49.2 Stress linearization example

Figure 49–2 shows an example of a stress line defined for an axisymmetric model of a pressure vessel.

Figure 49–2 Stress line through an axisymmetric model of a pressure vessel.

The stress line Section_A_B is defined through the vessel wall. Figure 49–3 and Figure 49–4 show the basic settings and computations, respectively, that you use to linearize the S22 stress component for the undeformed model shape.

Figure 49–3 Stress linearization basic specifications.

Figure 49–4 Stress linearization computations.

When you click OK or Apply in the Stress Linearization dialog box, Abaqus/CAE creates an X–Y plot of the S22 stress component (oriented normal to the stress line) and of the resulting linearized stresses, as shown in Figure 49–5.

Figure 49–5 Linearized stress plot.

The following output is also written to a file called linearStress.rpt:

********************************************************************************
Statically Equivalent Linear Stress Distribution across a Section,
written on Thu Sep 08 13:16:29 2005

Source
-------

   ODB: Job-1.odb
   Step: Step-1
   Frame: Increment      1: Step Time =    1.000

Linearized Stresses for stress line 'Section_A_B'


                       X           Y           Z       XY Shear 
                     Stress      Stress      Stress      Stress  
     Membrane    
(Average) Stress     -253.25     1342.83     1317.87     62.6914  

     Bending     
 Stress, Point 1     -209.126     218.605      140.32           0

  Membrane plus  
Bending, Point 1    -462.376     1561.43     1458.19     62.6914  

     Bending     
 Stress, Point 2       184.48    -206.046     -140.32           0  

  Membrane plus  
Bending, Point 2      -68.77     1136.78     1177.55     62.6914

   Peak Stress,  
     Point 1                0    -11.2393    -7.44218     12.0759  

   Peak Stress,  
     Point 2                0     30.1772     20.4924    -19.5983  
-------------------------------- INVARIANT RESULTS --------------------------
Bending components in equation for computing
membrane plus bending stress invariants are:   S22
                      Max.        Mid.        Min.       Tresca       Mises  
                      Prin.       Prin.       Prin.      Stress      Stress  
      Membrane    
(Average) Stress     1345.29     1317.87    -255.709        1601     1587.47

  Membrane plus  
Bending, Point 1     1563.6      1317.87    -255.413     1819.01     1709.45

  Membrane plus  
Bending, Point 2     1317.87      1139.6    -256.072     1573.95     1492.82

   Peak Stress,  
     Point 1          132.878    -10.5051    -209.861     342.738     298.137

   Peak Stress,  
     Point 2           186.93     27.7269    -119.828     306.758     265.724

The Y Stress corresponds to the S22 stress shown in Figure 49–5. The actual stress values plotted in the curve Section_A_B_S22 do not appear in the report. The linearized membrane and membrane-plus-bending stress curves are generated from the values shown for Y Stress. The reported invariants are calculated from the selected linearized components.