Foundations of Materials Science and Engineering
6th Edition
ISBN: 9781259696558
Author: SMITH
Publisher: MCG
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Chapter 7.10, Problem 50SEP
To determine
The effect of drilling a small hole just ahead of the crack-tip.
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A specimen of a ceramic material having an elastic modulus of 250 GPa (36.3 x 106 psi) is pulled in tension with a stress of 750 MPa (109,000 psi). Will the specimen fail if its “most severe flaw” is an internal crack that has a length of 0.20 mm (7.87 x 10-3 in.) and a tip radius of curvature of 0.001 mm (3.94 x 10-5 in.)? Why or why not?
Given your understanding of what initiates and controls failure in materials, which of the following will increase the failure strength or lifetime
of a test piece or component and why?
a. Polishing to reduce surface defects
b. Decreasing the temperature below the brittle-ductile transition temperature, to make it harder
C. Increasing its volume, to give a larger cross sectional area
d. Increasing the grain size so there are less grain boundaries to initiate failure
e. Decreasing the difference between the maximum and minimum stress values, as this effects the stress concentration factor
Which of the following statements are true?
(This question has more than one correct answer)
a. You should always apply safety factors when setting a materials specification
b. You should always design in small radii of curvature at profile changes
c. Crack propagation in ductile materials occurs when the stresses at the crack tip are greater or equal to the yield strength of
the material
d. The stress concentration factors for ductile materials are greater than expected
e. The stress concentration factors for brittle materials are less than expected
f. Crack propagation in brittle materials occurs when the stresses at the crack tip are greater or equal to the failure strength of
the material
Chapter 7 Solutions
Foundations of Materials Science and Engineering
Ch. 7.10 - What are the characteristics of the surface of a...Ch. 7.10 - Prob. 2KCPCh. 7.10 - Prob. 3KCPCh. 7.10 - Prob. 4KCPCh. 7.10 - Prob. 5KCPCh. 7.10 - Prob. 6KCPCh. 7.10 - Prob. 7KCPCh. 7.10 - Prob. 8KCPCh. 7.10 - Prob. 9KCPCh. 7.10 - How does the carbon content of a plain-carbon...
Ch. 7.10 - Describe a metal fatigue failure.Ch. 7.10 - What two distinct types of surface areas are...Ch. 7.10 - Prob. 13KCPCh. 7.10 - Prob. 14KCPCh. 7.10 - Prob. 15KCPCh. 7.10 - Describe the four basic structural changes that...Ch. 7.10 - Describe the four major factors that affect the...Ch. 7.10 - Prob. 18KCPCh. 7.10 - Prob. 19KCPCh. 7.10 - Prob. 20KCPCh. 7.10 - Prob. 21KCPCh. 7.10 - Determine the critical crack length for a through...Ch. 7.10 - Determine the critical crack length for a through...Ch. 7.10 - The critical stress intensity (KIC) for a material...Ch. 7.10 - What is the largest size (in mm) of internal...Ch. 7.10 - A Ti-6Al-4V alloy plate contains an internal...Ch. 7.10 - Using the equation KIC=fa, plot the fracture...Ch. 7.10 - (a) Determine the critical crack length (mm) for a...Ch. 7.10 - A fatigue test is made with a maximum stress of 25...Ch. 7.10 - A fatigue test is made with a mean stress of...Ch. 7.10 - A large, flat plate is subjected to...Ch. 7.10 - Prob. 32AAPCh. 7.10 - Refer to Problem 7.31: Compute the final critical...Ch. 7.10 - Prob. 34AAPCh. 7.10 - Prob. 35AAPCh. 7.10 - Equiaxed MAR-M 247 alloy (Fig. 7.31) is used to...Ch. 7.10 - Prob. 37AAPCh. 7.10 - If DS CM 247 LC alloy (middle graph of Fig. 7.31)...Ch. 7.10 - Prob. 39AAPCh. 7.10 - Prob. 40AAPCh. 7.10 - Prob. 41SEPCh. 7.10 - Prob. 42SEPCh. 7.10 - A Charpy V-notch specimen is tested by the...Ch. 7.10 - Prob. 44SEPCh. 7.10 - Prob. 45SEPCh. 7.10 - Prob. 46SEPCh. 7.10 - Prob. 47SEPCh. 7.10 - Prob. 48SEPCh. 7.10 - Prob. 49SEPCh. 7.10 - Prob. 50SEPCh. 7.10 - While driving your car, a small pebble hits your...Ch. 7.10 - Prob. 52SEPCh. 7.10 - Prob. 53SEPCh. 7.10 - Prob. 54SEPCh. 7.10 - Prob. 56SEPCh. 7.10 - Prob. 57SEPCh. 7.10 - Prob. 58SEPCh. 7.10 - Prob. 59SEPCh. 7.10 - The components in Figure P7.60 are high-strength...
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