SBIR-STTR Award

For optimal design of the personnel parachute, the ability to predict the opening forces during an airdrop is crucial. Solving this challenging technical problem will permit better design for both military and civilian parachutes, in terms of structural parameters and selection of materials. As a cost-effective solution to the current practice of overdesigning parachutes, a novel methodology for real-time characterization of the structural behavior of parachutes during inflation is proposed. This method is based on the application of fiber optic sensors embedded into the parachute fabric. Sensor measurements will be supported by mechanical testing and modeling. Two types of fiber optic sensors will be used to measure axial, bi-axial, and transverse deformation of a parachute canopy and suspension lines. An optical fiber Bragg grating (FBG) type sensor will be used as a short strain gauge for axial strain measurements. The second tripe of fiber optic sensors is based on the Modal Power Distribution (MPD) technique, developed by M. El-Sherif (project director) through several Army and DoD projects. Acting as a long length strain gauge, this is also the only sensor tripe that can be used in measuring transverse stresses. The integration of these two types will form a novel sensory system capable of measuring the dynamic structural behavior of a parachute during inflation. Axial, bi-axial, and drop lab tests, will be conducted to demonstrate the concept of the proposed methodology. During the optional tusk, this methodology will then be benchmarked using a small-scale model parachute. In Phase II, a normal airdrop test using a full-sized personnel parachute will be performed.

Benefits:
The developed methodology will be very useful in the redesign of parachute canopies or suspension lines with new materials. The developed technology will pave the way for future development of smart fabrics for military applications, such as clothing and tentage. In the commercial market, this technology will be useful for parafoils for sport jumping, canopy and suspension line design for fire fighters and rescue workers, sail design, and any flexible fiber network structure.

Keywords:
PARACHUTE CHARACTERIZATION FIBER OPTIC SENSORS SMART MATERIALS/STRUCTURES EMBEDDED DYNAMIC STRAIN

A novel methodology for real-time characterization of the structural behavior of parachutes during inflation is proposed. This method is based on using embedded fiber optic sensors for stress/strain field measurements. A number of sensors will be arranged in a two-dimensional array of elements. Some of these sensors will be positioned along the radial direction of the parachute canopy and others positioned in the hoop direction. Also, a number of sensors will be connected along the parachute suspension lines. These sensors will be integrated into an opto-electronic monitoring system. Remote sensing technology will be used for the transmission of information from this opto-electronic system to a ground station. During the Phase I work on this project, the concept of using two types of fiber optic sensors for monitoring stresses in canopy fabrics and suspension lines have been successfully demonstrated. The integration of these two types forms a novel sensory system capable of measuring the dynamic structural behavior of a parachute during inflation. The phase II work plan will be directed toward the development and calibration of the required sensors and the integration of these sensors into the sensory system. The tasks include the design and manufacturing of all the electronic components for signal processing, data acquisition, and remote display of the sensor output. Small-scale laboratory tests and wind tunnel tests will be performed for system evaluation and calibration. Finally, a normal full-scale airdrop test using a full-sized personnel parachute will be performed. The system output measurements will be coded and transmitted to a ground station.

Keywords:
smart parachute smart fabrics parachute characterization embedded sensors dynamic strain sensors nde techniques fiber optic sensors intelligent materi