This project is on the fundamental rate-dependent mechanisms governing the tensile behavior of ECC subjected to high strain-rate loading. By experimentally quantifying the rate dependencies on different material length scales (eight orders of magnitude, from microstructure scale to fiber-bridging mesoscale to composite macroscale), the rate dependent micromechanics-based theoretical models for microstructure tailoring of ECC will be developed. The knowledge derived will form the basis for developing a new generation of ECC which exhibits tensile strain-hardening and extreme tensile ductility under a wide range of high strain-rate loading. Such ECC should enhance the damage tolerance and safety of a broad range of civil and military infrastructure systems that may experience loading ranging from automobile impacts to bomb blasts.
Figure 1: Conceptual framework of the proposed research – scale linking
(Note: Arrows indicate linkages from one scale to next via micromechanical models. Forward arrow indicates property predictions of macro- or meso-scale based on information at a lower scale. Reverse of arrow directions implies materials tailoring, i.e. scale linking affords guidelines for deliberate manipulation of material microstructures at the fiber, matrix, and interface scales in order to attain desirable macroscopic composite properties).