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Demonstration Software Modelling Exercise Aids Taiwan’s Yachtbuilding Community

May 2, 2014

Well known for its electronics expertise, Taiwan also maintains a respected luxury motor yacht industry. In 1987, the country exported 1,755 vessels, worth more than $190 million (USD), and today, post-recession, it reportedly has the sixth-largest yacht building community in the world.

To advance its boatbuilding expertise, the country is constructing a dedicated yacht building precinct as part of the Kaohsiung Port City Reconstruction project. Taiwan’s yacht builders lacked expertise in CAD/CAE and composite layup optimization, particularly for carbon fibre composites. This caused them to outsource initial design work to foreign partners.

A joint venture between commercial and academic institutions created a demonstration capability to show builders how SIMULIA enables design iterations far earlier in the development cycle and traces problems during every stage of the pre-production process. This has shown that the number of issues found during development and manufacture can de dramatically reduced with a similar impact on modification costs and concept to delivery times.

Three significant areas were highlighted within the demonstration: composite layup architecture; ventilation and thermal analysis; and wave-impact transient analysis. The ability to optimise strength, stiffness and ventilation efficiency whilst accounting for structure performance and allowing for dynamic wave-slamming impact has become a critical component of every design.

The SIMULIA application portfolio, based on Abaqus finite element analysis (FEA), and Dassault Systèmes’ Simulayt simulation software were tapped for layup analysis and manufacturing process management. Abaqus CFD (computation fluid dynamics) came into play for ventilation and thermal analysis. Abaqus/Explicit was used for Coupled Eulerian-Lagrangian (CEL) analysis, which is central to slamming impact simulation. The CAD tool was Dassault Systèmes’ CATIA, which seamlessly integrates with all three CAE functions. The team used a 70-ft Monte Carlo-type yacht as a simulation benchmark because it is the median size for Taiwan’s yacht industry, and it conforms fairly closely to the proprietary specifications of most manufacturers.

The team was able to import geometry from CATIA and use Simulayt with the composite modeller for Abaqus (CMA) to analyse composite layups. The same models were reused for the CFD simulation, and material properties and conditions could be shared between models without duplication. CATIA Composites came into play at the detailed design stage, helping to optimize design for manufacturability, and it also generated the composite layup geometry, which could then be assigned to Abaqus with specified material properties and fibre orientation. An interface connects CATIA Composite and Abaqus CMA with automatic data transfer, eliminating the possibility of typos and tedious layer-by-layer property assignments. The Simulayt tool then simulated the forces on the composite structure during manufacturing, rounding out the analysis by predicting plant floor fabrication issues, such as hogging loads during hull lifting and demoldings that can be mitigated earlier in the development cycle. This makes it easier to meet production timeframes within budget.

In terms of slam loads and wave impacts, the team used Abaqus CEL to simulate the yacht’s transient and nonlinear varying response to these conditions in straight runs and turning manoeuvres. Slamming contact pressure on the hull also was output to determine structure loading under transient impact.