Projects

In this investigation, we presented a facile and cost-effective synthesis technique of a flexible multi-directional force sensing system, which is also favorable to be utilized in underwater environments. We made use of four flex sensors within a silicone-made hemispherical shell structure. Each sensor was placed 90° apart and aligned with the curve of the hemispherical shape. If the force is applied on the top of the hemisphere, all the flex sensors would bend uniformly and yield nearly identical readings. When force is applied from a different direction, a set of flex sensors would characterize distinctive output patterns to localize the point of contact as well as the direction and magnitude of the force. The fabricated sensor was experimentally calibrated and tested for characterization including an underwater demonstration.

In this study, we worked on a 3-digit end-effector capable of 6 degrees of shape sensing and 12 points of force sensing. The individual actuator is designed as a uni-directional, bellow-type, PneuNet actuator built from silicone material. Onboard sensors utilize widely available piezo-resistive components which allow the actuator to act as a low-cost entry to shape sensing and force sensing. A novel algorithm is proposed for shape estimations that reconstructs the shape of the soft actuator based upon embedded flex sensor measurements. Of unique design is the bellow-type actuator’s custom chamber layout which gives it the ability to resemble approximated closed curvature of a human pointer finger. The overall goal of this work is to exhibit a tangible design solution for waterproofed multi-modal sensing within the soft robotic design frame for various underwater robotic applications.

In this work, it has been demonstrated that the mechanical properties of pre-cracked (single layer) SL MoS₂ can be enhanced via symmetrically placed pores and auxiliary cracks around a central crack and position of such arrangements can be optimized for maximum enhancement of strengths. Such a study would help towards strain engineering based advanced designing of SLMoS₂ and other similar transition metal dichalcogenides.

In order to develop light weight electrical components, the nano-sized lead free solders have been identified as potential materials to provide better mechanical properties as compared to the conventional solders. Sn–Ag–Cu (SAC) solders have been widely acknowledged as one of the most promising replacements for Sn-Pb solders. In this work, the mechanical properties of nanocrystalline SAC305 (nc-SAC305) (96.5Sn-3.0Ag-0.5Cu) solder have been investigated through molecular dynamics (MD) simulations.

In this study, we evaluated the effect of temperature and strain rate on the pristine structures of single layer (SL) antimonene (Sb) (puckered (p) and buckled (b)) allotropes and disclose that high temperature degrades all the material properties of SLSb whereas ultimate tensile stress upturns while applied strain rate is increased. Moreover, we also inspected the impact of defect concentration on those structures. Our analysis also reveals that p-structure of SLSb is more dependent on chirality than that for buckled counterpart.

In this study, we assessed the mechanical properties and fracture mechanism of pre-cracked and defected single layer (SL) InSe nanosheet utilizing molecular dynamics (MD) simulations. We showed that the failure of pre-cracked and defected InSe nanosheet is controlled by brittle type fracture. We compared the brittle failure of Griffith prediction with the MD fracture strength and observed substantial differences that limit the applicability of Griffith’s criterion for SLInSe in case of nano-cracks.