b'Aerospace | Engineer InnovationThe U.S. Military has a problem. out of Georgia, U.S.A. bringing years of A problem that is eating away its assets,corrosion and Computer Aided equipment and budget annually -Engineering (CAE) expertise. Corrdesa corrosion.is helping the U.S. Navy implement a corrosion-resistant design approach Costing a cool US$25 billion per year,using Simcenter STAR-CCM+TM and 4 percent of the U.S. Department ofTeamcenter from Siemens PLM Defense (DoD) budget, corrosion isSoftware. Corrdesas corrosion analysis more than just an eyesore for theworkflow provides quick material military. The staggering economicselection to resist galvanic corrosion, impact aside, corrosion fromsaving thousands of testing hours and environmental interaction puts militarymillions of dollars for the U.S. Navy. equipment, mission readiness and lives at risk. The cost of corrosion is analyzedAn outdated method and a US$228 annually by a DoD Corrosion Office. Amillion repair billCorrosion Prevention Advisory BoardCorrosion is electrochemistry gone exists for all new military systems. Inrogue, degrading materials through the U.S. Navy and Marine Corps,reaction with their environmentair, surprisingly the worlds second largestwater, an electrolyte like salt water, or air force, corrosion costs US$3.6 billionother materials. U.S. Military assets annually and accounts for roughlyoperate in the harshest environments 30 percent of maintenance costs. freshwater, salt water and oceanic moisture. In the presence of these Truth is corrosion cannot be prevented,liquid electrolytes, dissimilar materials especially not in the harsh navalwith differing electric potentials in environments. NACE International, thecontact (either directly or indirectly) global corrosion authority, puts theare prone to galvanic corrosion. In annual cost of corrosion at US$2.5simple terms, galvanic corrosion is trillion worldwide and US$250 billion inelectric corrosion. One metal acts as an the U.S. But the cadmium andanode corroding quickly while the chromates that provide corrosionother acts as a cathode with slower protection are being phased out due tocorrosion. environmental concerns. The use of dissimilar materials such as carbon fiberToday, most corrosion resistant design composites and aluminum in theis done using the galvanic seriespresence of electrolytes creates galvanictables and charts ranking materials by corrosion, a problem that causestheir electric potential based on half-around 80 percent of structural failurecentury old materials and data. The in military aviation, and putting aircraftgalvanic potential difference between out of service for 25-30 days annually.the materials causes one to act as anode accelerating corrosion. Designers But 25-30 percent of these corrosionuse the tables to choose materials and issues could be avoided with bettercoatings based on their potential to corrosion management practices andcorrode. material selection. In monetary terms, thats a whole lot of dollars. Promising?But the data from these tables is less of Yes. But the current design guidelinesa science and more of a suggestion. and military standards are based onWhy? The potential is measured only for outdated science and data that areindividual metals, not accounting for inadequate for addressing modernother metals in proximity. The materials and their corrosive behavior. electrochemical kinetics, electrolyte composition and temperature are not The U.S. Military clearly has a problemconsidered. Meanwhile, aerospacetackling the colossal cost of corrosion.materials and coatings are constantly The solution? An unlikely ally inevolving to meet performance and Corrdesa, a small, 8-person companyenvironmental requirements.9'