The advanced properties and design flexibility of composite materials have garnered much attention among the military and defense communities. Composites are ideally suited for the demanding applications these fields often involve, and manufacturing technologies that can take advantage of composites’ benefits are highly sought after. Automated Dynamics works closely with military and defense clients to incorporate these materials in projects via the use of automated fiber placement (AFP).
In conjunction with the United States’ military, Automated Dynamics has created several major composite structures that can be described as high shock load parts. The long, thick-walled composite over-wrap is a state-of-the-art component that can only be successfully manufactured with Automated Dynamics’ experience and expertise in automated fiber placement of thermoplastic (TP) tapes. Additionally, Automated Dynamics is the world leader in on-the-fly (in-situ) consolidation of thermoplastic materials via AFP, removing the need for post processing.
Based on the early history of these components, AFP of thermoplastics will provide a new level of performance and robustness unobtainable through prior composite manufacturing methods. Early composite versions of defense hardware, such as cannons, lasted for very few uses before being scrapped. Even current composite body armor has a very limited use capability despite a multiple-shot tolerance requirement. As with all high-performance structures, there is a balance of requirements that must be met. Since materials have rate-dependent properties or rate-affected responses, high velocity projectiles impose a demanding combination of requirements on military hardware. Toughness for damage tolerance, hardness for impact resistance, and strength for high loading capacity must be built in to a part that is both lightweight and corrosion resistant. This demand has increased steadily with time as weapons continue to become more powerful and efficient.
Composite structures for military applications have, so far, been dominated by fiber-reinforced thermosets (TS-FRP) over thermoplastics (TP-FRP). They provide a mixed bag of performance. For example, TS-FRP structures have lower radar signatures than metal and good flammability resistance. However, TS-FRP materials tend to have limited resistance to hydrolysis, and studies have shown poor structural performance in fire despite their good flammability resistance (violent delamination from vaporized water).
Key Accomplishments and Capabilities
As practiced by Automated Dynamics, AFP enables greater design flexibility through tailorable manufacturing. After more than 30 years of innovation, Automated Dynamics has developed extensive experience and renowned expertise to meet the most challenging demands in automated composite fabrication. Some of these include:
- Connecting composite to metal intimately to efficiently transfer load and operate seamlessly
- Optimizing layup to align fibers along load paths to minimize amount of material needed
- Further reducing wall thickness and weight
- Mixing fiber type and orientation to modulate stiffness in a specific direction
- This is particularly useful for structures with large lever arms (e.g., cannons) to increase accuracy
- Automatically adding plies on-the-fly to strengthen or accommodate transitions; e.g., to metal connections
- Dampening vibration and improving dynamic strain tolerance; especially with the use of TP matrices
Out of Autoclave (OOA) & Out of Oven (OOO)
Out-of-autoclave and out-of-oven manufacturing is a daily practice at Automated Dynamics. Our thermoplastic parts require no secondary processing. For large structures, this is a dramatic cost benefit that’s been well documented. One such example of what is driving the demand for OOA can be found in a Composites Manufacturing article by Melinda Skea.
Another significant benefit of OOA/OOO is enabling and simplifying use of embedded sensors, electronics and wiring. It also facilitates manufacturing of complex structures that encase temperature-sensitive components. Components can be assembled and wrapped in a thermoplastic composite structure (which enables greater design flexibility and fabrication efficiency), rather than having to redesign those components to fit within a prefabricated composite shell. Automated Dynamics has demonstrated this advantage repeated for a large and complex military structure that had proven difficult to manufacture with autoclave-cured composite parts. Moving to OOA/OOO also produced a more robust manufacturing process and finished part with a useful life that is orders of magnitude longer than prior generation parts requiring autoclave curing.
In short, military and defense applications offer a key area of growth for thermoplastic composite parts and the use of automated fiber placement at Automated Dynamics. The well-established attributes of mobility, robustness and cost-effectiveness offer a perfect opportunity to take advantage of TP AFP for defense-related composite parts. Automated Dynamics has the technology and skill to exploit it to its fullest potential and exceed expectations.
For more information, contact:
Business Development Manager – Defense