Nils Otto Myklestad (March 24, 1909 – September 23, 1972) was an American mechanical engineer and engineering professor. An authority on mechanical vibration, he was employed by a number of important US engineering firms and served on the faculty of several major engineering universities. Myklestad made significant contributions to both engineering practice and engineering education, publishing a number of widely influential technical journal papers and textbooks. He also was granted five US patents during his career.
Myklestad was employed in various technical capacities by AiResearch, North American Aviation, Westinghouse Electric, Fairbanks Morse, and Bell Helicopter Company. He served on the faculties of California Institute of Technology, University of California, Cornell University, Illinois Institute of Technology, University of Illinois, Arizona State University and the University of Texas at Arlington. He was elected fellow of the American Society of Mechanical Engineers (ASME) in 1967 and fellow of the American Association for the Advancement of Science (AAAS) in 1969.
Biography
Early career
Nils O Myklestad was born in 1909 in Williston, North Dakota, United States but returned with his family to Europe where he was schooled and spent his childhood and youth. In 1932, Nils Myklestad graduated from the Den Polytekniske Læreanstalt (College of Advanced Technology), now Technical University of Denmark in Copenhagen, Denmark with a BS in Engineering.
Shortly afterwards he returned to the United States and was employed as an engineer by Westinghouse and Fairbanks Morse, 1932 -1937. He joined the University of California Berkeley in 1937 serving as a Teaching Assistant until 1938. In 1940 he moved to Cornell University as an Instructor in Mechanics, and studying under James N. Goodier, earned a Ph.D. in Engineering Mechanics from Cornell in 1940. In 1940 N. O. Myklestad was appointed Assistant Professor of Machine Design at Illinois Institute of Technology where he served until 1942.
Work at Guggenheim Aeronautical Laboratory
From 1942 to 1945 he was the Research Associate in charge of Vibration and Flutter, Guggenheim Aeronautical Laboratory, California Institute of Technology. It was during this time that he made a number of significant contributions to the theory and practice of engineering. In 1944, he published “A New Method of Calculating Natural Modes of Uncoupled Bending Vibration of Airplane Wings and Other Types of Beams”. An efficient numerical method for finding the undamped natural frequencies and mode shapes of structures modeled with numerous beam and inertia elements, the tabular procedure became known as the Myklestad Method. This approach while more complex, is similar to methods developed earlier for torsional systems, and in the introductory sections of Myklestad's article the path-finding work of Heinrich Holzer is credited. In 1945, a similar numerical method was published by M. A. Prohl, "A General Method for Calculating Critical Speeds of Flexible Rotors". As a consequence the method is also often called the Myklestad-Prohl method or Prohl-Myklestad method. See also Rotordynamics.
In any event, the practical importance of the Myklestad Method established a worldwide reputation for its author and has been, and continues to be to this day, widely used for calculation of natural frequencies and normal modes of rotating and nonrotating beam structures. The method has been used in many different applications including vibration analysis of airplane wings and fuselages, helicopter rotor blades, wind turbine blades, naval ship hulls, and rocket powered launch vehicles. The following citation examples, of about 1000 from a Google book search on 'Myklestad Method', show not only the range of structures analyzed by this method but the time span of its use as well.
When matrix methods became popular, the Myklestad Method was recast into what became known as the transfer matrix method.
During the time he was employed at the Guggenheim Aeronautical Laboratory, he extended the Myklestad Method to include coupled bending-torsion vibration. and also developed one of the first efficient and numerically accurate methods of calculating the flutter speed of a multi-mass airplane wing model. This approach was used in the flutter analysis of both the B-36 bomber and the Hughes Aircraft Spruce Goose flying boat (Hughes H-4 Hercules). During this highly productive period he also published the first version of his popular book Vibration Analysis.