Third Party Funds Group - Sub project
Start date : 01.08.2016
End date : 31.07.2020
With the development in the field of supercomputing and several breakthroughs in multi-scale theory, the focus has shifted towards development of new materials having extreme properties such as ultra-lightweight yet strong fiber reinforced composites. These new materials require development of new theories catering to large deformation, growth, fracture and most significantly the multi-scale effects. Besides, faithful constitutive models for these new materials (ranging from ultra-soft to ultra-tough and incorporating structure at all length scales) require bridging structural and deformation phenomena at nano-, micro- as well as macro-scales. This has increased the complexity of the governing equations.
One of the recent trends in designing lightweight high performance materials for extreme loading conditions is on development of architectured materials which have engineered architecture at the micro-scale. The various parameters of this architecture such as its repeating length, constituent unit cell morphology etc. affect the mechanical properties (stiffness, toughness, ductility etc.) at the macro-scale. In fact, the constituent unit cell is often comprised of nanorods which provide additional parameters to tune the macroscopic mechanical properties. For example, the length of the constituent nanorod, its diameter and thickness are some of the parameters which govern whether the constituent nanrod would undergo Euler buckling or shell-type buckling or just fracture. The transition from buckling to fracture at micro-scale would lead to transition from ductility to brittleness at the macroscopic level. Detailed analysis of these structures through multi-scale elasto-plastic simulation will be carried out as well as concurrent atomistic-continuum simulation to better understand the mechanisms of failure and buckling at nano- and micro-scales.
The governing equations which capture various multi-scale phenomena in heterogeneous materials have become highly non-linear and complex. The real challenge lies in how to efficiently and accurately capture the phenomena which occur at both multiple time scale and length scale in complex heterogeneous materials. The existing numerical tools would simply fail in such situations. The aim is to develop an efficient and stable time marching scheme to capture the multiple time scale events that occur in complex heterogeneous materials. Another challenge lies in implementation of the concurrent atomistic-continuum methods to accurately capture fracture in heterogeneous materials. The challenges here lie in the implementation of the hand shake region, the efficiency of the finite element discretization near the transition region etc. New and efficient finite elements, shape functions will be developed to cater to it.
It is expected that a comprehensive multi-scale theory and numerical tool will be in place to computationally design novel high performance materials displaying architectured non-classical mechanical properties and that are. This will pave the way to provide important input parameters to experimentalist to verify and develop such materials.