DD(X) UNDEX
DD(X) Machinery and Electronics Shock Mitigated Rafting: Test Articles

Joel Myers, Northrop Grumman Ship Systems
Mr. William "Skip" Dickson, Anteon
Vince Godino, Anteon
Russ Miller, Anteon

Jeff O'Brien, Anteon

Abstract:
The DD(X) approach for reducing the shock environment for machinery and electronics equipment is to employ shock mitigated rafting systems.  The reduced shock environment allows for the use of commercial-off-the-shelf (COTS) or modified COTS (MOTS) equipment rather than heavier and more expensive shock hardened equipment.  The shock mitigated rafts are designed to meet a shock environment defined by the shock response spectra (SRS) criteria.  The detailed designs, layouts, fabrication approach and materials for the test articles are discussed.

This paper focuses on the detailed design and fabrication of the test articles.  The materials used in construction and the connection details are discussed.  The design approach to satisfy shock is presented.  Global and local buckling, deflection and buckling requirements are addressed.

Several requirements must be met in addition to shock that influence the material selection and design details.  For example, the Electronic Modular Enclosure (EME) must provide electromagnetic interference (EMI) protection before, during and after a shock event.  Also, the machinery and electronics rafting designs must be producible with adequate ergonomics and maintainability for long-term ship application.

Photos of the test articles are presented.  Test articles were built and tested as part of the VV&A process.  Standard MIL-S-901D heavy weight tests using the floating shock platform (FSP) were performed.

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