Page 82 - Fundamental Of Design In Mechanical Engineering
P. 82

Example 1






           A steel bar of rectangular cross-section, 3 cm by 2 cm, carries an

           axial load of 30kN. Estimate the average tensile stress over a normal

           cross-section of the bar.






                      30kN                                                                      30kN





           Solution:


           The area of normal cross-section of the bar is:


                                              A = 0.03 x 0.02 = 0.6 x 10 m                    2
                                                                                       -3



           The average tensile over this cross-section is then






                                                              30    103                      2
                                              σ =  =                      = 50MN/m
                                                             0.6    10−3
                                                                                                                                    82
   77   78   79   80   81   82   83   84   85   86   87