Page 319 - Materials Science and Engineering An Introduction

Questions and Problems • 291

Symbol Meaning
s 0 Applied tensile stress
s max Maximum stress (cyclic)
s min Minimum stress (cyclic)

Important Terms and Concepts
brittle fracture fatigue life Izod test
case hardening fatigue limit plane strain
Charpy test fatigue strength plane strain fracture
corrosion fatigue fracture mechanics toughness
creep fracture toughness stress raiser
ductile fracture impact energy thermal fatigue
ductile-to-brittle transition intergranular fracture transgranular fracture
fatigue

REFERENCES

ASM Handbook, Vol. 11, Failure Analysis and Prevention, Dieter, G. E., Mechanical Metallurgy, 3rd edition, McGraw-
ASM International, Materials Park, OH, 2002. Hill, New York, 1986.
ASM Handbook, Vol. 12, Fractography, ASM International, Esaklul, K. A., Handbook of Case Histories in Failure Analysis,
Materials Park, OH, 1987. ASM International, Materials Park, OH, 1992 and 1993.
ASM Handbook, Vol. 19, Fatigue and Fracture, ASM In two volumes.
International, Materials Park, OH, 1996. Hertzberg, R. W., R. P. Vinci, and J. L. Hertzberg, Deformation
Boyer, H. E. (Editor), Atlas of Creep and Stress–Rupture and Fracture Mechanics of Engineering Materials, 5th edi-
Curves, ASM International, Materials Park, OH, 1988. tion, Wiley, Hoboken, NJ, 2013.
Boyer, H. E. (Editor), Atlas of Fatigue Curves, ASM Liu, A. F., Mechanics and Mechanisms of Fracture: An
International, Materials Park, OH, 1986. Introduction, ASM International, Materials Park, OH, 2005.
Brooks, C. R., and A. Choudhury, Failure Analysis of McEvily, A. J., Metal Failures: Mechanisms, Analysis,
Engineering Materials, McGraw-Hill, New York, 2002. Prevention, Wiley, New York, 2002.
Colangelo, V. J., and F. A. Heiser, Analysis of Metallurgical Stevens, R. I., A. Fatemi, R. R. Stevens, and H. O. Fuchs,
Failures, 2nd edition, Wiley, New York, 1987. Metal Fatigue in Engineering, 2nd edition, Wiley, New
Collins, J. A., Failure of Materials in Mechanical Design, 2nd York, 2000.
edition, Wiley, New York, 1993. Wulpi, D. J., Understanding How Components Fail, 2nd edition,
Dennies, D. P., How to Organize and Run a Failure Investigation, ASM International, Materials Park, OH, 1999.
ASM International, Materials Park, OH, 2005.

QUESTIONS AND PROBLEMS
Problem available (at instructor’s discretion) in WileyPLUS
Principles of Fracture Mechanics 8.3 If the specific surface energy for aluminum oxide
2
8.1 What is the magnitude of the maximum stress is 0.90 J/m , then using data in Table 12.5, compute
that exists at the tip of an internal crack having a the critical stress required for the propagation of
–4
–6
radius of curvature of 1.9 10 mm (7.5 10 an internal crack of length 0.40 mm.
in.) and a crack length of 3.8 10 –2 mm (1.5 8.4 An MgO component must not fail when a tensile
–3
10 in.) when a tensile stress of 140 MPa (20,000 stress of 13.5 MPa (1960 psi) is applied. Determine
psi) is applied? the maximum allowable surface crack length if the
2
8.2 Estimate the theoretical fracture strength of a surface energy of MgO is 1.0 J/m . Data found in
brittle material if it is known that fracture oc- Table 12.5 may prove helpful.
curs by the propagation of an elliptically shaped 8.5 A specimen of a 4340 steel alloy with a plane strain
surface crack of length 0.5 mm (0.02 in.) and a tip fracture toughness of 54.8 MPa1m (50 ksi1in.)
–4
–3
radius of curvature of 5 10 mm (2 10 in.), is exposed to a stress of 1030 MPa (150,000 psi).
when a stress of 1035 MPa (150,000 psi) is applied. Will this specimen experience fracture if the largest