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Mechanical Engineering

Undergraduate Major: Mechanical Engineering

Future Plans: Ph.D. in Engineering

Jose Cotelo

Jose Cotelo was born in Havana, Cuba, and immigrated to the United States at the age of 6. He is pursuing a bachelor’s degree in mechanical engineering with a minor in mathematics. He works with the Mechanics of Materials Research Group at UCF on applied and computational solid mechanics. Currently, he is studying the damage initiation and evolution in metal-matrix composites as his Honors in the Major thesis. He is fluent in Spanish and French, and hopes to pursue a graduate degree in aerospace engineering. His research interests include computational mechanics and aeroelasticity, applied solid mechanics, and structural dynamics.

SiCp Particle Fracture in Damage Evolution of AlSiCP30%

Conducted at the University of California, Irvine as part of the Summer Undergraduate Research Program

Mentors: Satya Atluri, Ph.D., Department of Mechanical and Aerospace Engineering, University of California, Irvine

Abstract: The damage process for an AlSiCp-30% metal-matrix composite (MMC) was studied using a micromechanics approach. Petrov-Galerkin boundary integral equations (BIEs) were implemented into a voronoi-cell finite element model to simulate a representative volume elemente (RVE) stress-strain response. Next, utilizing a Mori-Tanaka (MT) damage model, an algorithm was implemented into Matlab to calculate the nucleation rate and void porosity in the RVE. The relation between macroscopic and microscopic strain was determined using a homogenization scheme. This was then implemented into the damage model and the evolution of damage in the composite was determined by the onset of SiCp particle fracture. Void nucleation in the composite adhered to the dominant failure mechanisms: interface debonding and microphase particle fracture. Further work is necessary, particularly in incorporating viscoplastic parameters to the simulation.

Thermomechanical Damage Initiation and Evolution in A359-SiCp30%

Conducted at the University of Central Florida

Mentors: Ali P. Gordon, Ph.D., Department of Mechanical and Aerospace Engineering, University of Central Florida

Abstract: Abstract: Metal-matrix composites (MMCs) are well positioned to supplant current engineering metals where elevated specific strength is obligatory. Their superior mechanical properties and relatively low densities render them preferable in high-performance applications. Though previous work has been done to characterize the damage behavior of Aluminum based particulate reinforced composites, not much attention has been devoted to the microstructural mechanisms associated with thermomechanical deformation and rupture. In this work, the damage initiation and evolution in an A359-SiCp-30% MMC is characterized and simulated using voronoi-cell finite elements (VCFE). A VCFE mesh using a 3D representative volume element (RVE) is developed to determine the dominant damage mechanisms under mechanical loading at elevated temperatures. The evolution of damage is characterized by quantifying the void nucleation rate in and mean spacing between voids in the RVE. A critical stress state is determined to signify the formation of a macrocrack which may then be extended to an overall component analysis where useful remaining life (URL) may be predicted.

Mechanical Response of PLA under Monotonic and Cyclic Shear Loading

Conducted at the University of Central Florida as part of the NSF-CAMP Young Entrepreneurs Scholars Program

Mentors: Ali P. Gordon, Ph.D., Department of Mechanical and Aerospace Engineering, University of Central Florida

Abstract: A key challenge in developing new uses for 3 dimensional printing rapid prototyping technology is the gap in knowledge about the interactions and characteristics of various print conditions and how they affect the overall strengths of components. This study presents the effects of various print parameters and heat treatments on the torsional monotonic and fatigue response of specimens fabricated using fused deposition modeling (FDM) with polylactic acid (PLA). The ASTM E143 standard was the most relevant to this study and was used in the fabrication and monotonic testing of specimens, while the ASTM E606 standard was used in fatigue testing. Variables in production include wall thickness, infill density, vertical orientation, filament color, and post-print heat treatment at 100°C. Wall thickness, infill density, and orientation were tested across the useable range of the FDM machine. The manipulation of these variables is used to characterize the mechanical properties of components under either cyclic or monotonic shear loading. The relation of production variables and the manner in which they influence the mechanical properties provides insight to the feasibility of using FDM for rapid manufacturing of components for experimental, commercial, or consumer-level use. Continuing work is also being done to develop a coupled viscoplastic-damage constitutive model for PLA in shear.