1. Redundant structure with external force


2. Basic structure with external force $R$



External force $R$

0 large

Load on cut faces $X$

0 -$2\frac{\delta_0}{\delta_1}$

$-\frac{\delta_0}{\delta_1}$


3. Redundant structure with pair of forces $X$ at cut


4. Superposition of $2$ and $3$