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Prevention of Fatigue Crack Growth
Abstract Materials engineering plays a crucial role in the design and production of parts for industrial applications. The mining industry is a dangerous example of industrial repetition and cyclic loading. When improper materials are selected, fatal outcomes can result, such as the accident at the Markham Colliery in 1973. The Markham Colliery was one of 14 producing mines in North Derbyshire, England, and during the time of the accident it output 30,000 tons of coal per week and employed nearly 2,300 men. Due to the complete failure the mechanical braking system of the winding engine, which transported men and materials up and down one of the shafts, 18 men lost their lives and several others were seriously injured. This accident occurred because the braking system was not properly designed. Operation of the brake over its lifetime produced higher than estimated bending forces on the system and induced fluctuating stresses on the braking rod that it could not sustain. Crack propagation developed in the rod due to bending stresses and eventually extended until fracture occurred, sending the cage of men to the bottom of the shaft at nearly 30 miles per hour. This paper examines the loading situation and presents a solution in regards to materials engineering, which would have prevented accident. Based on the loading conditions of the rod and its environment, SAE 4320 type steel that’s undergone a heat treatment will exhibit the most desirable properties. This carbon steel will show significantly decreased intergranular fatigue crack initiation and higher bending fatigue resistance.
Introduction The Markham Colliery operated year round from 1913 to 1986 and was one of England’s premier mining operations. In 1973, 18 men lost their lives at the Markham Colliery due to a braking system failure in one of the descending shaft cages. The braking rod mechanism became progressively cracked due to fatigue
Abstract Materials engineering plays a crucial role in the design and production of parts for industrial applications. The mining industry is a dangerous example of industrial repetition and cyclic loading. When improper materials are selected, fatal outcomes can result, such as the accident at the Markham Colliery in 1973. The Markham Colliery was one of 14 producing mines in North Derbyshire, England, and during the time of the accident it output 30,000 tons of coal per week and employed nearly 2,300 men. Due to the complete failure the mechanical braking system of the winding engine, which transported men and materials up and down one of the shafts, 18 men lost their lives and several others were seriously injured. This accident occurred because the braking system was not properly designed. Operation of the brake over its lifetime produced higher than estimated bending forces on the system and induced fluctuating stresses on the braking rod that it could not sustain. Crack propagation developed in the rod due to bending stresses and eventually extended until fracture occurred, sending the cage of men to the bottom of the shaft at nearly 30 miles per hour. This paper examines the loading situation and presents a solution in regards to materials engineering, which would have prevented accident. Based on the loading conditions of the rod and its environment, SAE 4320 type steel that’s undergone a heat treatment will exhibit the most desirable properties. This carbon steel will show significantly decreased intergranular fatigue crack initiation and higher bending fatigue resistance.
Introduction The Markham Colliery operated year round from 1913 to 1986 and was one of England’s premier mining operations. In 1973, 18 men lost their lives at the Markham Colliery due to a braking system failure in one of the descending shaft cages. The braking rod mechanism became progressively cracked due to fatigue
References: [1] Demaid, Adrian. "Case Histories Involving Fatigue and Fracture Mechanics." The Markham Mine Disaster. 1986. [2] Calder, J.W. "Accident at Markham Colliery Derbyshire." London: 1793. [3] Wise, J.P. "Microstructure and Fatigue Resistance of Carburized Steels." Golden, Colorado: 2000. [4] Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness of Metallic Materials. A.S.T.M.West Conshohocken, PA: 2013. [5] Standard Practice for Statistical Analysis of Linear or Linearized Stress-Life and Strain-Life Fatigue Data. A.S.T.M.West Conshohocken, PA: 2013. [6] "SAE 4320." Steel Grades. SteelGrades.com, n.d. Web. 3 Dec 2013. .