after getting modal frequency in abaqus we know how mode shape of structure(beam) looks like but i am having problem in extraction of mode shape vectors.
If you want to extract mode shape vectors into external file, then go to Report->Field Output...
In the Variable tab select Position: Unique Nodal, U: Spatial displacement (you must request U in Field Output Request of the Frequency step in Model tree).
In the Setup tab select frame (mode), insert the file name (default is abaqus.rpt), and choose Output Format.