Technical University of Munich (TUM) is leveraging its powerful VABS software to accelerate design of composite helicopter rotor blades.
According to AnalySwift, TUM has used VABS for a variety of projects, including the Autonomous Rotorcraft for Extreme Altitudes (AREA) research project, in its Institute of Helicopter Technology, which is part of the Department of Mechanical Engineering.
AnalySwift explains that researchers at TUM, under the AREA project, used VABS to help in the design of a new rotor blade for a rotary-wing UAV (MTOW 30kg), which can operate at extreme altitudes (up to 9,000 meters). The main objective of this project is to gain knowledge during high altitude flight-tests about the performances and the autonomous flight control system. A secondary objective is to discover possible application scenarios such as environmental monitoring and search and rescue. According to the researchers, these types of rotary UAVS have been previously unavailable, due in part to several design challenges.
“The AREA rotor blade was completely designed, built and tested at the Institute of Helicopter Technology at the Technical University of Munich,” said Tobias Pflumm, PhD student at TUM. “The use of VABS has been a major part of my work on the design of helicopter blades. With VABS the determined sectional centre of mass, shear centre, stiffness and mass properties were fed back to the elastic beam CAMRAD II helicopter model of the UAV. The resulting sectional loads were transformed back into VABS to examine corresponding strains and stresses within the material frame for the application of composite failure criteria.”
“The preliminary design with VABS was followed by a detailed design of sub-components, as well as the design of the rotor blade’s moulds and construction documents,” said Pflumm. “To ensure safe operations appropriate test procedures such as computer tomography, three-point bending test of the homogeneous blade section, a pure tensile test to examine the bearing laminate strength as well as a combined load case with axial and flap loading and a pull out test of the balance chamber were performed. Last but not least, an analysis of the rotor blade eigenfrequencies was conducted with accelerometers.”
This research related to the design and construction of a UAV rotor blade for use in extreme flight altitudes is highlighted in publications authored by Pflumm and his colleagues.
AREA rotor blade designed at TUM with the help of VABS. It has a NACA23012 airofil with a radius of R=1,65m, chord length=100mm, Twist=-10° and taper of 60%c starting at r=0.6.
“We have worked with Technical University of Munich for several years now and are pleased they selected VABS to assist in their composite blade simulation,” said Allan Wood, President and CEO of AnalySwift. “TUM is conducting exciting research to address the unique challenges of designing a composite rotor blade meant for high-altitude environments.”
“The VABS program is a uniquely powerful tool for modeling composite blades and other slender structures, commonly called beams,” said Dr. Wenbin Yu, CTO of AnalySwift. “VABS reduces analysis time from hours to seconds by quickly and easily achieving the accuracy of detailed 3D FEA with the efficiency of simple engineering models.
“With VABS, engineers can calculate the most accurate, complete set of sectional properties such as torsional stiffness, shear stiffness, shear centre for composite beams made with arbitrary cross section and arbitrary material,” said Yu. “It can also predict accurate detailed stress distribution for composite beams.”
With continuous development spanning 20 years for performance and robustness, AnalySwift explains that VABS is used in the aerospace and wind energy industries for modeling complex composite rotor blades, wing section design, and simulating other slender composite structures. Developed at Georgia Institute of Technology (Georgia Tech) and Utah State University, VABS is available through AnalySwift at analyswift.com.
CAMRAD II is an aeromechanics analysis that incorporates a combination of advanced technologies (including multibody dynamics, nonlinear finite elements, and rotorcraft aerodynamics) to produce results for performance, loads, vibration, and stability of rotors and rotorcraft. CAMRAD II was developed by Dr. Wayne Johnson, and is distributed by Analytical Methods.