A Novel Meso-Scale Krouse Specimen for Bending Fatigue Characterization: Design Optimization and Experimental Validation

Miniaturized tests can offer significant material and time savings while still providing representative results comparable to macro-scale tests for relevant applications. Moreover, in challenging fields like hazardous materials research in nuclear, chemical, and similar industries, miniaturized testing presents an even more compelling and practical solution to counter safety, specimen preparation, and material disposal constraints. With an emphasis on optimization to guarantee maximum stress concentration, a uniform stress distribution, and the fact that failure always occurs within the gage, this study investigates the bending fatigue behavior of meso-scale Krouse specimens. Initially, theoretical and finite element analyses were performed for geometry optimization. Subsequently, the optimized geometry was experimentally validated through constant amplitude, load-controlled bending fatigue tests with prescribed stress ratio, R=0. Both theoretical framework and experimental validation confirmed the effective optimization of the specimen design for stress behavior. Furthermore, the S-N curve generated from the experiments demonstrated consistent patterns when compared with analytical and literature data, proving the validity of the optimized specimen design. The scientifically validated specimen design serves as a novel and innovative approach that could be applied in applications where small size, and bending loads are critical.