materials equations

Question 1

stress

Answer 1

force/cross sectional area

Question 2

strain

Answer 2

change in length/original length

Question 3

youngs modulus

Answer 3

stress/strain

Question 4

rigidity

Answer 4

EA

Question 5

stiffness

Answer 5

rigidity per unit length

k=F/change in length

Question 6

flexibilty

Answer 6

f=change in length/F

inverse of stiffness

Question 7

strain rate

Answer 7

change in strain/time

coeficient of viscosity (n)=stress/strain rate

Question 8

shear stress

Answer 8

shearing force/sheared area

Question 9

shear strain

Answer 9

angle sheared =x/d

Question 10

shear strength

Answer 10

shear force required to fracture/sheared area

Question 11

modulus of rigidity

Answer 11

shear stress/shear strain

Question 12

max shear stress

Answer 12

stress/2

Question 13

how are G and E linked

Answer 13

E/2 (1+v)

Question 14

variation in stress (bending)

Answer 14

stress = eE = y/rE

Question 15

bending moment

Answer 15

Mc=Fx

Question 16

bending strength

Answer 16

stress = eE=y/rE
Mmax = stress x I/y max

M/I = O/y = E/R

Question 17

shear stress (torsional)

Answer 17

G angel x r(ab)/L

Question 18

shear strain

Answer 18

angle r(ab)/l

Question 19

M applied twisting moment

Answer 19

J G angle of twist/L

M/J = Backwards J/R = G angle/L

Question 20

I for square and y max

Answer 20

bd3/12

1/2d

Question 21

i for circle and ymax

Answer 21

pie d4/64

1/2d

Question 22

i and y max for cylinder

Answer 22

pie/64 x (d4outer-d4inner)

1/2douter