Tools

The following tools are available:

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

Export Model to File - creates a 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 open Free Edge execute Tool - Free Edge from the main menu.

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

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

- display only groups of elements.

- 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 execute Tool - Mass and COG Table from the main menu.

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

Elements Count - first value is the amount of elements that were found on Selection. Second value is the 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 a Mass of all selections.

Selections can be defined using Selection List Control.

Moment Shear Force

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

To add Moment Shear Force execute Tool - Moment Shear Force from the main menu.

Select loads using Multiple Loads Selector.

Define selection using Selector Control

Force/Moment X/Y/Z - select what Forces and Moments to display in the table.

Coordinate system - present results in the selected coordinate system;

Horizontal Axis - axis along the length of the model;

Model Length - defined automatically = Maximum - Minimum along the Horizontal axis;

Portside Axis - axis along the height of the model (perpendicular to the Horizontal axis);

Step - model Length is divided by steps in a number of the locations 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 the location on the model. Press to set the origin to average coordinates from selection for all axes and min coordinate for the horizontal axis.

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

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

Press Fill Table to display the results.

- select direction and display plot:

Moment Ratio

Moment Ratio calculates K_c and B_m factors (Eurocode3), C_b reduction factor (AISC), C_m - moment ratio on the ends of 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:

B_m Equivalent uniform moment factor for EN 1993-1-2:

Four moment ratio tools are created by default for length y, length z and length torsional members with Y/Z moment ratios. To edit the respective Moment Ratio execute Tool - Moment Ratio - Moment Ratio Y / Z/ Torsional Y / Torsional Z from the main menu.

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.

B_m (EC3 Fire Design) - Equivalent uniform moment factor according to Eurocode3, Part 1-2 Figure 4.2.

Select Load using Load 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 a 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 using Load Selector Control.

Press Fill Table to display results.

Summarize per weld part

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.

Summarize per element

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: F_N1 = Average (F_N4, F_N5)

- For Element 2: Forces are transferred to Element 1 and Element 3, consequently result is 0;

- For Element 3: F_N3 = F_N6; F_N2 = F_N5

- 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:

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

- 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.

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 η coefficient (formula 7.37) from chapter 7.5.2 Torsional buckling of stiffeners.

To edit Effective Plate Width execute Tool - Effective Plate Width from the main menu:

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

- highlight selected plates/stiffeners;

- preview selected plates/stiffeners;

It is possible to display plot with results as labels:

To see the details of the calculations select a single plate and press :

Stress Gradient

Related Stress Gradients - is calculated to reduce peak stresses at the defined points of the model.

Calculations are based on normal and shear stress amplitudes at the reference point and point below the surface according to Equation 4.3.16 of Analytical Strength Assessment of Components in Mechanical Engineering, 5^th Edition, 2003:

, where

σ_1a, τ_1a - stress amplitudes at the reference point;

σ_2a, τ_2a - stress amplitudes in a distance Δs;

Δs - the distance between the reference point and the neighboring point below the surface;

Note: Stress Gradient is calculated on free edge nodes of shell elements for their top and bottom points of interest.

To edit Stress Gradient execute Tool - Stress Gradient from the main menu.

Select Load Group using Load Selector Control.

- add condition by type;

- edit selected condition;

- copy selected conditions;

- remove selected conditions;

- highlight selected conditions on the model;

- preview selected conditions on the model;

Define conditions and press Fill Table to display results.

Stress Gradient Conditions

Stress Gradient is calculated for each point of interest (top and bottom) of all reference nodes. The condition can be added by the following types:

Inward - select elements using Selector Control to find free edge nodes automatically (reference points) and take neighbor nodes (points below the reference point) from the selected elements to calculate stress gradient coefficient:

By Element Thickness - select elements using Selector Control to find free edge nodes automatically (reference points) and take the opposite points of interest for each node (points below the reference point) from the selected elements to calculate stress gradient coefficient:

By Custom Nodes - pick reference/related elements and set points below the surface manually:

- pick element/node from the model;

- update the list of nodes of Related/Reference element;

- apply selected related node to all selected reference nodes in the list;

Related Element - stresses at the related nodes will be taken from this element. Pick element from the model or set manually;

Reference Element - a list of reference nodes will be recognized automatically from the free edges of the element. Stresses at the reference nodes will be taken from this element. Pick an element from the model or set manually;

Related Nodes - points below the surface to calculate the stress gradient;

Reference Nodes - reference points to calculate the stress gradient;