SEDL / STP / STP877-EB / STP32879S

Development of an Automated Fatigue Crack Propagation Test System

Vecchio, RS
Lucius Pitkin, Inc., New York, NY

Jablonski, DA
Instron Corp., Canton, MA

Lee, BH
Instron Corp., Canton, MA

Hertzberg, RW
Materials Research Center, Lehigh University, Bethlehem, PA

Newton, CN
Materials Research Center, Lehigh University, Bethlehem, PA

Roberts, R
Materials Research Center, Lehigh University, Bethlehem, PA

Chen, G
Materials Research Center, Lehigh University, Bethlehem, PA

Connelly, G
Materials Research Center, Lehigh University, Bethlehem, PA

Pages: 23    Published: Jan 1985

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Abstract

An automated fatigue crack growth rate test system was developed to characterize the crack growth response of engineering materials as a function of the applied stress-intensity range. The test system utilizes DEC PDP 11 series minicomputers and a software feedback control loop to control testing at frequencies up to 100 Hz. Additional system flexibility is provided in its three control modes: constant-load amplitude, constant ΔK, and variable-ΔK test capabilities.

A comparison of crack growth rate data obtained using this automated system is made with data generated under manually controlled test conditions, for aluminum and steel alloys, and for engineering plastics.