Investigation of the mechanical behavior of FDM processed CFRP/Al hybrid joint at elevated temperatures

Abstract

This research is focused on investigating the mechanical behavior of Fused Deposition Modeling (FDM) processed CFRP/Al hybrid riveted joints at elevated temperatures. A two-pronged approach was adopted entailing experimental and computational domains. In the experimental thrust, the developed joint was evaluated for its mechanical behavior by employing Digital Image Correlation, micro-XCT, and fractographic analysis. The tensile testing was performed at four different temperatures, i.e., Room Temperature (RT), 50°C, 75°C, and 100 °C. At RT, the joint experienced net-sectioning in the CFRP sheet along with minute secondary bending. Further, distinct failure modes were noticed for each ply orientation where the inherent porosity/voids appeared as the governing factor for the damage progression. Novel constitutive models were developed using accrued strain and change in energy dissipation to estimate the damage progression. The damage accumulation was found to be more uniform in the 0° layer as compared to 90°. Moreover, the 90° layer exhibited a more catastrophic damage pattern toward final failure. At elevated temperatures, a significant reduction in mechanical properties along with a non-uniform warping/bending of the plies was noticed due to viscoelastic behavior change. The computational analysis, having a hierarchical approach, was performed for the validation of the experimental results, and both were found to be in good agreement.