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Self-Locating / Self-Fixtured Structure

A new joint detail that enables Self-Locating/Self-Fixtured (SLSF) deck construction for OR and VPM deck flats will reduce labor hours and costs. Electric Boat photo

Objective

An Integrated Project Team (IPT) is developing the manufacturing process for a new concept of fitting and joining the deck structures for Ohio Replacement (OR) submarines and the Virginia Payload Module (VPM). The new concept, the self-locating, self-fixtured (SLSF) method, will enable construction with notched beams that interlock and are continuous in both directions.

Background

The Navy Metalworking Center (NMC) is leading a Navy ManTech project that will develop and optimize a more efficient way of fabricating submarine deck structures, which have been traditionally constructed of many short, fitted pieces (intercostals) between continuous beams.

Technical Approach

The IPT will investigate cutting, weld joint methods, fixturing, and temporary bracing requirements, both with finite element analysis and trial fabrications, to determine the most efficient means of building these structures. A final mockup construction at Electric Boat Corporation will integrate the tooling, fixturing, weld sequencing, welding, handling, and post-construction straightening methods to be implemented by Electric Boat for construction of OR and VPM deck structures.

Benefits

The estimated savings are $3.02M on the first two OR hulls, and $760K on each of the eight VPM sections planned for Block V in the first five years following completion of the project, for a total five-year benefit of $12.1M.

Implementation

While the construction method is relevant for many platforms, including surface ships, OR and VPM are of particular interest for this technology. Transition of the project results to OR should occur in the second quarter of FY17 before detailed design begins, thus avoiding significant design change costs. Implementation is expected on the lead OR hull, and on the first VPM in the third quarter of FY19 at Electric Boat’s facility in Quonset Point, RI.

Status

Active

Stakeholder

Walter Smith
OHIO Replacement, CMC and HM&E Component Development Lead
PMS 397

Partners

General Dynamics Electric Boat Corporation
PMS 450 Virginia Class Program Office
DDL Omni
PMS 397 Ohio Replacement Program Office