Engineering Materials Ch 4

The flashcards below were created by user jpridgeon517 on FreezingBlue Flashcards.

1.             is defined as the resistance of a material to external elements such as force, load, or weight measured in pounds per square inch (PSI).
Stress
2.               is the amount of deformation or stretch that occurs over a standard gage length (2") expressed in inches or a percentage.
Strain
3. Stress is equal to                 divided by          .
• Applied force
• Cross-sectional area
4. Strain is equal to              divided by             .
• deformation
• original length
5. The four types of stress involved in strengths of materials are:
a. tension

b. compression

c. torsion

d. shear
6. The primary objective of the tensile test is to determine the                  a specimen can resist before taking a                set or before         occurs.
7.              materials will neck down through the plastic range before rupture occurs.
Ductile
8.               materials do not neck down significantly; instead, they fail sharply and abruptly at the maximum load(because brittle materials do not exhibit much plasticity).
Brittle
9. Proportional Limit
the stress value at which the elastic portion of the curve loses it's proportionality between stress and strain
10. Yield Stress
the top of the elastic region, where the amount of strain increases with little increase in stress.
11. Tensile strength
maximum load divided by original area.
12. Percent Elongation
• Lf = length at fracture
• Lo = length original
13. Percent Reduction of Area
(Ao-Af/Ao)x100

Ao=Area of original cross section

Af=Area of final cross section
14. Modulus of Elasticity
is a measure of the ability of a material to withstand changes in length when under lengthwise tension or compression.
15. Ductility
the property that allows a material to deform permanently, under tension.
16. Malleability
the property that allows a material to deform permanently, in compression.
17. Plasticity
the ability of a metal to be deformed permanently, without failing.
18. Creep
The plastic deformation resulting from the application of a long-term load.

is a slow, but steadily increasing strain applied to a material under load.

is important in structures as bridges, buildings and other load-bearing structures in which the members are subjected to long-term static loads.
19. Hardness
is generally referred to as a material's property that indicates resistance to surface penetration

may be either static or dynamic.

is measured by resistance to indentation.
20. Common static hardness tests:
Brinell

Rockwell

Vickers
21. The             hardness test is the oldest and most established method.
Brinell
22. Rockwell Scales
B - for testing materials of medium hardness.

C - for testing very hard materials.
23.                  hardness testers are indentation tests and depend on the calculation of energy absorbed by the specimen during the test.
Dynamic
24. The general outcome of an impact test is the determination of the energy required to           the specimen.
break
25.                   is an indication of how well a material can withstand shock loading.
Impact stregth
26.                is used to measure the transfer of energy required to break a given volume of material.
Impact testing
27. Two common forms of impact testing are:
Izod

Charpy
28.              is defined as the failure of a material due to repeated or cyclic stresses being applied to it.
Fatigue
29.                  is the stress at which a material fails by fatigue.
Fatigue strength
30. Three factors affecting fatigue are:
Temperature

Composition and structure of the material

Imperfections such as surface scratches, notches, inclusions, and other defects that can help initiate cracking.
31. NDT stands for
Non-Destructive Testing
32. NDT is typically used to identify defects such as                          , or              that might lead to the failure of the part.
voids, inclusions, cracks
33. Four types of NDT testing are:
magnetic particle

flourescent penetrant

x-ray

Ultrasonic
34.                   is an applied force that acts in a direction parallel to the plane in which the force is applied.
shearing stress
35. Direct shearing occurs when parallel forces are applied in opposite directions.

Single-shear forces occur along a            plane.

Double-shear forces occur between               planes simultaneously.
single, two
36. When a material is bent or flexed under a load, a portion of the cross section is under        and a portion is under              .
tension, compression
37. Somewhere between these two opposing forces is a              line, or axis, separating the forces. Along this axis, the specimen is                        in tension nor in compression.
neutral, neither
38. The                   of a beam is the displacement of a point on the neutral surface of a beam from its original position under the action of applied loads.
deflection
39. Compression
tends to compact or squeeze the specimen.
40. Torsion
uses a twisting motion to test the strength of the specimen.
41. Non-Destructive Testing
does not render the part unusable for its intended purpose.
42. Shear
applies force perpendicular to the primary axis of the part.
43. Hardness
measures the resistance to surface penetration.
44. Flexure
most commonly used to determine the cross-sectional geometry for a given application.
45. Fatigue
uses repeated, cyclic motions to determine the point of failure for a given part or specimen.
46. Creep
conducted over a very long period of time.
47. Tensile
tends to pull the specimen apart.
48. Impact
used to measure the transfer of energy required to break a specimen.
 Author: jpridgeon517 ID: 201510 Card Set: Engineering Materials Ch 4 Updated: 2013-02-19 16:58:10 Tags: Study Guide Folders: Description: blah, blah, blah Show Answers: