A 3D-printed instrumented surfboard fin for measuring fin flex

Abstract: In this paper, we used CAD design and 3D printing are used to fabricate instrumented fins for surfboards. The sensors incorporated into the fins included an in-house designed 3D-printed sensor (out of electrically conducting TPU) and a commercial obtained Wheatstone bridge sensor. Fins were subjected a type of load direction similar to what surfboard fins experience during characteristic surfing manoeuvres. Our results indicated that both sensors were able to measure the flex in fins, but only the Wheatstone bridge sensor exhibited a linear response over a fin flex range of up to 7.7 ± 0.1%. The commercial sensors exhibited linear response values of 160 ± 20 µV / (percentage of fin flex) and 180 ± 20 µV / (percentage of fin flex) during loading and unloading of the fin flex cycle, respectively. Graphical abstract: [Figure not available: see fulltext.]