NTS News Center

Latest News in Testing, Inspection and Certification

NTS News Center - Latest News in Testing, Inspection and Certification

Increasing Vibration Capabilities in Boxborough, MA

The already extensive dynamics testing capabilities at our Boxborough, MA location are about to get even better!

We are eagerly awaiting the arrival of our new Unholtz Dickie T2000 – 3 – PB. This new shaker has a 3 inch stroke and a rating of 25,000 force pounds for sine vibration, 23,000 force pounds for random vibration, and 67,000 force pounds for shock. It has a F2000 Field Power Supply and Heat Exchanger with 2 bays, and series/parallel stators for high SRS shock.

This will be the eighth T2000 for NTS across the US, our other T2000 shakers are in Fullerton and Los Angeles, CA, Chicago and Rockford, IL, Camden, AR and in Plano, TX (above on installation day in 2016).

Contact us today to get your vibration testing scheduled! The schedule will fill up fast! Request a quote here, or contact the Boxborough team today!

Essentials of Random Vibration and Shock Testing Training in Massachusetts

NTS ED T-2000 Vibration Test TableJoin us in Boxborough, MA as we host the Equipment Reliability Institute for their “Essentials of Random Vibration and Shock” testing course.

Learn the essentials of random vibration and shock testing with hands-on demonstrations!

Who is this course for?

This course is a must for technicians, engineers, managers, or anyone in need of practical knowledge about mechanical vibration and mechanical shock test, measurement, analysis, designing for dynamics and/or control.

To learn more about this course, click here!

To learn more about NTS Boxborough and their extensive vibration test capabilities, click here!

Lightning Protection of Wind Turbines

lightning protection for wind turbinesOver the past decade, we’ve all watched the world’s energy markets shift towards cleaner, alternative sources. Technological advancements in renewable industries like wind, solar, and tidal, have enabled us to make these potential solutions a reality. As research and development continue to improve efficiency, and drive down cost, these solutions will become more and more prevalent.

We still face considerable obstacles. Wind turbines, in particular, take on one of the largest hurdles; weather. Their fixed location poses unique challenges for turbine and blade manufacturers, which are expected to increase the longevity and reliability of their products without compromising effectiveness, or substantially raising costs. Lightning strikes can cause significant damage to turbines. This damage is extremely expensive to repair, and can shut a turbine down completely.

Severe storms are generally comprised of one or more cumulonimbus clouds, which can be several kilometers in height. As these clouds develop, warm air rises towards the top of the cloud. As the air rises, it becomes cooler. At the dew point, excess water vapor condenses into water droplets and forms the cloud.

When the air has risen high enough, the temperature can drop to -40 degrees Celsius –  water vapor within the cloud will freeze. As ice crystals and hailstones form, and become heavier, they fall through the cloud. When additional water droplets freeze onto the hailstone, small splinters of ice chip off, many of which are positively charged (electrically). Together, these can deposit a net negative charge. Vertical winds carry these smaller splinters upwards into the cloud, while the hailstone falls until it reaches warmer air.

This process causes pockets of electrical charge to form within the cloud, which creates strong electric fields. These electric fields allow charge from the surface of the earth to be “pulled” upwards. in an effort to become charge neutral (typically through tall objects and structures). As these charges get closer together, the electric field in the air further intensifies until it reaches levels of ~30,000V/cm.

When the field intensity reaches these levels, air begins to break down, allowing charge (in the form of current) to flow through the air. Sharp objects significantly intensify the electric field, forming corona (also called St. Elmo’s Fire). Charge from the lightning cloud begins propagating towards the earth. At some point, charge from objects on the ground begins flowing upwards. When these two flows meet, a conductive channel is formed, and lightning occurs.

