Week 3

AIM: TO CHECK THE GIVEN COMPONENT FOR GEOMETRICAL ERRORS AND MESH WITH THE GIVEN ELEMENT QUALITY CRITERIA.

SOFTWARE : ANSA V19.15( HERE V MEANS VERSION ).

ABOUT ANSA : 1) ANSA WAS DEVELOPED BY BETA CAE SYSTEMS.

2) ANSA STANDS FOR "AUTOMATIC NET GENERATION FOR STRUCTURAL ANALYSIS.

3) HERE NET GENEATION MEANS MESHING - SIMPLY IT LOOKS LIKE A NET TYPE STRUCTURE.

ANSA IS A PREPROCESSOR TOOL WHICH IS USED FOR PREPROCESSING THE VARIOUS COMPONENTS OR PARTS OR PRODUCT.

ANSA PHASES: THERE ARE EIGHT PHASES IN ANSA

1) IMPORT A CAD GEOMETRY.

2) GEOMETRY CLEANUP.

3) SKIN/ MID SURFACE GENERATION.

4) SHELL/SOLID MESHING.

5) ELEMENTARY QUALITY CHECK.

6) MESH IMPROVENMENT.

7) APPLY LOAD AND BOUNDARY CONDITIONS.

8) EXPORT INPUT FILE.

1) IMPORT A CAD MODEL : HERE IT IS THE FIRST STEP IN ANSA TO IMPORT THE CAD GEOMETRY OR A CAD MODEL IN ANSA .

BUT ANSA WILL NOT TAKE ALL THE FILE FORMATS , IT WILL TAKE SOME .

LIKE FOR EXAMPLE :1)STEP- ( *.STEP /*.step/*.stp/*.STP).

2) IGES- (*.IGES/*.iges/*.igs/*.IGS).

3) STL- (*.stl).

2) GEOMETRY CLEANUP: HERE WE HAVE TO REMOVE ANY EXTRA SURFACES, HOLES, ANY GEOMETRICAL ISSUES, ANY UNNESSARY CONS , HOT PPOINTS, CUTS ETC.

IN THIS GEOMETRY CLEANUP WE WILL USE THE CHECK MANAGER FOR CHECKING ANY GEOMETRICAL ERRORS IN THE IMPORTED CAD MODEL.

3)SKIN/MID SURFACE GENERATION : A MID IS A NEUTRAL FACE WHICH IS GENERATED FROM THE DESIGN AND CAD WHICH IS GIVEN TOOLS FOR ANY PARTICULAR SHOLUD HAVE DIFFERENT THICKNESS AND DIFFERENT VOLUME TO IT.

(OR )

THE CONVERSION OF 3D CAD MODEL INTO 2D MODEL BY USING THE MID SURFACE .

4) SHELL OR SOLID MESHING :

1. SHELL MESHING: TRIANGULAR AND QUAD ELEMENTS ARE COMES UNDER THIS MESH.
2. SOLID MESH: IN THIS ANY TYPE OF STRUCTURAL OR UNSTRUTURAL MESH COMES UNDER THIS CATEGEORY.IT AGAIN CLASSIFIED INTO TWO TYPES.

1. TETRAMESH : IT IS FOR UNSTRUCTURAL 3-D MESH.
2. HEXAMESH: IT IS FOR STRUCTURAL 3-D MESH.

5) ELEMENTARY QUALITY CHECK : IT CHECKS THE DEVIATION OF QUAD ELEMENTS FROM A RECTANGUALR SHAPE. ANY WRAPAGE IS FOUND AND IT ALSO CHECKS THE MIN LENGTH , MAX LENGTH , JACOBIAN, ANGLE, QUAD ANGLE AND MUCH MORE.

6) MESH IMPROVEMENT: IT IS USED FOR IMPROVE THE MESH BY USING MACRO CUT OR BY DECREASING OR INCREASING THE MESH SIZE .

7) APPLY LOAD AND BOUNDARY CONDITIONS:BY APLLYING THE VARIOUS LOADS ON THE CAD MODEL.

8) EXPORT INPUT FILE: IT IS THE LAST STEP IN THE PREPROCESSOR.

PROCEDURE FOR MESHING:

1) IMPORT A CAD GEOMETRY.

BEFORE GIVING THE TOPO TO THE GIVEN MODEL.

2) GIVE THE TOPO OF THAT CAD MODEL OR GEOMETRY.

AFTER GIVING THE TOPO TO THE GIVEN MODEL.

3) AFTER GIVING THE ORIENTATION OF THE CAD MODEL. IN THE ABOVE FIGURE IT SHOWS TWO COLOURS FOR INSTANCE YELLOW IS NEGATIVE AND GREY IS FOR POSITIVE.

FOR INSTANCE THE ANSA GIVES THE ORIENTATION VIEW AS GREY COLOUR. BY CLICKING THE ORIENTATION IT CHANGE THE ORIENT VIEW WITH EITHER OF THAT COLOUR.

4) BY ADDING THE NEW TEMPLATE WITH ANY NAME. FOR TEMPLATE GO TO CHECK MANAGER AND RIGHT CLICK AND SELECT NEW TEMPLATE AND CHANGE THE NAME.

5) IMPORTED CAD GEOMETRY SUCCESSFULLY, THEN NEXT WE HAVE TO DO GEOMETRY CLEANUP BY USING THE CHECK MANAGER.IF ANY GEOMETRICAL ERRORS ARE PRESENT IN THAT WE HAVE TO REMOVE BY USING AUTOMATICALLY OR MANUALLY .

