Using Siemens software to help develop a race boat
07 November 2016
In the middle of 2014, the Land Rover BAR team began a 2 ½ year timetable to design, evaluate and verify an ACC (America’s Cup Class) catamaran.
Crucially, teams are not allowed to launch their America’s Cup Class catamarans until 150 days before the first event of the 2017 America’s Cup Qualifiers. The bulk of design, analysis and performance testing must be completed on much smaller-scale test models.
The Land Rover BAR team is using NX software and Teamcentre software from product lifecycle management (PLM) specialist Siemens. NX and Teamcentre provide an integrated virtual environment for digital modelling and simulation. Software implementation, training and support services are being provided by Siemens PLM Platinum Partner Majenta PLM.
At the pinnacle of sailing technology
Martin Whitmarsh, chief executive officer of Land Rover BAR, underlines the technical challenge: performance differentiation is usually created by shaping a hull to reduce drag; enhancing the way in which keel and rudder systems create a ‘righting’ moment; and using the sails for maximum thrust. These principles still apply to the America’s Cup, but only one percent of the surface area of the boat is actually in the water when racing. Aerodynamic considerations therefore become important, especially as these boats can go 2.8 times the speed of the wind.”
The design team must produce a light and efficient system that can cope with enormous loads yet remain within the margins of safety. For Land Rover BAR, the use of NX and Teamcentre is critical for simulating the performance of the daggerboards (retractable keels); evaluating the aeroelastic capability of the wing; defining the behaviour of composite materials; modelling the hydraulic systems; optimising development processes; and streamlining workflows.
The fastest boat wins
By the start of 2016, testing was fully underway and the America’s Cup Class wing-foiled catamaran was in development.
The shape of a daggerboard dictates how effective it is in converting forward motion into lift and Land Rover BAR relies heavily on the ability of NX to produce hundreds of geometries at the press of a button.
Likewise, the fixed wing sail, which acts as the engine of the boat, is crucial to speed. Under the rules of the race the wing has to weigh at least 450kg and must be a certain shape when in dock. Passive deformation, which may sometimes enhance performance, is only acceptable when out on the water; on the other hand, some sailing conditions call for a stiff wing. The Land Rover BAR designers really need to understand the limits of what is both possible and desirable. They have therefore coupled a fully detailed 3D model of the wing using NX, with a high-level stick model developed with Femap software, and a detailed composite model created using the Fibersim portfolio of software for composites engineering (the laminate modelling and draping toolset integrated with NX). This combination of models is being used with computational fluid dynamics (CFD) analysis tools from Siemens PLM Software.
Simon Schofield, designer, Land Rover BAR explained that the scripting capabilities of NX allowed them to create a user interface for the CFD coding and set up an aeroelastic simulation process entirely within NX. With geometry, aeroelastic optimisation and structural analysis all in NX, they use NX Nastran to run a sweep of imaginary deformed shapes and pick out the trends of what they want to achieve; they need to know if it is possible to produce a shape using NX and still meet the rules. Having everything in one environment really speeds up productivity because they are not transferring files in and out.
Realising the dream boat
Together, NX and Teamcentre enable a complete and comprehensive development process from concept to the surface of the sea.
Use of the analysis tools integrated with NX enables the design team to optimise the structure of metallic parts made through the additive manufacturing method. Andy Claughton, the team’s chief technology officer explained they were looking at the workflow for additive manufacturing. Rather than designing a component for normal machining, the team planned specifically for 3D printing by starting with an envelope of material on which they marked boundary areas and attachment pins.
By annotating 3D models with NX PMI (product and manufacturing information) mark-ups, the design team can convey the exact manufacturing requirements of a 3D model to downstream partners. This detailed guidance is carried through to drawings for suppliers who require 2D data.
Reassuring control and consistency
Land Rover BAR uses Teamcentre to manage all technical files and documents so that specifications, design calculations, analysis data, simulation results and material properties are in the correct order and associated with the right CAD models. The team’s use of Teamcentre controls the release process and governs all workflows leading up to manufacturing. This enables 15 to 20 people to collaborate very closely on the same model.
Within Teamcentre is the complete provenance for every component and each configuration of the boat. All the individual parts on the 2016 test boat will have a complete bill of materials (BOM). Good control of the BOM is extremely important as the component count on these boats is very high; the shore team needs to be able to keep track of each configuration and perhaps most critical is the fact that prior to each race the team needs to submit design substantiation documents to demonstrate class rule compliance.
In the technologically driven environment of Land Rover BAR, the engineering team dictates the tests that the sailing team must conduct. The team’s mission control centre has a live video link to the test boat and designers can see exactly what is happening as they assess data received from the various sensors positioned around the boat. Sailing can then be followed by a thorough and informative debriefing session for sailors and engineers.
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