RamSeries manual


Loads

Data->Loads   

When a load is assigned to entities, it is automatically inserted in the active loadcase. See the loadcases section for details.

Point load

This is a load applied to one point of the structure. Default units are Newtons for the force components and Newton·meter for the momentum components. Sign of the components is equal to that defined for the constraints. 3D solids loads have only three components.

Self weight

If this condition is applied to a beam, shell element or solid element, the load due to its self-weight is applied, based on the specific weight and other parameters described in the properties.

This condition can be applied to either lines for beams, surfaces for shells and volumes for the solid analysis.

Beam pressure loads

There are three types of pressure loads for beams:

1.      Global beam load

2.      Global projected beam load

3.      Local beam load

In all the cases the pressure applied is given in Newton/meter in default units. In the global load, the load is given related to the global axes. The global projected load is given also in global axes but the length considered of the beam is orthogonal to the load. Local load is related to the local axes defined in the properties section. A load of  (0,0,-P) N/m in either case would be (for a beam of length L):

 


In the Local beam load there is an additional field that is the local torsor momentum.

Shell surface loads

There are five types of surface loads for shells:

1.      Global shell load

2.      Global projected shell load

3.      Local shell load

4.      Triangular load

5.      Hydrostatic load

In all the cases the pressure applied is given in Newton/meter2 in default units. In the global load, the load is given related to the global axes. The global projected load is given also in global axes but the area considered of the shell is orthogonal to the load. Local load is related to the local axes defined in the properties section. A load of  (0,0,-P) N/m2 in either case would be (for a shell of length L and width W):

 


Triangular load is like a Global shell load but with a triangular variation in its values. It is defined by two points, given by its coordinates, and pressure values associated to each one of these points. The pressure assigned to the elements that project between the points is a linear interpolation between the two values. The elements that project outside have a pressure value of zero.

Example:

Hydrostatic load is defined related to the gravity direction entered
in the problem data section. The reference coordinate is related to that direction. Self-weight water is given, in default units as N/m3.

 

Shell face load

With this condition it is possible to apply a pressure to a line that is a boundary of a shell surface. The pressure is given in default units in N/m. If the local axes field is set to Global, the pressure vector is given related to the global axes. Option Automatic permits to define an automatic local axes system that is different for every element. Pressure vector will be related to these axes. This last option is useful to assign a local pressure to the boundary of the shell. Check: Data->Conditions->Loads->Shell face load->Draw->Draw all conditions->Only local axes to see the automatic local axes defined.

Triangular and hydrostatic face load are defined equal to the ones in shell surface loads.

Solid Surface loads

There are five types of surface loads for solids:

1.      Global pressure load

2.      Global projected pressure load

3.      Local pressure load

4.      Triangular load

5.      Hydrostatic load

In all the cases the pressure applied is given in Newton/meter2 in default units. In the global load, the load is given related to the global axes. The global projected load is given also in global axes but the area considered of the contour of the solid is orthogonal to the load. Local load has only one component and it is the normal pressure to the contour surface. Its value is positive when the pressure points inwards the volume. A load of  (0,0,-P) N/m2 in either case would be (for a solid contour surface of length L and width W):

Note: In the local load the value would be +P

 


Triangular and hydrostatic loads are defined equal to the ones in shell surface loads.

Temperature load

It is possible to define for every beam a load due to changes in temperature. The values to enter are:

·        Alpha (a): The constant expressed in 1/ºC (Celsius degrees)

·        Delta T (DT): Temperature increment in Celsius degrees.

The deformation added to the beam is: