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Zahabul Islam

Publications and source records attributed to Zahabul Islam.

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Thermo-mechanical Characterization of 2D hexagonal Boron Phosphide (h-BP)

This study explores the thermo-mechanical properties of a two-dimensional (2D) monolayer hexagonal boron phosphide (h-BP). h-BP is predicted to possess a moderate band gap, high thermal stability, and excellent carrier mobility, making it suitable for advanced electronic, sensing, and energy applications. A classical molecular dynamics (MD) potential for h-BP was developed using density functional theory (DFT) calculations. The derived parameters were implemented in MD simulations to evaluate mechanical behavior under tensile loading along both zigzag and armchair directions at varying temperatures (300 K to 900 K). The results reveal significant anisotropy in mechanical performance, with higher tensile strength and elastic modulus in the zigzag direction across all temperatures. Increasing temperature reduces both tensile strength and stiffness due to thermal softening and increased atomic vibrations. The influence of structural defects was also investigated, revealing that Stone-Wales and vacancy defects reduce the tensile strength and failure strain of h-BP, with the two-atom vacancy producing the most pronounced mechanical degradation due to localized stress concentration and premature crack initiation. These findings provide a foundation for future research on the mechanical stability of h-BP in extreme environments.

cond-mat.mtrl-sci

Multiscale reduced-order modeling of fused filament fabricated composites

Defects such as voids are observed at multiple length scales of an additively manufactured composite material. Modeling such defects and their multiscale interaction is crucial for the materials performance prediction. In this work, we study as-built defects in fused filament fabricated Polycarbonate/Short Carbon Fiber (PC/SCF) composite samples. The microscale and mesoscale voids along with the mesoscale layer orientations have been studied using a mechanistic reduced-order model. Our result indicates that the microscale intrabead voids interact with the mesoscale interbead voids and significantly degrade the mechanical response of the printed composites compared to the microscale microstructure without voids. The mesoscale layer orientations also influence the stress-strain response and show better performance when the load is applied to the bead direction. The efficient reduced-order modeling approach used in this work provides a way to evaluate multiscale design aspects of additively manufactured composite materials.

cond-mat.mtrl-sci