In recent years, out of autoclave (OOA), under vacuum pressure only (VBO) cure processing of composites has been one of the most significant fields in the composite sector. For more than 20 years, Toray Advanced Composites, USA (TCAC) has invested a considerable amount of time to develop and enhance this technology.
The company has launched several exceptional OOA products that are operating in the Aerospace, General Aviation, and Space arenas with remarkable results. With the growing demand for higher performance OOA systems together with the expectation to match or even surpass most properties of autoclave cured systems, an increasing number of technical innovations have been developed by TCAC.
This article is presented to strengthen the technology yielding open-hole properties, higher compression following impact retention (CAI), much higher inter-laminar fracture toughness (GIC, GIIC), and in-plane shear with better moisture resistance and service temperature capabilities than the existing advanced OOA systems. The latest TC380 epoxy prepreg system also provides considerably lower void content after cure with improved room temperature working life.
Introduction
The earlier Toray article on this topic described the developments made in the drive to offer composite materials for cost-effective aerospace structures that allow reduced carbon emissions and greater fuel efficiency. Since these and other mission needs require an increasingly higher percentage of metal replacement, it becomes more important to develop composite materials that facilitate economical production as well as inspection of the entire range of aircraft structures by fully leveraging the benefits.
These benefits may be derived from composites, including structural integration and bonded structures, automated production, flexible manufacturing techniques (RTM, VARTM, VBO, press, and many in-situ consolidation techniques), and lower cost tooling.
The earlier article explained the extensive 20+ year Toray OOA material legacy, allowing the production of thousands of general space vehicles, aviation aircraft, and UAVs as well as the development of robust, inspectable, environmentally stable, production-friendly materials, resulting in the development of TC350-1, TC275 and TC275-1.
This article describes the new developments in extending OOA material capability for major aerospace structures. TC380 retains the most significant features of the earlier generation of sophisticated OOA epoxies.
- Inspectability
- Extremely low fabricated void content (below 2%)
- High toughness
- Amenable to automated fabrication
- Great tack and handleability
- Cure temperature flexibility (135 °C (275 °F) to 180 °C (356 °F))
TC380 also provides:
- Excellent balance of open-hole compression and compression following impact
- Very high in-plane shear properties
- Extremely high fracture toughness (GIC, GIIC)
- Long room temperature out times
- Exceptional hot-wet properties (121 °C (250 °F) hot-wet service)
- Traditional lay-up and manufacturing methods: no special handling needed
TC380 maximizes the capability of designers to create even very large sophisticated aerostructures at minimum cost and weight across a broad range of configurations and manufacturing methods.
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This information has been sourced, reviewed and adapted from materials provided by Toray Advanced Composites.
For more information on this source, please visit Toray Advanced Composites.