Structural Analysis Lab
Computational Mechanics Group
The Computational Mechanics Group at IIT Kanpur exists with the belief that modern numerical methods can go a long way in enriching our knowledge of how microscopic mechanisms collude to produce macroscopic effects in materials, particularly in relation to their deformation and failure behaviours under various external conditions. We try and work with as real materials as is possible to represent computationally rather than with 'computonium', the ideal material of choice (and many a times wisely so) for many other workers in this field. Also, we do not envisage that models to seamlessly connect the micro to the macro scales are possible or even particularly desirable. We prefer to work at a particular level of detail, try to gain insights that enrich our understanding of the next coarser level and help us build models at increasingly larger length scales. After all, engineering design needs continuum level models and 'gross' things like stresses, strains etc to be computed. So, however detailed your microscopic model and understanding might be, it will be technologically useful only if it either helps in building models at the macro time and length scales or you happen to be interested in doing engineering on the material at the microscale itself. This approach of sequentially going up the length and time scale ladder makes us a bit like the blind men groping the elephant, but if we had allowed enough groping, who knows, the blind men might have figured out the truth!
There are numerous aspects of microscale knowledge that assumes importance when you want to understand materials. The deformation of a material under the action of externally applied forces is the result of many microstructural adjustments. Deformations often tend to get intense in a small region of the material. Fracture of materials most often occurs catastrophically at 'human' time and length scales but the material may actually be accruing microstructural damage due to intense deformations accumulating over a long time. The nature of damage accumulation or microstructural adjustments also depend on the underlying cause of the deformation, most importantly the temperatures and rate at which these events happen. It is sometimes important to know the micro-level story in order to keep the possibility of doing microscopic tweaks alive.
An essential feature of multiphase materials is the presence of interfaces, which add a new twist to the story. Interfaces may be required to be strong or weak depending on the end use of the material but understanding the chemical nature of the bonding at the interface is the key to imparting it with desirable characteristics. With the advent of materials with nanometer sized phases, engineering the interface has become the key element in designing these materials.
At the moment we are working on a variety of problems that have broadly been described in the last two paragraphs. Some of these problems require heavy computations and therefore, some work needs to be done on perfecting and honing computational methods. Moreover, experimental support for some problems is essential in order to address real materials. To do these we try --- and have had a reasoanble degree of success so far --- to sweet talk, cajole and/or threaten unsuspecting experimentalists into performing experimental simulations of our computational experiments.