A simple 2D model of 121 QU8 elements is used in the example. It is a component on a conveyor belt used to carry coal. It has a single loadcase containing displacements, nodal stresses, gauss-point stresses, and loading data. This loading data is used to display the constraints, and the applied loads at the end of the exercise.
Step 1 |
Initialize FEMVIEW
UTILITY READ VIEWDATA LEVER.FVI FEMV LEVER |
Step 2 |
Examine loadcases and select results
UTILITY TABULATE LOADCASES |
The results consist of a single loadcase named `L1' described as `MAXIMUM END
LOAD'. There are nodal stresses, displacements, and gaussian stresses. LOADS
DATA is present.
RESULTS LOADCASE L1 |
Select nodal stresses (component XX)
RESULTS NODAL STRESS SXX |
Step 3 |
Display contours
PRESENT CONTOUR LEVELS 10 |
Figure 12.1: 10 line contours
Ten contour lines are displayed giving an overall impression of results values. Maximum and minimum values appear in the results monitor.
Display contours by DATUM and LEVELS :-
PRESENT CONTOUR DATUM 0 LEVELS 12 |
12 contour lines are displayed between maximum and minimum values, at equal intervals calculated by the program, and a datum contour at the specified value. |
Contours by DATUM and STEPS :-
PRESENT CONTOUR DATUM 0 STEPS .5E5 |
Contour lines are displayed at the specified datum value, and at increments
above and below this value, as specified by the step value
PRESENT CONTOUR LEVELS 3 |
Three contour lines are displayed: the middle contour line is at a value midway
between minimum and maximum results values
PRESENT CONTOUR LEVELS 1 |
A single contour line is displayed at a value midway between minimum and maximum
results values
PRESENT CONTOUR LEVELS 14 |
14 values are contoured : this would be the maximum number of contour lines that could be displayed on a 16 colour device such that each contour line would have a unique colour
PRESENT CONTOUR VALUES 0 .2E5 .5E5
Figure 12.2: Contouring by Values
Contour lines are displayed at the specified value or values.
Contours by FROM and TO :
PRESENT CONTOUR FROM 0 TO .1E6 LEVELS 9
Contour lines are displayed at both the FROM and TO values, while there are 9 intermediate contours displayed.
PRESENT CONTOUR FROM 0 TO .1E6 STEPS .2E5
Contour lines are displayed at both the FROM and TO values, while intermediate contours are displayed with the specified increment starting from the FROM value upwards.
PRESENT CONTOUR FROM .1E6 TO 0 STEPS -.2E5
Colours are reversed by reversing FROM and TO values, and giving a negative step. This is used to colour smaller values in red, as with safety factors or the highlighting of compressive stresses
Step 4 | Contouring options |
Change to a display of the complete mesh
VIEW MESH
Present a simple contour display by DATUM and STEP on which to investigate advanced features of contouring, including control of colour modulation, annotation, and keylines
PRESENT CONTOUR DATUM 0 STEPS .4E5
PRESENT OPTIONS CONTOUR LINES MODULATE 3
3 colours are used in the colour modulation of the contour lines
PRESENT OPTIONS CONTOUR LINES MODULATE 5
5 colours are used in the colour modulation of the contour lines
PRESENT OPTIONS CONTOUR LINES MODULATE ALL
All available contouring colours on the current graphics device are used in the colour modulation of the contour lines
PRESENT OPTIONS CONTOUR LINES ANNOTATE 1
Every contour line segment is annotated as it is drawn; this can give a very crowded picture
PRESENT OPTIONS CONTOUR LINES ANNOTATE 2
Every second contour line segment is annotated as it is drawn element by element
PRESENT OPTIONS CONTOUR LINES ANNOTATE 10
Every tenth contour line segment is annotated as it is drawn element by element
PRESENT OPTIONS CONTOUR LINES ANNOTATE OFF
Annotation is switched off: this can be useful if many contour lines are displayed
PRESENT OPTIONS CONTOUR LINES ANNOTATE 5
The default is annotation every fifth contour line segment
PRESENT OPTIONS CONTOUR LINES KEYLINE 2
Figure 12.3 Keyline set to 2
Every second contour line is a keyline and is annotated : lines in between are not annotated
PRESENT OPTIONS CONTOUR LINES KEYLINE 4
