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Texas A&M University researchers developed a computational study that validates using shape-memory alloys to reduce airplane noise during landing.

“When landing, aircraft engines are throttled way back, and so they’re very quiet. Any other source of noise, like that from the wings, becomes quite noticeable to the people on the ground,” says Dr. Darren Hartl, assistant professor in the Department of Aerospace Engineering. “We want to create structures that won’t change anything about the flight characteristics of the plane and yet dramatically reduce the noise problem.”

During takeoff, engines are the primary source of noise; when landing, airplane engines are mostly idling. The wings are reconfigured to slow the airplane and prepare for touchdown.

The front edge of the wing (the leading-edge slat) moves forward from the main structure, creating a gap where air rushes in, circulates violently, and produces noise. A filler that snaps out autonomously as the slat deploys would provide a smoother aerodynamic profile that reduces flow unsteadiness and resultant airframe noise.

Earlier work from Hartl’s collaborators at NASA showed that fillers used as a membrane in an elongated S-shape within the slat-wing space could circumvent the air circulation and lessen the jarring sound. However, the research lacked a systematic analysis of candidate materials that can spring back after landing.

Hartl’s researchers performed comprehensive simulations to investigate if a membrane made of a shape-memory alloy could assume the desired S-shaped geometry during descent and then recess into the front edge of the wing for landing. Their analysis considered geometry, elastic properties of the shape-memory alloy, and aerodynamic flow of air around the material during descent. As a comparison, researchers also modeled the motion of a membrane made of a carbon-fiber-reinforced polymer composite under the same airflow conditions.

Hartl’s team had to perform calculations hundreds to thousands of times before the motion of the materials was simulated correctly, proving that the shape-memory alloy and the composite could change their shape to reduce air circulation and thereby reduce noise. However, they also found the composite had a narrower range of designs that would cancel noise.

Hartl and his team plan to validate the results of their simulations with experiments.

“We might be able to create smaller structures that can reduce noise and don’t require the S-shape, which are actually quite large and potentially heavy,” Hartl says.

Texas A&M University College of Engineering

This research is funded by the Engineering and Physical Sciences Research Council, the Royal Academy of Engineering [UK], and the NASA Langley Research Center.

Read the research paper in the Journal of Aircraft: https://arc.aiaa.org/doi/full/10.2514/1.C036070.

The ability to bring clean air to large spaces and workpieces has been a significant breakthrough for manufacturers whose work involves hazardous air pollutants such as hexavalent chromium, isocyanates, and volatile organic compounds (VOCs). Portable enclosures serve as an all-in-one sanding, coating, and painting booth where workers simply change filters for each task.

But for aerospace and defense (A&D) contractors, it can be difficult to balance the movements of large workpieces requiring many operations without creating backlogs. Contractors increasingly need flexibility to do surface prep, sand, paint, and coat in the same area simultaneously. So, Duroair has taken its engineering ingenuity to a new level by designing a multi-chamber booth that accommodates up to three separate clean-air operations simultaneously.

Each chamber has the patented six-stage DuroPure™ air filtration system. The three chambers can be used independently, or interior walls can be removed to perform one or two functions. The enclosure can be accessed from the front or the side, and the unit can be fixed or retractable on wheels.

How the DuroPure™ air filtration system works

DuroPure™ industrial air filtration technology captures more than 99% of particulates and exceeds EPA and OSHA requirements. The unvented recirculating solution doesn’t require ducting or make-up air. It places less expensive filters in front of more expensive, technically advanced filters for protection and longer life.

The first three stages capture particulates to less than one micron. The third stage filter can be changed to accommodate MERV 15, HEPA, and NESHAP 319 standards, providing the manufacturer with the flexibility to do different operations. The final three stages are a gas filtration process before the clean air is recirculated back into the shop space.

Solutions for compliance, flexibility

Duroair’s clean air solutions cost less to build than traditional systems that require a permanent footprint and venting and can be costly if a facility is at its EPA limit for exhaust stacks. Duroair solutions can be installed within days and weeks – not months – and can be retracted in hours and moved or stored in a fraction of the space.

The clean air solutions also offer A&D manufacturers flexibility for 3D printing and additive manufacturing (AM) to radically reduce the number of parts or design complexity and assembly, reduce costs, save time, and increase scale of production.

Duroair’s retractable clean air solutions bring clean air to the workpiece and help you:

• Avoid disrupting adjacent manufacturing or maintenance operations
• Save material handling costs
• Reduce or eliminate outsourcing
• Find agile ways to safeguard critical tasks without impacting productivity
• Ensure employee safety
• Improve your bottom line

To learn more, visit www.duroair.com/amd

1) What new, innovative technologies has Greenleaf introduced to increase productivity when machining aerospace components?

