Previous: Governing Field Equations
We have understood methods to define the kinematic state (strain) and the kinetic state (stress) at a body. Before we establish a relationship between the two, we need to understand the governing laws of physics and mechanics that are applicable to the bodies. They may be expressed in differential (local) or integral (global) form.
We have already defined balance laws (Balance of forces and moments (linear and angular momentum)). We also need to develop energy balance (mechanical and thermal). This is the first law of thermodynamics. Then there is a directional requirement of flow of thermal energy (second law).
=
Heat flow /area.
=Net heat flow =
Consider
the X direction
The
equation is similar in the other direction. Thus
where
k-
thermal conductivity
- temperature gradient
Next: 4.14 Conservation of Energy
10/25/01 0:46:35