Topics in Experimental Dynamics Substructuring, Volume 2:  Proceedings of the 31st IMAC, A Conference and Exposition on Structural Dynamics, 2013, the second volume of seven from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Structural Dynamics, including papers on:   Nonlinear Substructures SEM Substructures Wind Turbine Testbed – Blade Modeling & Correlation Substructure Methods SEM Substructures Wind Turbine Testbed Frequency Based Substructures Fixed Base Substructure Methods Substructure Methods SEM Substructures Wind Turbine Testbed Frequency Based Substructures Fixed Base Substructure Methods