Representative research

This page gives examples of the type of problems which excite us currently

Mean field homogenization

Homogenization is a fundamental problem in mechanics of heterogenous materials. Homogenization is concerned with the derivation of equations for averages. In composites this is usually the average stiffness. There are several ways of homogenizing composites with simple fiber geometry. However, there is sometimes confusion as to which is more accurate or fit for a specific requirement. An important consideration is damage modelling where micro stresses are important. Other requirements like low computation cost are not trivial. Besides, pre-existing homogenization techniques/formulations must be adapted (or new methods developed) for novel composites where architecture might not be simple.

We have extensive experience with studying suitability of mean field and FE based homogenization methods and extending them for novel composites like wavy fiber composites, strand composites, textile composites, short fiber composites with imperfect interface etc. Finite element methods are used extensively to validate and benchmark pre-existing methods. Also, the group has developed significant expertise to generate complex microstructure in an efficient manner

Novel strategies for joining composite materials

The broad area of our research is enhancing the structural integrity of composite structures. Novel methods are proposed wherein material and geometrical modifications are adapted to realize different tailoring schemes to increase the structural efficiency of joints. Present research work can be broadly classified into two categories: -

· Material and geometrical modification to adhesive bond-layer in single lap adhesive joint (SLAJ) and tubular adhesive joints (TAJ).

· Material and geometrical modification to the adherend in SLAJ AND TAJ.

Here, we deal with peak stress reduction, uniform distribution of load, increasing joint toughness, and failure loads without significant alternation to joint stiffness.

New ideas like through the thickness compliance tailoring to adhesive/adherend, reinforcement of adherend with additional adhesive layers, designing unsymmetrical joints, and many more are explored. Numerical and experimental approaches are adapted for our work. Additionally, analytical work will also be explored in due course of time.

Multiscale modelling and characterization of 3D printed composite materials

Our research work is related to multiscale modelling and characterization of 3D printed thermoplastics and short fiber reinforced thermoplastics. The aim is to understand the complexity of the FDM process and how the various parameters affect the final print quality, so that potential of the FDM process for producing functional, load-bearing structural components can be understood.

The objective is to predict and/or experimentally characterize the fiber length distribution, fiber orientation distribution, and voids as a function of manufacturing parameters such as printing speed, nozzle diameter, layer thickness and nozzle temperature. Damage characterization across several length scales is performed using state of the art equipment. The research will then focus on developing multi-scale numerical predictive tools for the mechanical properties (strength, stiffness, and failure strain), accounting the geometrical variations of constituent materials at the microscale. The research will also include the validation of homogenized results and experimental results at various levels (multiscale analysis).

Tailored Materials

Our aim is to develop engineering materials which have interesting properties such as high stiffness and high strain to failure, auxetic lattices with enhanced stiffness etc. Using a combination of analytic, numerical modelling and experimental work, the group has developed understanding of tailored micro-structured materials under different dynamic loading conditions. Another important objective of this project is to study the damping properties and energy absorption of the engineered materials/structures. These microstructures have many complex design details. So, 3D printing technique such as FDM, is used to print these intricate engineering materials.

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