis of models. It isused in a wide range of industries like automotive, aerospace etc., and also isextensively used in academic and research institutions due to its capabilityto address non-linear problems. The Abaqus interface is shown in figure 1.

Figure 1: Abaqus Interface

Get familiar with the icons in the tool bar especially the zoom icons whichare absolutely necessary in the modeling process.

2 Problem Description

Lifetime equations for micro-electronic solder needs to be predicted in orderto guarantee reliable in-field operation of micro-electronic components. Typ-ical micro-electronic solder is shown in figure 2. The solder joints are underthermo-mechanical stress due to the change in temperature during in-fieldoperation. Basically, there is a mismatch in coefficient of thermal expansionbetween boards and components. This might lead to thermal fatigue failures

3

and can be very catastrophic. Figure 3 shows the failure of solder joint aftermany cycles in operation.

Figure 2: Microelectronic Solder

Figure 3: Microelectronic Solder after 3000 cycles of operation

3 Pre-processing

Pre-processing is the initial phase of a finite element analysis program. Thisphase includes various modules for creating a model, defining material prop-erties, specifying boundary conditions and external loads and meshing theassembly of the model.

1. Start Abaqus CAE.

2. Click Create Model Database to create a new model.

3. The previous chapter explains the different sections of Abaqus.

4. Continue with the next section for creating various parts of the model.

4

3.1 Part

Part module is used to build different parts of the model. So, for convenience,divide the whole model into various parts and create each part using thismodule. Later all the parts can be assembled to form the entire model.Here, the model is divided into five parts - Ceramic, Cap, Solder, Copperand PC Board. What follows now is a step-by-step procedure to create eachof these parts.

3.1.1 Ceramic

1. In the menu bar, click Part -> Create. Enter the name Ceramic andselect 3D, Deformable, Solid->Extrusion and enter Approximate sizeas 10 (See Figure 4).

Figure 4: Create Ceramic Part

2. Click Rectangle icon to create a rectangle. On the grid draw an arbi-trary rectangle. Click Add Dimension tool and click the left side and

5

left-click to enter the dimension. Enter 0.25 and press enter. Selectthe bottom side, left-click and enter 1.0 for the dimension and pressenter. Cancel procedure by pressing the ”X” mark in the ”promptarea”(remember to do this every time you want to come out of a pro-cedure and you can also press Esc key to exit an operation).

3. At the bottom click Done (Sketch the section for the solid extrusion).Enter depth of 0.625 and click OK.

4. From the menu bar, click Shape -> Blend -> Round/Fillet. Selectthe five edges as shown in Figure 5(Multiple edges can be selected byholding shift key). Click Done. Enter radius of 0.03. Click Done.

Figure 5: For ceramic - Select the edges as shown

3.1.2 Cap

1. In the menu bar, click Part -> Create. Enter the name Cap and select3D, Deformable, Solid->Extrusion and enter Approximate size as 10.

2. Click Rectangle icon to create a rectangle. On the grid draw an arbi-trary rectangle. Click Add Dimension tool and click the left side andleft-click to enter the dimension. Enter 0.25 and press enter. Select thebottom side, left-click and enter 0.3 for the dimension and press enter.

6

3. In the menu bar, click Add -> Fillet. Enter fillet radius as 0.03 andpress enter. Now, select the top and right side edges of the rectangle.Fillet has been created.

4. Click Add -> Point and create three points, one on the top left cornerof the rectangle and two on the corners of the arc of the fillet(See Figure6). Click Edit -> Transform -> Translate and click Copy. Now, selectthe points 1 and 2(holding shift key) and click Done. Enter 0,0 for thestart position, press enter and then enter 0,0.005 for the endpoint andpress enter again. Repeat the same procedure for point 3 and enter0.005,0 for the endpoint. Repeat the same procedure for point 1 andenter 0.135,0.01 for the endpoint. Repeat the same procedure for point3 and enter 0,-0.095 for the endpoint. Repeat the same procedure forpoint 3 and enter 0.01,-0.095 for the endpoint.

