Units

Before starting to define this or any model, you need to decide which system of units you will use. Abaqus has no built-in system of units. Do not include unit names or labels when entering data in Abaqus. All input data must be specified in consistent units. Some common systems of consistent units are shown in Table 1.

Table 1. Consistent units.
Quantity SI SI (mm) US Unit (ft) US Unit (inch)
Length m mm ft in
Force N N lbf lbf
Mass kg tonne (103 kg) slug lbf s2/in
Time s s s s
Stress Pa (N/m2) MPa (N/mm2) lbf/ft2 psi (lbf/in2)
Energy J mJ (10−3 J) ft lbf in lbf
Density kg/m3 tonne/mm3 slug/ft3 lbf s2/in4

The SI system of units is used throughout this guide. Users working in the systems labeled “US Unit” should be careful with the units of density; often the densities given in handbooks of material properties are multiplied by the acceleration due to gravity.