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Chapter 9 Fracture Testing
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Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Jan 22, 2016

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Mollie Pomfret
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Page 1: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Chapter 9Fracture Testing

Page 2: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

(a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen.

Impact TestingImpact TestingCharpy Impact Testing

Page 3: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Energy absorbed versus temperature for a steel in annealed and in quenched and tempered states. (Adapted with permission from J. C. Miguez Suarez and K. K. Chawla, Metalurgia-ABM, 34 (1978) 825 .)

Energy Absorbed vs. Temperature

Page 4: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Effect of temperature on the morphology of fracture surface of Charpy steel specimen. Test temperatures Ta < Tb < Tc < Td. (a) Fully brittle fracture. (b, c) Mixed-mode fractures. (d) Fully ductile (fibrous) fracture.

Temperature Effect on Fracture Appearance

Page 5: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Energy absorbed, cleavage area ,and lateral expansion as a function of temperature of testing for AISI 1018 steel (cold drawn).

Charpy Testing of Steel: DBTT

Page 6: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Drop-Weight Test Specimen

Page 7: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Charpy V-notch curve for a pressure-vessel steel. Note that the NDT temperature determined by the drop-weight test corresponds to the high-toughness region of the Charpy curve. Pneumatic pressurization; material: 21/4 Cr-1 Mo steel, yield stress 590 MPa. (After W. J. Langford, Can. Met. Quart., 19 (1980) 13.)

Charpy V-notch Curve for a Pressure Vessel Steel

Page 8: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

(a) Typical oscilloscope record of an instrumented Charpy impact test. (b) Schematic representation of (a).

Instrumented Charpy Test

Page 9: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Typical ASTM standard plane-strain fracture toughness test specimens. (a) Compact tension. (b) Bending. (c) Photograph of specimens of various sizes. Charpy and tensile specimens are also shown, for comparison purposes. (Courtesy of MPA, Stuttgart.)

Fracture Toughness Test Specimens

Page 10: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Schematic of typical load–displacement curves in a KIc test.

Load Displacement Curves vs. Fracture Toughness Test

Page 11: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Plastic zone at the x1 crack tip in a plate of finite thickness.

Plastic Zone at Crack Tip

Page 12: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Assembly for measuring displacement in a notched specimen.

Clip Gage for Displacement Measurement

Page 13: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Procedure for Measuring Conditional KQ

Page 14: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Checklist for the KIc Test

Page 15: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Variation in Kc with flaw size, specimen thickness, and specimen width.

Variation of Kc with Specimen Dimensions

Page 16: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Load vs. Crack Opening Displacement

Page 17: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Plastic Hinge Mechanism

Page 18: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Method for determining JIc. (a) Load identical specimens to differentdisplacements. (b) Measure the average crack extension by heat tinting. (c) Calculate J for each specimen. (d) Plot J versus a to find JIc.

J-Integral Testing

Page 19: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Normal stresses along a section of beam for a linearly elastic material.

Flexure Test

Page 20: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Application of load and bending moment diagrams for(a) three-point bending and (b) four-point bending tests.

Three-Point and Four-Point Bend (Flexure) Tests

TThree-Point

Page 21: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Shematic drawing of the miniaturized disk-bend test. (Adapted from H. Li, F. C. Chen, and A. J. Ardell, Met. Trans A, 22 (1991) 2061.)

Miniaturized Specimen:Four-Point Bending

Page 22: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Fracture-testing methods for brittle materials. (a) Double-cantilever beam (DCB). (b) Double torsion. (c) Notch flexure.(d) Chevron notch

Fracture Testing Methods for Ceramics

Page 23: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

(a) Schematic of the test arrangement and the details of the notch plane. (b) The chevron tip length, a0, can be measured from optical micrographs of broken specimens. (c) Chevron short-rod specimen.

Chevron Notch Test

Page 24: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Fractures produced by hardness indentations in (a) AsS3 glass (courtesy of B. R. Lawn and B. J. Hockey) and (b) Al2O3.

Hardness Indentation in Brittle Materials

Page 25: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Schematic representation of indentation generating a plastic deformation region and a semicircular crack.

Plastic Deformation and Crack in Indentation of Brittle Material

Page 26: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Comparison between conventional and indentation fracture toughness determinations for glasses and ceramics. (From G. R. Anstis, P. Chankitul, B. R. Lawn, and D. B. Marshall, J. Am. Cer. Soc., 64 (1981) 533.)

Fracture Toughness for Ceramics and Glasses Comparison of Results

Page 27: Chapter 9 Fracture Testing. (a) Charpy impact testing machine. (b) Charpy impact test specimen. (c) Izod impact test specimen. Impact Testing Charpy Impact.

Indentation tests for the determination of toughness of bond between substrate and thin film; (a) Method used for ductilecoating on brittle substrate (typicalof electronic components); (b) Method used for brittle coatingson ductile substrate; (c) Calculated normalized energy release rate as a function of normalized crack diameter.

(Adapted from J. J. Vlassak, M. D. Drory, and W. D. Nix, J. Mater. Res., 12 (1997) 100.)

Adhesion of Thin Film to Substrate: Testing