Advanced structural integrity management software is capable of using a structural Computer Aided Design (CAD) geometry to track the condition of a marine or offshore asset in a virtual environment. ABS Nautical Systems Hull Manager 3D (HM3D) converts a 3D CAD model to a database that stores vessel condition information and provides the ability to track condition changes due to structural degradation. Ultrasonic thickness measurements are mapped directly onto the 3D model such that visualization and utility functions can help determine the remaining life and calculate critical global strength parameters, such as the section modulus and cross sectional areas. Finite Element Analysis (FEA) based structural reassessments are also facilitated through functionality that allows the auto creation of Finite Element (FE) models in the as-gauged condition and export the models to relevant finite element analysis solvers using the add-on link within HM3D to Altair’s Hyperworks® software. Hyperworks then generates an FE mesh (global or local models, as required by the user) along with the structural properties (metadata), such as the material grades and gauged thickness. Today, structural engineers face difficulty in practically applying automesh capability to complex or detailed as-built geometry. This is especially true when considering marine and offshore structures, where those assets tend to be very complex geometrically. The challenge posed in this project was to use the as-built structural CAD model as the input and automesh assisted algorithm for creating an FE model along with all the topological metadata, such as material grade and thickness.

1. Automated Finite Element Model Creation Using Hull Operational Condition Data for Marine and
Offshore Assets
Eka Kristanto, Sameer Kalghatgi, Chris Serratella – ABS
Advanced structural integrity management software is capable of using a structural Computer Aided
Design (CAD) geometry to track the condition of a marine or offshore asset in a virtual environment. ABS
Nautical Systems Hull Manager 3D (HM3D) converts a 3D CAD model to a database that stores vessel
condition information and provides the ability to track condition changes due to structural degradation.
Ultrasonic thickness measurements are mapped directly onto the 3D model such that visualization and
utility functions can help determine the remaining life and calculate critical global strength parameters,
such as the section modulus and cross sectional areas.
Finite Element Analysis (FEA) based structural reassessments are also facilitated through functionality that
allows the auto creation of Finite Element (FE) models in the as-gauged condition and export the models
to relevant finite element analysis solvers using the add-on link within HM3D to Altair’s Hyperworks®
software. Hyperworks then generates an FE mesh (global or local models, as required by the user) along
with the structural properties (metadata), such as the material grades and gauged thickness.
Today, structural engineers face difficulty in practically applying automesh capability to complex or
detailed as-built geometry. This is especially true when considering marine and offshore structures,
where those assets tend to be very complex geometrically. The challenge posed in this project was to
use the as-built structural CAD model as the input and automesh assisted algorithm for creating an FE
model along with all the topological metadata, such as material grade and thickness.
To assist HyperMesh in performing this automeshing operation, specific sets of rules were developed for
each marine and offshore asset type. These rules were developed based on ABS rule and process
requirements for FEA. For example, primary longitudinal stiffeners are important for the overall strength
of the structure; therefore in idealizing the structure, the longitudinal stiffener positions are fixed while
other secondary stiffeners can be moved around within certain limits. Similar challenges exist when
consolidating structures to simplify the geometry, such as in the case of simplifying resulting meshing
problem by removing common thickness plate seams.
While element qualities between an automesh and a manual process vary (with the manual process
allowing for better mesh quality initially), with some minimal effort, fine-tuning the rule sets for
automeshing can be improved quickly to approach the quality derived from a much more labor-
intensive manual process.
Results show that automesh for targeted structure is possible. Manual work is still needed to upgrade
the element quality, but the time it takes is reduced to one or two days for a typical ship shaped Floating
Production Storage and Offloading (FPSO) unit.

2. .
FEM of FPSO from HM3D Fe-Toolkit