This first of three volumes includes papers from the second series of NODYCON, which was held virtually in February of 2021. The conference papers reflect a broad coverage of topics in nonlinear dynamics, ranging from traditional topics from established streams of research to  those from  relatively unexplored and emerging venues of research. These include

• Fluid-structure interactions         
• Mechanical systems and structures        
• Computational nonlinear dynamics        
• Analytical techniques                 
• Bifurcation and dynamic instability        
• Rotating systems 
• Modal interactions and energy transfer
• Nonsmooth systems