During a lightning strike, currents of up to (and even greater than) 200,000A travel between the cloud and the object where the lightning channel formed. Wind turbine blades have a sharp, aerodynamic profile – this not only allows them operate efficiently; it also makes them extremely susceptible to lightning strikes. Without suitable conduction paths to safely carry such high current, this transfer of energy can devastate a wind turbine blade.damaged wind turbine blade

Most wind turbine manufacturers strive to make blades and turbines that are more reliable, and can withstand natural phenomena such as lightning. These designs attempt to provide “preferred” current paths for the lightning current; conductive meshes over the exterior of the blades, lightning receptors (preferred lightning attachment locations), and large down conductors, help carry high currents safely to ground.

All of these precautions require highly-detailed planning that includes proper grounding of conductors, shielding of signal wires, wire routing, providing parallel current paths, etc. Despite the complexity of these designs, the benefits are significant; the effects of lightning are not entirely negated, but damage can be significantly reduced – instead of a total blade replacement, getting the turbine up and running again becomes a maintenance and repair exercise.

lightning damage repair progressionThe repair may be straightforward, but it’s still physically demanding. Most modern wind turbine blades are several dozen meters in length. The turbine tower itself can extend 50-100 meters above the ground. Maintenance workers must climb the tower, or be carried up to the blade via a crane. The repair generally involves removing the exterior coating, prepping the damaged area for repair, repairing the laminate, and reapplying the exterior coating.

The physics of nature make lightning almost unavoidable. Therefore, manufacturers must build an effective lightning protection design into the blade.

Most modern design approaches leverage a combination of numerical simulation and testing. Utilizing numerical simulation, electromagnetic models for wind turbine blades can be developed to analyze distributions between structural carbon, and surface protection layers. These models allow the determination of what is electromagnetically important, such as voltages or currents induced throughout the blade, including CFRP pultrusions, heater elements, surface protection layers, and down conductors. They capture critical design details such as material thicknesses, conductor routing, and receptor locations. Further evaluation exposes conductive materials and associated performance risks, such as arcing between blade elements, excessive current in structures, and induced transients into control systems.

After modeling is complete, one or several candidate protection designs is proposed, intending to conduct lightning current with lowest potential for damage or repair. In order for the model data to be considered high fidelity, it needs to be validated by replicating exactly the measurements taken during laboratory tests, and comparing them to the analytical data to determine correlation. This is typically done with high voltage strikes, high current physical damage testing and induced transient tests.

Lightning will always affect wind turbines. It’s complicated, and requires a well thought out design to reduce the severity of damage. If a good protection design is implemented, lightning damage can be reduced to a standard maintenance/repair operation, rather than a total loss.

Justin McKennon is a Senior Engineer and Manager of Simulation and Modeling at the NTS Pittsfield, MA location that specializes in lightning testing and protection services. Justin has a Bachelor’s and Master’s degree in Electrical Engineering from the University of Massachusetts, Dartmouth. He specializes in simulating and modeling the electromagnetic effects of lightning on wind turbine blades, electrical components, aircraft, and other structures. 

 

Love that muddy water? Slurry Testing at NTS Detroit

Slurry testing is a specialty at NTS Detroit testing laboratory. It is a great way to gauge the durability of products at the risk of failure due to various environmental operating conditions. Commonly used in the automotive industry to test rotating components such as motors, alternators, and bearings, slurry testing implements the use of one of our mud slurry test rigs or fabrication of a custom test setup to expose your product to the different environments it would encounter during end-use.

Slurry Testing Dana Inc

Also referred to as mudsplash testing, mudbath testing, mud resistance testing, or muddy water durability testing, it is a fast and consistent method to determine things such as overall durability, seal quality, or leakage. This testing can be done at specified temperatures, for various durations, using any combination of mud, salt, or dust, and with radial and/or axial load applied. It commonly goes hand in hand with dynamometer testing. We can also determine if a component can maintain its original properties during exposure to slurry, such as its ability to dissipate heat. A unique test we offer exposes prop shafts to hot/cold, salt/sand slurry, and torque/speed, all while monitoring the bearing temperatures with infrared cameras.  Our expertise encompasses nearly every aspect of a vehicle’s drive train including Hybrid and EV.

