Fiber Sensing Helps Validate Viability of the PRSEUS Concept in General Aviation

Josiah Fee Mechanical Engineer Lightwave Division

Composites are a vital part of today’s and tomorrow’s aircraft innovation. With their high strength-to-weight ratio compared with metals, composites have opened up the possibilities for a number of novel aircraft structural designs. One such design is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. This involves using a stitched skin and stringer-and-frame carbon fiber preform design for the structural element, which introduces damage-arrest capabilities. PRSEUS designs have previously been evaluated by NASA and Boeing Research and Technology for transport category pressurized vehicles. In a paper published at the recent AIAA SciTech Conference, researchers from Embry-Riddle Aeronautical University evaluated the potential for PRSEUS as structural members in general aviation. For their test, a previously damaged single stringer PRSEUS specimen (18” x 6”) was instrumented with fiber optic sensors along its length. Five strain gages where also placed along the length of the fiber sensor for reference. The structure was then installed in a load frame and loaded in compression. Luna’s ODiSI B system was used to measure the strain profile along the structure throughout loading. The ODiSI B provides high density strain measurements down to 1.28 mm spatial resolution and has a 20 m maximum sensing length. It also provides data acquisition rates up to 250 Hz. There was an exceptional match between the temporal strain profile measured by the ODiSI B and the strain measured by the gages at discrete locations. An example of this is shown in the figure below where strain is reported from 3 fiber locations right beside a single foil gage.

  The researchers went on to optimize their finite element models in comparison with experimental validation. Due to its light weight and energy absorption capabilities, the composite PRSEUS design offers advantages in airworthiness and crashworthiness over the currently used aluminum design. For more information, the full paper can be accessed here. To learn more about applications of fiber optic sensor technology, visit the sensing section of our website. *** Publication Reference: Samaksh Behl, et al., “On the Study of PRSEUS - Structural Integrity and Wing Design for General Aviation Aircraft”, Proceedings of the American Institute of Aeronautics and Astronautics Science and Technology Forum 2015, January 2015. Top Figure: Boeing 787 structural test. Image from Lewis University website.