Portions of the article describe work that was funded by the U.S. Naval Air Command. The program paired VEXTEC's probabilistic modeling capability (called Virtual Life Management or VLM) with Purdue's CAPRI software, which models local surface stresses near contact points. Chrysler provided an extensive amount of test data of 9310 case hardened sun gears that were subjected to many demanding cycles on a dynamometer. Although designed to industry standards, about 4% of tested gears showed pitting damage. VEXTEC's simulations also showed that 4% of gears would suffer pitting damage.
The Navy was interested in using the VLM approach to analyze helicopter gears, which were made of Pyrowear 53. Notched, three-point bend data from technical reports were used to calibrate the model. Analysis was then performed on baseline gears, and those which had been superfinished to a very smooth surface. Virtual Life Management showed that superfinishing more than doubled gear life.
The goal of the program was to develop a model that could quickly evaluate changes in design, material or processing. This was accomplished with probabilistic models that simulated the actual failure process. The benefits of this approach include (1) Reduced physical testing, (2) Accelerated research and development plus reduced time to market, and (3) Reduced warranty costs due to increased accuracy of life calculations. This approach can be used on all kinds of components, not just gears. To date it has been used in the aerospace, automotive, defense, electronics and medical device industries.
The article may be viewed at http://www.gearsolutions.com/
VEXTEC (http://vextec.com) was founded in 2000 and has developed its patented technology on virtual material modeling and predicting product durability. VEXTEC offers its Virtual Life Management (VLM) Services, to a variety of commercial and government customers. In addition, it also provides failure analysis and component re-design services through its VFA Engineering Group (http://failure-