Nature of Mechanical Machine Design - Mechanical Engineering ...

Nature of Machine Element Design - Iteration• At the initial stages of machine design, we face a dilemma. Thedesigner can not predict with accuracy what environmental loads theuser will subject the machine to. The dilemma can be resolved onlyby iteration, which means to repeat, or to return to a previous state.We must assume some trial configuration for each part; use the massproperties of that trial configuration in dynamic force analysis todetermine the forces, moments, and torques acting on the part, andthen use the cross-sectional geometry of the trial design to calculatethe resulting stresses.• Most likely, on the first trial, we will find that our design failsbecause the materials cannot stand the levels of stresses presented.We must then redesign the part by changing shapes, size, materials,manufacturing processes, or other factors in order to reach anacceptable design. It is generally not possible to achieve a successfulresult without making several iterations through this design process.UPRM –Spring 2005 INME 4012 - Lecture 1 9