1. AUTO FIX IS USED TO FIX THE ISSUES WITH THE CAD MODEL SOMETIMES THE ANSA AUTOFIX MAY NOT FIX SOME ISSUES THEN WE WILL GO TO MANUALLY.
2. BELOW FIGURE REPRESENT THE GEOMETRICAL ERRROS IN THE CAD MODEL AND WE HAVE TO FIX IT BY EITHER AUTOFIX OR MANUAL.

1. FIRST GO WITH AUTOMESH.

2. KINDLY THE ANSA FIX SOME GEOMETRY ISSUES. BELOW FIGFURE REPRESENT THE AUTO FIX.

A) BY USING MANUAL FIX WE HAVE TO CLEAN THE REMAINING THINGS. BELOW FIGURE REPRESENT THE MANUAL FIX.

B) MANUAL FIX OF WHOLE COMPONENT.

C) AFTER REMOVING THE GEOMETRICAL ISSUES , IT SHOWS LIKE THE BELOW.

D) NOW IT IS COMPLETELY FREE OF GEOMETRICAL PROBLEMS , TRIPLE CONS, DOUBLE CONS, UNCHECKED FACES, MACROS, ETC.(HERE SINGLE CONS IS IN RED COLOUR, AND DOUBLE CON IS IN YELLOW COLOUR.

E) FOR INSTANCE THE CONS ARE CREATED IS DEPENDING ON THE SURFACE SHARING.

FOR EXAMPLE ANY COMPONENT HAVE TWO SURFACES ie UPPER SURFACE AND LOWER SURFACE, AND ALSO IT SHARES WITH ANOTHER SURFACES WITH ANOTHER COMPONENT SO HERE DOUBLE CONS AND TRIPLE CONS OCCURS(TRIPLE CONS ARE IN BLUE COLOUR IT INDICATES IT SHARING MORE THAN TWO SURFACES.

3) SKIN/MID SURFACE GENERATION : TO CONVERT THE 3-D CAD MODEL INTO 2-D MODEL.

A) FIRST WE HAVE TO CHECK THE THICKNESS OF THE COMPONENT FOR OFFSET. TO IDENTIFY THE THICKNESS GO TO MEASURE AND MEASURE THE THICKNESS BETWEEN THE TWO CONS OR HOT POINTS.

BELOW FIGURE SHOWS THE THICKNESS OF A GIVEN COMPONENT TO OFFSET.IN OBSERVING THE BELOW FIGURE THE THICKNESS IS ~.75.SO WE GIVE THE OFFSET VALUE AS .75/2=.375 IS THE CORRECT OFFSET OFFSET OF THIS COMPONENT.

B) THE OFFSET DISTANCE IS .75 , SELECT EITHER UPPER OR LOWER SURFACE , BY PUT THE COMPONENT IN ENTITY MODE AND OFFSET IT.

C) THE BELOW FIGURES SHOWS THE THICKNESS OF THE COMPONENT.

D) WE HAVE TO ASSIGN THE NEW NAME OF PSHELL LIKE NEW COMPONENT.

HERE I AM SELECTED MANUAL MID SURFACE BECAUSE IT IS EASY TO PROCESS THE COMPONENTS, BUT IN ANSA AUTO MID SURFACE IT TAKES MORE TIME AND ALSO IT DEPENDS ON THE HARDWARE OF THE PC.

5) ELEMENTARY QUALITY CHECK: THERE ARE SOME VALUES GIVEN FOR CHECKING THE QUALITY.

1)ASPECT RATIO -3

2)WRAPING -15

3) JACOBIAN- 0.7

4) MIN LEN- 2

5)MAX LEN-7

6)AVG LEN -5

7)MIN QUAD ANGLE-45

8)MAX QUAD ANGLE- 135

9)MIN TRIAS ANGLE -30

10)MAX TRIAS ANGLE-120

11)TRIAS PERCENTAGE- 15

A) BELOW FIGURE REPRESENTS THE MESHING OF EACH COMPONENT.

1)BELOW FIGURE REPRESENT THE OUTER HOOD COMPONENT.

2) IT IS FREE OF QUALITY FOR INSTANCE THE COMPONENT FREE OF JACOBIAN, MIN LENGHT, MAX LENGTH, ASPECT RATIO, ETC.

BELOW FIGURE SHOWS THE QUALITY CRITERIA CHECK OF THE OUTER HOOD PORTION.

3) BELOW FIGURE REPRESENT THE MESHING AND QUALITY CRITERIA OF LATCH COMPONETS.

4) MESHING OF THE ANOTHER LATCH COMPONENT.

5) QUALITY CRITERIA CHECK OF THE ABOVE COMPONENT SHOWN BELOW.

6)QUALITY CRITERIA CHECK OF MAIN HOOD COMOPNENT AFTER MESHING.

RESULT: EACH COMPONENT SATISFIED THE EACH QUALITY CRITERIA , AND BY GIVING THE PROPER MESH FLOW.

1)ASPECT RATIO -3

2)WRAPING -15

3) JACOBIAN- 0.7

4) MIN LEN- 2

5)MAX LEN-7

6)AVG LEN -5

7)MIN QUAD ANGLE-45

8)MAX QUAD ANGLE- 135

9)MIN TRIAS ANGLE -30

10)MAX TRIAS ANGLE-120

11)TRIAS PERCENTAGE- 15

ALL COMPONENTS SATISFIED ALL THE QUALITY CRITERIA ASPECTS BY ABOVE MENCTIONED DATA.