Accuracy and Distortion Control Challenges in Lightweight Structural Unit Assembly at Northrop Grumman Ship Systems

Shipboard applications of lightweight structures have increased over the past decade in both military and commercial vessels. Severe distortions have emerged as a major obstacle to the cost-effective fabrication of such lightweight structures. With a recent major initiative funded by the US Navy Office of Naval Research, Northrop Grumman Ship Systems (NGSS) has undertaken a comprehensive assessment of lightweight structure technology. This program includes a comprehensive investigation of the fabrication and assembly processes for thin steel structures and their contributions to the final dimensional accuracy and distortion. As part of this effort, substantial work was done to characterize current dimensional quality performance in partial subunit (PSU) and combined partial subunit (CPSU) assemblies, and to identify contributing factors to dimensional inaccuracy and distortion in unit assembly stages. This information will be used by NGSS as a basis for improvements in fitting and welding processes, jigging and fixturing methods, dimensioning and tolerancing, and accuracy control processes. This paper summarizes the current dimensional quality performance in PSU and CPSU at NGSS, and the factors contributing to current performance.

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Accuracy and Distortion Control Challenges in Lightweight Structural Unit Assembly at NGSS

10.5957/smc-2005-p29 ◽

2005 ◽

Author(s):

M. Spicknall ◽

E. Hodges ◽

T. D. Huang

Keyword(s):

Dimensional Accuracy ◽

Steel Structures ◽

Cost Effective ◽

Naval Research ◽

Accuracy Control ◽

Contributing Factors ◽

Quality Performance ◽

Lightweight Structures ◽

Office Of Naval Research ◽

Welding Processes

Shipboard applications of lightweight structures have increased over the past decade in both military and commercial vessels. Severe distortions have emerged as a major obstacle to the cost-effective fabrication of such lightweight structures. With a recent major initiative funded by the U.S. Navy Office of Naval Research, Northrop Grumman Ship Systems (NGSS) has undertaken a comprehensive assessment of lightweight structure technology. This program includes a comprehensive investigation of the fabrication and assembly processes for thin steel structures and their contributions to the final dimensional accuracy and distortion. As part of this effort, substantial work was done to characterize current dimensional quality performance in partial sub-unit (PSU) and combined partial sub-unit (CPSU) assemblies, and to identify contributing factors to dimensional inaccuracy and distortion in unit assembly stages. This information will be used by NGSS as a basis for improvements in fitting and welding processes, jigging and fixturing methods, dimensioning and tolerancing, and accuracy control processes. This paper summarizes the current dimensional quality performance in PSU and CPSU at NGSS, and the contributing factors to current performance.

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World psychology and the role of the Office of Naval Research.

American Psychologist ◽

10.1037/0003-066x.40.2.235 ◽

1985 ◽

Vol 40 (2) ◽

pp. 235-237

Author(s):

Richard E. Snow

Keyword(s):

Naval Research ◽

Office Of Naval Research

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CAD Of Anticorrosive Protection Of Steel Structures

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2019.09.18-23 ◽

2019 ◽

pp. 18-23

Keyword(s):

Protective Coating ◽

Computer Aided Design ◽

Steel Structures ◽

Cost Effective ◽

Operating Conditions ◽

Computational Tool ◽

Protection Method ◽

Cost Effective Method ◽

The Cost ◽

Aided Design

The choice of cost-effective method of anticorrosive protection of steel structures is an urgent and time consuming task, considering the significant number of protection ways, differing from each other in the complex of technological, physical, chemical and economic characteristics. To reduce the complexity of solving this problem, the author proposes a computational tool that can be considered as a subsystem of computer-aided design and used at the stage of variant and detailed design of steel structures. As a criterion of the effectiveness of the anti-corrosion protection method, the cost of the protective coating during the service life is accepted. The analysis of existing methods of steel protection against corrosion is performed, the possibility of their use for the protection of the most common steel structures is established, as well as the estimated period of effective operation of the coating. The developed computational tool makes it possible to choose the best method of protection of steel structures against corrosion, taking into account the operating conditions of the protected structure and the possibility of using a protective coating.

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