©2015 American Bureau of Shipping. All rights reserved.

Eka Kristanto, Sameer Kalghatgi, Chris Serratella

ABS Asset Integrity Management Team

Houston, TX

8 October 2015

Automated Finite Element Model Creation

using Structural Condition Data

for Marine & Offshore Assets

ALTAIR TECHNOLOGY CONFERENCE

2

Challenges & Solution

Challenges:

Creating a FE Model from as built geometry

takes weeks

Updating element thickness (as gauged, future

predicted) is labor intensive and takes a few

weeks to months depending on the age of the

asset

Solution:

Automatic FE Model creation from Structural

Condition model (HM3D database) is

accomplished in 1 – 3 days

Element thickness (as gauged, future

predicted) is automatically assigned in a few

hours

3

ABS Structural Integrity Management Suite

Hull Manager (HM)

Inspection workflow management tool, high level asset condition

tracking, anomaly management using 2D model

Hull Manager 3D (HM 3D)

Advanced visualization with 3D CAD model converted

into relational database

Capture the condition (gauging, anomalies, critical areas)

of asset structures

Enables tracking asset condition in 3D environment

HM3D – FE Toolkit

Create Global and Local FE Model using thickness from HM3D

based on various thickness methodologies such as: gauged, future

predicted, historical corrosion rates

4

HM3D: What does it do?

Condition Information:

Anomaly and repair

management (create, plan and

resolve)

Gauging planning and tracking

(export to HM web as

spreadsheets and import back)

Corrosion levels in color coded

view

Anode condition

Trending:

Remaining life prediction

Cross-section and section modulus

Structural analysis interface

(FE interface tool) to enable

reassessment in current or future

condition

Value for Clients: A foundation for structural integrity management that enhances the understanding of asset structural condition to

minimize downtime and assess structural health for continued service and asset life extension assessment

Collect

Corrective Action:

Repair planning and estimation

(steel wt., surface area)

Adding brackets and stiffeners

Anode replacement

An

aly

ze

Act

Rep

ortSIM Database & Plan

Management:

Inspection plans

Display of structural details

and critical areas

Life Cycle and Time History

5

Solution: Link HM3D to HyperMesh

HyperMesh

HM3D

FE CollectionFE

Mesh

Idealized Geom

HM3D – FE Toolkit

Whole Asset

Element thickness (as gauged, future predicted) is automatically assigned in a few hours (2 hrs)

Automatic FE Model creation in HyperMesh from Structural Condition model (HM3D database)

is accomplished in 1 – 3 days (2 days)

6

FE Collection

FE Collection is a collection of structures and may be the entire asset, or few compartments or localized

structural elements

FE Collection is created in HM3D and exported to HM3D-FE Toolkit in HyperMesh along with all

metadata including thickness and material

In HM3D structure thickness is assigned by user based on either “As Gauged”, “Forward Aged”, “Future

Trending” and accounts for ungauged structures

7

Defeature & Idealization

Raw Geometry

from HM3D is

defeatured and

idealized based on

custom rules

Determines quality

of mesh

Idealization (and

Mesh) is done

automatically

8

Defeature & Idealization

Automated

idealization is rule

based

User may also

determine how the

geometry needs to

be idealized

User may edit

idealized geometry

prior to meshing

9

ABS Mesh Generation Rules

Mesh Size and Density:

Mesh sizes in longitudinal, transverse and vertical directions

Mesh density between two adjacent web fames for and aft of a

transverse bulkhead

Mesh density over the depth of the double bottom floors,

girder, side transverse webs, side stringers, vertical webs and

horizontal stringers on transverse bulkheads

Mesh Shape:

Aspect ratio ≤ 3

Taper ≤ 10

Warping ≤ 5 degree

Internal angle ≥ 30 degree

10

Mesh Generation – 1D

3 Holds – 1D Elements3 Holds – 1D Elements

11

Mesh Generation – 2D

3 Holds – 2D Elements

12

Mesh Generation – 2D

Typical Bulkhead

Typical Stringer

Typical Frame

3 Holds – 2D Elements

13

Conclusion

Automesh on shipshape FPSO

(3 holds) was successfully

conducted with thickness

measurement data

Creation of global FE model with

thickness data was achieved in

2 days compared to 1~2 months

when building from scratch

Time saved in creating a FE model

directly from a structural condition

model is over 75%

www.eagle.org

©2015 American Bureau of Shipping. All rights reserved.