A \frac{3}{4} -in-diameter steel tension rod is 5 \mathrm{ft} long and carries a load of 15 kip. Find the tensile stress, the total deformation, the unit strains, and the change in the rod diameter.
A \frac{3}{4} -in-diameter steel tension rod is 5 \mathrm{ft} long and carries a load of 15 kip. Find the tensile stress, the total deformation, the unit strains, and the change in the rod diameter.
\sigma=\frac{F}{A}=\frac{15000}{(\pi / 4)\left(0.75^{2}\right)}=33950 \mathrm{psi}=34.0 \mathrm{kpsi} \quad .
\delta=\frac{F L}{A E}=\sigma \frac{L}{E}=33950 \frac{60}{30\left(10^{6}\right)}=0.0679 in
\epsilon_{1}=\frac{\delta}{L}=\frac{0.0679}{60}=1130\left(10^{-6}\right)=1130 \mu \quad
From Table A-5, v=0.292
\epsilon_{2}=-v_{\epsilon_{1}}=-0.292(1130)=-330 \mu \quad .
\Delta d=\epsilon_{2} d=-330\left(10^{-6}\right)(0.75)=-248\left(10^{-6}\right) in .
Table A-5
Material | Modulus of Elasticity E | Modulus of Elasticity G | Poisson’s Ratio | Unit Weight w | ||||
Mpsi | Gpa | Mpsi | GPa | lbf/in^{3} | lbf/ft^{3} | kN/m^{3} | ||
Aluminum(all alloys) | 10.4 | 71.7 | 3.9 | 26.9 | 0.333 | 0.098 | 169 | 26.6 |
Beryllium copper | 18 | 124 | 7 | 48.3 | 0.285 | 0.297 | 513 | 80.6 |
Brass | 15.4 | 106 | 5.82 | 40.1 | 0.324 | 0.309 | 534 | 83.8 |
Carbon steel | 30 | 207 | 11.5 | 79.3 | 0.292 | 0.282 | 487 | 76.5 |
Cast iron(gray) | 14.5 | 100 | 6 | 41.4 | 0.211 | 0.26 | 450 | 70.6 |
Copper | 17.2 | 119 | 6.49 | 44.7 | 0.326 | 0.322 | 556 | 87.3 |
Douglas fir | 1.6 | 11 | 0.6 | 4.1 | 0.33 | 0.016 | 28 | 4.3 |
Glass | 6.7 | 46.2 | 2.7 | 18.6 | 0.245 | 0.094 | 162 | 25.4 |
Inconel | 31 | 214 | 11 | 75.8 | 0.29 | 0.307 | 530 | 83.3 |
Lead | 5.3 | 36.5 | 1.9 | 13.1 | 0.425 | 0.411 | 710 | 111.5 |
Magnesium | 6.5 | 44.8 | 2.4 | 16.5 | 0.35 | 0.065 | 112 | 17.6 |
Molybdenum | 48 | 331 | 17 | 117 | 0.307 | 0.368 | 636 | 100 |
Monel metal | 26 | 179 | 9.5 | 65.5 | 0.32 | 0.319 | 551 | 86.6 |
Nickel silver | 18.5 | 127 | 7 | 48.3 | 0.322 | 0.316 | 546 | 85.8 |
Nickel steel | 30 | 207 | 11.5 | 79.3 | 0.291 | 0.28 | 484 | 76 |
Phosphor bronze | 16.1 | 111 | 6 | 41.4 | 0.349 | 0.295 | 510 | 80.1 |
Stainless steel(18-8) | 27.6 | 190 | 10.6 | 73.1 | 0.305 | 0.28 | 484 | 76 |
Titanium alloys | 16.5 | 114 | 6.2 | 42.4 | 0.34 | 0.16 | 276 | 43.4 |