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A compound bar is made using stainless steel tube with an aluminium alloy bar positioned concentrically inside it, and rigidly fixed at each end. The cross sectional area of the tube is 400mm^2 and the cross sectional area of the bar is 300mm^2. The combination is in tension and limiting stress in the aluminium alloy is 60MN/m^2.

Calculate the maximum (1) Stress

(2) Tensile load

σ alumimium =60MN/m^2

E of (s)stainless=180GN/m^2

E of (a)aluminium=120GN/m^2

Area of the tube is 400mm^2

Area of aluminium bar is 300mm^2

Area of stainless tube is 300-400=100mm^2

σa/Ea=σs/Es→σa=σs*Ea/Es

σa=σs*120/180→σa=σs*.666

60=σs*.666→σs=60/.666=90

Answer (1)

(2)Tensile load

F=Fs+Fa

F=σs*As+σa*Aa

F=60*100+90*300

F=6000+27000

Past paper question Is the answers right or wrong?

Calculate the maximum (1) Stress

(2) Tensile load

σ alumimium =60MN/m^2

E of (s)stainless=180GN/m^2

E of (a)aluminium=120GN/m^2

Area of the tube is 400mm^2

Area of aluminium bar is 300mm^2

Area of stainless tube is 300-400=100mm^2

σa/Ea=σs/Es→σa=σs*Ea/Es

σa=σs*120/180→σa=σs*.666

60=σs*.666→σs=60/.666=90

Answer (1)

**σs=90MN/m^2**(2)Tensile load

F=Fs+Fa

F=σs*As+σa*Aa

F=60*100+90*300

F=6000+27000

**F=33000 or 33KN**Past paper question Is the answers right or wrong?

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