Gasser F. Abdelal

Finite Element Analysis for Satellite Structures

Features 7 Provides the guidelines to use finite elements in each phase of designing a satellite structure, but also includes practical examples and illustrations to explain how they can be applied 7 Introduces an approach which applies stochastic finite element method in analysis of satellite structure and uses finite element method in manufacturing simulation to reduce cost across three different manufacturing processes 7 Explains how to practically use manufacturing simulations to improve design and reduce project cost, how to prepare static and dynamic test specifications, and how to use finite element method to investigate in more details any component that may fail during testing

Stochastic Finite Element and Satellite Structure Design

Throughout design development of satellite structure, stress engineer is usually challenged with randomness in applied loads and material properties. To overcome such problem, a risk-based design is applied which estimates satellite structure probability of failure under static and thermal loads. Determining probability of failure can help to update initially applied factors of safety that were used during structure preliminary design phase. These factors of safety are related to the satellite mission objective. Sensitivity-based analysis is to be implemented in the context of finite element analysis (probabilistic finite element method or stochastic finite element method (SFEM)) to determine the probability of failure for satellite structure or one of its components.

Manufacturing Simulation Using Finite Element

Using nonlinear finite element method to simulate the manufacturing process can help to optimize its design parameters and produce better parts. The main topics discussed in this chapter are riveting, shot peening, and material removal (end mill). Riveting is used for assembly, shot peening is used for metal forming or to improve fatigue, while material removal is used for shaping or fixing imperfect part. The simulation steps using ABAQUS software of each of these manufacturing processes are discussed in detail including listing of ABAQUS input files. Projects are suggested at the end of each section for the reader to use it for practice or graduation projects.

Satellite Configuration Design

This chapter discusses the process of integration of the subsystem components and development of the satellite configuration to achieve a final layout for a satellite; the process will be applied on a test case and it is called “Small Sat”. The Small Sat structural configuration is designed to accommodate all of the mission components. All mechanical requirements are derived from the satellite’s configuration. The process used to create the satellite configuration of Small Sat is described. It begins with mission definition, launch vehicle selection, and subsystem identification. This is followed by a description of the satellite composition, and the major design constraints that guide the configuration design. Then a configuration development process is presented to create the preliminary configuration. Finally, the issued layout drawings and the calculated mass properties for the developed satellite are presented.

Satellite Structural Design

The process to develop the structural design of a “Small Sat” is discussed and applied on a practical design case. It shows how to derive Small Sat’s structural requirements from the satellite configuration. Then, it addresses the iterative design procedure used to create the current design. It also discusses the worst load cases to which the satellite is exposed during ground, launch, and space environments. A simplified finite element analysis of the satellite structure is then performed to size the preliminary design of the structure. Finally, the structural module descriptions are presented. In this chapter, the process used to develop the structural design of “Small Sat” is described. It shows how to derive Small Sat’s structural requirements from the satellite configuration. Then, it addresses the iterative design procedure used to create the current design. It also discusses the worst load cases to which the satellite is exposed during ground, launch, and space environments. A simplified finite element analysis of the satellite is then performed to size the preliminary design of the structure. Finally, the structural module descriptions are presented.

Qualification Testing Phase of Satellite Structure

The development of the satellite structure necessitates a good understanding of the static and dynamic characteristics of the satellite to establish design and test loads. Static strength verification is accomplished by a static-centrifugal test. Static tests objective is verification of strength of the satellite structure in accordance with accepted types of loading and determination of load-carrying ability of the structure. Dynamic tests objectives are the estimation of the vibration-transfer coefficients to the mounting seats of the satellite‘s components, modal frequencies of the satellite structure components and satellite structure as a whole, effect of the impact loads on satellite’s equipments mounting accuracy, and verify the electrical equipments function due to vibrations. The full list of qualification tests is discussed in this chapter. Then, finite element method is used to investigate cracks that were initiated during air transportation vibration test of satellite structure strength mockup.