About CTMA

Projects
- emerging
- active
- completed

Services
- LPDI
- Technology Roadmapping

Newsletter
- current

- past issues

- subscribe

Web Links
- DoD Sites
- DoD Facilities
- related sites

Join NCMS

Past Symposiums

Submit Project Ideas

Site Map

NCMS
Homepage
 

Process Substitution Methodology for Composites

The Process Substitution Methodology project for composite materials provided immediate benefit to the Department of Defense (DoD) war fighting capability during missions in Afghanis­tan, Kosovo and Iraq. Rapid revisions were made to process methods for the Predator B unmanned air vehicle (UAV) that eliminated periods when the weapons system could not be operated and reduced vulnerability of the system to attack. Although specific cost data is not available, this single application of the methodology almost certainly provided benefits well in excess of the project costs. A further indication of the benefits of the project is the independent acquisitions (outside of the project funding) of the additional hardware and systems to support the process substitution methodologies developed during this project. These systems are currently being applied to improvements within the constraints of existing legacy specifications but with the goal of evolving to next generation processes.

The project team members included General Atomics, responsible for both design and production of a complete weapons system, The Aerostructures Corporation (TAC), a division of Vought Aircraft Industries, that builds commer­cial and military composites such as the Airbus 340 wing panels and the aft fuselage of the Navy V-22 at a high production rate (24 hours seven-days-a-week) and Kestrel Aircraft Company that provides composite aircraft certifications. Tech­nology providers included the University of Oklahoma, Advanced Processing Technology, Inc. (AvPro) and the Advanced Composites Office (ACO) of the Air Force. Repair Depots included Ogden Air Logistics Center (OO-ALC), Oklahoma City Air Logistics Center (OC-ALC) and Corpus Christi Army Depot (CCAD). This broadly based team provided the range of talent and challenges to address the needs of the new approach and to pose the critical issues associated with introduction of the technology. The ACO provided critical analysis testing and resources in support of the project.

The primary goal of this project was to develop and install the basic tools required to support material state management approach upon which the substitution methodology is based. The rapid revision of the processes that allowed for expan­sion of the Predator mission is just one example of how this technology can be applied.  The material state management approach provides production personnel and support engineers with visibility on the effects of changes in process on the cure rate and cure state of the composite. This enables rapid decisions because the material state data relates directly to the pro­cess outcome and to the performance of the structure. In contrast, the existing legacy ap­proach specifies only the processing time and temperature without identifying the effects on the material properties. Without knowledge of the effect of a process change on product per­formance, it is impossible for the responsible parties to approve a change to the process. 

If a significant process change is needed, the legacy methodology requires a lengthy search through the design data and material pedigree, back to the original qualification data. These searches are costly and frequently exceed the time available for repair. The result is that raw materials and finish products are often scrapped because of an inability to demonstrate “goodness” even if they could actually meet all performance criteria. The inability to demonstrate “goodness” has a severely limiting effect on any improve­ment that involves a significant change to the process. It drastically contributes to cost because “good” materials and components are rejected and scrapped when they do not meet fixed process or storage criteria. Optimization of the process for producing the best product is not possible since it is the process itself that is specified not the process outcome.

The major achievement of this project has been the installation of the early building blocks that supports the new material state management approach to composite material processing. It is especially significant because, unlike research projects carried out in isolation, this project has been carried out with the active participation of Production and Repair Activities. The resulting products are now being used daily for Produc­tion Activities. This project has achieved the first phase on a roadmap intended to shift the focus of composites processing from fixed process cycles to flexible processes that can adapt to variations in materials and process environments and insure the proper material state properties of the end product. 

The early benefits which fully justify the past funding levels and included rapid response to the needs of an UAV will need additional effort to fully address the more stringent needs of manned aircraft and high rate composite pro­duction. In order to implement change in these applications, it will be necessary to generate new data based on the new methodologies that meet or exceed the same criteria as the legacy specifications for these products.

One of the major barriers to progress in the past has been the lack of a reliable means to generate, predict and validate material properties across the full range of affected activities. A major achievement of this project is the installation a basic upgradeable version of this capability in activities with the full range of responsibilities and authority to make change as the data is generated.

Program Manager: Chuck Ryan, (734) 995-4905, chuckr@ncms.org