Thermodynamic Work consumed during Manufacturing Processes P M V Subbarao Professor Mechanical Engineering Department I I T Delhi Estimation of manufacturing works!!!

Innovative Design to modify Pressure volume Diagram

Thermodynamic definition of Plastic Deformation Work Themodynamically simple displacement work : A bar of initial length l 0 is subjected to a force F acting upon an area A 0 and an extrusion dl occurs, the work consumed is: Work consumed by unit volume of extruded material is:

Most Generic Extrusion Work Stress and strain are tensors. The generalized work consumed can be represented as:

Effective strain & Stress Effective stress and strain are defined for each extrusion case as: Von Mises proposed an expression for effective stress as:  i are called as principle stresses and obtained as roots of a cubic equation :

The simplified form of specific work equation is

Specific work done during Extrusion of Axi- symmetric incompressible solids

Common Models for Extrude Materials Ductile aluminum alloys are most preffered material for extrusion. For infinitesimally slow extrusion.

Impact of Thermodynamic Analysis of Extrusion

Displacement work during Metal Cutting Themodynamically simple displacement work : The total cutting work consumed in machining can be defined as the sum of shear work and friction work. Also defined as primary shear work and secondary shear work.

Simple model for Primary Shear Work Primary shear work is estimated as: The layer to be removed of thickness t 1 transforms into the chip of thickness t 2 as a result of shear deformation that takes place along a certain unique plane AO. This plane is inclined to the cutting plane at an angle ϕ. This is called as single shear plane model. This plane moves with at velocity V s parallel to F s relative to Tool

Comprehensive model for Primary Shear Work Plastic zone LOM is limited by shear line OL, along which the first plastic deformation in shear occurs. Shear line OM along which the last shear deformation occurs.

Line LM is “the surface of the cut”. The plastic zone LOM includes “a family of shear lines along which growing shear deformation are formed successively.” This shape of the deformation (plastic) zone is based on the multiple experimental studies and this is more than a very serious statement. Based on this model the specific work consumption is:

Effective Plastic Zone Stress during Metal cutting