Mechanics

Front 1

Steps for FBDs

Back 1

1) Select system.

2) Replace all other objects by the forces/ moments they exert on the system.

Front 2

Basic Problems of M.O.M.

Back 2

1) Is it strong enough?

2) Is it stiff enough?

Front 3

Statically Determinate Structure.

Back 3

A structure for which the equations of statics are sufficient for calculation of the external loads on members.

Front 4

Statically Indeterminate Structure

Back 4

A structure for which the equations of statics are not sufficient for calculation of the external loads on the member.

Front 5

Stress

Back 5

Force/Area (Force per unit area).

Front 6

Normal Stress

Back 6

Stress perpendicular to some specified surface.

Front 7

Extensional Strain

Back 7

Epselon = delta/L

(Elongation/Original length)

Front 8

1 Ksi

Back 8

Kip/in^2

Front 9

Pascal

Back 9

N/m^2

Front 10

Nominal stress(conventional,Engineering)

Back 10

Force/Original area.

Front 11

True stress

Back 11

Force/ true area.

Front 12

Sign convention

Back 12

Tensile stress and strain are positive compressive are negative.

Front 13

Elastic limit

Back 13

Max stress that can be applied without permanent deformation.

Front 14

Hooke's law

Back 14

For many materials strain is proportional to stress, for low values of stress.

Front 15

Proportional limit

Back 15

Maximum stress for which stress is proportional to strain.

Front 16

Modulus of elasticity

Back 16

E = stress/strain.

Front 17

Plastic deformation

Back 17

Deformation that remains after a load is removed.

Front 18

Ductility

Back 18

Capacity for significant plastic deformation prior to fracture.

Front 19

Creep

Back 19

Continued plastic deformation under a constant load.

Front 20

Fatigue

Back 20

Failure associated with cyclic loading.

Front 21

Poisson's ratio

Back 21

Nu = - latitudinal strain/longitudinal strain

Front 22

Range of poisson's ratio

Back 22

1/4<1/3

Front 23

Hooke's law for shear.

Back 23

G = Tao/gamma

Front 24

Modulus of rigidity.

Back 24

G = E/(2(1 + Nu))

Front 25

Normal load names

Back 25

Allowable, working, design.

Front 26

Factor of safety

Back 26

Failure stress/Design stress.

Front 27

Deflection for a uniform axially loaded member.

Back 27

Del = PL/AE

Front 28

Principal planes

Back 28

The planes of sigma max, sigma min, and Tao = 0

Front 29

Tao max occurs on?

Back 29

A plane that is 45° from the planes of sigma max and sigma min.

Front 30

Tao max (In-plane)

Back 30

Front 31

Tao max

Back 31

Front 32

Sigma (p1,p2)

Back 32

Front 33

Sigma(n)

Back 33

Front 34

Tan(2theta(p))

Back 34