In 1823, the Cauchy stress tensor was defined in three-dimensional geometric space as:

Fxx Fxy Fxz

Fyx Fyy Fyz

Fzx Fzy Fzz . . (1)

The Cauchy stress tensor is clearly incomplete because it does not contain time and must be modified to take the 4x4 form:

Fxx Fxy Fxz Fxt

Fyx Fyy Fyz Fyt

Fzx Fzy Fzz Fzt

Ftx  Fty Ftz   Ftt . . . (2)

Or,

∇2xx ∇2xy ∇2xz ∇2xt [U]

∇2yx ∇2yy ∇2yz ∇2yt [U]

∇2zx ∇2zy ∇2zz ∇2zt [U]

∇2tx ∇2ty  ∇2tz  ∇2tt [U] . . . (2*)

Where t is time in the 4-dimensional unit space xyzt.

and Fxy= ∇^2yx U(x,y,z,t). . ., etc.

This tensor is called the Cairo-Cauchy  tensor to distinguish it from the steady-state Cauchy tensor.

Note that:

1- Formula 2 reduces to Formula 1 as dU/dt)partial approaches zero.

2- The stationary Cauchy tensor 1 cannot handle time-dependent cosmic events, unlike the Cairo Cauchy tensor 2.

More Ismail Abbas M. Abbas's questions See All
Similar questions and discussions