chapter 9 Flashcards

1
Q

mechanical responses of structures are related to

A

injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

when external forces imposed are resisted by internal forces it causes

A

deformation of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

external applied load: stress
deformation caused: ___

A

strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

mechanical stress

A

how an applied force is distributed over the body it acts on

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

cross-sectional area: the force is the resultant of the

A

intermolecular bond forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

the cross-sectional area of the imaginary plane is the area over which ____ force is applied

A

internal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

3 principal stresses depending on applied loading

A

tension, compression, shear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

axial stress

A

external forces act perpendicular to the analysis plane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

uniaxial load

A

external forces are colinear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

tensile stress occurs at the _____ as a result of a force or load pulling the molecules apart at that plane

A

analysis plane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

tension causes body to deform by

A

stretching (elongating)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

bone cross-sectional area depends on

A

plane of analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

larger cross-sectional area=___stress

A

lower

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

smaller cross-sectional area=___stress

A

higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

cross sectional area: 1cm^2
tensile force applied: 700,000N
what is the max tensile stress

A

7GPa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

compressive stress occurs at the analysis plane as a result of ______ at that plane

A

a load squeezing the molecules together at that plane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

compression causes body to deform by shortening or elongating

A

shortening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

shear stress is a ____ stress

A

transverse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

shear stress acts parallel to____as a result of non-collinear forces sliding molecules at that plane

A

analysis plane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

sprains are in ____
strains are in ____

A

ligaments/tendons
muscle/cartilage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

compression is

A

bruises of soft tissue, crushing fracture of bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

shear is

A

blisters on skin, joint dislocation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

when external forces are not uniaxial more complex loading occurs as (3)

A

bending, torsion, combined loads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

complexity of loading reflects ___, ___ and ___ of external forces imposed

A

number, direction and location

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

bending load

A

nonaxial
tension and compression produced at the analysis plane from 3 or more forces creating force couples at opposite ends of the object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

bending loads cause the body to deform by

A

curving

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

torsion load

A

nonaxial
shear stress acts parallel to the analysis plane as a result of opposing torques applied about the long axis of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

torsion causes body to deform by

A

twisting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what resists torsion

A

tubular and hollow cross-section of bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

combined loading

A

bones under complex loading from gravity, tendons ligament and other bones, contact forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

sustained loading a combination of

A

tension, compression, simple shear loads, bending, torsion

32
Q

strain quantifies the materials ____

A

deformation

33
Q

linear strain

A

change in an objects length

34
Q

linear strain produced by

A

tensile or compressive stress

35
Q

change in orientation of an objects molecules

A

shear strain

36
Q

shear strain produced by

A

shear stress

37
Q

liner strain deformation by

A

tensile or compressive stress (change in length)

38
Q

linear strain reported in ____ terms, describing change in length

A

absolute

39
Q

linear strain reported in ____ as proportional length change

A

relative

40
Q

unit of linear strain

A

dimensionless; is a ratio

41
Q

poissons ratio

A

width of an object also changes as it lengthens or shortens

42
Q

poissons ratio range

A

.1 to .5

43
Q

stress-strain relationship describes

A

behavior of material under load

44
Q

elastic behavior

A

material deforms and returns to original length when unloaded

45
Q

plastic behavior

A

material deforms but doesn’t return to original length
permanent deformation

46
Q

slope of the stress-strain curve

A

elastic modulus

47
Q

stiff material: ___ strain per unit of stress (___ E)

A

less, large

48
Q

pliant material: ___ strain per unit of stress (___ E)

A

more, low

49
Q

elastic limit

A

the yield point for a material on the o/e curve

50
Q

stress above the elastic limit causes

A

permanent deformatin

51
Q

example of plastic behavior

A

ankle sprain; ligaments get stretched and dont hold the bones together as closely as they once did

52
Q

mechanical strength of a material

A

max stress a material can withstand before failure

53
Q

yield strength

A

stress at the elastic limit
disruption of internal organization

54
Q

max stress material can withhold
material starts to give away

A

ultimate strength

55
Q

stress level where total failure occurs
breakage or complete rupture of materialfailure strength

A

failure strength

56
Q

strain exhibited when ____ occurs

A

total failure

57
Q

ductile material exhibits a ____ failure strain

A

large

58
Q

brittle material

A

exhibits a low failure strain
deforms minimally before giving away

59
Q

toughness

A

ability of a material to absorb energy before failure

60
Q

are bones or ligaments/tendons tougher

A

ligaments/tendons

61
Q

active element of connective tissue

A

muscle

62
Q

passive elements of connective tissue

A

bone, cartilage, ligament, tendon

63
Q

____ is very stiff while ___ is pliant

A

collagen, elastin

64
Q

failure strain of collagen

A

8-10%

65
Q

failure strain of elastin up to ___%

A

160

66
Q

isotropic

A

stiffness similar in different directions

67
Q

stiffness dependent on load direction

A

ansiotropic

68
Q

bone: ___% mineral, ____% collagen, ___% water

A

45, 30-35, 20

69
Q

strongest and stiffest material in musculoskeletal system

A

bone

70
Q

bone strength affected by rate of

A

loading

71
Q

cartilage: ___% water, ___%collagen

A

60-80, 10-30

72
Q

what cartilage covers bone ends at joints

A

hyaline (articular) cartilage

73
Q

fibrous connective tissue specialized in

A

joints

74
Q

tendons and ligaments: ___% water, ___%collagen

A

70, 25

75
Q

do ligaments or tendons have more elastin

A

ligaments

76
Q

what determines muscle stiffness

A

active component, sarcomere

77
Q

tendons and ligaments collagen fibers in bindles aligned with

A

functional axis