Optimal Design of a Hexakis Icosahedron Vacuum Based Lighter than Air Vehicle
Abstract
Due to the rising cost and scarcity of helium, new methods to ensure buoyancy for lighter-than-air vehicles (LTAVs) are being sought. One alternative under study uses an internal vacuum to reduce the weight to buoyancy ratio. Its a novel approach; however, the vacuum presents challenges for the vehicles structure. The structure must have minimum mass while preventing buckling and excess stress throughout the frame and membrane. The structure under analysis is a hexakis icosahedron with a membrane covering. Achieving minimum mass involves optimizing the structure under the loading conditions. Finite-element analysis (FEA) and direct-search methods are employed, providing an optimal design under various regimes. Specically, ABAQUS Ris used as a FEA modeler, and mesh-adaptive direct search (MADS) is the optimization procedure. The goal of this research is to reduce the diameter of the vehicle using optimization techniques to a goal size of 31 inches (0.7874 meters). The smallest design to date has a diameter of 20 feet (6.096 meters). This research demonstrates the feasibility of two designs, one at 15 feet (4.572 meters) and another at 4 feet (1.2192 meters). The problem formulation includes multiple black-box objectives and constraints. Results for a number of designs are presented and compared.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 23, 2017
- Accession Number
- AD1051601
Entities
People
- Joseph R. Schwemmer
Organizations
- Air Force Institute of Technology