Cubit 16.04 User Documentation
Create Force [id] [Name <'name'>] [ {Add|On} {Nodeset|Surface|Curve|Vertex|Face|Tri|Edge|Node} <entity_list>] [Force Value <val>] [Moment Value <val>] [Direction { direction_options}]
Create Force [id] [Name <'name'>] [ {Add|On} {Nodeset|Surface|Curve|Vertex|Face|Tri|Edge|Node} <entity_list>] [ Vector <val> <val> <val> <val> <val> <val>]
Modify Force {id_list|'name'|all} [Name <'name'>] [ {Add|Remove} {Nodeset|Surface|Curve|Vertex|Face|Tri|Edge|Node} <entity_list>] [Force Value <val>] [Moment Value <val>] [Direction { direction_options}]
Modify Force {id_list|'name'|all} [Name <'name'>] [ {Add|Remove} {Nodeset|Surface|Curve|Vertex|Face|Tri|Edge|Node} <entity_list>] [ Vector <val> <val> <val> <val> <val> <val>]
A CUBIT user has the ability to create forces on 0D, 1D, and 2D entities. A force can be created using the direction syntax (see Specifying Direction). If the vector keyword is used, the first three values are the force components, and the last three values are the moment components.
The use of the force and moment keywords specify the type of load. If both a force and a moment are to be applied, first create one of them, then modify it to add the other. Note that every instance of a force or moment keyword must have an accompanying value keyword.
Regarding force and moment keywords, the following detail may be helpful:
A user may create a force and moment at the same time, but can only specify a direction once. If the force and moment have the same unit vector, it will be successful. If a users wants to create a force in the direction 1,2,3 and a moment in the direction 1,0,0, the user will have to create one, then add the other by modifying it.
Create Pressure [id] [Name <'name'>] [{Add|On} {Sideset|Surface|Curve|Face|Tri|Edge} <entity_list>] [Magnitude <value>] [TOP|Bottom] [PRESSURE|Totalforce]
Modify Pressure {id_list|'name'|all} [Name <'name'>] [{Add|Remove} {Sideset|Surface|Curve|Face|Tri|Edge} <entity_list>] [Magnitude <value>] [TOP|Bottom] [PRESSURE|Totalforce]
Cubit users can create pressure boundary conditions on 1D and 2D entities. Positive surface pressures acting on solid elements are defined as pointing into the face of the elements. Pressures are always normal to the face. For shells and independent surfaces, a ‘left-hand-rule’ is employed. Point your left thumb at the surface in question. If the direction your fingers curl matches the direction of ascending vertex numbering, the direction of the pressure vectors will match the direction of your thumb.
The value variable is the magnitude of the pressure boundary condition. If the user leaves this value blank, CUBIT will assign the pressure magnitude to zero (possibly a trivial case) and issue a warning. Typing a negative value will not flip the direction of the pressure arrows on the display; instead, the pressure magnitude will be negative.
The pressure and totalforce keywords are used to modify the pressure boundary condition. The pressure keyword is the default. All pressures applied with this keyword present (or with both of these keywords absent from the command string) are pure pressures. If the user enters the totalforce keyword, the pressure magnitude is divided by the area of the surface the pressure is acting on (or the length of the curve, for a curve pressure). In effect, the user is entering a force that is treated and exported as a pressure.
Create Heatflux [id] [Name <'name'>] [{Add|On} {Sideset|Surface|Curve|Face|Tri|Edge} <entity_list>] [Value <value>]
Create Heatflux [id] [Name <'name'>] [{Add|On} {Sideset|Surface|Face|Tri} <entity_list>] [Top <value> Bottom <value>]
Modify Heatflux {id_list|'name'|All} [Name <'name'>] [{Add|Remove} {Sideset|Surface|Curve|Face|Tri|Edge} <entity_list>] [Value <value>]
Modify Heatflux {id_list|'name'|All} [Name <'name'>] [{Add|Remove} {Sideset|Surface|Face|Tri} <entity_list>] [Top <value> Bottom <value>]
A CUBIT user may apply heat flux boundary conditions to 1D and 2D entities, including thin-shell elements.
Heat fluxes can be applied to thin-shell elements as well. The same rules apply to thin-shell heat fluxes as to thin-shell temperatures: thin-shell heat fluxes can only be applied to surfaces and heat flux boundary conditions cannot contain regular and thin-shell heat flux values (see journal below). However, thin-shell heat flux commands do not contain gradient or middle keyword options. Only top and bottom keywords are supported.
Create Convection [id] [Name <'name'>] [{Add|On} {Sideset|Surface|Curve|Face|Tri|Edge} <entity_list>] [Surrounding {<value>| Top <value> Bottom <value>} Coefficient {<value>| Top <value> Bottom <value>}]
Modify Convection [id] [Name <'name'>] [{Add|On} {Sideset|Surface|Curve|Face|Tri|Edge} <entity_list>] [Surrounding {<value>| Top <value> Bottom <value>} Coefficient {<value>| Top <value> Bottom <value>}]
A Cubit user can apply convection boundary conditions to 1D and 2D entities. Convection is a transport of thermal energy that is proportional to the difference between the surface temperature and the temperature of the surroundings.
The surrounding keyword specifies the temperature surrounding the entity with the convection boundary condition.
The coefficient keyword is a convection coefficient, in units of energy per length times time times temperature (i.e., [energy]/([length]*[time]*[temperature]) ).