Tools

The following tools are available:

• Free Edge;
• Mass and COG Table;
• Moment Shear Force;
• Moment Ratio;
• Weld Summation Tool.
• Effective Plate Width.

Export Model to File - creates text file with materials, properties, nodes and elements ids without the model data. The file is used to debug user problems without having the customer model.

Free Edge

Free Edge Tool automatically finds free edges between the elements.

To run Free Edge execute Tools - Free Edge from the main menu. Alternatively, use the Tools context menu:

Press Find and the table will be filled with the groups of elements that has Free Edges.

Press All to select all groups from the list and None - to deselect;

Press to display only groups of elements.

Press to highlight the selected groups of elements.

- export selected groups to Femap;

- export selected groups to components;

Mass and COG Table

Mass and Center of Gravity Table is used to automatically calculate mass and center of gravity characteristics on the user-defined selections.

To add Mass and Center of Gravity click Tools - Mass and Center of Gravity - Add in the main menu.

Selection - elements that will be intersected with the selections defined below;

Elements Count - first value is amount of elements that were found on Selection. Second value is total amount of elements that exist in the model;

COG X, Y, Z - coordinates of the center of gravity;

Mass - mass of the selection.

Note: Overall row is Mass of all selections.

Selections can be defined using Entity List Selector.

Moment Shear Force

In order to check the validity of a ship Moment Shear Force can be performed.

Select loads using Load selector.

Select what Forces and Moments to display in the table.

Coordinate system - present results in the selected coordinate system.

The Horizontal Axis should be along the length of the model. Model Length is defined automatically = Maximum - Minimum along the Horizontal axis. Portside Axis - the vertical Axis.

Model Length is divided by steps in a number of the location where Forces and Moments will be calculated (N = Moment Length / Step).

By default forces and moments are calculated around [0;0;0]. Selection option Redefine Origin and click to select location on the model. Press to set origin to average coordinates from selection for all axes and min coordinate for horizontal axis.

Sum of Forces and Moments are calculated based on Grid Point (Elemental-Nodal ENFO, ENMO) Forces/Moments. Pay attetion the results are included in analisys.

For Load Group it is possible to show Min/Max/Abs values and also show loads from load group that contains min/max values (option Relevant Min/Max).

Press Fill Table to display the table.

Press and select results to plot:

Press to display the plot.

Moment Ratio

Moment Ratio calculates K_c factor (Eurocode3), C_b reduction factor (AISC360-10), C_m - moment ratio on the ends of a members found by Beam Member Finder.

It is used in the moment reduction factors calculations in the following standards: API 2A RP (table D.3-1), ISO 19902 (table 13.5-1) and Norsok N004 (table 6-2):

And moment reduction factors according to Eurocode3 (table 6.6):

C_b (Aisc2010) lateral-torsional buckling modification factor for AISC360-10 is calculated for the Moment Ratio Torsional Y and Z:

C_b lateral-torsional buckling modification factor for AISC ASD 89 (Section F1.3) is calculated for Moment Ratio Torsional Y and Z:

Four moment ratio tools are created by default for length y, length z and length torsional members with Y/Z moment ratios.

To display the Moment Ratio execute from the context menu Edit.

The following dialog will be displayed:

M1(end min) and M2(end max) - the bending moment on the ends of the beam member.

M1/M2 - the moment ratio between the ends of the beam member..

Min/Max - the minimum/maximum bending moment over the full member.

K_c - the reduction factor according to Eurocode3, Part 1-1 Table 6.6.

C_b(Aisc89) - the lateral-torsional buckling modification factor according to AISC ASD 89.

C_b(Aisc2010) - the lateral-torsional buckling modification factor according to AISC360-10.

Select Load using Selector Control.

- plot moment ratios (M1/M2) for the selected members;

- plot ids for the selected members;

- plot Cm Type for the selected members. Cm type can be changed in Beam Member Finder:

- plot K_c factor;

- plot C_b factor for AISC ASD 89 or AISC 360-10;

- highlight the selected beam members;

- preview only selected beam members.

