The following two equations contain corrections, respectively, for Eqs. (16) and (17):
$σr,j−αE(1−v)(12Tave−12 ∑j=0jTjVj∑j=0jVj)=0$
(16)
$σc,j−αE(1−v)(12Tave+12 ∑j=0jTjVj∑j=0jVj−Tj)=0$
(17)