Structural Optimization with Probabilistic Fracture Constraints in the Multidisciplinary Radome Optimization System (MROS) (2007)


Successful design of high performance, low cost, missile radomes clearly requires the capability to tailor electrical performance, analyze high-speed aerodynamics and aerothermodynamics, and ensure the structural integrity under extreme thermal and hydrometeor environments of materials that are not structurally optimal. What is less readily apparent is that these analyses are tightly coupled and the interactions among them cannot be neglected. While the traditional engineering approach separates analyses into disciplines, rapid design and optimization demands that analyses be performed in a multi-disciplinary manner. In order to achieve better, more capable vehicles, the failure to achieve an early and accurate representation of the physics within and among disciplines will result in failure of the program.

A traditional barrier to multi-disciplinary analysis has been the time involved with passing data between analyses of different disciplines. In fact, many processes in the past have required input from the engineer for the modeling of all interactions between disciplines. This invariably takes a significant amount of time, and is often infeasible for use early in the design process or for processes requiring iteration. Recently, significant advances have been made in the development of automated systems that perform integrated analysis. An excellent example of such a system is the Integrated Hypersonic Aeromechanics Tool (IHAT).1 With the use of IHAT, an engineer can perform a multidisciplinary analysis in which the vast majority of time is invested in the analyses within the disciplines. In addition to this streamlined analysis capability, IHAT offers a broad range of optimization techniques through the inclusion of the DAKOTA (Design Analysis Kit for Optimization and Terascale Applications) toolkit.2 This allows the engineer to gain an understanding of the physics of the problem early in the design process that would not have been feasible in the past.

The Multidisciplinary Radome Optimization System (MROS) has taken the multidisciplinary approach and the optimization capability present within IHAT and focused them on the radome design problem. Noteworthy capabilities of the MROS system relative to IHAT include: electromagnetic performance analysis, incorporation of solid thermal and structural models, and probabilistic fracture analysis. Probabilistic fracture analysis is included in MROS due to the fact that many radomes are constructed from ceramic materials which are brittle and have significant dispersion in strength. This paper describes the MROS system in overview (including all disciplines considered), with special attention paid to the structural analysis details.