Uday Hasmukh Kalyani

Biography

I am a full-time PhD researcher & a part time lecturer in the Department of Aerospace, Mechanical and Electronics Engineering at SETU, Carlow campus for the past 3.5 years. I am completing my PhD (level 10) in structural analysis of PCBs and their Chassis of Launcher Environment. I have completed my MSc in Mechanical Engineering with Project Management from Lancaster University. Prior to my Masters, I have worked for 7 years in manufacturing and design areas involving products from automotive and aerospace sectors. I intend to continue research in structural analysis of spacecraft post PhD and work as a full-time engineering lecturer.

Research Project Description

Electronic systems on spacecraft are highly susceptible to their launch environment and this can lead to intermittent, latent or permanent failures. These failures may be functional (i.e., loss of signal output) and/or mechanical (i.e., fatigue failure of solder joints) in nature. These harsh environments include Random Vibration Acceleration Spectral Density (ASD) and Shock Response Spectrum (SRS) from launch and pyro-technique events. The aim of this research is to investigate and optimise electronic chassis design and populated PCBs’ based on their structural response from spacecraft environmental acceleration loads using analytical and experimental methods.

The research is divided into four phases. Phase 1 involves parametric Finite Element Models (FEMs) of PCBs and electronic components that study the effect of a range of typical material property considerations on structural eigenfrequency. In phase 2, the effect of electronic component inclusion and their location on eigenfrequency of the PCB is analysed. Phase 3 & 4 involves an investigation into active and passive damping techniques for populated PCBs and their chassis’ that are exposed to high level SRS typically found in space launchers.

Publications and Outputs

1. Kalyani, U. H. & Wylie, M., 2020. Modal finite element analysis of PCBs and the role of material anisotropy. St. Petersburg, Russia, Vibroengineering Procedia.

PCBs are epoxy resin-impregnated and cured sheets of counter woven glass fabric (e.g. FR4) laminated between thin sheets of Copper. The nature of the PCB is inherently anisotropic and inhomogeneous but previous modal FEMs of PCBs have assumed isotropic or anisotropic material properties. This paper details part of a research program aimed at gaining a better understanding of accurately modelling PCB’s dynamic behaviour. New investigations into the impact of material anisotropy and the effect of material orthogonal plane definition (Ex and Ey) on eigenfrequencies is analysed.

2. Kalyani, U. H. & Wylie, M., Impact of PCB Modal Finite Element Model Parameters on Ariane 5 Shock Response Spectrum Analysis, in European  Conference on   Spacecraft   Structures, Materials and   Environmental   Testing (ECSSMET 2021). 2021, ECSSMET: Germany. p. 1-5.

This research examines Printed Circuit Board Finite Element Modelling (FEM) considerations and their impact on resultant Von Mises stress from the Ariane 5 clamp and release and L/V stage separation Shock Response Spectrum. The impact of transverse isotropic material properties (Ex, Ey assignment), PCB Aspect Ratio, IC package density and fixed Boundary Conditions on the modal characteristics is examined.

3. Kalyani, U. H. & Wylie, M., The Effects of Lead and Lead-free Solder on the Modal Characteristics of populated PCBs, 11th European Solid Mechanics Conference (ESMC 2022), Galway, Ireland.

Leaded solder (e.g., Sn37Pb) is traditionally used in aerospace electronic Ball Grid Array (BGA) packages due to its proven reliability over a range of environmental conditions. The industry has been gradually shifting towards Lead-free solder (e.g., SN100C) to comply with RoHS standards but there is a reluctance in the Space industry to adopt Lead-free solder because of some potential issues. In the Space environment, this includes “Tin-Whisker” formation which can cause shorts. One additional issue using Lead-free solder may be the structural response of the BGA/PCB to acceleration loads, a result caused by in differing of their Young’s moduli (E). This research is aimed at investigating the impact of BGA solder (Lead V Lead-free Young’s Moduli (E)) on the BGA/PCB structural response.

4. Kalyani, U. H. et al., 2022. GTA teaching practice development in the time of Covid: A collective-reflective on how “having the chats” led to much more. Postgraduate Pedagogies Journal, 1-5.

Postgraduate research students who teach, also referred to as graduate teaching assistants (GTAs), have consistently been described as essential contributors to Higher Education (HE), given the crucial teaching role that they perform. Adopting a qualitative approach, this co-authored paper, which we describe as a ‘collective reflective’, details how, through involvement in a peer support initiative, we, as a group of GTAs, were able to reflect on our role and shape our identity as teachers.