Nauticus Hull Finite Element Analysis - a complete software package for ship structural analysis according to the Common Structural Rules for Tankers.

Nauticus Hull Finite Element Analysis may be performed as an integrated part of ship design.

This is achieved through the exceptional speed of modelling, but equally important and unique is the way the user may utilise the information stored in the concept model in order to automatically generate a FEA model in accordance with rule requirements. Nauticus Hull Finite Element Analysis Tank supports the Common Structural Rules for oil Tankers as well as Container Vessels and other ship types. Finite Element Analysis of Bulk Carriers is covered by Nauticus Hull Finite Element Analysis Bulk.

Nauticus Hull FEA Tank has undergone a major upgrade to fully support the new Common Structural Rules for Tankers ensuring that DNV and our customers still have the most efficient tool for ship structural design. The Common Structural Rules for oil tankers cover all double hull tankers above 150 m in length. Finite element analysis is mandatory for structural assessment of the hull structure within the cargo region. The structural analysis is to cover at least three cargo tanks of the midship cargo tank region. In addition to external and internal pressure, the finite element model must also include global vertical and horizontal wave bending moments and shear forces. The Nauticus Hull Ship Modeller is now fully upgraded with automatic load generation according to these new rules.

The Nauticus Concept Model
The modelling job starts with creating a 3D concept model. The model is created with the Nauticus Ship Modeller, and contains all data required for carrying out a finite element analysis. Typically, the concept model includes information such as:

• Ship geometry and structure including name and properties
• Full description of tanks and holds automatically generated
• Rule design loads and or direct calculated loads
• Mesh control on lines and surfaces

FEA Idealisation
Based on the concept model, the idealiser automatically generates an input file to the finite element pre-processor included in Nauticus Hull. The process is fully controlled by the user through the FEA analysis option dialog where parameters such as mesh size, model extent, stiffener representation, loading conditions and boundary conditions are selected.

Typical information automatically brought forward to the FEA program through the idealisation process are:

• Geometry and structure types including stiffeners represented as beam elements, cut-outs etc
• All structural elements represented in sets with logical names
• Selected load conditions
• Boundary conditions
• Net scantlings

The user is given full control over the operations in order to maintain his possibilities to make all necessary engineering judgements required for proper structural analysis.

Finite Element Analysis
The FEA package included in Nauticus Hull is based on the well-known engineering system Sesam. Sesam is recognised as the most advanced and comprehensive software system for structural and hydrodynamic analysis available to the offshore and maritime industries. Sesam is an integrated, comprehensive and open analysis system comprising more than 20 different programs including efficient pre-and post-processors, advanced hydrodynamic analysis programs and powerful structural analysis programs. Through Nauticus Wave, the system also allows highly automated transfer of directly calculated hydrodynamic loads onto the structural finite element analysis model.
Patran-Pre is used as a general-purpose finite element pre-processor. This is DNV Software's version of the Patran™ Pre-processor from MSC Software ™. Patran is recognised as one of the most advanced finite element pre-processors, and widely used in the shipbuilding industry.

Post Processing
The new rule requirements introduce a shift towards more computerisation of the rule formulations and structural assessment. The Automatic Buckling Check (ABC) included in the Nauticus FEA software is now supporting both PULS and the existing DNV Rules, covering both longitudinal and transverse material of the cargo hold model. The software includes standarized reports that can be exported to Word or Excel for further processing.

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