Figure 6: Section sketch for cap - Three points created

5. See Figure 7. Connect points 1 and 4 using Add -> Line -> ConnectedLines. Also, draw a line through points 8 and 9 as shown in the figure.Suppose, while performing any of these operations if a point vanishesthen you have to undo and zoom in to the area and complete theoperation(keep this in mind). Now, click Add -> Spline and draw aspline through the points 4, 5 and 6(you might have to zoom in a bit).Repeat the same procedure for the points 7 and 8(first click point 7then click somewhere in the middle(as shown) and then click point 8).Now click Add -> Arc -> Center/Endpoints. Select the center of thecircle(for the arc) and then select the two endpoints of the arc.

7

Figure 7: Create spline through the points 4-5-6 and 7-8

6. Click Edit -> Split, select the right edge of the rectangle and then thehorizontal line passing through the center of it. Now, click Edit ->Delete and select the left edge, bottom edge and the bottom half of theright edge(hold shift while selecting all three). Click Done. Now, clickEdit -> Transform -> Mirror and click Copy. Then, pick the centerhorizontal line as the mirror line. Now select all the entities above themirror line. Click Done. A mirror image is created. Now delete thecenter horizontal line. Click Done to exit the section sketch. Enter0.595 for depth and press OK.

7. In the menu bar, click Shape -> Solid -> Revolve. Select the planesection(C-Section) at the back(see figure 8) of the cap. Select one ofthe edges in the middle portion(vertical line in the C-Section). Sectionsketch appears(inverted C). Now click Edit -> Transform -> Translateand click Copy. Select all the edges in the middle portion and alsothe arcs at the top and bottom. Click Done. Enter 0,0 for the startposition, press enter and then enter 0.1,0 for the endpoint and pressenter again. In the section which was copied to the right, draw straightlines at top and bottom ends to make it a closed figure. Click Edit

8

Figure 8: Cap - After the section sketch has been extruded

-> Transform -> Translate and click Move. Now select all the entitieswhich were just copied(closed figure) and click Done. Enter 0,0 for thestart position, press enter and then enter -0.1,0 for the endpoint andpress enter again. Now, click Add -> Construction -> Vertical andclick on one of the centers of the arcs. Cancel the operation(X mark).Click Done to exit the section sketch. Enter angle as 90 degrees andpress OK.

8. In the menu bar, click Shape -> Solid -> Revolve. Select the topsection. Select the edge on the right. Section sketch appears. Nowclick Edit -> Transform -> Translate and click Copy. Select all theedges in the top portion(3 edges). Click Done. Enter 0,0 for the startposition, press enter and then enter 0,0.1 for the endpoint and pressenter again. Click Edit -> Transform -> Translate and click Move.Now select all the entities which were just copied(closed figure) andclick Done. Enter 0,0 for the start position, press enter and then enter0,-0.1 for the endpoint and press enter again. In the section which wascopied, draw a straight line at the left end to make it a closed figure.Now, click Add -> Construction -> Horizontal and click on the centerof the arcs(top). Click Done to exit the section sketch. Enter angle as90 and press OK. Repeat the above procedure for the bottom section.Finally, it should look like as shown in figure 6.

9. Click Shape -> Wire -> Sketch. Select the face marked one(the facefacing east) in the figure 6 and select one of the right edges. Using

9

Figure 9: Cap - After the edges have been revolved

connected lines tool draw the rectangle as shown in figure 7(wire sketchnumber 1). Now, click Shape -> Wire -> Point to point, select Chainedwires and click Add. All the points will be shown. Now select two pointsat a time and complete the crooked rectangle number 2 as shown infigure 7. Now, click Shape -> Solid -> Loft and click Insert Before.Select all the edges of plane 3(six edges to make it a closed loop) infigure 7. Then, click Insert After and select all the edges in the plane 1.Now, click the tab Transition and select method as Select path. clickAdd. Now, select the edges one by one going from plane 3 to plane1(two edges in plane 2, 4 and 5). Click OK when done. See figure 8.

