that a certain strain level for the composite beam geometry with specific scale and layup can be accurately replicated in a smaller scale with a different layup. Because large structures are tested for fatigue life must routinely withstand cyclic strain levels over a long period of time (i.e. on order of weeks), the presented results suggest that small-scale models designed using structural similitude can facilitate and expedite the fatigue testing process of the large composite structures. The scaled-down models can be manufactured with a reduced cost and time and be tested on higher frequencies and similar induced strain levels as their full-scale parent component for a fatigue test to achieve the desired number of cycles for certification purposes. 7.4 Conclusion In this study, composite laminated I-beams with different length scales and layups were designed using the structural similitude and distorted layup technique. The designed models were manufactured and tested in a quasi-static four-point bending test under adjusted loads. The strain fields of the beams were measured along the midline of the bottom flange of the beams for increasing loading steps. The normal strain distributions of the beams for the load steps were compared to each other to demonstrate the static similarity. According to the results, all the designed beams with different layups and length scales showed a comparable normal strain field for the prescribed loads. The similarity of the strain fields between different scales and applicability of the distorted layup scaling in design of the scaled laminated beams were experimentally demonstrated. Acknowledgments This material is based upon work supported by the National Science Foundation under Grant Number 1230884 (Achieving a Sustainable Energy Pathway for Wind Turbine Blade Manufacturing). 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