## Function

- Local Direction Force Sum provides internal forces on a selected line or plane in beam, plate and solid elements. The resultant forces and the acting point are calculated on the basis of all the nodal forces included in the selected plane.
- Once a detail analysis is carried out for a specific part of the structure, this function conveniently calculates the member forces for structural design.

## Call

From the main menu, select **[Results] tab > [Type : Analysis result] > [Detail Result] group > [Local Direction Force Sum]**

## Input

### Mode

Assign the method of selecting the subject plane that includes the nodes where internal forces are to be combined

**Solid Face Polygon Select**

Define an arbitrary polygon to specify the faces of solid elements contained within that polygon.

**Plate Edge Line Select**

Define an arbitrary line to specify the edges of plate elements that coincide with that line.

**Plate Edge Polygon Select**

Define an arbitrary polygon to specify the edges of plate elements that are in contact with that polygon.

### Type of Element

Check on desired element types to be included in the resultant force calculation. For Line Select mode, beam and plate elements can be selected. For Polygon Select, beam, plate, and solid elements can be selected.

### LoadCase/Combinations

Select a desired load case or load combination. Envelop Type load combination cannot be selected.

### Tolerance

Tolerance defining a line or polygon

### Coordinate Input

**Positions** : Enter the GCS coordinates of the points necessary to assign a line or polygon

Enter the coordinates of the points, or click the entry field and the desired points to automatically enter the coordinates. To select Plate Edge Line Select, enter the coordinates of the two points defining a line and additionally enter the coordinates of the 3rd point that defines the direction as to which side of the elements are to be considered.

**z Vector** : Enter a vector to define the z-axis of the local coordinate system to which Result Output is referenced

Solid Face Polygon

(The sectional forces are calculated using the nodal forces of the elements marked with dashed lines.)

Plate Edge Line

Plate Edge Polygon

The sum of nodal internal forces for each element is calculated at the center of the selected plane section with respect to the local coordinate system. When defining a polygon, the local axes are determined by the entry sequence of the coordinates of the points (right hand rule). If the z-vector is not defined, the direction from the 1st to 2nd point of the polygon becomes the local z-axis by default. Click [Apply] in the Local Direction Force Sum dialog box to review the local coordinate axes displayed at the centroid.

**Local coordinate system convention (when z-vector is not specified)**

**Resultant Force Location** : Dimension center will be automatically entered for resultant force location once a plane has been defined. The user can modify the location by entering global X, Y, and Z-coordinates directly.

### Resultant Force Location

Auto-Calc.: By default, resultant forces are calculated at a dimension center. When only plate elements exist, the resultant force location is automatically calculated as a gravity center.

User Input: Input the desired coordinates in GCS to calculate the resultant force. This option is useful when calculating the resultant force for more than two types of elements.

### Result Output

Produce the position of the centroid of the defined section and the sum of internal forces for each direction.

The sectional forces are calculated using the element forces at the user-defined region's nodal points. The left figure provides an example of calculating sectional forces for a single solid element.

The forces in each direction are equal to the sum of the element forces in that direction at the nodal points.

The calculation method for the moments in each direction is as follows, where dy5 represents the distance in the y-direction from the centroid to nodal point 5.

### Name

Define a name, which will be used to register in a list of centroid locations of defined sections and internal force sums for each direction.

**Text output** : Calculated results are produced in a text file. Using this function allows us to save multiple locations where we wish to find the sums of internal member forces, which can be output in a text file.

**Table Output** : Calculated results are produced in a table . Using this function allows us to see multiple locations where we wish to find the sums of internal member forces, which can be output in a table. On clicking the Table Output option, the records activation dialog box is displayed, from where you can select the load cases for which to display the local direction force sum in a tabular format.