For the selected member the bending moment diagram is displayed. End moments, Min/Max over the full member are shown with labels:

Example: Calculation of the reduction moment factors Cm according to ISO 19902:

Weld Summation Tool

Weld Summation tool is used to summarize Grid Point Forces that will be used in Weld Checks to calculate the weld stresses.

Press to automatically highlight single selected weld/weld part from the list.

There are two methods available:

• Summarize per weld part - summarize forces at all welded nodes of the respective weld part;
• Summarize per elements (beta) - calculate forces at each welded node of respective weld part element. Force is summed from neighbor elements that contain only one welded node;

Show results only for welded parts - display only welded parts of the welds in the table. The non-welded parts do not provide results in weld checks.

Select Load and press Fill Table to display force summation for all welded parts.

Summarize per element

This method is used for the straight welds. Weld length and a coordinate system are taken from the Weld Finder Tool.

Forces are summarized over the weld nodes (41 - 47) using elements only from the respective weld part (101 - 126).

Weld part origin is used to calculate a moment arm for extra moments from the forces.

After forces are summarized, they are transformed into a weld part coordinate system.

This method calculates forces for each node and related element from a weld part. Besides the weld length and a coordinate system are calculated for each weld node taking into account neighbor weld part elements.

Weld length is a sum of the half of the element's length along the weld direction from both sides of the weld node (L2-L6 on the picture):

Note: If the weld is not closed the weld length for the start and for the end nodes is taken as a full length along the weld direction of the neighbor element (L1 and L7 on the picture).

Elements that are attached with one node to the weld are not taken into account in weld checks. Forces/moments are transferred to the neighbor elements by the portion of their weld length in the calculations:

F1=f*(a/(a+b)); f2-f*(b-(a+b));

Note: For non-welded nodes, the result is taken by the following rule: For Element 1: result for N1 = average result of N4 and N5. For Element 3: result for N3 = result for N6; result for N2 = result for N5.

To display force/moment define the direction in Plot group box and press Plot. The values will be displayed according to the selected method. The example of full weld part:

Note: Force and moments for the elemental method will show the absolute maximum value on the element from among its welded nodes.

- open Weld Finder Tool to recognize welds;

Press Clear all results to recalculate forces. All results in weld checks will be cleared automatically after confirmation

- highlight selected weld parts;

- preview selected weld parts;

- display criteria plot for selected direction:

- display colored weld plot with weld ids as labels;

- display forces as labels for selected weld parts;

- display moments as labels for selected weld parts;

Note: Forces and moments labels for the elemental method will display the values from all the welded nodes of the element.

- draw coordinate systems based on selected Method. Per full weld, the method uses information from the Weld Finder Tool. Per element, the method calculates a coordinate system at each node. Averaged vectors from the neighbor elements are used:

-detailed information about single weld part, including results for each element/node.

Weld Stresses

Stresses due to forces are calculated using the weld area, and due to moments using the inertia of the full weld.

Note: Forces are retrieved from the Weld Summation tool and calculations are based on the selected method: per full weld (averaged on weld part) or per elements (abs max result over element corners).

Note: Weld inertia is calculated assuming that an effective weld section is horizontal and the weld is double-symmetric.

Stresses are rotated into weld X, Y, and XY directions and translated to points on the weld face at each end of the weld (T1, T2, B1 and B2).

Following matrix of rotation is used:

- Von Mises stress at a certain point. Stress is used in calculations of weld capacity in design standards;

Effective Plate Width

Effective Plate Width - calculates effective plate width for a stiffener subjected to longitudinal, transverse and shear stress according to DNV-RP-C201 Buckling strength of plated structure, Chapter 7.3 Effective plate width. Also it calculates ? coefficient (formula 7.37) from chapter 7.5.2 Torsional buckling of stiffeners.

To open Effective Plate Width execute Tools - Effective Plate Width in the main menu:

Select Load using Load Selector and press Fill Table. List of all sections with stiffeners and their related plates will be shown.

- highlight selected weld parts;

- preview selected weld parts;

It is possible to display plot with results as labels:

To see the calculations details select single plate and press :