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11.3 The session

The exercise begins with reading in the results and model data from file into FEMVIEW. A series of graphs are then produced to show the main features of the graphing module. Finally users are asked to generate particular displays, to consolidate their knowledge of this section.

Step 1 Read results data and enter FEMVIEW

UTILITY READ VIEWDATA TRANS1.FVI

FEMV TRANS1

  Display the full mesh with shrunken elements

VIEW OPTIONS SHRINK;VIEW MESH

LABEL MESH NODES

  The model consists of ten QU8 elements and four 3 noded beams

Step 2 Look at the loads

  The model contains two loadcases : the first CONDUC has TEMP values varying with time from time=0 (step 0) to time=20 (step 46), seconds THERMO is a static loadcase, and has values of THERM1 and THERM2

UTILITY TABULATE LOADCASES

[00n.bmp]

Figure 11.1: Model with node labels

Step 3 Plot a graph of temperature against time for certain nodes.

A loadcase can be selected either by loadcase name or loadcase name and increment. A range of loadcases can be selected by specifying the increment range, or the time range.

First we select the required loadcase and step range.

RESULTS LOADCASE CONDUC 0 TO CONDUC 46

  The select the required attribute.

RESULTS NODAL TEMP

  Present the graph for node 2.

PRESENT GRAPH NODES 2

If desired we can present a graph for several nodes.

PRESENT GRAPH NODES 2 53 4

Step 4 Plot a graph of temperature against time for certain elements.

  The temperatures also exist as element results, which we select.

RESULTS ELEMENT TEMP

PRESENT GRAPH ELEMENT 2 9 10 11

  It can be seen that the mean value for each element is plotted. We can change the way the one value for each element is calculated.

RESULTS RANGE EL-RESULT MAX

DRAWING DISPLAY

  We have complete control over which value for each element is graphed.

PRESENT GRAPH ELEMENT 9 MIN 9 MAX 11 NODE 1 11 NODE 2 11 NODE 3

Step 5 We could have used PRESENT GRAPH PROMPT instead for graphing of element nodal temperature against time for certain nodes (e.g. node 53).

PRESENT GRAPH PROMPT

LOADCASES

CONDUC 0 TO CONDUC 46

1

ELEMENT TEMP

10 NODE 53

Specify the limits to the axes.

PRESENT OPTIONS GRAPH AXES XMIN 0 XMAX .1 YMIN 20 YMAX 28

You could select a smaller range of loadcases.

RESULTS LOADCASE CONDUC BELOW .1

EYE FRAME

Label the points on the graph.

PRESENT OPTIONS GRAPH POINTS LABELS

You can use the cursor to get feedback on values anywhere on the graph.

PRESENT OPTIONS GRAPH FEEDBACK .336 .481

Swap the graph axes.

PRESENT OPTIONS GRAPH AXES SWAP

  Clear the previous setting.

RESULTS STACK CLEAR

PRESENT OPTIONS GRAPH AXES SWAP;

PRESENT OPTIONS GRAPH POINTS LABELS OFF;

VIEW MESH

Step 6 The model also contains a static loadcase "THERMO" with two nodal attributes "THERM1" and "THERM2". Plot a graph of these temperatures against distance along two lines of nodes:

The line of nodes along the top edge, and the line of nodes along the bottom edge.

First of all we construct the required lines, giving them suitable names to be saved under.

CONSTRUCT LINE NODES TOP_EDGE THROUGH 24 2

CONSTRUCT LINE NODES BOT_EDGE THROUGH 4 1

Select the required loadcase and results attributes

RESULTS LOADCASE THERMO

RESULTS NODAL THERM1

Present the graph along both of the lines.

PRESENT GRAPH LINE TOP_EDGE BOT_EDGE

Step 7 Display more than one attribute on the same graph.

We first add the current attribute to the results stack.

RESULTS STACK ADD

Then we select the second attribute and force the graph to be redrawn.

RESULTS NODAL THERM2

DRAWING DISPLAY

   

You can specify limits to individual axes.

PRESENT OPTIONS GRAPH AXES 1 YMAX 1400;

PRESENT OPTIONS GRAPH AXES 2 YMIN 200

Change the size and position of the graph on the screen.

PRESENT OPTIONS GRAPH RESIZE .396E-1 .804 .816 .203

Return to the original settings.

PRESENT OPTIONS GRAPH RESIZE FRAME;

EYE FRAME

Specify that a single axis is used.

PRESENT OPTIONS GRAPH AXES SINGLE

You can shift the graph on the screen and zoom out by a factor.

EYE SHIFT .850 .294 .850 .378

EYE ZOOM FACTOR .8

Or zoom in on a particular bit of the graph.

EYE ZOOM IN .479 .558 .694 .465

[graph1.gif]

Figure 11.2: Superimposed Graphs

Step 8 Now we want to plot a graph of one results attribute against another.

We can do this using the command PRESENT GRAPH RESULTS. Therefore, to display a graph of THERM2 against THERM1 for the nodes in line "TOP_EDGE", use:

EYE FRAME;

PRESENT GRAPH RESULTS

NODAL THERM1

1

NODAL THERM2

LINE(S)

TOP_EDGE

THERMO

We can do the same for both lines, this time using PRESENT GRAPH PROMPT.

PRESENT GRAPH PROMPT

RESULTS

NODAL THERM1

1

NODAL THERM2

LINE(S)

TOP_EDGE BOT_EDGE

THERMO

Step 9 Calculate the value of each integral.

RESULTS CALCULATE INTEGRATE LINE

RESULTS CALCULATE INTEGRATE OFF;

Step 10 Set an axis to have a log scale.

PRESENT OPTIONS GRAPH AXES YLOG

Step 11 Finally you can specify the thickness of lines and no points.

PRESENT OPTIONS GRAPH LINES THICK;

PRESENT OPTIONS GRAPH POINTS SYMBOLS OFF

RESULTS RANGE EL-RESULT ALL

[graph2.gif]

Figure 11.3: Graph of multiple results attribute on two lines


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