op2中数据块前面的内容
下面是FourCQUAD4_Static.op2文件block前面的内容，有些op2不一样，但是都差不多
4,3,4
12,month(int),day(int), year(int),12
4,7,4
28,NASTRAN FORT TAPE ID CODE - ,28
4,2,4
8,OS2022 ,8
4,-1,4 # end of record (flag)
4,0,4 # end of file/label (flag)
再往后就是block的数据块
GEOM2数据块理解
下面是FourCQUAD4_Static.op2文件的GEOM2S块的结果。GEOM2存的是单元的结点连接关系，下面代码中的2958,51,177表示的是CQUAD4
4 2 4
8 'GEOM2S ' 8 # Record 0: block name
4 -1 4 # Read end of record (expecting -1)
4 7 4
28 102 1538 260 0 8736 0 0 28 # trailer,
4 -2 4 # End of trailer (expecting -2)
4 1 4 # Logical Record Type (expecting 1)
4 0 4 # End of Logical Record Type (expecting 0)
4 2 4 # gino
8 'IGEOM2X ' 8
4 -3 4 # End of Gino (expecting -3)
---------------- # recordID = 1
4 1 4
4 0 4 # Logical Record Type: type
4 59 4 # TableLength=59 (2958 51 177 represent cquad4)
236 2958 51 177 1 1 6 7 10 5 0 0 0 0 null null null null
2 1 5 10 3 4 0 0 0 0 null null null null
3 1 7 8 9 10 0 0 0 0 null null null null
3 1 7 8 9 10 0 0 0 0 null null null null 236
# 4 int 4 # if multi-table,in table loop
# 4*int ... 4*int
4 -4 4 # End of this Record
---------------- # recordID = 2
4 1 4
4 0 4 # Logical Record Type: type
4 3 4 # TableLength=3
12 12-byte 12
4 -5 4 # End of this Record
---------------- # recordID = 3
4 1 4
4 0 4 # Logical Record Type: type
4 0 4 # TableLength=0, break, out of record loop
