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Hamid Alemohammad

 

Research Interests

• Multi-scale additive manufacturing
• Embedded sensors and smart structures
• Laser micro/nano material processing and microfabrication
• Pedagogical methods in engineering education

Research Background

       My research has been focused on  multi-scale (micro- and macro-scale) additive manufacturing (AM) with applications in smart systems and embedded sensors, printed electronics, and biomedical systems. My research contributions include process development, process characterization and optimization, mechatronics systems design and manufacturing, and multi-physics modeling and analysis. 

Additive Manifacturing of Embedded Sensors and Smart Structures:  Fiber optic sensors have changed the sensing industry over the past years. The photoelasticity, thermo-optics, and opto-chemical effects in optical fibers enable high fidelity detection of mechanical, thermal, and chemical parameters. My research was focused on leveraging the advantages of micro- and macro-scale additive manufacturing to embed optical fiber sensors in metal structures for mechanical and thermal measurements. I developed a patented micro-printing process based on Aerosol Jet Deposition for selective coating of optical fibers with metal thin films to enhance sensing performance of optical fibers and embed them in metal structures. Additionally, laser metal deposition (e.g., laser cladding) was utilized for embedding optical sensors in metallic structures of steel and tungsten carbide-cobalt (WC-Co) to realize the development of smart machining tools.

 

Additive Manufacturing for Multi-Chip Assembly and Packaging:  TThe world in transforming into a nexus of connected and intelligent devices known as the “Internet of Things”. The key elements of the Internet of Things are pervasive microelectronic products that are thin, light, inexpensive, and flexible. The relentless needs for increasing the functionality of microelectronic systems while reducing their size and weight and having the advantages of thinness and flexibility call for novel technologies for the integration and assembly of multi-chip products. My research aimed at direct writing (DW) of off-chip interconnects for the development of flexible and ultra-thin microelectronic products. The printing process is a combination of aerosolization, deposition, and laser sintering of metal nanoparticle suspensions. My research involved optimization of the micro printing process by studying the electrical and mechanical properties of printed thin film interconnects and correlating the thin film characteristics to deposition and sintering process parameters.

Micro-scale AM for Surface Texturing:  The cell adhesion, infiltration and proliferation of biocompatible materials can be improved by surface patterning. Magnesium is an attractive material for biodegradable devices mainly due to its biocompatibility, bioresorption capability, and low elastic modulus. My research was focused on patterning of magnesium with silver nanoparticles printed by laser-assisted maskless microdeposition process.  The study of the microstructure  and geometry of the printed silver layers and the diffusion at the Mg/Ag interface were the focus of this research. A modeling platform using finite element analysis and diffusion was also developed for evaluating compositional profiles across the interface.

Ag-Mg Micro-Deposition