3.1.3 Solder

1. In the menu bar, click Part -> Create. Enter the name Solder andselect 3D, Deformable, Solid->Extrusion and enter Approximate sizeas 10.

2. Click Rectangle icon to create a rectangle. On the grid draw an arbi-trary rectangle. Click Add Dimension tool and click the left edge andleft-click to enter the dimension. Enter 0.6 and press enter. Select thebottom edge, left-click and enter 0.6 for the dimension and press enter.

3. At the bottom click Done (Sketch the section for the solid extrusion).Enter depth of 1.0 and click OK.

4. In the context bar, click Module -> Assembly. Now, click Instance

10

Figure 10: Cap - Creating wires

Figure 11: Cap - Part created

-> Create. Select Ceramic, Cap and Solder and toggle on auto-offsetfrom other instances and click OK. Now, click Constraint -> CoincidentPoint and select the center of the top arc in the ceramic and the cor-responding point in the cap so that they fit together(figure 12). ClickConstraint -> Coincident Point and select the two points as shown inthe figure. Now, click Instance -> Translate and select the solder in-stance. Click Done. Enter 0,0,0 for starting point and -0.27,0,0 for the

11

end point. Click Yes.

Figure 12: Solder - Coincident points

Figure 13: Solder - Cut the geometry of cap in the rectangular solid

5. Click Instance -> Merge/Cut. Give part name as Solder-1. Select Cutgeometry and click Continue. Now, select the solder for the instanceto be cut and select the other two(ceramic and cap) for the instancesthat will make the cut(holding down the shift key). Click Done. SelectPart -> Solder-1 in the context bar. See figure 14.

6. Click Shape -> Cut -> Extrude. Select the front facing plane and thenthe right edge. Now, click Add -> Point and click on the top-left point.Click Edit -> Transform -> Translate and click Copy. Select the point

12

Figure 14: Solder - After using Merge/Cut instance

that was just created and enter 0,0 for start point and 0,-0.02 for theend point. Now, draw a rectangle(covering the entire area towards thebottom and towards the right) with the copied point as its top-leftcorner. Click done and then click OK in the window that opens.

7. Click Shape -> Cut -> Extrude. Select the front facing plane and thenthe right edge. Now, draw a spline(Add -> Spline) as shown in figure15 and make it a closed figure by drawing lines 1,2 and 3. Click Done.In the window that opens select type as blind and enter depth as 0.595and click OK.

8. Click Shape -> Cut -> Extrude. Select the left facing plane and thenthe right edge. Now, draw a spline(Add -> Spline) as shown in figure16 and make it a closed figure by drawing lines 1,2 and 3. Click Done.In the window that opens select type as blind and enter depth as 0.270and click OK. See figure 17.

9. Click Tools -> Partition and select Face -> Sketch. Select the bottomface. Click Done and select the edge which is on the right. Now, drawa spline as shown in figure 18 and click Done.

10. Click Shape -> Cut -> Loft. Click Insert before. Now, select theedges holding down shift button as shown in figure 19 and click Done.Then, click Insert after and select the edges as shown in figure 20 andclick Done. Now, click the tab Transition and select method as Select

13

Figure 15: Solder - Front view, section sketch to extrude solid

Figure 16: Solder - Side view, section sketch to extrude solid

Figure 17: Solder - Top view, after the extrusion on both sides

path. Click Add. Select the top curve and the bottom curve(one afteranother, by clicking add) which was created using partition methodand click OK. Now, remove the part that got cut by using Shape ->Cut -> Extrude and by selecting any face and any edge draw a closed

14

Figure 18: Solder - Bottom view, section sketch

figure around it. Click Done and click OK. Finally, the solder shouldlook something like figure 21.

Figure 19: Solder - Insert before operation(select the edges as shown)

11. Click Tools -> Geometry Repair and select Edge -> Remove redundantentities. Now, select the edges(holding shift) as shown in figure 22 andclick Done. The edges are now merged into one.

