Modern aircraft are powered by gas turbine engines that pass air through a series of stages where it is compressed, ignited, and expelled. This process creates a high-pressure exhaust that is used to drive rotating engine parts and produce thrust.
Powered by Air
Airbus A380 – the world’s largest passenger airplane
Aircraft require tremendous engine power to achieve liftoff and flight. A fully-loaded Airbus A380 – the largest passenger jet in operation – can weigh over 500 tons at takeoff, requiring four massive engines combining for 300,000 pounds of thrust.
The engines need to propel the plane fast enough to generate sufficient lift to overcome the force of gravity. But unlike land vehicles that push against the ground with powered wheels, aircraft generate thrust via propellers or engines that push against the air.
Gas turbine engines are filled with airfoils or “blades” of varying sizes attached to a rotating axle. The blades move air through the different stages of the engine, compressing and expanding the gas to produce thrust that propels the plane forward. Continue reading →
Images of the fractured blade. Credit: avherald.com
The Australian Transport and Safety Bureau (ATSB) has issued its interim report on a scary engine failure that rocked an Airbus A330 in June. AirAsia flight D7-237 was bound for Kuala Lumpur, Malaysia when a fan blade in the plane’s left engine suddenly fractured. Passengers were startled by the loud explosion at 38,000 feet, and pilots shut down the engine prompting a diversion to Perth Airport for an emergency landing.
The plane shook violently during the two-hour return to Australia, and the captain urged passengers to watch the engine and pray for safety. The incident went viral on social media, with videos of the plane “shaking like a washing machine”, and controversy over the pilot’s comments.
We wrote about the incident last month, outlining the dangers of fatigue cracking and the power of laser peening to prevent these critical failures. Now the ATSB has stated publicly for the first time that metal fatigue was the likely culprit.
The World’s Most Powerful Surface Enhancement Technology
Laser peening is a fascinating marriage of electromagnetic physics and materials science. The process uses high-energy lasers to strengthen metals, producing robust components that are highly resistant to failure. Laser peening (LSP for short) plays a critical role enhancing critical parts for critical industries. You’ll find laser peened parts in aircraft engines, power plants, and heavy machinery around the world.
If you’re new to the world of laser peening, we’ve got a wealth of technical content available at your fingertips. (Check out our library of papers and patents!) But before taking that deep dive, here are five interesting facts to put this revolutionary enhancement process in perspective.
1) Light Can Strengthen Steel
It’s worth taking a step back to consider the awesome implications of peening metal with lasers. We’re using pulses of light to strengthen steel and titanium, replacing old-world peening techniques with new-age technology.
Metal enhancement has come a long way
It used to be done with hammers. The rounded head of a ball peen has long been used by blacksmiths to pound and shape forged components. These brute-force blows put compressive stresses into tools and armor, but their enhancement benefits weren’t fully realized until the 1920s when a budding auto industry adopted shot peening to strengthen springs.
Shot peening is another brute-force enhancement method using high-velocity impacts to generate compressive stress. The process requires thousands of pellets or particles, launched toward a workpiece to produce a thin accumulation of surface compression. It’s messy and imprecise, and the benefits extend just fractions of a millimeter beneath the surface.
Laser peening transcends the old barrage-based methods, taking surface enhancement to another level. Coherent photon pulses impart compressive stresses many times deeper than hammers or shot pellets could ever achieve. With all due respect to the burly blacksmiths of the world, laser peening has moved metal enhancement out of the dark ages with blasts of light.
Game of Thrones is a cultural phenomenon. Conceived by American novelist George R.R. Martin, this fantasy epic has been adapted by HBO into one of the highest-grossing TV series of all time. The story takes place in a vast fantasy realm, with most of the plot focused on a land called Westeros – a dynastic empire reminiscent of medieval Europe.
The series has soared to widespread popularity thanks in part to the breadth of themes it delivers: Mystery, romance, action, intrigue – Game of Thrones brings them all and pulls no punches. With an average price tag of $10 million per episode, the show overlaps complex political trickery with heart-pounding action and dazzling special effects.
But amidst all the sex and swordplay, Game of Thrones presents some valuable lessons that still resonate in modern life. I’m not talking about courage or chivalry – this is a laser peening blog after all. I’m talking about material enhancement. And this billion-dollar fantasy franchise has more to say about it than you might think. Continue reading →
Laser peening produces deep compressive residual stresses that extend component service lifetimes and improve performance. The key to laser peening’s effectiveness is the generation of a powerful shockwave – but how does this process enhance the metal surface?
LSPT Senior Engineer Stan Bovid explains the mechanics in this excerpt from a recent live webinar. Click here to sign up for our next live training event, or contact us to arrange a private presentation for your team.
David Lahrman is a certified trainer for Metal Finishing News International (MFN). David provides insights and instruction on metal finishing for this worldwide network, and he wrote a feature article for the July 2017 issue of MFN Magazine.
MFN International – July Issue – 2017
Laser shock peening is a powerful, targeted method for enhancing metal fatigue strength using high-energy laser pulses. Like shot peening, laser peening imparts beneficial compressive residual stresses in the surface of a component to impede crack initiation and propagation. Unlike shot peening, laser peening is only applied to fatigue-critical areas to provide enhanced resistance where parts are most susceptible to failure. Laser peening is commonly applied along the edges of compressor turbine airfoils to protect against foreign object damage and erosion, or applied along the dovetail root to prevent fretting fatigue, stress corrosion cracking and fracture.