Enabling Technologies for Unified Life-Cycle Engineering of Structural Components (1991)

This report addresses the application of unified life-cycle engineering approaches to the design, manufacture and application of structural components and is further focussed on structural components for advanced military weapons systems.

Unified life-cycle engineering (ULCE) is a design engineering environment in which computer-aided design technology is used to continually assess and improve the quality of a product during the active design phases as well as throughout its entire life cycle by integrating and optimizing design attributes for producibility and supportability as well as for performance, operability, cost, and schedule.

The interest in the application of ULCE to the structural components of advanced weapons systems is prompted by the observation that in these systems the life-cycle cost is dominated by product support, with data for manned aircraft showing that 70 percent of life-cycle cost is associated with support after deployment.

The objective of the study was to identify and evaluate priorities for research and development in life-cycle engineering. The goal was to identify the enabling technologies that underpin ULCE, determine their readiness for application, and identify the research and development required to make them available in a 10-year period.

The development of complex military weapons systems has always required that the design team make numerous decisions regarding the application of new, unproven technology to achieve improved performance. The design team is often unable to achieve its design goals using well-established technology with known reliability, producibility, and cost. This continuing need for increased performance has generally led the design team to select the technological approach that offers the highest performance consistent with program cost and schedule constraints. Consequently, new systems usually require considerable maturation during the manufacturing and support phases of their life cycle. A fundamental goal of ULCE is to achieve as much of this maturation as possible during the design phase, thereby reducing the life-cycle costs and improving the reliability, availability, and maintainability of new weapons systems once they are deployed.

The basic approach envisioned for ULCE would utilize a series of computer-aided design tools and databases with capabilities consistent with the level of design then underway (conceptual or detailed). This approach would be sufficiently integrated to permit the conceptual design to

form the foundation of the detailed design without repeating or recreating prior operations. This new capability would permit the designer to analyze a system for the wide range of factors involved in the performance of a system or of its individual components. For example, the designer could perform a preliminary design using the computer-aided design (CAD) module of the ULCE system, evaluate its structural requirements by using the finite element models (FEM) module of the ULCE system, make a materials selection from the materials database of the ULCE system and evaluate the materials long-term resistance to environmental degradation under the expected operational conditions using the corrosion module of the ULCE system. To insure that the information in the ULCE system is constantly up to date, a ''Lessons Learned'' module would be required to input new performance data.

To reach its conclusions and recommendations, the committee examined the current and desired future environments for five factors in a product's life cycle: design, manufacture, product support, materials, and information systems. By analyzing the differences between the current and desired states and grouping like elements and eliminating redundancies, a list of needs and concerns was generated. From these needs and concerns the following set of four critical issues was developed and recommendations relating to each issue identified. Since this report, in general, deals with military systems, the recommendations are addressed to the federal government, specifically the Department of Defense (DOD). It is recognized that many of the recommendations would actually be implemented by industry under DOD guidelines. Moreover, the recommendations are applicable to industries that are using ULCE or concurrent engineering in their own planning irrespective of whether the work is undertaken for the government or not.

• ULCE-driven development of materials processing and repair methodologies requires integration of research and development across disciplines.

Initiate and focus on materials research and characterization appropriate to the needs of ULCE.

Improve communication of ULCE needs within the materials community and governmental funding agencies.

• Advanced analytical modeling and simulation methods that would lead to actual component manufacture, operation, and logistics do not exist to the extent required.

Develop a model life-cycle cost calculator.

Accelerate the development of CAD-CAM systems that incorporate complete product descriptions material performance data, and manufacturing process information as well as features-based modeling for use with product and process modelers that support producibility, reliability, serviceability, etc.

Expand the application of analytical methods.

• The information system for an integrated team approach to ULCE is inadequate.

Build and implement a conceptual, system-level information reference model.

Develop and coordinate standard representations for entities in the ULCE system for unambiguous, reliable, and efficient retrieval, manipulation, and transfer of data.

Develop a rapid analysis tool for the conceptual design phase that embodies producibility and supportability.

• The ULCE team will need to make key decisions while still operating with incomplete information.

Develop and enhance capabilities to relate field observations to design attributes.

Develop improved sensor-based tools for periodic or continuous monitoring to assess remaining structural integrity of component materials.

Initiate and promote education and training in ULCE concepts and methods.

Develop better techniques to deal with missing or uncertain information.

The committee concluded that because the development of ULCE requires a strong interdisciplinary research and development program involving a number of technologies; e.g., computer, materials, analytical modeling and simulation, decision theory as well as an equally strong educational commitment to support the program, the following general recommendations should be addressed prior to consideration of those identified under the critical issues:

• The overall scale of the ULCE effort should be defined; a detailed R&D plan and budget for a 10-to 15-year technology development program must be prepared.

• A demonstration project for ULCE should be established using a major subsystem or module of a current vehicle and then redesigning, reengineering or remanufacturing the subsystem or module.

• Lead responsibility for developing and implementing ULCE should be assigned to the Air Force, since it already has made a commitment to ULCE and generated a strong commitment to the concept. Mechanisms should be provided for calibrating with the Services and other government agencies.

The ULCE approach is not feasible at this time because current information systems are inadequate, the mathematical modeling capability is far less than needed, and materials data is lacking and fragmented. Further, to take full advantage of technological advances, decisions will have to be made in the absence of complete information; processes and technologies for minimizing risks in this area are not robust.

The breadth of issues to be addressed is vast. Although many of the technical goals may prove difficult or even impossible to achieve because of fundamental limits resulting from the computational complexity of the tasks, the committee is optimistic that a useful ULCE system can be developed by the year 2000 if sufficient resources are devoted to its development. This report provides a basis for initiating the longer-term, higher-risk research efforts as well as the

foundation for a more detailed analysis of the alternative technical approaches for meeting ULCE goals.

Any successful program will require the active participation of some of the best minds in the country, exceptional program management skills, and a considerable financial investment. The committee believes that, even though the challenges are major, the benefits justify initiating a significant research program as soon as possible.