To turn the concept of hypersonic flight into reality, there exists a dual imperative: developing materials that outperform those from the 1970s and innovating novel ways to utilize these existing materials effectively. This led to making of 3D Printed Ramjet. The extreme conditions of heat and pressure that hypersonic vehicles will encounter further underscore the critical need for optimized, weight-saving 3D printed structures, which must be complemented with high-performance 3D printed metals and ceramics. In response to these challenges, the Department of Defense’s Lightweight Innovations For Tomorrow (LIFT) Institute, in collaboration with Velo3D, Lockheed Martin, and Vibrant, a non-destructive testing firm, has embarked on a mission to advance the development of 3D printed hypersonic propulsion systems.
Lockheed Martin’s Role in Pioneering 3D Printed Ramjet
Lockheed Martin, serving as a major contractor, has played a pivotal role in this endeavor by proposing a 3D printed ramjet engine designed to evolve into a scramjet engine. Their journey began with a design of experiments project employing powder bed fusion with Inconel 718 material. Subsequently, two towering 3D Printed Ramjet engines, standing at 751 millimeters, were 3D printed using the Velo3D Sapphire 1 MZ machine. These components boasted extraordinarily thin walls, interspersed with minuscule 500-micron holes. Rigorous testing of these parts and related coupons provided valuable insights into system reliability and variations between different manufacturing machines.
Dr. John Keogh, Engineering Director at LIFT, highlighted the significance of data-driven strategies for validating and certifying components right out of the 3D printer. This approach departs from the statistically driven practice of manufacturing multiple parts before gathering performance data. The goal is to identify the physical quality signatures present in process data and expedite post-process inspections for precise certification of components for hypersonic flight like 3D Printed Ramjet.
Revolutionizing Testing with Vibrant’s Process-Compensated Resonance Testing
To evaluate the components, the team turned to Vibrant’s Process-Compensated Resonance Testing (PCRT), a rapid, non-destructive method that employs a component’s natural resonance frequency to detect cracks, occlusions, porosity, and overall build quality. Resonance data is integrated with in-situ monitoring, and this combined dataset is meticulously analyzed to fine-tune optimal machine parameters.
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Hypersonic flight, traveling at Mach 5 or above, introduces extreme heating at leading edges. Sharp radii are particularly problematic, leading to intense heating, necessitating substantial radii in reentry vehicles from space. However, hypersonic vehicles like 3D Printed Ramjet engine require some semblance of a vanguard for aerodynamic purposes, while also contending with formidable and dynamic forces at such speeds. These challenges are an intricate interplay of aerodynamics, mechanics, thermal management, and chemistry, all compounded by the need to work with materials that can withstand these harsh environments.
A Collaborative Journey Towards Hypersonic Advancement
This initiative, managed by LIFT, is part of a larger partnership with the American Lightweight Materials Manufacturing Innovation Institute, a member of the Manufacturing USA network. With a budget exceeding $100 million and a diverse membership of over 300 academic institutions and businesses, LIFT is also known for collaborating on groundbreaking projects like MELD’s jointless vehicle hull. Another critical endeavor by the institute is the Hypersonics Challenge, conducted on behalf of the Department of Defense’s Office of the Under Secretary of Defense for Research and Engineering, focusing on identifying materials and manufacturing methods conducive to creating components for hypersonic vehicles.
The team aims to leverage this wealth of knowledge and ongoing experiments to accurately predict and assess the elusive fatigue properties of 3D-printed components of the 3D Printed Ramjet. The ultimate aspiration is to produce components that emerge from the 3D printer already meeting stringent quality standards. Given the multifaceted challenges presented by hypersonics, success hinges on extensive collaboration. Hypersonic technology is inherently a collective endeavor, as the obstacles are too monumental for any single entity to conquer in isolation. 3D Printed Ramjet represents the pinnacle of technological advancement, poised to reshape global power dynamics in the future. Thus, this initiative marks a promising beginning, with the anticipation of many more collaborative projects on the horizon.