Session: 01-10-01: Structures in Extreme Environments

Paper Number: 158305

158305 - Optimization Analysis of Prestressed Large Antenna Structure 

As humanity moves further into space exploration, the structural integrity and efficiency of space structures become critical. Among these properties, the stiffness-to-mass ratio is a key metric that defines the viability of structural systems for space applications. Significant research has focused on enhancing the mechanical properties (such as stiffness) of individual materials used in these structures. However, relying solely on improving the properties of individual materials has inherent physical and practical limitations such as manufacturing complexity and extremely high costs. To address these limitations, an alternative approach must be explored—one that leverages structural (as a complete unit) design rather than just individual material improvements. Hence, prestressing structural members offers an opportunity to enhance the mechanical performance of space structures, such as antennas or trusses. This approach unlocks a broader design space with fewer physical constraints, enabling the creation of structures with extraordinarily high strength-to-mass ratios, and paving the way for more efficient and robust structures for future space missions.

Prestressed structures are essential for space applications for several reasons, including their adjustable stiffness, exceptional strength-to-mass ratio, and the ability to eliminate free play or backlash in structural components (backlash).  Astresomesh is the state of art for prestressed antennae in space, developed by Northrop Grumman. Astresomesh currently could achieve a maximum diameter of 22 meters. However, the demand for reflector antennas exceeding 22 meters in diameter is growing. Larger antennas (more than 100 m) are crucial for future space missions as they enable high gain and narrow beamwidth, both of which are essential for efficient signal transmission, precise data handling, and long-distance communication.

In this research, we are designing and modeling a large Carbon fiber-reinforced polymers (CFRP) antenna manufactured using frontal polymerization. The study shows cable pretension can increase the stiffness and specific area of mesh antenna structures compared to non-pretensioned structures. The numerical analysis is conducted using ABAQUS software. Moreover, the model evaluates various configurations of prestressed trusses, analyzing and optimizing parameters such as member length, the angle between truss members, carbon volume friction, and truss thickness. The results demonstrate that increasing the thickness significantly enhances the beam's stiffness. However, the increase in thickness also leads to a corresponding rise in mass, which can be a critical limitation for space applications. This is where prestressing shines. By applying prestress, it is possible to achieve a stiffness increase of over two orders of magnitude while maintaining the same mass, making the design far more efficient for space structures.

This analysis will provide insights into how cable pretensioning (prestressing) affects the stiffness and specific area of large mesh antenna structures, and serve as a foundational guide for future space missions aiming to construct antennas. This work also aligns with the recently announced "Illinois Mission," which aims for in-space manufacturing by fabricating (CFRP) tubes via frontal polymerization in orbit.

Presenting Author: Nawaf Rasheed University of Illinois Urbana-Champaign

Presenting Author Biography: PhD student at University of Illinois Urbana-Champaign, working on In-Space Manufacturing, and space truss design. Currently leading mechanical design team for "Illinois Mission"