What is the reason for the development of new construction of materials for human use? (Select all that apply.)
1 answer:
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Answer:
yield strength before cold work = 370 MPa
yield strength after cold work = 437.87 MPa
ultimate strength before cold work = 440 MPa
ultimate strength after cold work = 550 MPa
Explanation:
given data
AISI 1018 steel
cold work factor W = 20% = 0.20
to find out
yield strength and ultimate strength before and after the cold-work operation
solution
we know the properties of AISI 1018 steel is
yield strength σy = 370 MPa
ultimate tensile strength σu = 440 MPa
strength coefficient K = 600 MPa
strain hardness n = 0.21
so true strain is here ∈ = = 0.223
so
yield strength after cold is
yield strength =
yield strength =
yield strength after cold work = 437.87 MPa
and
ultimate strength after cold work is
ultimate strength =
ultimate strength =
ultimate strength after cold work = 550 MPa
Answer:
equivalent stiffness is 136906.78 N/m
damping constant is 718.96 N.s/m
Explanation:
given data
mass = 120 kg
amplitude = 120 N
frequency = 320 r/min
displacement = 5 mm
to find out
equivalent stiffness and damping
solution
we will apply here frequency formula that is
frequency ω = ω(n) √(1-∈ ²) ......................1
here ω(n) is natural frequency i.e = √(k/m)
so from equation 1
320×2π/60 = √(k/120) × √(1-2∈²)
k × ( 1 - 2∈²) = 33.51² ×120
k × ( 1 - 2∈²) = 134752.99 .....................2
and here amplitude ( max ) of displacement is express as
displacement = force / k × ( )
put here value
0.005 = 120/k × ( )
k ×∈ × √(1-2∈²) = 1200 ......................3
so by equation 3 and 2
solve it and we get
∈ = 1.00396
and
∈ = 0.08869
here small value we will consider so
by equation 2 we get
k × ( 1 - 2(0.08869)²) = 134752.99
k = 136906.78 N/m
so equivalent stiffness is 136906.78 N/m
and
damping is express as
damping = 2∈ √(mk)
put here all value
damping = 2(0.08869) √(120×136906.78)
so damping constant is 718.96 N.s/m