15

Figure 20: Solder - Insert after operation(select the edges as shown)

Figure 21: Solder - Part created

3.1.4 Copper

1. In the menu bar, click Part -> Create. Enter the name Copper andselect 3D, Deformable, Solid->Extrusion and enter Approximate sizeas 10.

16

Figure 22: Remove redundant entities on the edge shown

2. Click Rectangle icon to create a rectangle. On the grid draw an arbi-trary rectangle. Click Add Dimension tool and click the left edge andleft-click to enter the dimension. Enter 0.06 and press enter. Selectthe bottom edge, left-click and enter 0.63 for the dimension and pressenter.

3. At the bottom click Done (Sketch the section for the solid extrusion).Enter depth of 0.8 and click OK. See figure 23.

Figure 23: Copper - Part created

17

3.1.5 PC Board

1. In the menu bar, click Part -> Create. Enter the name PC Board andselect 3D, Deformable, Solid->Extrusion and enter Approximate sizeas 10.

2. Click Rectangle icon to create a rectangle. On the grid draw an arbi-trary rectangle. Click Add Dimension tool and click the left edge andleft-click to enter the dimension. Enter 1.6 and press enter. Select thebottom edge, left-click and enter 3.5 for the dimension and press enter.

3. At the bottom click Done (Sketch the section for the solid extrusion).Enter depth of 2 and click OK. See figure 24.

Figure 24: PC Board - Part created

18

3.2 Property

Property module is used to define properties of various materials used in themodel. Then, sections are created and materials are assigned to each section.This section of creating the properties of materials can be done later also, ifrequired to do so.

1. In the context bar click Module -> Property to enter into propertymodule.

2. In the menu bar, click Material -> Manager.

3. A new window opens. Now click the button Create to create newmaterial.

4. Enter the material name Ceramic and click Mechanical -> Elasticity-> Elastic. Now, enter the value 220000 MPa in the box below Young’sModulus and 0.3 for Poisson’s Ratio. Click Mechanical -> Expansionand enter 8E-6 for Expansion Coeff alpha. Click OK.

5. Click Create. Enter the material name Cap and click Mechanical -> Elasticity -> Elastic. Now, enter the value 120000 MPa in the boxbelow Young’s Modulus and 0.31 for Poisson’s Ratio. Click Mechanical-> Expansion and enter 1.6E-5 for Expansion Coeff alpha. Click OK.

6. Click Create. Enter the material name Solder-SnAgCu and click Me-chanical -> Elasticity -> Elastic. Now, enter the value 35000 MPa inthe box below Young’s Modulus and 0.34 for Poisson’s Ratio. ClickMechanical -> Expansion and enter 2.3E-5 for Expansion Coeff alpha.Click Mechanical -> Plasticity -> Creep. In the drop-down menu forLaw select Hyperbolic-Sine and enter the values shown in the tablebelow. Hyperbolic-sine law is given by:

ε̇ = C sinh(aσn)e

−QRT (1)

Where ε̇ is the strain rate, C is the power law multiplier, a the hyper-bolic law multiplier, n the stress order, Q the activation energy and Rthe universal gas constant. The values of these parameters have beentaken from reference 2.

Power Law Hyperb Law Eq Stress Activation Universal GasMultiplier(/s) Multiplier(/MPa) Order Energy(J/mol/K) Const(J/mol/K)

4.41E5 0.005 4.2 4.5E4 8.314

19

Click OK.

7. Click Create. Enter the material name Copper and click Mechanical-> Elasticity -> Elastic. Now, enter the value 90000 MPa in the boxbelow Young’s Modulus and 0.32 for Poisson’s Ratio. Click Mechanical-> Expansion and enter 1.65E-5 for Expansion Coeff alpha. Click OK.

8. Click Create. Enter the material name FR4-PC Board and click Me-chanical -> Elasticity -> Elastic. In the drop-down menu for Type se-lect Engineering Constants and tick the checkbox next to Use temperature-dependent data and enter the following values. Directions 1,2 and 3refer to the X, Y and Z directions respectively in the material. Thevalues have been taken from reference 3.

