刚性横梁AB悬挂于三根平行杆上。l=2m,F=40kN,a=1.5m,b=1m,c=0.25m。δ=0.2mm。1杆由黄铜制成,A1=2cm2,E1=100GPa
刚性横梁AB悬挂于三根平行杆上。l=2m,F=40kN,a=1.5m,b=1m,c=0.25m。δ=0.2mm。1杆由黄铜制成,A1=2cm2,E1=100GPa,α1=16.5×10-5/℃。2杆和3杆由碳钢制成A2=1cm2,A3=3cm2,E2=E3=200GPa,α2=α3=12.5×10-6/℃。设温度升高20℃,试求各杆的应力。