Structural Element toolbar

Create the structural element for a beam.

 

Beam structural elements will contain the following properties:

 

 

Material

 

Only structural and generic materials are allowed to be assigned to linear structural elements, that is, structural/ prestressing steel, concrete or generic material.

 

Cross section I-J ends

 

For this version, linear structural elements must have same cross section (constant along the line) for both I-J ends.

 

Beam offsets

 

Coordinate values that locate the node with respect to the default origin of the cross section (center of gravity) specified in the section axes system.

 

 

 

Where:

              

OSIZ	Offset Z-coordinate with respect to section gravity center
OSIY	Offset Y-coordinate with respect to section gravity center

 

This concept is widely explained in the Beam-Shell offsets chapter.

 

Beam mesh controls

 

User can take more control in the meshing process by using one of the following element size specifications:

Relation of 20:

         

Relation of 0.01:

 

 

 

Relation of 20:

Relation of 0.01:

 

 

Executing a congruent mesh is one of the most important target in our model, therefore, user must fix properly the mesh to the structural element depending on its dimensions.

 

Beam hinges

 

Hinges between beam structural elements can be defined. User must select which of the element local direction (or both) as the revolute axis and in which end (I, J). The possibilities are (mixed configurations are possible):

 

 

 

 

 

Shear effects: this option could be activated if the user wants to take into account the transverse shear effects.

 

If the user would like to know more about the beam finite element, some pieces of information are provided in the Finite element characteristics chapter.

 

 

Create the structural element for a truss.

 

Truss elements (tension only or compression-only link elements) will contain the following properties:

 

 

Properties bar is showed ahead to be more widely defined:

 

 

Material

 

Only structural and generic materials are allowed to be assigned to linear structural elements, that is, structural/ prestressing steel concrete or generic material.

 

Cross section I-J ends

 

For this version, linear structural elements must have same cross section (constant along the line) for both I-J ends.

 

Truss mesh controls

 

User can take more control in the meshing process by using one of the following element size specifications:

Relation of 20:

 

Relation of 0.01:

 

 

 

Relation of 20:

Relation of 0.01:

 

 

Executing a congruent mesh is one of the most important target in our model, therefore, user must fix properly the mesh to the structural element depending on its dimensions.

 

If the user would like to know more about the truss finite element, some pieces of information are provided in the Finite element characteristics chapter.

 

Create the structural element for a shell.

 

 

Shell structural elements will contain the following properties:

 

 

Properties bar is showed ahead to be more widely defined:

 

 

Material

 

Only structural and generic materials are allowed to be assigned to shell structural elements, that is, structural steel, concrete or generic material.

 

Thickness

 

 In CivilFEM the shell elements are numerically integrated through the thickness, which can be whether variable or constant through the entire shell structural element.

 

For further information, click on the link Variable thickness.

 

Shell offsets

 

Values that locate the node with respect to the default origin of the section (midplane).

 

This concept is widely explained in the Beam-Shell offsets chapter.

 

Shell mesh controls

 

User can take more control in the meshing process by using one of the following element size specifications:

 

Control	Automatic: CivilFEM establishes the shell finite element edge size automatically. Edge length: This option assures that the length of shell finite element edge size of given structural element is no less than the given number. Number division: The user defines the number of element divisions in U and V directions of the shell element. Parasolid: This mesh control takes into account the curvature check, besides providing the possibility of creating a parasolid geometry to mesh by direct approach.
Element type	Triangle or quadrilateral finite element
Algorithm	Advancing front mixed mesher. Advancing front mesher. Delaunay triangulation mesher. Overlay mesher with quadrilaterals.
For quadrilateral meshes, the advancing front method is recommended while the Delaunay method is recommended for triangular meshes.
Mesh transition	Sets mesh transition parameter. Its default value is 1. When the value is bigger than 1, the element size at the central area will be larger. When the value is smaller than 1, the element size at the central area will be smaller.

