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Load

Loading is a model of physical influences acting on the real structure. The program can model the physical effects of several types: the forces and moments, self-weight of the structure, imposed deformation of the structure and the effect of temperature changes on the structure. Loads are arranged into load cases.

Force loads

The force loads can act on members or joints. These loads can be point forces and moments and continuous loads. For the exact determination of the load, the load case, in which the load belongs, the element (member or joint) to which the load is applied, the position and the load value have to be specified.

Deformation loads

The load induced by the support deformation can be applied only to joints that are supported in corresponding directions. This is valid both for movements and rotations.

Self-weight

Self-weight load is generated automatically when the load case with type "Self-weight" is created. The self-weight is generated as a continuous load in a negative direction of the global axis Z. The value of this load is determined by the cross sectional area of the member and the specific density of the material. No additional loads can be added into this load case. Additional loads have to be specified in the load case with the code "Force"

Temperature loads

The temperature load can be used for modelling the effects of temperature change on structure. The temperature load is defined as a temperature increment relative to the common conditions, where no stresses induced by thermal load appear. The positive values of thermal load mean temperature increase, the negative values mean temperature drop.

The general input of thermal change in space isn't simple and consist of two parts. First part describes the temperature development along the rectangular plane (perpendicular to member), second part defines the position of cross-section in this plane. The rectangular plane is given by dimensions dy and dz, the temperature increments are marked as t_h-upper, t_d-bottom, t_l-left and t_p-right side of rectangle. At least one value has to be specified. The maximum number of entered values is three. The thermal distribution along the rectangular plane is calculated using following rules: The thermal increment is constant for whole area if one value is specified. For two specified values, the temperature distribution is calculated with the help of plane, that has gradient in the direction of line between specified values. Three specified values define the thermal distribution unambiguously. Fourth value is calculated according to the plane given by three specified values.

The position of the cross-section in the rectangular plane is given by the coordinates of the centre of gravity in this plane. The left bottom corner is considered as an origin.

As a default, dimensions of rectangular plane are equal to the maximum dimensions of member cross-section.