COSMOS Lab at UCF
About the lab
The Complex Structures and Mechanics of Solids (COSMOS) Lab is located at 117 Barbara Ying Center at the University of Central Florida, Orlando campus. The basic philosophy of the lab is the discovery, fabrication and design of novel materials using extensive computations, modeling and experimentation. The tools of mechanics, scientific computing and 3-Dimensional printing all play an important role in this endeavor. If you are interested in joining our group please drop by an email with your CV and the type of engagement (Visiting Position, MS, PhD) you envision at ranajay.ghosh AT ucf DOT edu.
COSMOS Lab Website:
COSMOS Lab Website:
Featured projects (1)
Limitation of bio-compatible materials and relentless Darwinian natural selection have forced life forms to evolve incredible strategies to foster survivability. Some of these strategies are highly counter intuitive. For instance, heterogeneity and free standing surface components (such as dermal modifications found in nature) are often avoided in man-made systems due to poorer material properties, interface failure and operating strength (think of dislocations in monocrystals and microcracks in glass panels). On the contrary, natural systems are inherently hierarchical, branched and heterogeneous such as bone, gecko’s feet and scales on animals. Research indicates that these designs are often inherently multifunctional (bones are strong and can store chemicals), ultralight (dermal scales significantly improve mechanical protection and insulation while adding little weight) and can transcend natural limits of chemicals making them (blue pigments which are incredibly difficult to synthesize are still found in nature but by optical manipulation through photonic crystal like architecture). My research interest lies in discovering the underlying mechanisms behind these high performance strategies and amplify them in man-made material systems such as next generation multifunctional & ultralight aerospace structures, super efficient vehicles and high performance buildings.
Featured research (3)
Biomimetic scale-covered substrates provide geometric tailorability via scale orientation, spacing and also interfacial properties of contact in various deformation modes. No work has investigated the effect of friction in twisting deformation of biomimetic scale-covered beams. In this work, we investigate the frictional effects in the biomimetic scale-covered structure by developing an analytical model verified by finite element simulations. In this model, we consider dry (Coulomb) friction between rigid scales surfaces, and the substrate as the linear elastic rectangular beam. The obtained results show that the friction has a dual contribution on the system by advancing the locking mechanism due to change of mechanism from purely kinematic to interfacial behavior, and stiffening the twist response due to sharp increase in the engagement forces. We also discovered, by increasing the coefficient of friction potentially using engineering scale surfaces to a critical coefficient, the system could reach to instantaneous post-engagement locking. The developed model outlines analytical relationships between geometry, deformation, frictional force and strain energy, to design biomimetic scale-covered metamaterials for a wide range of applications.
In this letter, we investigate the geometrically tailorable elasticity in the twisting behavior of biomimetic scale-covered slender soft substrate. Motivated by qualitative experiments showing a significant torsional rigidity increase, we develop an analytical model and carry out extensive finite element simulations to validate our model. We discover a regime differentiated and reversible mechanical response straddling linear, nonlinear, and rigid behavior. The response is tailorable through the geometric arrangement and orientation of the scales. The work outlines analytical relationships between geometry, deformation and kinematics, which can be used for designing bio-inspired scale-covered materials.