Session: 03-12-02: Testing and Characterization

Paper Number: 136493

136493 - Analysis of Stress Concentration Effects in Column Bending Test Fixtures Through Virtual Testing 

High strain composite (HSC) materials exhibit exceptional resilience and stiffness, making them ideal for deployable space structural applications. However, the widespread application of HSCs is impeded by a lack of understanding of their failure mechanics in the large curvature regime. Recent studies have highlighted the column bending test (CBT) fixtures as a pivotal method for assessing the moment-curvature response in the large curvature regime. However, due to the small free length of the test samples for achieving large curvatures, stress concentration effects due to clamping are thought to have strong influence on the material response.  To address this issue, this study introduces a finite element model to virtually replicate the CBT setup, allowing for the analysis of stress concentration effects during the bending process. This model incorporates the rigid compression-bending fixtures, enabling a precise simulation of the test conditions. By mimicking the motion of the fixtures, the model provides insights into through-thickness stress distribution within the HSC sample both near and away from the clamped regions. The numerical results are also validated with experiments. The virtual simulation of the test conditions allows for validation of the CBT approach for testing HSC materials in the large curvature regime, while offering a comprehensive understanding and quantification of stress concentration effects on the material response. This contribution enhances the grasp of HSC failure mechanics and advances the reliability and precision of testing methodologies, crucial for the effective integration of HSC material in deployable space structures.

Presenting Author: Miguel Mireles University of Texas at El Paso

Presenting Author Biography: Miguel Mireles is a first-year graduate student at The University of Texas at El Paso, Department
of Aerospace and Mechanical Engineering. He completed his BS in 2023 from UTEP and his
interests are in the characterization of composite shell structures for deployable space
structural applications.