因需要分析主应力方向变化，查了好久，用了这段代码，但这个总是无法运行，有知道的麻烦给看看，我用的5.0版本的。
def get_principal
p_z=z_nearall(10,5,10)
arr1 = array(3)
arr2 = array(9)
zone.stress.prin.dir(p_z,arr1,arr2)
;z_pstress(p_z, arr1, arr2)
command
print "Major principal stress: " , arr1(1)
print "Intermediate principal stress: ", arr1(2)
print "Minor principal stress: ", arr1(3)
print "Major principal stress direction: ", arr2(1), arr2(2), arr2(3)
print "Intermediate principal stress direction: ", arr2(4), arr2(5), arr2(6)
print "Minor principal stress direction: ", arr2(7), arr2(8), arr2(9)
endcommand
end
@get_principal