A new installation fixture and procedures will help prevent cracking/crazing of transparent armor windows on aircraft carriers. NNS Photo
A Navy Metalworking Center (NMC) Rapid Response project will develop, build and demonstrate a prototype fixture that will improve TA window installation and identify a protective covering to prevent corrosive agents from initiating cracking / crazing.
Transparent armor (TA) windows on aircraft carrier island decks are experiencing cracking / crazing after installation, most likely a result of the installation process itself combined with exposure to humidity and chemicals.
Preliminary analyses of the TA window failures indicate that the condition may be a result of residual stresses caused by uneven torquing of mounting bolts during installation combined with chemical exposure during construction, overhaul, and service. An NMC project team, which includes the CVN 78 Program Office and Newport News Shipbuilding (NNS), will leverage a fixture concept that NNS initially developed to improve the installation process. This portable fixture is needed to position and hold the window in place and to enable uniform torquing of the mounting bolts. The project team will develop a new conceptual fixture, tooling, and procedures or modify the existing ones.
If successful, this project will avoid an estimated $322,000 in TA window replacement costs on CVN 78 new construction, along with the CVN 72 overhaul that NNS is conducting. The projected cost avoidance on the remaining (CVN 73 – CVN 77) Nimitz Class overhauls is estimated to be $715,000. These figures are technical estimates and will require validation.
Once the CVN 78 Program Office and NNS accept the project-developed technology, NNS will install TA windows on CVN 78 using the prototype fixture and procedures starting in July 2014. NNS will continue to implement the technology on all future overhauls and new construction.
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