E1(MPa) E2(MPa) E3(MPa) Nu12 Nu13 Nu2319300 8300 19300 0.4 0.15 0.4

G12(MPa) G13(MPa) G23(MPa) Temp(K)8400 8400 8400 293

Click Mechanical -> Expansion and select Type as Orthotropic andenter the following values.

alpha11 alpha22 alpha331.5E-5 8.4E-5 1.5E-5

Click OK.

3.2.1 Assign Sections

After the materials have been creates we need to assign these materials tothe parts which were previously created.

1. Click Section -> Create. Enter name as Ceramic. Select Solid ->Homogenous and click Continue. From the material list select Ceramicand click OK.

2. Click Section -> Create. Enter name as Cap. Select Solid -> Homoge-nous and click Continue. From the material list select Cap and clickOK.

3. Click Section -> Create. Enter name as Solder. Select Solid -> Ho-mogenous and click Continue. From the material list select Solder-SnAgCu and click OK.

20

4. Click Section -> Create. Enter name as Copper. Select Solid -> Ho-mogenous and click Continue. From the material list select Copper andclick OK.

5. Click Section -> Create. Enter name as PC Board. Select Solid ->Homogenous and click Continue. From the material list select FR4-PCBoard and click OK.

6. In the context bar select part as Ceramic. Click Assign -> Section.Select the ceramic by clicking on it and click Done. In the window thatopens, select Ceramic from the list and click OK.

7. In the context bar select part as Cap. Click Assign -> Section. Selectthe cap by clicking on it and click Done. In the window that opens,select Cap from the list and click OK.

8. In the context bar select part as Solder-1. Click Assign -> Section.Select the solder by clicking on it and click Done. In the window thatopens, select Solder from the list and click OK.

9. In the context bar select part as Copper. Click Assign -> Section.Select the copper by clicking on it and click Done. In the window thatopens, select Copper from the list and click OK.

10. In the context bar select part as PC Board. Click Assign -> Section.Select the PC Board by clicking on it and click Done. In the windowthat opens, select PC Board from the list and click OK.

Now, the sections have been assigned to the parts with corresponding mate-rial.

3.3 Assembly

In this module, all the parts created earlier can be put together(assembly)to get the required model. After doing this we can apply the necessaryconstraints and loads on the assembly.

1. Select Module -> Assembly. Click Instance -> Create. Select Ceramicand Cap holding down Ctrl. Now, click Constraint -> Coincident pointand select the center of the top arc in the ceramic and the correspondingpoint in the cap so that they fit together.

2. Click Instance -> Create, select Solder-1 and toggle on auto-offset fromother instances. Repeat the same procedure as before to make thesolder fit right under the cap. See figure 21.

21

Figure 25: Three instances assembled

3. Click Instance -> Create, select Copper and toggle on auto-offset fromother instances. Now, click Constraint -> Coincident point and selectthe top-left corner of copper and bottom-left corner of solder.

4. Click Instance -> Create, select PC Board and toggle on auto-offsetfrom other instances. Now, click Constraint -> Coincident point andselect the top-left corner of PC Board and bottom-left corner of copper.Then, click Instance -> Translate and select PC Board instance. Enter0,0,0 for the start point and -0.7,0,0 for the end point and click yes andthen OK. Now, all the instances have been assembled and take a lookat the assembled model by rotating the figure. See figure 26.

5. Click Instance -> Merge/Cut. Enter part name as Full-Model, selectMerge ->Geometry and select Retain in intersecting boundaries sectionand click Continue. Now, select all the instances and click Done. Allthe instances are now merged and a new part by name Full-Model hasbeen created.

3.4 Step

This module is used to perform many tasks, mainly to create analysis stepsand specify output requests.

