怎么修改才能达到目的？

jiiezh

初学python作abaqus后处理，请指点一下：

读取job-a.odb，对Step-2的Mises应力与Step-1的Mises应力相减；如何以云图的形式显示Step-1中各个积分点的Mise应力减去500后结果？
   
from abaqus import*
from abaqusConstants import*
import visualization
myViewport=session.Viewport(name='Example',origin=(10,10),width=150,height=150)
myOdb2=visualization.openOdb(path='Job-a.odb')
myOdb=myOdb2
myViewport.setValues(displayedObject=myOdb)
firstStep=myOdb.steps['Step-1']
secondStep=myOdb.steps['Step-2']
frame1=firstStep.frames[-1]
frame2=secondStep.frames[-1]
stress1=frame1.fieldOutputs['S']
stress2=frame2.fieldOutputs['S']
dels=(stress1-stress2)/0.0135
delx=sqrt(abs(dels*0.675*0.675))
values=stress1.values
for v in values:
  print (v.nodeLabel,v.data[0])