Every fourth contour line is a keyline and is annotated : lines in between are not annotated
PRESENT OPTIONS CONTOUR LINES KEYLINE 1
The default is that every line is a keyline and is annotated every fifth contour line segment
PRESENT OPTIONS CONTOUR FILL
Solid colour can be used on graphical displays that are capable of area fill
PRESENT OPTIONS CONTOUR FILL MAX
It is possible to fill each element in a colour representative of the highest result value occurring within the element
PRESENT OPTIONS CONTOUR FILL MIN
It is possible to fill each element in a colour representative of the lowest result value occurring within the element
PRESENT OPTIONS CONTOUR FILL ALL
The default for contour fill is that all results will be used to contour each element face
PRESENT OPTIONS CONTOUR EDGES
The mesh can be displayed using colour modulation so that each edge is coloured so that it is representative of the result values along that edge
PRESENT OPTIONS CONTOUR EDGES MAX
Colours are modulated so that each edge is coloured so that it is representative of the highest result value within that edge
PRESENT OPTIONS CONTOUR EDGES MIN
Colours are modulated so that each edge is coloured so that it is representative of the lowest result value within that edge
PRESENT OPTIONS CONTOUR EDGES ALL
The default is that the full range of result values within the edge will be used for colour modulation along the edge
Select contour lines and an outline view
PRESENT OPTIONS CONTOUR LINES
VIEW EDGES
Turn off all contour annotation
PRESENT OPTIONS CONTOUR LINES ANNOTATE OFF
Select 30 levels of contour
PRESENT CONTOUR LEVELS 30
This results presentation mode can be used to give a feeling of the flow of the stress and the rate of change of stresses within the model
PRESENT CONTOUR LEVELS 60
The closeness of the contour lines gives an indication of stress gradient
PRESENT CONTOUR LEVELS 100
The maximum number of line contours allowed are 100 levels : which are possibly too many levels for this model
PRESENT OPTIONS CONTOUR FILL
Figure 12.4: Contour fill plot
If there are not sufficient colours to permit a requested operation, the colours will be mapped, and a warning will be issued
PRESENT CONTOUR LEVELS 13
With contour fill, one more colour than the number of colours specified will be required to colour code the picture
Step 5 | Contouring element results |
So far in this tutorial, only nodal values have been used for contouring. Elementwise nodal values or gauss-point values may also be used
UTILITY TABULATE LOADCASES
RESULTS GAUSSIAN G SXX
PRESENT CONTOUR LEVELS 13
If elementwise values, or gauss-point values are used there will typically be discontinuities at the element boundaries
DRAWING CONTENTS TEXT POSITION
results discontinuities here
DRAWING CONTENTS POINTER POSITION
Text and pointers can be added to the picture to draw attention to points of interest
EYE ZOOM IN .5 .424 .684 .619
Discontinuities can indicate where the mesh needs to be refined further. Averaged nodal values will smooth out these discontinuities.
DRAWING CONTENTS TEXT DELETE ALL;
DRAWING CONTENTS POINTER DELETE ALL;
PRESENT OPTIONS CONTOUR FILL MAX
In this display the highest gauss-point result within the element determines the colour used for contouring.
PRESENT OPTIONS CONTOUR FILL ALL;
RESULTS CALCULATE VONMISES
PRESENT CONTOUR LEVEL 13
A display of von mises equivalent stress calculated from the gauss-point values using contour fill
RESULTS CALCULATE P-STRESS P1 2DSORT
PRESENT CONTOUR LEVELS 12
Repeat with principal stress P1 and twelve levels of contour
RESULTS CALCULATE P-STRESS P2 2DSORT
PRESENT CONTOUR LEVELS 12
Repeat with principal stress P2 and twelve levels of contour
Step 6 |
A display of loading and constraints for this analysis
RESULTS OFF;EYE FRAME UTILITY TABULATE LOADCASES RESULTS LOADCASE L1 |
The display of constraints superimposed on the deformed mesh
VIEW OPTIONS DEFORM ALL
LABEL MESH CONSTRNTS
The display of the applied loading using 3D vectors
RESULTS NODAL END ALL
PRESENT OPTIONS VECTORS 3D-HEADS
PRESENT VECTORS
A dotted outline representation is useful to superimpose the undeformed mesh on the picture
EYE LOCATE
Figure 12.5: Loads and Constraints