Theory Manual Version 3.4
$\newcommand{\lyxlock}{}$
Section 6.2: Elastodynamics Up Section 6.2: Elastodynamics Subsection 6.2.2: Virtual Work

### 6.2.1 Governing Equations

The linear momentum balance for elastodynamics is where is the density, is the acceleration, is the Cauchy stress, and is the body force per mass. The angular momentum balance is satisfied by letting . The integrated form of the mass balance equations yields where is the density in the reference configuration and , where is the deformation gradient. The acceleration is given by the material time derivative of the velocity , evaluated either in a spatial or a material frame,
Section 6.2: Elastodynamics Up Section 6.2: Elastodynamics Subsection 6.2.2: Virtual Work