Metal to composite bolted joint behavior evaluated at impact rates of loading

Metal-composite bolted joints form an integral part of a majority of structural components and finds extensive usage in aircraft and automobile industries where they could be subjected to either static or time dependent loadings. Extensive literature exists addressing bolted joint behavior under static rates of loading. However, limited studies exist which define mechanical response of metal-composite bolted joints under dynamic rates of loading. This is vital to better understand its crashworthiness characteristics when it is subjected to impact loading. In our current investigation, we have attempted to address this aspect via experimental characterization of 4142 alloy steel-E glass ply epoxy resin composite bolted joint under impact loading using a split Hopkinson tension bar. Quasi-static measurements have also been conducted simultaneously to distinguish not only the maximum bearing strength but also the operational modes of failure corresponding to different edge distance to hole diameter (e/d) ratios. Dynamic response of the metal-composite bolted joint was observed to be significantly higher than its static counterpart. Asymptotic region of failure mode alteration exists and is observed to be dependent on loading rate transfer. This study provides beneficial information in assisting subsequent design of bolted joints where behavior under impact loading is of main concern.