The complex modulus consists of two components, the storage and the loss moduli. The storage modulus (or Young’s modulus) describes the stiffness and the loss modulus describes the damping (or viscoelastic) behavior of the corresponding sample using the method of Dynamic Mechanical Analysis (DMA). The complex modulus is the sum of the storage and loss modulus where the loss modulus is multiplied with i, the imagining unit.
The complex modulus is designated with a*.
E*= E‘+iE‘‘ and for the G modulus G*= G‘+iG‘‘