Uniform stress corrosion and corrosion cracking of structural steels

A New Model for the Mechanochemical Corrosion of a Thin Spherical Shell

“…If a structural element, immersed in an aggressive environment, is subject to mechanical stresses, then the so-called mechanochemical effect may occur (i.e. corrosion accelerated by stress) [1,2].…”

“…Previous solutions for thin shells [4] do not depend on the internal and external pressures themselves, but only on their difference (see [18]). However, the hydrostatic pressure can affect the corrosion rate [1]. Accurate solutions for the doublesided corrosion of shells under internal and external pressure based on the solutions of Lamé problems for thick cylinder and sphere are rather cumbersome [19][20][21][22][23][24][25].…”

“…The corrosion process affects the shell sizes: the inner radius increases while the outer radius decreases from the initial time t 0 values denoted respectively by r 0 and R 0 . According to [1,3], the rates of corrosion on the inner and outer surfaces are:…”

“…where the constants a r , a R , m r , and m R are determined experimentally [1]. In general, they are different under tension and compression; σ(r, R, p r , p R ) is the maximum principal stress assumed to be identical through the entire thickness.…”

“…Naturally, the solution derived using (2) does not depend on the pressure values p r and p R , but only on the difference p r − p R . However, it is known that the hydrostatic pressure p = min{p r , p R } could affect the corrosion kinetics [1]. To take into account the effect of the hydrostatic pressure p we suppose that the effective stress is defined by the more accurate formula [26]:…”