Concept explainers
A plastic-lined steel pipe has the cross-sectional shape shown in the figure. The steel pipe has an outer diameter d1= 100 mm and an inner diameter d2= 94 mm. The plastic liner has an inner diameter d1= 82 mm. The modulus of elasticity of the steel is 75 times the modulus of the plastic.
- Determine the allowable bending moment Mallowif the allowable stress in the steel is 35 M Pa and in the plastic is 600 kPa.
i.
The allowable bending moment if the allowable stress for steel is 35 MPa and plastic 600 Kpa
Answer to Problem 6.2.8P
Allowable bending moment for plastic, Mallowableplastic = 1050.8 N-m
Allowable bending moment for Copper, Mallowablesteel =768.25 N-m
Explanation of Solution
Given:
Allowable stress for steel, ssteel = 35 MPa
Allowable stress for plastic, splastic= 600 kPa
d1= 82 mm
d2= 94 mm
d3= 100 mm
Esteel= 75*Eplastic
Concept Used:
Calculation:
Conclusion:
Allowable bending moment for plastic, Mallowableplastic = 1050.8 N-m
Allowable bending moment for Copper, Mallowablesteel =768.25 N-m
ii.
The value of the diameter of the copper rod for a balanced design
Answer to Problem 6.2.8P
The maximum moment is 1050.76 N-m in balanced condition
Explanation of Solution
Given:
Allowable stress for titanium, sti = 840 MPa
Allowable stress for titanium, scu= 700 MPa
Outer Diameter of the titanium rod, d2 = 40 mm
Eti= 110 GPa
Ecu= 120 GPa
Concept Used:
Calculation:
Conclusion:
The maximum moment is 1050.76 N-m in balanced condition
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