Answer:
Ps=19.62N
Explanation:
The detailed explanation of answer is given in attached files.
3. An underground copper pipe is used to transport oil under a factory. It is very important that this pipe does not oxidize, so
1 answer:
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Answer:
the life (N) of the specimen is 46400 cycles
Explanation:
given data
ultimate strength Su = 1600 MPa
stress amplitude σa = 900 MPa
to find out
life (N) of the specimen
solution
we first calculate the endurance limit of specimen Se i.e
Se = 0.5× Su .............1
Se = 0.5 × 1600
Se = 800 Mpa
and we know
Se for steel is 700 Mpa for Su ≥ 1400 Mpa
so we take endurance limit Se is = 700 Mpa
and strength of friction f = 0.77 for 232 ksi
because for Se 0.5 Su at cycle = (1600 × 0.145 ksi ) = 232
so here coefficient value (a) will be
a =
a =
a = 2168.3 Mpa
so
coefficient value (b) will be
a = -log
b = -log
b = -0.0818
so no of cycle N is
N =
put here value
N =
N = 46400
the life (N) of the specimen is 46400 cycles
Answer:
The endurance strength for the rod is 434.6 MPa
Explanation:
Since the rod is used in rotating bending, we need to use Marin equation given by
Here S stands for the endurance strength for rotating bending, is the endurance strength, and
are the parameters for Marin surface modification factor.
Endurance strength.
We can start finding the endurance strength, from the directions we know that the hardness was found to be 300 Brinell, thus for such value we can find the ultimate tensile strength using
Replacing the hardness we get
Now since the ultimate tensile strength has a value less than 1400 MPa, we can find the endurance strength using
Replacing the tensile strength we get
Parameters for Marin surface modification factor.
From the directions we know that the drill rod has a ground surface finish, so then from tables we get
Thus the surface factor will be
Replacing values and the ultimate tensile strength
Then we can find the rotating shaft factor, for a diameter of 10 mm, we can use the equation
Replacing the diameter we get
Estimating endurance strength for rotating shaft.
We can replace now all values we have found in Marin equation.
Thus the endurance strength for the rod is 434.6 MPa