Latest version of ABS CSR SafeShip

18 Jul 2006

ABS has released an enhanced new version of the CSR SafeShip for Tankers software. The new version 6.8 is an upgrade of the previous version 6.63, which shipyards have been using to evaluate tanker designs for conformance with the new IACS Common Structural Rules (CSR) since February 2006. The new release includes the latest CSR requirements including Corrigenda 1 of the Rules and incorporates the considerable feedback that has been gained from industry over the last several months.

ABS had been working with leading shipyards, especially in Asia, for an extended period prior to the introduction of the CSR in April 2006, assisting the yards to develop new designs that conform to the more technically advanced Rules.

"This cooperation has been invaluable for both the yards and for the ABS engineering staff," said Dr. Kirsi Tikka, Vice President for Special Projects at ABS who has spearheaded the ABS Common Rules program. "It meant that some shipyards had new CSR compliant designs available to offer shipowners as soon as the new Rules took effect. The first order for a CSR-compliant tanker to ABS class was placed in April and others have followed. These designs have been developed using the new ABS CSR SafeShip software."

The software has proved to be a powerful tool which incorporates all the CSR structural assessment requirements in a single comprehensive rule check package. It uses an advanced graphic user interface for modeling the hull form, the compartments and the structural members. The unique features such as automatic copy functions for repeat structural members and the ship-specific templates assist designers to generate a 3-D structural model including longitudinal and transverse members as well as complex configurations such as the intersection of corrugated bulkheads with other structures.

The software generates a NAPA Model which provides the steel weight for the structure and can be further developed into a complete NAPA Steel model if desired by the shipyard. NAPA is widely used by shipyards around the world as an integrated part of their design process and ABS CSR SafeShip is the only classification software that incorporates a NAPA Model from the outset.

"In furthering the development of the SafeShip software, the challenge has been to balance the designer?s sometimes competing needs," explains Tikka. "At the earliest stage of development, a designer?s preference is for speed and ease of use. Yet the more information that can be generated initially, the faster and easier it is to complete the latter stages of the design that involve more complex analysis. By introducing elements such as the NAPA modeling during the Initial Scantling Evaluation not only is the entire classification verification process improved, but also the design can be then more easily integrated with the other design tools and functions adopted by a shipyard that go beyond class."

ABS CSR SafeShip uses Prescriptive Rule Spreadsheets for the CSR Initial Scantling Evaluation (ISE). This approach provides a simplified method that promotes transparency and avoids a ?black box? approach to the engineering calculations. The spreadsheets have been developed for easy verification of the intermediate and final results and for easy evaluation of alternatives thus providing flexibility in the design process.

An ISE conducted using SafeShip comprehensively covers the prescriptive requirements for the global hull girder, local plate and stiffeners, primary support members, applying the specified yielding, buckling and fatigue acceptance criteria, while automatically applying the appropriate net thickness values in accordance with the CSR philosophy. The ABS SafeShip system is also unique in that its ISE considers the whole ship, covering the forward and aft ends of the ship as well as the midship region of the vessel.

The subsequent CSR Total Strength Assessment (TSA) process requires a mandatory Finite Element Analysis which, in the SafeShip software, is supported by an extensive graphic user interface for generating the 3-D FE model, the tank information as well as the boundary constraints and design loading. The general data is imported from the ISE module to eliminate repeat data entry.

The system also offers a standalone option for TSA with a graphic user interface when only the FE analysis is needed. The model generation includes global, local and fatigue models which are required to carry out the total strength assessment for the CSR. Alternatively, the system also includes the flexibility to import most independent user-generated FE models which are then loaded and assessed using the SafeShip system. The system offers user-friendly tools to check and view the model. Different parts of the model can be selected for strength, fatigue or buckling evaluations.

To assist the designers to identify critical areas for local mesh modeling and analysis, SafeShip incorporates local strength screening. SafeShip also incorporates the advanced buckling check for a complete Rule Check package. The SafeShip TSA module is a powerful tool which brings the benefits of the final rule verification to the earliest stages of the design process. This provides designers with the information necessary to finalize the scantlings at the outset, simplifying the subsequent design process.

"ABS is committed to providing the most comprehensive technical support possible to both shipyards and shipowners as they adjust to the application of the new Common Structural Rule requirements to their designs," Tikka stressed. "This latest version of CSR SafesShip provides a technically advanced yet simple and logical tool that, in its earlier iterations, has already clearly demonstrated the advantages it brings to the design development process. We are continuing to work with NAPA and with our clients to complete development of comparably advanced software for application to bulk carrier designs that will be a significant technical improvement over the initial system that is being used at present."

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