The usage of composites in aircraft like A350 XWB has resulted in weight saving, reduced life cycle costs, higher cabin pressure and humidity as compared to the metallic fuselages leading to increased passenger comfort. The assembly of such a composite fuselage shell is usually realized by floating frame concept where frames are located above longerons and are attached to the fuselage skin using clips at each frame-stringer intersection. All the clips have to be assembled, drilled, sealed and riveted which can render the process to be quite laborious, expensive and time-consuming. In case of A350XWB composite fuselage, there are about 8000 thermoplastic clips and more than 60,000 fasteners to connect them to skin.
CSIR-National Aerospace Laboratories and AIRBUS teams collaborated on the “Innovative design and development of a Cocured Composite Fuselage Shell with Corrugated Frames” using carbon epoxy composites. In this project, a novel ‘Corrugated Frame Concept’ was proposed by CSIR-NAL and Airbus in which frames are ‘Self-Stabilising’ because of corrugations on web. This new design concept coupled with cocuring process eliminated all clips.
The primary objective of this work was to conceive, design, analyze and manufacture a demonstrator representing a frame bending test panel of approximately 1.5m in circumferential direction and 1.9m in longitudinal direction. CSIR-NAL team carried out the conceptual design, detail design and development of the demonstrator and Airbus team was responsible for the sizing and stress analysis. SHM studies were also performed at stiffened panel level to detect low velocity impact damages. The fuselage demonstrator was realised at CSIR-NAL. Subsequently, the demonstrator was subjected to quality checks like dimensional checks and ultrasonic testing to verify the consolidation levels and detect porosity.
INFUSE demonstrator was handed over to Dr. Matthew Orchard, Head of Competence Center- Airframe, Airbus by Mr. Jitendra J. Jadhav, Director CSIR-NAL on 14-03-2019. Mr. Andrew Dunn, Mr. Sandeep Thakur and Mr. Avinash Kumar Yadav of Airbus and Team-ACD (Advanced Composites Division of CSIR-NAL) were present during the handover.