Let us consider the following truss structure:
In calculation we assume that P1 = P2= P3 = 10 [kN] and L=1[m].
Now let’s assume that the forces changes in the 5% i.e
P1= P1 ± 2.5%
P2= P2 ± 2.5%
P3= P3 ± 2.5%
If we calculate the relative error of axial forces
then we will get the following results:
We can see that in some cases the relative error
of calculation is equal to 60%.