Earlier this year, Greenleaf launched the XSYTIN^®-360 line of solid ceramic end mills. We took our successful XSYTIN^®-1 phase-toughened ceramic material, already very well known throughout the aerospace industry, and used that as the base material for XSYTIN-360. Our ceramic material, unique cutting geometry, and edge prep combination provides up to 10x the productivity and tremendous cost savings compared to carbide end mills. As new materials and new machines require faster cutting parameters in a more abrasive environment, XSYTIN-360 is the answer.

Greenleaf also recently introduced G-9610, a titanium turning grade that uses a unique coating process that provides a very smooth, lubricious coating. Coupled with a sub-micron substrate, it offers increased performance in the semi-finish and finish turning of titanium alloys. This additional carbide grade provides aerospace customers with a new weapon that will offer marked improvements in productivity.

These ceramic end mills can be run in a broad range of workpiece materials including high-temperature alloys, hardened steels, ductile cast irons, and compacted graphite iron. Applications such as periphery milling, slotting, pocketing, ramping, and profiling are common for these end mills. The toughness of the XSYTIN-1 material allows the end mills to have a much broader speed-and-feed operating range, allowing them to run on various machining centers with increased productivity. These are extremely versatile tools that change the game when it comes to overall value in high-performance end milling.

In heat-resistant super alloys (HRSA), these ceramic end mills typically run between 1,300 surface feet per minute (sfm) and 2,000sfm, compared to traditional carbide end mills that run 150sfm to 200sfm. In certain milling applications, we can feed these end mills in the range of 0.0014 inches per tooth (ipt) to 0.0044ipt, which significantly increases material removal rates. There are tremendous opportunities to improve productivity and reduce tool consumption with XSYTIN-360.

G-9610 was designed for semi-finish and finish turning applications in titanium alloys. Many components in aircraft engines use titanium because of its high strength and low weight, but this material can cause issues when manufacturing these components. G-9610 has proven to be more resistant to build-up edge, chemical and abrasive wear, and loss of hardness at high temperatures – common issues when machining titanium alloys. This grade also performs well in the finish turning of nickel- and cobalt-based HRSA materials.

5) What are the G-9610 operating parameters?

Titanium machining capabilities vary by the phase and alloy. G-9610 can be applied at speeds from 195sfm in semi-finishing beta or near-beta alloys to 360sfm in alpha phase alloys. In alpha-beta alloys such as Ti-6Al-4V, this grade is capable of semi-finishing at 230sfm and finishing at 295sfm. When G-9610 is applied with high-pressure coolant, these speeds can be increased by an additional 20%.

For more information:
greenleafcorporation.com

There are many benefits for using wireless gages, whether as a gage only or with an advanced data collection system – a process gaining acceptance and momentum for the highest levels of quality control.

By eliminating backpacks and cables, there’s less equipment to purchase, startup costs are decreased, and related maintenance requirements are reduced within the manufacturer’s tool calibration program.

This way, operator subjectivity is removed when manually transcribing data. The time spent manually recording data is no longer a concern. In addition, wireless tools eliminate any recording measurement errors from manual entries. In simple terms, wireless provides speed, convenience, and ease of collecting and storing data.

Whether for International Organization for Standardization (ISO), government, aerospace, medical requirements, or smaller shops, the need for accurate data is crucial for traceability to demonstrate qualified parts or to trace any manufacturing errors. Accurate measurement data provides assurance for the end user and insurance for the manufacturer.

Also, wireless gages promote a cleaner work environment by removing the need for a log journal and pens/pencils, making an ideal setup for lean manufacturing.

5) Quality control is the last step when producing manufactured parts, so if a bad part slips by, it can result in problems in the final product assembly or final product.

Using wireless precision gages, inspectors can measure with confidence to qualify the part. With a simple push of a button, measurement data is stored for future analysis or history purposes. The time and money saved by going wireless and implementing a data collection system is incomparable. Digital calculators are available that can demonstrate that.

With Internet of Things (IoT) and Industry 4.0 being the omnipresent new paradigm in manufacturing, increasing the speed, amount, and accuracy of data generation is critical. Precision measurement data acquisition/collection for quality control applications benefits significantly from wireless and mobile retrieval. Wireless Data Collection systems, such as those from Starrett, should be mobile, exceptionally robust with levels of encryption/protection, suitable for multiple needs ranging from unrestricted distances and gage compatibility, and easy to use and integrate into automated manufacturing operations. Solutions should dramatically increase productivity, reduce errors, provide full documentation, and automate the acquisition process.

The L.S. Starrett Co.
starrett.com/datasure4