Some specifications that call out slurry testing include ISO16750, Continental Spec CS11982, and Ford Laboratory Test Method FLTM BI 168-01.

Click here to discuss this and other automotive testing needs with our experts!

Review of the 2017 IPC Reliability Forum

The IPC held their inaugural Reliability Forum this April in Chicago and by all accounts, the event was a resounding success!

NTS participated along side other industry experts from raw material and equipment suppliers, PCB fabricators, contract manufacturers and OEMs.

William Graver, NTS senior analyst, presented on a number of major reliability concerns in today’s environment in his session “Is test an unnecessary evil, or a life-saving necessity?”

You can read a full write up of the event, as well as other news from the IPC here: The PCB Magazine, July 2017.

Aerospace Industry Update: AS91XX Series of Standards Transition Deadline Approaching

As I’m sure our Aerospace industry clients are aware the AS91XX:2016 series of standards (AS9100, AS9120 and AS9110) has undergone a major revision with release dates late last year.

The aerospace standard AS9100 was published on 20th September 2016. AS9120 and AS9110 were also published in November 2016.  The aerospace standards have the same transition deadline as the ISO 9001:2015 standard, September 2018. Therefore the AS standards were released approximately eight months after the ISO 9001:2015 standard, the “three year” transition will actually be less than 18 months for aerospace companies.

NTS sister division, NQA is the leading quality management systems registrar to the aerospace industry. If you would like to learn more about the transition and how NQA is helping our aerospace clients through it, click here.

EMC Essentials Training at NTS Longmont, CO Testing Laboratory

Learn how to design electronic products to comply with electromagnetic compatibility (EMC) requirements at the NTS Longmont, CO EMC test laboratory.

This short course is a unique blend of theory, application and demonstration. Besides the excellent book, EMI Troubleshooting Cookbook for Product Designers, you’ll have the option to purchase the excellent textbook from Würth Electronics: Trilogy of Magnetics, at a discount. A special module has been added to course materials, which discusses some examples from the book. In addition, Würth and other vendors will be demonstrating their latest EMC related instruments and filter components.

Day one of this two day course will introduce basic EMC theory; units of measurement, time and frequency domain, differential and common mode currents, radiated emissions, PC board layout, shielding, transmission lines and magnetics. In addition, special guest presenter, Dr. Eric Bogatin, will present a segment on “Power Distribution Network (PDN) Design for Low EMI”.

Day one is crucial to understanding the day two presentation, as it will also include demonstrations of many of the basic product design principles.

The second day of the course will cover bench top EMI measurements and troubleshooting. We’ll continue with ESD and system design, followed up with practical, low-cost, tools and techniques that can be used for pre-compliance measurements as well as troubleshooting EMC problems in a more formal setting. We’ll demonstrate several probing and analysis techniques that will help identify EMC issues quickly. Several actual case studies will also be described.

If you are a technician, engineer, manager, or anyone tasked with the job of getting a product through EMC compliance testing in the Colorado region, this is the training for you! Click here to review the full agenda and speakers and register today!

Non-Destructive Evaluations

Non-destructive evaluations (NDEs) are a critical first step in the failure analysis of a product or component. NDE testing looks closely at a device under test without altering it in any permanent way. This is the fastest and most economical way of collecting data that can be used to pinpoint the root cause of a failure or make other improvements that will enhance quality control or performance.

NTS offers a range of non-destructive inspection services from our Chesapeake laboratory. Leveraging sophisticated equipment and the expertise of our engineers, we can design testing programs that provide actionable information and accurate results for a range of products.

