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Unit Consistency

Unit Consistency

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Unit Consistency

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In RADIOSS data for any unit system can be provided, but it is very important to keep the unit consistency. If your model did not keep unit consistency, this will lead to the incorrect results (unexpected behavior) or sometimes may lead to an error in the calculation.

Basic Units

 

SI

 

 

CGS

Hydro

US

Japanese

Length

m

mm

mm

cm

cm

in

mm

Mass

kg

Mg (Ton)

kg

g

g

lb

kg

Time

s

s

ms

s

µs

s

ms

Plane angle

rad

rad

rad

rad

rad

rad

rad

Temperature

K

K

K

K

K

K

K

Frequency

Hz

Hz

Hz

Hz

Hz

Hz

Hz

Gravity

9.81

9.81E+03

9.81E-03

9.81E+02

9.81E-10

386

9.81E-03

 

SI Unit Example

 

SI Unit Example

Length

symbol_m

Mass

symbol_kg_unit

Time

symbol_S_unit

Plane angle

symbol_Rad

Temperature

fail_tab_temp

Frequency

symbol_Hz

Gravity

9.81

Solid angle

sr

Rotational
velocity

symbol_Rad_s

Area

symbol_m_2

Volume

symbol_m3

Moment of area (inertia)

inter_type20_m4

Consumption

symbol_m_2

Speed

fail_lad_SI_k

Acceleration

symbol_m_s2

Tension

symbol_m_s2

Lineic mass

symbol_kg_m

Surface mass

symbol_kg2

Volume mass

symbol_kg

Mass flow

symbol_kg_s

Volume flow

symbol_m3_s

Quantity of movement

symbol_kg_m_s

Kinetic moment

symbol_kg_m_s

Moment of
inertial (l)

symbol_kg_m2

Moment of force

symbol_Nm

Force

symbol_N_unit

Linear force

fail_lad_SI

Stiffness

fail_lad_SI

Rotational
stiffness

symbol_Nm_Rad

Rotational
damping

symbol_Nms_Rad

Torsion damping

symbol_kg_m2_s_rad

Viscous damping

symbol_kg_s

Damping for bending

symbol_Ns_m

Quadratic bulk viscosity

fail_tbutch

Dynamic viscosity

symbol_PaS

Kinematic
viscosity

symbol_m2

Density

symbol_kg

Power

symbol_W

Energy

symbol_J

Enthalpy

symbol_J

Entpory

symbol_heat2

Strain rate

fail_johnson

Permeability

symbol_Rad_s

Time relaxation

symbol_S_unit

Thermal
expansion

inter_type20_therm

Thermal conductivity

inter_type9_therm

Thermal
resistance

inter_type20_therm

Specific heat
(Cp, Cv)

symbol_heat_specific

Specific heat capacity (Cp)

symbol_heat_vol

 

Verifying Consistency

Use basic units Mass, Length, or Time so you can get all other units you need. See below:

consistency_eq

 

For example, using base unit [kg], [mm], or [ms], will provide the following units force, pressure or density.

consistency_eq2

 

Checking Unit

Property Card

•Check the thickness unit in property if it is shell

Material Card

•Check density unit
•Check E-modulus
•Check stress unit if possible

Load

•Check force unit
•Check gravity unit, if using /GRAV

Length

•Measure the geometry length unit with HyperCrash or HyperMesh

All units must be consistent.

 

Most Popular Units (with steel examples)

Mass

Length

Time

Force

Energy

Stress

Density

Young's module

Gravity

Yield stress

kg

m

s

N

J

Pa

7.8e+03

2.1e+11

9.81e+00

2.06e+05

g

mm

ms

N

mJ

MPa

7.8e-03

2.1e+05

9.81e-03

2.06e+02

kg

mm

ms

KN

J

GPa

7.8e-06

2.1e+02

9.81e-03

2.06e-01

Mg (ton)

mm

s

N

mJ

MPa

7.8e-09

2.1e+05

9.81e+03

2.06e+02

g

cm

micros

10^7N

10^5J

Mbar

7.8e+00

2.1e+00

9.81e-10

2.06e-06