Compact Tension Specimen
The Compact Tension (CT) specimen is widely used in fracture mechanics to determine the fracture toughness of materials. Its design allows for the creation of a stress concentration at a crack tip, facilitating the study of crack propagation under controlled conditions.
Overview
Key Features:
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Geometry: A compact, rectangular specimen with a notch and holes for loading pins.
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Dimensions: Standardized by ASTM E399 for plane strain fracture toughness testing. Dimensions are proportional to the specimen thickness.
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Notch and Pre-crack: A sharp notch is machined, and often a fatigue pre-crack is introduced to simulate a natural crack.
Testing Procedure:
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Specimen Preparation: Notch and fatigue pre-crack are introduced.
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Mounting: Loading pins are inserted through the holes, and the specimen is placed in the testing machine.
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Loading: Tensile load is applied to open the crack.
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Measurements: Load versus displacement data is recorded to calculate the stress intensity factor K.
Applications:
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Determining plane strain fracture toughness KICK_{IC}KIC​ of materials.
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Evaluating crack growth resistance.
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Used in materials selection for critical components where fracture toughness is a key concern.