KARI is the leading national institute in researching and developing technology related to the aerospace industry. The main role of the rotor technology team in KARI is to develop rotor systems for aircrafts, as well as to research technology related to rotorcrafts, such as those used in helicopters. Using CAE software, the team is able to perform structural analyses, especially geometrically nonlinear analysis and dynamic analysis, for both design examination and experiment preparation.

The technology of rotor systems is developing fast

As time goes on, the KARI rotor technology team has obtained a more practical know-how of their rotor system’s development coupled with leading technology capabilities. “We have done projects on semi-torque systems, next generation rotor systems, performance improvements for rotors of unmanned helicopters, hub developments for bearingless rotors and so forth. We have also conducted research on aerodynamics and noise, structural dynamics, as well as test and evaluation methodologies,” explained Tae-Joo Kim, senior researcher of KARI rotor technology team.

“The technology of rotor systems is developing fast. From articulated rotors to hingeless rotors and bearingless rotors, the weight of these products is becoming lighter and the cost and installation time is steadily becoming lower. The rotor technology team has been putting tremendous effort into continuously researching core technologies in the rotor industry, as well as attempting to localize these technologies. We currently possess the same technology as that of many developed countries,” said Kim.

Incomparable nonlinear analysis experience with midas NFX

“For high speed rotors, experiments are conducted mainly based on fatigue and dynamic properties. Also as the usage of composite materials is gaining popularity in the industry, there have been requests regarding the effective design and evaluation of composite materials. CAE holds an important position here, not only in validating designs, but also in gathering data that helps to predict the result of the experiment before it is carried out,” explained Young-Joong Ki, senior researcher.

The rotor technology team uses midas NFX for dynamic analysis, to find solutions for reducing vibration and noise. “We started to use midas NFX in 2010, during the development of bearingless rotor hubs. At that time, we already had several CAE programs which were commonly used in the aerospace industry, but we decided to purchase midas NFX nonetheless. What convinced us of NFX’s capabilities was its outstanding technical support and attractive maintenance fee. midas NFX also has great speed and convergence performance for nonlinear analysis, which allows us to conduct geometrically nonlinear analyses in a much shorter time frame.”

“The interface of midas NFX is also very straightforward. Menus are composed in a way that users can easily access the necessary functions following the workflow of a typical analysis process. The analysis result is trustworthy and we have compared NFX’s analysis data with experimental data several times, mainly for static analysis and geometrically nonlinear analysis, and there is almost no difference in error. On top of that, if we factor in the price and the quality of technical and training support, there aren’t many other comparable software packages out there, which come close to NFX”, said Kim.

KARI rotor technology team plans to increase the usage of midas NFX in its new civil helicopter project. “We’re going to face many difficulties as we continue researching and developing in the rotor industry, but we think CAE technology can help us. That’s why we need to extend its usage and gain more knowledge on CAE tools. We look forward to attending more CAE training seminars from the NFX team, as well as communicating with other users to exchange the “know-hows” of the software with each other,” said Kim.