George Rankine Irwin facts for kids
George Rankin Irwin (born February 26, 1907 – died October 9, 1998) was an American scientist. He became very famous for his work on how materials break, a field called fracture mechanics. This science helps engineers understand how strong different materials are and how they might crack or snap.
Contents
Early Life and School
George R. Irwin was born in El Paso, Texas. His family later moved to Springfield, Illinois, where he went to school.
He attended Knox College in Galesburg, Illinois. He earned a degree in English in 1930. After studying physics for another year, he went to the University of Illinois at Urbana-Champaign from 1931 to 1935. He earned his Ph.D. (a high-level science degree) from the University of Illinois in 1937. His main research was about the weight of lithium isotopes (different forms of the same element).
Working as a Scientist
In 1937, George Irwin joined the US Naval Research Laboratory (NRL) in Washington D.C.. He worked there until 1967. At the NRL, he studied ballistics, which is the science of how projectiles (like bullets) move and hit targets. He figured out ways to measure the force a projectile uses to go through something. He did this important work during Second World War.
His research also helped create new types of nonmetallic armors, which are special protective materials. He noticed that even thick, bendy metals like steel could break suddenly during tests. This made him very interested in brittle fracture, which is when a material breaks without bending or stretching much first.
In 1946, he became in charge of the brittle fracture project at the NRL. He was promoted several times, becoming the superintendent of the Mechanics Division in 1950. He stayed in this important role until he retired from government service in 1967.
Understanding How Things Break
In the 1940s, scientists used ideas from A. A. Griffith to understand brittle fracture. Griffith's idea was that cracks in very brittle materials (like glass) would grow if the material's stored energy changed in a certain way. However, this idea didn't work well for all materials or for objects with different shapes.
Irwin noticed that when metals broke, some energy was used up in a non-elastic way at the tip of the crack. This means the metal changed shape permanently, not just temporarily. He used this observation to improve Griffith's idea. He added the idea of "plastic work of fracture," which is the energy used to permanently deform the material as a crack grows.
As part of this work, Irwin came up with a key idea called the Stress Intensity Factor. He also defined the critical plane-strain stress intensity factor (KIC). This KIC is a special number that tells you how much stress a material can handle before a crack starts to grow quickly. It's like a strength rating for materials when they have a crack.
He also helped create many standards and led committees for the American Society for Testing and Materials (ASTM). These standards help make sure materials are tested and used safely.
Later Career and Collaborations
In 1967, Irwin was invited to Lehigh University as a special professor. He worked with Paul C. Paris, who is known for predicting how cracks grow in aircraft. Irwin stayed at Lehigh for five years. During this time, he worked with many other important scientists in the field of fracture mechanics, including:
- F. Erdogan, on cracks in thin-walled structures.
- A. A. Wells, on how to describe breaking in steel structures that are usually bendy.
- F. A. McClintock and John W. Hutchinson, on how to understand fracture when materials bend a lot before breaking.
- James R. Rice, on a method called the J integral to figure out when cracks start to grow in bendy materials.
- L. B. Freund and M. F. Kanninen, on how cracks move and stop very quickly.
After retiring from Lehigh University in 1972, Irwin joined the University of Maryland, College Park. There, he continued his work on how cracks behave when they move very fast, called dynamic fracture. He especially looked at how to stop cracks and what this meant for safety in places like nuclear power plants.
Awards and Memberships
George Irwin was a member of the America National Academy of Engineering. He was also a Foreign Member of the Royal Society of London, which is a very old and respected scientific group.
He received many awards and honors throughout his career, including:
- 1946 - Naval Distinguished Civilian Service Award
- 1947 - Knox College Alumni Achievement Award
- 1959 - ASTM Charles B. Dudley Medal
- 1960 - RESA Award for Applied Research
- 1961 - Ford Foundation Visiting Professorship, University of Illinois
- 1966 - ASTM Award of Merit
- 1966 - American Society of Mechanical Engineers (ASME) Thurston Lecture
- 1967 - Fellow, ASTM
- 1969 - University of Illinois Engineering Achievement Award
- 1969 - U. S. Navy Conrad Award
- 1969 - Alumni Achievement Award, University of Illinois
- 1973 - SESA Murray Lectureship Award
- 1974 - Lehigh University Academic Leadership Award
- 1974 - ASTM honorary member
- 1974 - American Society for Metals Sauveur Award
- 1976 - The Grande Medaille Award of the French Metallurgical Society of France
- 1977 - ASME Nadai Award
- 1977 - B. J. Lazan Award from the Society for Experimental Mechanics
- 1977 - Honorary degree, doctor of engineering, Lehigh University
- 1977 - Election to the National Academy of Engineering
- 1978 - ASTM-Irwin Award
- 1979 - Francis J. Clamer Clauier Medal of the Franklin Institute
- 1982 - Governor’s Citation for Distinguished Service to Maryland
- 1982 - Tetmajer Award of the Technical University of Vienna, Austria
- 1985 - Fellow, Society for Experimental Mechanics
- 1986 - ASME Timoshenko Medal
- 1987 - ASM Gold Medal for Outstanding Contributions to Engineering and Science
- 1987 - Elected to foreign membership, British Royal Society
- 1988 - ASTM Fracture Mechanics Award and the George R. Irwin Medal
- 1989 - Honorary membership in Deutscher Verband für Material Prufung
- 1990 - Honorary membership in the American Ceramic Society
- 1990 - Albert Sauveur Lecture Award
- 1992 - George R. Irwin Research Award, University of Maryland
- 1993 - Engineering Innovation Hall of Fame at the University of Maryland
- 1998 - A. James Clark Outstanding Commitment Award University of Maryland
- 1998 - Appointed Glenn L. Martin Institute Professor of Engineering
