FROM DIGITAL TWIN TO WELD DISTORTION CONTROL

ICCAS 2019 offered an extensive range of topics.

 

A review by J L Martin, ICCAS International Programme Committee: UK member

The bi-annual ICCAS conference is renowned for a philosophy of ‘Practical Application’ of computing technologies. The majority of papers presented involve discussion on use of computing tools in the field, improvement of implemented computing systems, development of processes to ensure maximum benefit is gained from applying the technology, and research verified in the field or during trials. ICCAS has a strong international participation, and papers address a wide variety of topics: Fig 1 illustrated the range of papers presented in Rotterdam in September 2019.

An interesting aspect of the ICCAS conference is the indication of global trends in the industry on applying computing technologies. ICCAS 2019 was no exception.

A particularly notable trend is the increased effort expended during the concept and early stages of design. It has become apparent over recent years that a major proportion of the cost of a ship is committed at concept design, with organisations increasing the concept/early design process by taking advantage of the availability of computing technologies.

Papers at ICCAS 2019 presented several innovative ideas to apply during the early design stage of the ship product lifecycle.         

General arrangement layout during early design was particularly addressed in several papers. An advanced system for Naval Engineering Techniques aims to procure more effective and affordable naval units by understanding design space and identifying efficient design solutions. Queuing networks are used to analyse variations in layout in process driven ships such as LPD’s and Cruise Ships and allow for comparison of layouts and optimisation based on process performance. A highly interactive generic algorithm based layout exploration and optimisation method is proposed for generating spatial configuration of a ship.

A methodology for estimating weight and space demands of distributed ship service systems, electrical, fluids, HVAC, beyond those associated with ship propulsion systems are being applied during early design, and an expert system for ship design with automated computing techniques and tools to interact on critical decisions during early design was presented. Virtual Reality technologies used in Human Factors engineering to provide an ergonomics-focused design perspective were described and explained.

A further noticeable trend observed during the conference was the increase in consideration of the concept of ‘Digital Twin’ as a methodology for managing data. In addition to the papers specifically dedicated to the topic, digital twin was mentioned in several other papers as a future potential development. Digital twin discussions involved a range of diverse ideas. Different proposals for digital twin for the marine design, build, and operational environment were analysed to clarify the differences with discussion on results of a joint initiative to create a digital twin compared to the identified alternate methodologies. The current role of the digital twin was explored demonstrating the benefits and path towards an integrated cross enterprise digital environment. Guidance for successful application of digital twin in shipbuilding was offered based on lessons from other industries use, together with the challenges faced when adopting such an approach. The use of games engines as a technology for augmented and virtual reality was proposed as the framework to enable an accurate 3D representation of a vessel, its simulated behaviours, and all of the data needed through the lifecycle of a ship, as a possible basis of a digital twin.

ICCAS has shown an increasing trend for acceptance of Virtual Reality tools with ICCAS 2019 having a high proportion of interesting papers on the subject, seen as a beneficial to productivity and quality. Simple and intuitive use of VR by operators who are not CAD trained was proposed as a key consideration for implementing and operating a successful Virtual Reality system. Who should use a VR system, how, when, and why they should use it, and the selection and use of available viewing technologies, were discussed. How visualisation is used as an ‘intersection area’ between different design fields was defined, comparing CAD models by loading files from engineering tools to analyse the design whilst remaining in the VR environment. Significant findings on emerging best practices for effective collaboration on ship design in VR were also presented, with benefits achieved through application of the technologies during design, engineering and construction phases. Of equal importance to VR visualisation, is analogy with real time simulations in the form of information received through input devices. The concept that there is constant need to present controls and menus and the use of ‘virtual reality joysticks’ and a new form of menu was offered.

Operating a ship at sea is an environment where the implementation of on-board computing technologies is becoming a critical contribution of performance, cost minimisation, and environmental efficiency. Information collected at sea is being fed back to ship owners and ship designers to improve future vessels, as described in several ICCAS papers. Big Data – the real time interface of equipment and sensors whilst at sea – is enabling a better understanding of how a ship behaves in operational conditions. Papers on defining the operational profile of a ship using available information, optimisation of coastal routing based on the ocean environment, design for emission optimisation in compliance with regulations, collision avoidance based on deep reinforced learning algorithm, and a tracking method for navigation using image based object detection were all presented and discussed.