 

A more extended description about the Mesh algorithm will be provided in the corresponding chapter. In addition the Measuring mesh quality has its own headland, in which some aspects about the shape of the elements will be properly cleared.

 

Executing a congruent mesh is one of the most important target in our model, therefore, user must fix properly the mesh to the structural element depending on its dimensions.

 

Coordinate system

 

By default, the shell structural element orientation uses the projection of the global cartesian coordinate system.

 

Shell reinforcement

 

Reinforcement in shells shall be defined in many ways:

 

Bending reinforcement

 

The following diagram shows the reinforcement configuration according to X, Y directions:

 

 

Data needed to define axial + bending reinforcement are:

 

Angle of reinforcement	Angle between the reinforcement with respect to the Y-element axis (Wood Armer’s method).
Reinforcement definition	Number of bars per unit length Separation between bars Total amount
Number of bars	Number of bars per unit length at X bottom, X top, Y bottom and Y top layers.
Spacing	Distance between bars length at X bottom, X top, Y bottom and Y top layers.
Φ	Reinforcing bars diameter length at X bottom, X top, Y Bottom and Y top layers.
Total reinforcement	Reinforcement area per unit length at X Bottom, X top, Y bottom and Y top layers.
Braced/Not braced	Reinforcement situation.
THETA	Angle of the compression struts with element X-axis.
Reinforcing steel	Reinforcing material to be used.

 

In plane shear reinforcement

 

The following diagram shows the reinforcement configuration according to X, Y directions:

 

 

Data needed to define in-plane reinforcement are:

 

Reinforcement definition	Number of bars per unit length Separation between bars Total amount
Number of bars	Number of bars per unit length at X, Y layers.
Spacing	Distance between bars length at X, Y layers.
Φ	Reinforcing bars diameter length at X, Y layers.
Total reinforcement	Reinforcement area per unit length at X, Y layers.
Reinforcing steel	Reinforcing material to be used.

 

Out of plane shear reinforcement

 

The following diagram shows the reinforcement configuration according to X, Y directions:

 

 

Data needed to define out of plane reinforcement are:

 

Reinforcement definition	Number of bars per unit length Separation between bars Total amount
Number of bars	Number of bars per unit length at X, Y layers.
Spacing	Distance between bars length at X, Y layers.
Φ	Reinforcing bars diameter length at X, Y layers.
Total reinforcement	Reinforcement area per unit length at X, Y layers.
Reinforcing steel	Reinforcing material to be used.

If the user would like to know more about the shell finite element, some pieces of information are provided in the Finite element characteristics chapter.

 

Create the structural element for a solid.

 

Solid 3D structural elements will contain the following properties:

 

 

Properties bar is showed ahead to be more widely defined:

 

Material

 

There is no material restriction for solid structural elements, any material can be assigned (including soil and rock materials).

 

Coordinate system

 

By default, the solid structural element orientation uses the projection of the global cartesian coordinate system.

 

Solid mesh controls

 

User can take more control in the meshing process by using one of the following element size specifications:

 

Control	Edge length: This option assures that the length of shell finite element edge size of given structural element is no less than the given number.
Element type	20-node hexahedron 8-node hexahedron 10-node tetrahedron 4-node tetrahedron
Algorithm	Type of meshing algorithm Advancing front mixed mesher. Advancing front mesher. Delaunay triangulation mesher. Overlay mesher with quadrilaterals.
The surface mesh is created on every individual surfaces. In order to create 3D mesh, the nodes on the outlines of each surface mesh should be merged with the closest nodes on their neighboring outlines. The merging process is controlled by sweep tolerance. The process is done internally.
Mesh transition	Sets mesh transition parameter. Its default value is 1. When the value is bigger than 1, the element size at the central volume will be larger. When the value is smaller than 1, the element size at the central volume will be smaller.

