This work presents the design, fabrication, and experimental validation of a directional piezoelectric sensing platform based on architected lattice structures produced via additive manufacturing. Two configurations were developed: PIZCAL, a single-material lattice with geometric anisotropy, and Hybrid PIZCAL, a multi-material extension that incorporates passive polymer regions to further enhance directional sensitivity. Both structures were printed using a piezoelectric ABS–BaTiO₃ composite, with selective integration of PLA in the Hybrid design to mechanically isolate non-target axes. Finite element simulations, microstructural analysis, and electromechanical testing were conducted to assess the piezoelectric performance along the Z, Y, and X axes. The Hybrid PIZCAL achieved a 293% increase in Z-axis voltage-per-mass output compared to a monolithic bulk cube and a 256% increase over the regular PIZCAL. Additionally, off-axis responses were reduced by over 20%, confirming the effectiveness of material zoning in suppressing unwanted piezoelectric activity. These results demonstrate that combining architectural control with passive-active material segmentation enables programmable, high-fidelity directional sensing.

The Annular Core Research Reactor (ACRR) is an under moderated pool type reactor capable of pulses with energy yields exceeding 300 MJ. Because the ACRR has an epithermal neutron spectrum, different materials can be used to tailor the neutron energy spectrum to meet experimental needs. These experiment fixtures, colloquially called buckets, have operational limits to prevent softening and melting of materials caused by heating due to neutron and gamma reactions with materials. This work presents a transient thermal analysis performed on the frequently used 44-inch lead-boron bucket (LB-44) using Ansys Mechanical 2022 to more accurately determine operational limits required to prevent melting and softening of the materials. For the analysis the heating of the materials was determined using Monte Carlo N-Particle (MCNP) 6.3. Methodology  Material Properties: Ansys Granta MI material database used to obtain thermal properties for B 4 C powder, Pb, Al 6061 T6 in bucket  Geometry: CAD model imported and simplified in Ansys SpaceClaim, hexahedral meshing performed using Ansys Mechanical  Heating Inputs: Energy depositions in material calculated using MCNP 6.3, power profile data obtained from Razorback simulations of a $3.50 pulse  Thermal Loads: Stagnant, horizontal air convection load applied at the PbB top, constant temperature assumed at base Acknowledgements: I would like to express gratitude to Brandon Aguirre and the entirety of the 01314 team for their involvement, mentorship, and comradery throughout the completion of this project. You all have given me an incredible

The Annular Core Research Reactor (ACRR) is an under moderated pool type reactor capable of pulses with energy yields exceeding 300 MJ. Because the ACRR has an epithermal neutron spectrum, different materials can be used to tailor the neutron energy spectrum to meet experimental needs. These experiment fixtures, colloquially called buckets, have operational limits to prevent softening and melting of materials caused by heating due to neutron and gamma reactions with materials. This work presents a transient thermal analysis performed on the frequently used 44-inch lead-boron bucket (LB-44) using Ansys Mechanical 2022 to more accurately determine operational limits required to prevent melting and softening of the materials. For the analysis the heating of the materials was determined using Monte Carlo N-Particle (MCNP) 6.3. Methodology  Material Properties: Ansys Granta MI material database used to obtain thermal properties for B 4 C powder, Pb, Al 6061 T6 in bucket, as well air and steel in cavity  Geometry: LB44 CAD model imported and simplified in Ansys SpaceClaim, hexahedral meshing performed using Ansys Mechanical, surrounding air gap and cavity liner are generated in Ansys Spaceclaim  Heating Inputs: Energy depositions for each segment calculated using MCNP 6.3, power profile data obtained with Razorback simulations of a maximum pulse ($3.50)  Thermal Loads: A constant temperature of 22°C assumed at the outer cavity lining along with a water convection load, conduction acts as primary heat transfer method through air gap, air convection applied to top of LB44 bucket Acknowledgements: I would like to express gratitude to Brandon Aguirre and the entirety of the 01314 team for their involvement, mentorship, and comradery throughout the completion of this project. You all have given me an incredible internship experience at Sandia. Results  P mat equation used to determine internal heat generation for each of the materials, e dep obtained using MCNP  Figure 7 displays a temperature gradient throughout each of the materials for the LB44 bucket. The temperature and heating graph (figure 4) displays the change in temperature with time  As expected, the B 4 C powder experiences the most heating, since 10 B has a high thermal neutron capture cross section and high energy exoergic reaction (2.79MeV)  Results from the analysis are validated by the heating equation below

Additive manufacturing (AM) enables the integration of multiple materials into architected designs with tailored functional material performance. In this work, modular layered structures composed of barium titanate (BTO) and polylactic acid (PLA) were fabricated using direct ink writing and fused filament fabrication to investigate compressive properties and directional piezoelectric sensing. Mechanical testing indicated that bulk BTO demonstrated high stiffness but was prone to brittle failure. In contrast, PLA exhibited ductile behavior with lower strength. However, the layered PLA-BTO structure achieved an optimal balance between strength and strain tolerance, facilitated by interlayer sliding and stress redistribution. Cyclic compressive testing conducted under a load of 5 N along the predetermined sensing axis exhibited significant directional piezoelectric selectivity in the layered PLA/BTO structure. This observation underscores the highly anisotropic piezoelectric performance of the structure, with the most pronounced voltage output along the x -axis (approximately 2.2 V), moderate response along the y -axis (approximately 0.9 V), and negligible activity along the z -axis (approximately 0.04 V). This anisotropy sensing capability is attributed to structural segmentation, where PLA layers act as insulating barriers and BTO layers form continuous charge pathways along selected axes. These results highlight the potential of AM-enabled layered architectures for programmable anisotropy, offering pathways toward localized directional sensing and energy-harvesting applications in robotics, aerospace, and structural health monitoring.

Foreign Objects (FO) within an aircraft fuel tank present a serious risk of damage and possible catastrophic loss of the aircraft. As such, aircraft manufacturers place great emphasis on the thorough inspection of fuel tanks before they are closed and sealed. If a FO was left undetected in the tank then it could migrate throughout the fuel system due to phenomenon such as aircraft maneuvers and fuel sloshing and could potentially clog filters and pumps, block fuel tubes, or create structural damage which could harm the integrity of the aircraft. While industry carefully develops the physical inspection techniques for the fuel tank and implements preventive actions to mitigate the entry of FO into the tank during manufacture, there is no documented analysis about how the FO could move throughout the fuel system. In fact, current computational fluid dynamic (CFD) analysis of fuel systems is built on the assumption of FO-free fluid, and finite element methods (FEM) treat the fuel system as a solid body. This paper will propose a representative aircraft fuel tank design and create a methodology for evaluation of FO migration within that fuel tank. The methodology will include physical experimentation of a fuel tank prototype and documentation of FO migration characteristics for distinct types of FO and present the FO migration results expressed in terms of risk. Additionally, a simulation approach will be created to analyze not only fluid flow, but also the movement of a FO within that fluid flow. These results will enable a new understanding of how FO impacts an aircraft fuel system which can be useful for future FO-resilient fuel tank design and safer aircraft operation.