NDE Testing Services

Different products with different issues demand different testing programs. Non-destructive failure testing at NTS may involve any of the following:

  • Visual inspections: A thorough visual inspection is the most basic form of NDE testing. We can inspect a nonfunctioning component to confirm the product meets original specs, and to determine when and how any physical damage occurred.
  • Optical microscopy: Optical microscopy gives our engineers a closer look at a device under test. It is often required to understand how a material has degraded or identify how a component has become contaminated or corroded.
  • CT scanning: X-ray CT scanning provides high-resolution 3D images of the internal components of your product, letting our team pinpoint failure modes without altering the device under test. Our Chesapeake facility features a 450kV microfocus system that can scan objects up to 37” in diameter, creating a sophisticated data set that includes information from internal features and surfaces that would be otherwise hidden.
  • 3D metrology: Our 3D metrology services provide fast, accurate internal surface dimension measurements with a resolution of 0.001” or better. Results are fully traceable and testing takes just minutes. 3D metrology NDE testing is useful for geometric inspections and reverse-engineering.
  • Laser mapping: Our nondestructive testing facilities include a BEMIS-SC™ laser mapper — a sophisticated tool specifically for measuring gun bores ranging from .22 to .50-cal. As a result, we are able to provide certification, recertification and other commercial gun barrel inspection services.

Using the above technologies and other powerful tools, we can perform qualitative and quantitative nondestructive testing for clients ranging from defense and aerospace contractors to commercial electronics manufacturers. Our labs are ISO 17025- and A2LA-accredited to perform root failure analyses for highly-complex components and products.

Benefits of NDE Testing

Non-destructive inspections have multiple benefits for manufacturers. Powerful imaging equipment allows for accurate, in-depth analyses of failed components. Testing early in the manufacturing cycle can reduce the risk of liability issues down the line, saving you money without having to sacrifice an expensive prototype. This, in turn, leads to a higher-quality product at a lower cost.

NTS engineers will work closely with you to identify your testing needs and put together a non-destructive testing program that provides you with useful, usable information. With these results, we can recommend improvements that will reduce the risk of future failure.

For more information, use our online form to request a quote.

How will MIL-DTL-901E affect your shock qualification?

Photo: Navy.com

For the past 30 years, MIL-S-901D has defined requirements for shock qualification of items installed on U.S. Navy Combatants. For the duration of this period, there have been rumors of a new and improved specification revision. That time has finally come.

MIL-DTL-901E, revision to MIL-S-901D of 1989 has been approved and released as of 20 June 2017. The new “detail specification” or DTL per DOD 4120.24M is an evolutionary document that includes changes from MIL-S-901D, Interim Change #2, the 2012 DSCR-2 initiative clarification letters and cost reduction strategies, and the Total Ownership Cost (TOC) reduction provided by the Deck Simulating Shock Machine (DSSM).

For most Navy shipboard shock practitioners, the most impactful change to the document is the addition of the Medium Weight Deck Simulating Shock Test.  This test is primarily performed on Class II, deck mounted equipment and utilizes the DSSM. The DSSM is typically used in lieu of performing a heavyweight shock test series.

The DSSM shock test machine at NTS Rustburg

In the early 2000s, we recognized that the current model for shock qualification of a vast majority of the proliferating Class II, Deck Mounted, COTS equipment was not sustainable from a costs and schedule perspective.

So, in collaboration with HII-NNS partners, NTS led the pioneering development of a more cost and schedule effective land-based approach to meet this new challenge. These efforts culminated in the fabrication of the DSSM Generation I machine that has been in use at NTS Rustburg, VA since 2004.

The success of the Generation I DSSM led to the development of a scaled-up Generation II machine that is specified in MIL-DTL-901E. All of the certification testing that was necessary prior to inclusion in the new MIL-DTL was conducted at NTS. We have been routinely conducting shock qualification testing on the DSSM as an Alternate Shock Test Vehicle since 2015.

The DSSM development is yet another example of NTS’ focus on customer driven innovation. If you have questions concerning the new MIL-DTL-901E detail specification and how it may affect your program or have a need for Medium Weight Deck Simulating Shock Tests contact our experts today!