Influence of agglomeration and waviness phenomena on torsional oscillation of MWCNTs-reinforced composite rods

There are some inevitable challenges during the manufacturing of reinforced composite structures. Agglomeration of reinforcement and wavy reinforcement are in this category. These phenomena possess remarkable effects on the mechanical behavior of reinforced composite structures. In the current research, the effect of agglomeration and waviness of reinforcements on torsional dynamic characteristics of multi-walled carbon nanotubes (MWCNTs) reinforced composite rods subjected to two various boundary conditions have been evaluated. Three dissimilar cross-section shapes have been considered to understand the effect of cross-section shapes on torsional behavior of MWCNTs-reinforced composite rods. A new form of Halpin-Tsai homogenization model has been exerted to estimate the material properties of composite structures. Additionally, Timoshenko-Gere theory in conjunction with the Hamilton’s principle has been employed to derive the partial differential governing equation of MWCNTs-reinforced composite rods. Afterward, the obtained equation was solved using an analytical approach. The precision of the methodology utilized has been evaluated against the results of previous studies documented in the literature. Ultimately, the effects of various significant parameters on the changes in natural torsional frequency have been analyzed and presented in a series of tables and figures. Based on the obtained results, the rectangular rod has the highest torsional frequency and also the effect of MWCNTs’ volume fraction depends on the consideration of waviness and agglomeration factors. At a greater volume fraction of MWCNTs, the agglomeration factor is more effective than the waviness factor and vice versa.