Quantification of the Effects of Strain Rate and Nano-Reinforcement on the Performance of Adhesively Bonded Single-Lap Joints

The aim of this study is to present an efficient and effective technique to strategically investigate and classify the influence of a set of manipulated parameters that affect the mechanical properties and performance of adhesively bonded joints formed by an adhesive that is reinforced by various types of carbon nanoparticles (NPs). Specifically, single-lap joints (SLJs) are considered in this study. The selected parameters include the adherend types (i.e., carbon fiber-reinforced polymers (CFRPs) and glass fiber-reinforced polymers (GFRPs)), three types of nanoparticles (i.e., carbon nanofibers (CNFs), multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs)), different weight-percent (wt.%) of GNPs (i.e., 0, 0.5, 1%), and three different strain (or loading) rates, classified as static, quasi-static and impact loadings, herein. The study employed two mixed-level full factorial design of experiments (DOE) to evaluate the contribution of the aforementioned parameters, including the effect of their interactions on the enhancement of the averaged ultimate shear strength (AUSS) of the SLJs. The DOE study was conducted using the strength data (AUSS) obtained through testing of 108 SLJ specimens. The results indicate that among the considered parameters, NPs (wt%), adherend type, and strain rate had a greater effect on AUSS. According to the DOE conducted in this study, the greatest AUSS (19.9 MPa) could be obtained when 1.0 wt% GNP was used to reinforce the SLJs with CFRP adherend and subjected to the highest strain rate (HSR). This combination yielded a 32% enhanced AUSS compared to the SLJs formed by the neat adhesive.