unit of measure

Generally the unit system which can be followed is : 

Length: millimeter = mm

Mass: tonne = tonne

Time: second = s

Pressure - MPa

Refer below post also.

Be careful here.  As far as I know there is no 'default' unit system in HyperMesh.  It is up to the user to make sure a consistent unit system is being used throughout the model and simulation.  For mechanical simulations the base units are length, mass, and time.  Displacements from the simulation will be in the same units as length.  This could be millimeters, inches, feet, yards, miles, furlongs, etc.  Pressure is a derived unit involving length, mass, and time.  If length is millimeters, mass is tonnes, and time is seconds then pressure will be MPa.  Another common unit system (at least in automotive) is length in millimeters, mass in kilograms, and time in milliseconds.  In this case pressure is GPa.  The key is to make sure the derived units (force, moment, pressure, stress, to name a few) are consistent with the base units (length, mass, and time).

Thank you so much for the answers.