 

A more extended description about the Mesh algorithm will be provided in the corresponding chapter. In addition the Measuring mesh quality has its own headland, in which some aspects about the shape of the elements will be properly cleared.

 

Executing a congruent mesh is one of the most important target in our model, therefore, user must fix properly the mesh to the structural element depending on its dimensions.

 

If the user would like to know more about the solid finite element, some pieces of information are provided in the Finite element characteristics chapter.

 

Create the structural element for a cable.

 

Cable structural elements will contain the following properties:

 

 

The different finite element types available for solid structural elements are described in the corresponding chapter.

 

Properties bar is showed ahead to be more widely defined:

 

Material

 

Material is limited to steel, either regular steel, reinforcement steel or prestressing steel. One important consideration is the material law chosen for the steel material. If the default steel behaviour is used, the material will behave with an asymmetric material law (almost no compression resistance and normal tension resistance). If the law is change to plastic behaviour, the actual plastic law will be used. This implies that the compression branch of the material law will be the one defined by the plastic law.

 

Cross section I-J ends

 

For this version, linear structural elements must have same cross section (constant along the line) for both I-J ends.

 

Only cable sections can be used to define a cable structural element.

 

Temperature prestressing

 

The cable element used is a non-linear element. Non-linearity implies an approximate solution using a non-exact approach. To help the convergence of the model, the user can define an initial prestressing temperature that will act as an initial tension in the cable.

 

Cable mesh controls

 

User can take more control in the meshing process by using one of the following element size specifications:

 

 

 

Executing a congruent mesh is one of the most important target in our model, therefore, user must fix properly the mesh to the structural element depending on its dimensions.

 

 

Create the structural element for a solid.

 

Solid 2D structural elements will contain the following properties:

 

 

Properties bar is showed ahead to be more widely defined:

 

Material

 

There is no material restriction for solid structural elements, any material can be assigned (including soil and rock materials).

 

Coordinate system

 

By default, the solid structural element orientation uses the projection of the global Cartesian coordinate system.

 

Solid 2D mesh controls

 

User can take more control in the meshing process by using one of the following element size specifications:

 

Control	Automatic: CivilFEM establishes the shell finite element edge size automatically. Edge length: This option assures that the length of shell finite element edge size of given structural element is no less than the given number. Number division: The user defines the number of element divisions in U and V directions of the shell element. Parasolid: This mesh control takes into account the curvature check, besides providing the possibility of creating a parasolid geometry to mesh by direct approach.
Element type	Triangle or quadrilateral finite element
Algorithm	Advancing front mixed mesher. Advancing front mesher. Delaunay triangulation mesher. Overlay mesher with quadrilaterals.
For quadrilateral meshes, the advancing front method is recommended while the Delaunay method is recommended for triangular meshes.
Mesh transition	Sets mesh transition parameter. Its default value is 1. When the value is bigger than 1, the element size at the central area will be larger. When the value is smaller than 1, the element size at the central area will be smaller.

 

A more extended description about the Mesh algorithm will be provided in the corresponding chapter. In addition the Measuring mesh quality has its own headland, in which some aspects about the shape of the elements will be properly cleared.

 

Executing a congruent mesh is one of the most important target in our model, therefore, user must fix properly the mesh to the structural element depending on its dimensions.

 

If the user would like to know more about the solid finite element, some pieces of information are provided in the Finite element characteristics chapter.

 

 

 

Dummy Shell

 

Creates a dummy shell structural element.

 

This structural element is quiet different from the others. Dummy shells are used to extract the stress fields of solid elements and integrate them in order to obtain the forces and moments. Stresses are integrated along the normal to the geometries selected.

 

Mesh of dummy shells is based on the mesh of the 3D solid elements and the geometries selected.

 

Dummy shells have no influence in the solution of the model. So boundary conditions or loads applied on them are ignored.

 

After solving, the dummy shells are solved and the results of forces and moments are stored in the result file (only available for .rcf result file)