Aerospace engineering requirements composite materials

Introduction engineering requirements for aerospace composite materials... 

Most non-aerospace CMC applications require long service lives. For these applications CMC components must avoid creep rupture and must exhibit creep strains lower than 1 percent after 10,000 hours of service (e.g., at 1,200°C [2,192°F] and 100 MPa [14.5 ksi]) components must also be chemically and microstructurally stable. These stringent demands present major challenges to researchers and engineers, particularly for material development and accelerated testing. The performance objectives limit the material choices to polycrystalline oxides, SiC, or amorphous Si-C-N-B compositions (single-crystal fibers are not affordable). 

The aerospace industry has recognized the major benefits associated with fiber-rein-forced composite materials [1]. The more popular techniques available for composite production are the traditional wet layup or autoclave and resin transfer molding. Efforts to further reduce processing time and improve part quality have focused on improved process control. To date, this has been based on off-line techniques. The need for online cure monitoring is widely recognized, and this will require the development of suitable in-mold sensors. The Engineering Composites Research Centre has investigated and concentrated on the specific problems encountered in the aerospace industry. 

In high-tech strnctnral applications, where strength, stiffness, durability and light weight are required, epoxy resins are seen as the minimum standard of performance for the matrix of composite structures. For these reasons, in aerospace applications epoxy resins have been the norm for years in this engineering held the main consideration for materials selection is strictly connected with performance, leaving the material cost as a detail of secondary importance. 

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