1. Select Module -> Step. Click Step -> Create. Type Extra-Step forname and select Procedure type -> General -> Visco and click Con-tinue. In the description field enter Abkhlung and enter time period as30. Go to incrementation tab and enter the following. Type:Automatic,

22

Figure 26: All instances(Ceramic, Cap and Solder) assembled

Maximum number of increments:10000, Increment size:Initial=0.5, Min=1E-6, Max=30, Tolerance=0.005 and Integration:Explicit/Implicit. Go toOther tab and select Iterative method and select ramp linearly overstep. Click OK.

2. Select Module -> Step. Click Step -> Create. Type Step-1-Abkhlungfor name and select Procedure type -> General -> Visco and click Con-tinue. Enter time period as 10. Go to incrementation tab and enter thefollowing. Type:Automatic, Maximum number of increments:10000,Increment size:Initial=0.5, Min=1E-6, Max=10, Tolerance=0.005 andIntegration:Explicit/Implicit. Go to Other tab and select Iterativemethod and select ramp linearly over step. Click OK.

3. Select Module -> Step. Click Step -> Create. Type Step-2-Halten-40C for name and select Procedure type -> General -> Visco andclick Continue. Enter time period as 900. Go to incrementation taband enter the following. Type:Automatic, Maximum number of incre-ments:10000, Increment size:Initial=0.5, Min=1E-6, Max=900, Toler-ance=0.005 and Integration:Explicit/Implicit. Go to Other tab andselect Iterative method and select ramp linearly over step. Click OK.

23

4. Select Module -> Step. Click Step -> Create. Type Step-3-Aufheizenfor name and select Procedure type -> General -> Visco and click Con-tinue. Enter time period as 10. Go to incrementation tab and enter thefollowing. Type:Automatic, Maximum number of increments:10000,Increment size:Initial=0.5, Min=1E-6, Max=10, Tolerance=0.005 andIntegration:Explicit/Implicit. Go to Other tab and select Iterativemethod and select ramp linearly over step. Click OK.

5. Select Module -> Step. Click Step -> Create. Type Step-4-Halten-auf-125C for name and select Procedure type -> General -> Visco andclick Continue. Enter time period as 900. Go to incrementation taband enter the following. Type:Automatic, Maximum number of incre-ments:10000, Increment size:Initial=0.5, Min=1E-6, Max=900, Toler-ance=0.005 and Integration:Explicit/Implicit. Go to Other tab andselect Iterative method and select ramp linearly over step. Click OK.

3.5 Interaction

As the name suggests, this module is used to define various interactionswithin the model or interactions between regions of the model and its sur-roundings. The interactions can be mechanical or/and thermal. Analysisconstraints can also be applied between regions of the model.

3.6 Load

Load module is used to define and manage various conditions like loads,boundary conditions and predefined fields.

1. Select Module -> Load. Click BC -> Create. Select Displacement/Rotationand click Continue. Select the whole of left section(plane) and holddown control key to deselect the bottom-left point(see figure 27). ClickDone and then just tick the box next to U1 to constrain that degree offreedom.

2. Click BC -> Create. Select Displacement/Rotation and click Continue.Select the corner point which was previously not selected and clickDone and then just tick the box next to U2 to constrain that degree offreedom.

3. Click BC -> Create. Select Displacement/Rotation and click Continue.Select the whole of front section(plane X-Y)(for easier selection clickthe icon in the ”prompt area” and select faces from the list and then

24

Figure 27: Boundary Condition on the left face - U1 constrained

select ”by angle” from the list in the prompt area) and click Done andthen just tick the box next to U3 to constrain that degree of freedom.

Figure 28: Boundary Condition on the front face - U3 constrained

4. Click Predefined Field -> Create. Select Other -> Temperature andclick Continue. Select the whole assembly and click Done and thenenter 421 for the magnitude of temperature. Click OK.

25

Figure 29: Predefined Field - Initial temperature for the entire model

3.7 Mesh

This is one of the most important modules since accuracy of the resultswill depend on the meshing of the assemblies. This module can be used togenerate meshes and even verify them.

