Deven Mhadgut

My PhD research is focused on the structural dynamics of deployable tape-spring booms. The boom under study is bistable, and a replica is planned to be the primary payload on board Ut ProSat-1, a student-built satellite at Virginia Tech. The boom will be deployed passively and then retracted using a stepper motor. The deployer has a novel design and its performance will be tested in space. The satellite has two IMUs: one at the boom tip (on a flex circuit) and another inside the satellite on a PCB. In the absence of an active vibration source, these sensors measure the transverse acceleration at the end of each deployment. I plan to replicate those results on the ground. Last year, I determined that FEA using conventional CAD approaches was insufficient for these thin deployable structures. Consequently, I adopted a reverse engineering approach for modal analysis, utilizing a higher fidelity 3D scanned model to achieve better correlation. The next step was to start with the actual environmental simulations. I began with thermal vacuum tests in our environmental chamber. I also focused on an experimental data-driven modeling approach to obtain material parameters based solely on system input and output via vector fitting. While these data-driven models demonstrated higher accuracy, I found that the system varies significantly with changes in loading, and I am planning to use parametric modeling to improve upon that.

During my mechanical analysis internship at Benchmark Space Systems, I performed critical structural, thermal, and fluid dynamics simulations to validate flight hardware and optimize in-house testing. I conducted comprehensive risk assessments for thruster PCBAs, utilizing modal analysis and random vibration simulations while developing a steady-state conduction model for discrete EEE components to ensure safety at high sink temperatures. To support liquid filter development, I validated experimental burst tests through non-linear structural analysis, achieving high correlation with theoretical thin-plate formulas. My work in propellant tank dynamics involved predicting slosh frequency modes using Modal Acoustics in Ansys and developing novel methodologies to model the motion of hyperelastic diaphragms under pressure gradients. Additionally, I spearheaded a random vibration test comparison, demonstrating that an in-house setup using a head expander and corner-control averaging provided a high-fidelity match to industry-standard external survey data. This experience culminated in the delivery of formal technical reports and Standard Operating Procedures (SOPs) to guide future design and verification workflows.

As a mechanical engineer at CCAR, I worked closely with LASP on the structural and thermal design of a 6U cubesat, AEPEX. The primary mission of the satellite was to image and measure high-altitude X-ray emissions for the quantification of energetic particle precipitation (EPP). I was responsible for chassis design and major decisions related to component placement inside it. I also assisted the science team by designing the science instrument enclosure. In order to validate these designs I performed all kinds of structural analyses in solidworks including modal, static and random vibration. The static and dynamic loading tests were based on requirements defined by the cubesat dispenser and the launch provider. In addition to this, I was tasked with the thermal design of the instrument and the overall spacecraft. Day-in-the-life test cases were simulated in Thermal desktop in order to ensure thatall elements of the spacecraft are maintained within temperature limits under the worst case cold (eclipse), worst case hot conditions, and nominal operations. I also created some preliminary thermal-vacuum test plans for further verification. Finally, I also designed and manufactured a prototype of the X-ray imaging instrument for future ground testing.

As Mechanical and Thermal Design Lead for three CubeSat missions at CU Boulder, I have specialized in transitioning theoretical concepts into flight-ready hardware. For the COSMO mission, I designed a 6U bus structure in SolidWorks, ensuring full compliance with Nanoracks deployer constraints. At LASP, I served as the thermal lead for INSPIRESat, a 27U international satellite, where I utilized Thermal Desktop to model worst-case hot and cold scenarios and ensure component safety across the entire orbit. Additionally, for the CANVAS mission, I performed comprehensive structural FEA, including static loading, buckling, and random vibration analysis, while also designing and manufacturing a specialized payload holder from PEEK polymer. These experiences have developed my ability to design for the rigorous constraints of the space environment while maintaining a strict focus on manufacturability.

Dates: 05/2019 - 05/2020

 

My senior design project helped me gain some invaluable hands-on experience. I also got the opportunity to hone my communication skills by presenting my project findings and defending my design decisions to both faculty and peers. In this project, the drag coefficient of a model rocket was calculated using two different methods and the results were compared. The reasons for the difference in values were also discussed.The nose cone ogives and the fin aerofoils were optimized for minimum drag. A high fidelity finite element(FE) model was created in Ansys-Fluent. The velocity and pressure contours were plotted(as shown below), and the drag coefficient was obtained. This was followed up by experimental wind tunnel testing. The nose cone and fins, made of nylon, were fabricated via selective laser sintering(SLS) and a PVC pipe was used for the rocket body. An open jet wind tunnel was used to provide the necessary thrust and a force balance was designed to measure the drag force experienced by the rocket. Based on the results and the thrust force of the rocket motor selected, the trajectory of the flight of the model rocket was mathematically simulated in Matlab. Finally, the experimental results were used to validate the FE drag coefficient values.