Advancing Aerospace Testing and Research at NIAR

Since 1985, Wichita State University’s National Institute for Aviation Research (NIAR) has met the aerospace industry’s need for research, design, testing and certification, earning a global reputation for innovating to the highest technological standards. NIAR brings together university, government and industry to advance technologies for a host of aviation-related applications.

NIAR’s 120,000-square-foot facility is home to 15 labs, with research in aerodynamics, aging aircraft, crash dynamics, advanced materials, structural components, computational mechanics, and several other fields. Today, MTS solutions and consultative expertise play a prominent role in many areas within the institute.

NIAR employs MTS equipment and know-how to advance aerospace testing and research in four key areas, all of which ultimately enable safer, more reliable aircraft to be manufactured in a far more efficient manner.

Advancing new best practices for material and structures testing and usage

The NIAR Structures Lab provides research and testing services for specimens ranging from material samples to large-scale aircraft structures. This work allows commercial, general aviation and military organizations to find new ways of reducing manufacturing costs while improving operational efficiency.

This lab is equipped with a wide variety of standard and custom MTS test fixtures and extensometers, including a laser extensometer and KGR-type extensometers for adhesive testing. MTS environmental chambers facilitate static and spectrum fatigue testing in temperatures ranging from -200°F to 2,500°F, as well as in humidity-controlled and salt-fog environments. Advanced MTS software, FlexTest digital control technology and multi-channel data acquisition provide the flexibility required to perform almost any type of materials testing or research project imaginable.

Relying heavily on MTS solutions, the NIAR Structures Lab completed several significant research and testing programs during 2006. Much of the research was dedicated to speeding the development of advanced aircraft structures, such as the Boeing 787 and Airbus A380. This research will help drive aircraft vehicle development during the next decade, as emerging technologies continue to be applied to aircraft design throughout the industry.

Testing projects for 2006 included intensive adhesive characterization and element testing of fatigued and damaged bonded joints, solely through the use of MTS software and hardware. The tests identified characteristic responses of bonded structures to real-world manufacturing and repair defects, along with the effects of lightning strikes and low-velocity impacts on the residual strength of bonded joints. This work will help establish future guidelines for adhesive and process controls for bonded structures.

The team also investigated the intricacy associated with the use of unconventional advanced composite materials in aircraft structures, through finite element analysis and subcomponent testing. From their findings, the lab developed a simplified methodology for mechanical property calculation of non-orthogonal braided composites for tapered structures.

The flexibility, functionality and ease-of-use of MTS solutions has enabled the NIAR Structures Lab to pursue all manners of advanced research without hesitation, making this lab one of the busiest and most sought-after of its kind.


2. Simplifying fatigue testing

The NIAR Fatigue and Fracture Lab conducts mechanical testing of various materials for material suppliers and aircraft manufacturers, as well as for the FAA and the U.S. Air Force. These tests are typically conducted to generate design allowables, fatigue and damage properties of materials under constant amplitude or spectrum loading. This information is typically used during the screening phase of a material, or to populate the pyramid necessary to support the “building block” approach adopted by manufacturers to certify a product.

Since its inception, the Fatigue and Fracture Lab has relied heavily upon MTS to help it readily adapt to the ever-changing needs of its customers. The lab uses a broad range of MTS equipment, software and accessories, ranging from servohydraulic load frames, to digital servocontrollers, to software and a host of transducers, extensometers, and strain and displacement measuring devices.

While conducting bending tests, MTS displacement gages monitor maximum deformation at the center of the specimen. During fatigue tests, MTS extensometers monitor material compliance under fatigue loading. MTS software enables elaborate testing programs to be created, which are capable of triggering different commands depending on test specimen response.

These MTS solutions enable NIAR to improve productivity by reducing time spent designing, setting up, and running tests, and by easily accommodating constantly evolving testing requirements. For example, the lab can use built-in functions of MTS software to quickly and almost automatically create test programs. New lab technicians can also be trained to set up test methods using MTS equipment in as little as two months.


3. Enabling more efficient and insightful crash testing

In the 1980s, the FAA began requiring certification for all airplane seats, meaning all major aerospace companies needed an independent facility to conduct proprietary testing. The NIAR Crash Dynamics Lab has become the premier resource for performing this task.
In 2005, the lab installed a new, state-of-the-art MTS accelerator sled. This horizontal MTS crash system employs a servohydraulic drive to achieve speeds of 81 km/h, with a 1,500kg payload. Impact pulse peak profiles can be adjusted to reach acceleration of 65 Gs with the same payload, or 75 Gs with a 1,000kg payload. The system also features industry-leading data acquisition capabilities, and leverages the lab’s high-resolution digital video system to capture high-velocity simulations at 1,000 frames per second.

The new MTS crash simulator greatly simplifies test run setup compared to the system it replaced. The Crash Dynamics team is now able to make pulse adjustments “on the fly” using the simulator’s advanced actuation and control system, saving valuable lab time, increasing throughput and enhancing the team’s confidence in its test data.

Another MTS crash simulator benefit includes the ability to rapidly decelerate, which helps keep the test article intact for inspection by the FAA. NIAR’s MTS crash simulator was designed to decelerate at 1.3 Gs or lower — an impressive feat considering the lab’s test track is only 70 feet long, compared to the 125-foot tracks many other labs use.


4. Supporting new innovations in friction stir welding

The NIAR Advanced Joining Lab provides research in one of the most rapidly advancing fields in aviation: friction stir welding (FSW). This solid-state technology forms a continuous joint from a metal material by generating frictional heating and sufficient forging and extruding properties, with no melting required.

FSW provides multiple benefits over traditional mechanical joining methods, including improved joint strength, reduction in manufacturing time and reduced manufacturing complexity. It also expands material selection to include such previously non-weldable materials as high-strength aluminum and metal matrix composites.

The NIAR Advanced Joining Lab was established almost entirely around the MTS I-STIR (Intelligent Stir Welding for Industry and Research) Process Development System (PDS). Suitable for research, prototyping or short production runs, the MTS I-STIR PDS is the first fully instrumented FSW research system capable of performing load-controlled welds along three independent axes, delivering greater flexibility in weld configurations.

Using the MTS solution, the Advanced Joining Lab team can perform such tasks as selecting experimental materials and welding separate panels of the metal to determine specific structural and material properties. Engineers have absolute flexibility to accomplish their current research activities and pursue more advanced projects that may bear fruit in the future. The lab is also able to take part in a broader range of collaborative research projects with leading universities across the country.




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