3.7.1 Partitioning

1. Select Part -> Full-Model from the list in the left window. SelectModule -> Mesh. See figure 30.

2. Click Tools -> Partition. Select Cell -> Extend face, select the entiremodel and click Done. Select the face as shown in the figure 31 andclick Create partition. A partition should be created and it shouldturn green(structured mesh). Repeat the same procedure for the facesas shown in the figure 32 and 33 and now entire PC Board should turngreen(figure 33).

3. Select Cell -> Extrude/Sweep edges, select the entire model and theedge 1(choose by edge angle) as shown in figure 34. Click Done. SelectExtrude Along Direction and select the edge 2(pointing down) as shownin the same figure. Check for direction and flip if required. Click Createpartition. See figure 35.

26

Figure 30: Partitions are required for the whole model(for orange coloredones, it is mandatory)

Figure 31: Partition - Extend face

27

Figure 32: Partition - Extend face

Figure 33: Partition - Extend face

28

Figure 34: Partition - Extrude edges

29

Figure 35: Partition - The edges have been extruded

30

4. Select Cell -> Define cutting plane, select the entire model and clickDone. Then, click Point and Normal. And select point and normal asshown in the figure 36 and click Create partition. See figure 37.

Figure 36: Partition - Select the point as pointed by the arrow and the linein pink

5. Select Cell -> Define cutting plane, select the entire model and clickDone. Then, click Point and Normal. And select point and normal asshown in the figure 38 and click Create partition. See figure 39.

6. Select Cell -> Define cutting plane, select the entire model and clickDone. Then, click Point and Normal. And select point and normal asshown in the figure 40 and click Create partition. At the end of thisoperation, the model should look similar to figure 41.

31

Figure 37: Partition - At the end of previous operation

32

Figure 38: Partition - Select the point as pointed by the arrow and the linein pink

Figure 39: Partition - At the end of previous operation

33

Figure 40: Partition - Select the point as pointed by the arrow and the linein pink

Figure 41: Partition - At the end of previous operation

34

7. Select Cell -> Define cutting plane, select the entire model and clickDone. Then, click Point and Normal. And select point and normal asshown in the figure 42 and click Create partition. At the end of thisoperation, the model should look similar to figure 43.

Figure 42: Partition - Select the point as pointed by the arrow and the linein pink

Figure 43: Partition - At the end of previous operation

35

8. Select Cell -> Define cutting plane, select the entire model and clickDone. Then, click Point and Normal. And select point and normal asshown in the figure 44 and click Create partition. At the end of thisoperation, the model should look similar to figure 45.

Figure 44: Partition - Select the point as pointed by the arrow and the linein pink

Figure 45: Partitioning done - Everything is green!

36

Now, you can proceed to the meshing section but it is suggested that youtry different partitioning methods and analyze the results. In the processyou will be able to learn how to partition any complicated geometry withminimum partitioning.

3.7.2 Meshing

1. Click Mesh -> Controls. Select the entire model, click Done and selectStructured from the list and click OK.

2. Click Mesh -> Element Type. Select the entire model, accept thedefault options and click OK.

3. Click Seed -> Part. In the approximate global size field enter 0.01 andclick OK.

4. Click Seed -> Edge Biased. Switch to wire-frame view. Select theedges(click near the left end of the edges) as shown in the figure 46 andclick Done. Enter bias ratio as 10 and number of elements as 18.

Figure 46: Edges biased towards the solder(left)

5. Click Seed -> Edge Biased. Select the edges(click near the top end ofthe edges) as shown in the figure 47 and click Done. Enter bias ratioas 10 and number of elements as 18.

37

Figure 47: Edges biased towards the solder(top)

38

6. Click Seed -> Edge Biased. Select the edges(click near the right end ofthe edges) as shown in the figure 48 and click Done. Enter bias ratioas 10 and number of elements as 8.

Figure 48: Edges biased towards the solder(right)

7. Click Seed -> Edge Biased. Select the edges(click near the bottom endof the edges) as shown in the figure 49 and click Done. Enter bias ratioas 10 and number of elements as 16.

