SOW_DNV_NL-FEA_090616_(2).docx

STATEMENT OF WORK (SOW) FOR

SPECIAL STUDIES FOR NON-LINEAR FINITE ELEMENT STRUCTURAL ANALYSIS OF A US COAST GUARD PATROL CUTTER

CONTENTS

1. INTRODUCTION

1.1 The United States Coast Guard (USCG) Surface Forces Logistics Center (SFLC) has been involved in a number of structural analysis efforts requiring limiting load prediction using non-linear Finite Element Analysis (FEA) programs. The non-linear FEA is used to determine the ultimate strength of patrol boats and cutters in efforts to provide operator guidance and manage the structural integrity through the remaining service life of the hull structure.

1.2 The objective of this effort is to develop a detailed FEA model of a Sentinel Class Fast Response Cutter (WPC) 154 hull for use in non-linear FEA ultimate strength analysis of the deckhouse 01 level and determine the sensitivity of initial plating and stiffener deformations as part of a Root Cause Analysis (RCA).

2. REFERENCE MATERIAL

2.1 The Tasks of this project require information about existing cutter classes, their performance and design. GFI reference materials to be provided include: structural drawing of the Fast Response Cutter (FRC) hull and deckhouse, Hull CAD model, and 3D laser scan point cloud results. The Contractor shall also review the structural model tests results and WASIM hydrodynamic predictions for the FRC.

3. SCOPE OF WORK – The work shall be accomplished through the following tasks.

3.1 Task 1 – Develop FRC FEA models. The Contractor shall develop a hull FEA model for the FRC hull to include bow and forward deckhouse structure. This shall include but limited to the hull and house structure from Frames 0 to 28, not including the pilothouse using the ABACUS FE program and non-linear analysis approach used by DNV on previous USCG Cutters. This FEA model shall be based on structural configuration provided by the USCG as a starting point for refined modeling of the 01 foredeck area. The FEA modeling may use sub-models for more efficient analysis if required. Hull form definition shall be provided in IGES format by the USCG to facilitate model development.

3.2 Task 2 – Identify Hull Loading. The Contractor shall review photographs of the deformations in the 01 foredeck and related 3D laser scan geometric definitions in the deck to facilitate definition of conditions contributing to the deformations. This shall include effects of residual stress, temperature effects (60deg C deck and 30deg C ambient nominal temperatures), and both hull girder and local slam loading that could contribute to the foredeck deformation. New WASIM simulations may be conducted to supplement the prior effort if required to supplement model test data. This review shall identify loading conditions that are to be applied to the FRC FEA model. Forces applied to the FEA model that produce equivalent hull sheer and bending loading is acceptable. Application of hydrodynamic load predictions may be used to facilitate load application to FEA models. Potential for shipping green water or solid spray loading on the deckhouse shall be identified based on model test video. The Contractor shall review 3D laser scan of the 01 foredeck and evaluate as input to initial deflections along with construction tolerances. The Contractor shall develop a letter report describing the load conditions to be used in the NL-FEA for USCG review and comment prior to starting Task 3. Comment by WAMack: Why isn’t this being included under 2.1 above?

3.3 Task 3 – Conduct NL-FEA. The Contractor shall use the FEA models developed in Task 1 and the loading developed in Task 2 to conduct a NL-FEA to reproduce deformations observed in the 3D Laser Scans. The Contractor shall apply weight, moment and sheer load cases to the detailed model and return the limiting moment and stress analysis. The Contractor shall determine the relationships between initial deformations of plating, longitudinal plating stiffeners and associated collapse moments. The loads developed as part of Task 2 shall be related to wave conditions producing the loads for the RCA.

3.4 Task 4 – Provide Documentation. The Contractor shall develop draft and final reports documenting the results of Tasks 2 and 3 and include RCA findings related to the loading and structural configuration strength capacity.

4. DELIVERABLES AND SCHEDULE

4.1 DELIVERABLES – The Contractor shall include in the letter report deliverables to SFLC all photographs, illustrations, charts, graphs, tables, calculations, text, analyses, algorithms, conclusions and recommendations developed as a part of this project.

4.2 MODIFICATIONS - Modifications to Contractor submittals required by the Government reviewers, if judged by the Contractor to be outside the scope of this SOW, shall be discussed at a meeting of the Government technical and contracting personnel with Contractor representatives.

4.3 SCHEDULE – The following schedule of events shall be followed by the Contractor in carrying out the provisions of this Statement of Work. When either party becomes aware of their inability to conform to this schedule, they shall so advise the other party, in writing, propose an alternate schedule, and provide justification.

5. QUALITY ASSURANCE

5.1 The Government reserves the right to witness the validation procedures and validation processes of any part of the project development at whatever site such action is taking place.

5.2 The Government shall review the contents and format of the deliverables in their entirety prior to issuing approval.

6. SECURITY CLEARANCE

6.1 This work is not classified. No security clearance is required.

7. USE OF GOVERNMENT FURNISHED MATERIAL

7.1 Government furnished material and information referenced in 2.0 shall be used for the delivery order only and shall not be used or disseminated for any other purpose.

8. NOTES

8.1 DELIVERY DESTINATION – All items to be delivered under this work statement shall be delivered to the SFLC-ESD technical point of contact, Mr. Karl Stambaugh, with a documenting cover letter at the following address:

For each deliverable a copy of the cover letter shall be provided directly to the Contracting Officer at the following address:

8.2 RIGHTS IN DATA – All data regardless of form or medium are considered to be solely the property of the US Coast Guard and shall not be released without the written consent of the USCG.