Another continuing trend noted at ICCAS conferences is the increased use of computing technologies in manufacturing and production. An advanced augmented reality system was described for the inspection of complex pipes in the pipe manufacturing shop. This resolves complex setting up of jigs and measuring tools normally required for post pipe bending inspection. The logical process flow between panel fabrication and assembly stages through simulation was presented as a means to address the problem of fabrication, assembly, and block erection that are not addressed in typical lean production methodologies used in mass produced products such as cars. Exploration of available laser scanning technologies as an aid to detail design, particularly for refit projects were described, an example of ever increasing use of laser technologies in the industry. Analysis and prediction of weld deformation was addressed with a process of defining a weld sequence to minimise the deformation. A methodology was presented for forming sheet metal shell plates in a steel press by defining press position, press angle, and press load, using augmented reality to inspect the formed plate and reduce/eliminate the need for template ‘sets’ as traditionally used for shell plate bending manufacture. Use of a discrete particle swarm optimisation algorithm to  identify sub-assembly divisions for hull structure based on clustering techniques was proposed to improve the ‘’experience’ method of sub-assembly breakdown whilst significantly reducing cost and time. In production engineering. The movement, turning and lifting of large fabricated blocks is critical and complex, a proposed assessment tool for ship block lifting based on dynamics and physics to make process safer and more efficient was demonstrated. The procedure is a combination of multibody dynamics and finite element methods to calculate the motion, stress, deformation of a block, and wire tensions when lifting.

A topic not generally discussed, but of significant interest to all shipbuilding and marine structure fabricators and operators is paint. A project database was presented which allows engineers and specialists to access legacy information when designing paint schedule, to enable assessment of paint weight and application cost, providing information to the production departments. A new concept of using paint replacement film was proposed, demonstrated by application on a bulk carrier.

.A particularly interesting production based paper on the evacuation of employees during the build stage of a very large complex ship in a build dock was presented. The paper described the analysis of escape routes, determining the need for duel escape paths when one is blocked, marking the escape routes to be clearly seen, particularly in cases of limited vision such as emergency lighting or smoke, and calculating the number of access gangways needed from ship to shore for swift evacuation of up to 1300 people. This is a common and extremely important problem in all shipyards and the paper offered a very practical, tried and tested, innovative methodology that was implemented and used successfully.

 

A ship operation paper that attracted high interest from delegates involved ship motion prediction of quiescent periods using wave sensor and Lidar systems, a technique to safely expand ship operating deck limits. Applied to a ship-air interface for the use of helicopters on naval vessels, the technology is equally applicable to any at sea launch and recovery operation, such as boats or offshore operations transferring items from ship to fixed structures. Verification and validation of simulation results by means of sea trials were discussed, with the quiescent period prediction identifying when the ship motion is most favourable to perform the launch/recovery operation in high seas.

CAD and Engineering databases have been evolving continuously over the past 30 plus years and ICCAS always has a large amount of papers on the subject. CAD/EDM/Digital databases were addressed by a wide range of authors, with the technologies moving towards use in early design and use in manufacturing and production. The digital twin concept described above is based around a high quality comprehensive CAD 3D model. The digital model is a term used by several authors discussing the collection and management of ever increasing quantities of CAD and engineering database data through the lifecycle of a ship.

Engineering tools, a mainstay of ICCAS since the first conference in 1973, have increasing understanding and are used often with innovative application. Using functional analysis to ensure value for money in complex engineering projects by analysing differing layers of data, representing customer requirement, functional breakdown and performance and engineering solutions, illustrated a logical approach to cost analysis. Buckling assessment software using Finite Element modelling conforming to Common Structural Rules was discussed. A non-linear Finite Element model is used for calculating container and lashing forces for efficient container stowage. Hull form generation, a long term ICCAS topic attracted alternate solutions. Coons patches were proposed for creating a hull form for structural analysis.

ICCAS offers authors an opportunity to present on how their company are using advanced technologies to ensure high quality, cost effective solutions for design, build and/or operation of ships and marine structures. It offers delegates the opportunity to see how computing technologies are successfully being applied across the international industry, and it enables engineers to exchange views and opinions on common problems.

ICCAS 2021 will be held in Japan.

ICCAS 2019 proceedings, printed and digital, are available from The Royal Institute of Naval Architects.

 

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