Figure 49: Edges biased(Top view) towards the solder

39

8. Click Seed -> Edge Biased. Select the edges(click near the top end ofthe edges) as shown in the figure 50 and click Done. Enter bias ratioas 10 and number of elements as 8.

Figure 50: Edges biased(Top view) towards the solder

9. Now, click the create display group icon, select ceramic from the listof sets and click replace. Click Seed -> Edge By Number. Select theedges as shown in the figure 51 and enter 14 for the number of elements.

Figure 51: Ceramic - ”Edge by number” operation for the edges shown

10. Click Mesh -> Controls and select all the cells except the ones in thecorner edge(see figure 52). Click Done and in the window that opensselect Sweep and click OK. Then, click Mesh -> Region and select allthe cells(the whole ceramic) and click Done. See figure 53.

40

Figure 52: Ceramic - Select all except the cells in green

Figure 53: Ceramic Mesh

11. Now, click the create display group icon, select cap from the list of setsand click replace. Click Mesh -> Region and select all the cells andclick OK.

41

12. Now, click the create display group icon, select solder from the list ofsets and click replace. Click Seed -> Edge By Number. Select the edgesas shown in the figure 54 and enter 14 for the number of elements.

Figure 54: Solder - ”Edge by number” operation for the edges shown

13. Click Mesh -> Controls and select all the cells except the ones in thecorner edge(see figure 55). Click Done and in the window that opensselect Sweep and click OK. Then, click Mesh -> Region and select allthe cells(the whole solder) and click Done. See figure 56.

Figure 55: Solder - Select the cells as shown

42

Figure 56: Solder Mesh

14. Now, click the create display group icon, select PC Board from the listof sets and click replace. Click Mesh -> Region and select all the cellsand click OK.

15. Now, click the create display group icon, select copper from the list ofsets and click replace. Click Mesh -> Controls and select all the cells.Click Done and in the window that opens select Sweep and click OK.Then, click Mesh -> Region and select all the cells and click OK.

Figure 57: Complete Mesh of the model

43

It should be noted that the mesh created above is not a perfect mesh.There are quite a few dark patches which should not have been there.I would suggest, since you have gained a little experience in Abaqusnow, you to experiment with the mesh by playing around with the meshcontrols, seeding etc., so that you will become familiar with differentkinds of meshes. Then, you can try to create a better mesh than thisone and be proud of doing it.

3.8 Job

Job module can be used to create and manage analysis jobs and submit themfor analysis.

1. Select Module -> Job.

2. Click Job -> Manager. In the window that opens, click Create. Enterjob name as 3DSolder and click Continue. Now, just explore all thetabs and leave the default options as it is. Click OK. Now, select thecurrent job and click Submit. After the job has been submitted, theanalysis can be monitored by clicking Monitor.

44

4 Postprocessing

The results generated from the analysis can be enormous so it requires ad-ditional processing which is termed postprocessing.

4.1 Visualization

Here the model can be viewed and various plots can be generated.

4.1.1 Selecting the field output to display

1. Select Result -> Field Output from the main menu bar. Here, one ofthe various parameters like CEEQ, PEEQ, stress components etc. canbe selected. Click OK.

4.1.2 Plotting

1. To plot undeformed shape select Plot -> Undeformed Shape from themain menu bar.

2. To plot deformed shape select Plot -> Deformed Shape from the mainmenu bar.

Here, not all the modules of postprocessing are explained. You can exploredifferent modules and try to generate plots for different parameters and getmeaningful results out of them.

45

Bibliography

1. Abaqus 6.7-4 Documentation.

2. Improving Solder Joint Reliability of WLP by Means of a CompliantLayer , Lee Hun Kwang et al., International Electronic ManufacturingTechnology 2006

3. FEM-Simulationen und Zuverlssigkeit von Advanced Packages LWF,Uni Paderborn, IFM, TU Berlin

46