Ratcheting in pressurized pipes and equipment: A review on affecting parameters, modelling, safety codes, and challenges

Abstract

The current study has attempted to comprehensively review ratcheting response of materials involving various influential parameters such as loading spectra, thermal cycles, stress levels, stress raisers, strain rate, and visco‐plasticity and material types with a focus on pressurized pipes and equipment. The mechanism of deformation, types, and the rate of progress over stages of ratcheting were discussed. Safety design codes and procedures were highlighted for reliable design of pressurized pipes against progressive ratcheting and to safeguard the system against catastrophic failure at which both mechanical and thermal ratcheting were integrated. Boundaries and demarcation of ratcheting‐shakedown zones developed based on Bree's diagram were employed to assess plastic deformation accumulation over stress cycles. Shakedown and ratcheting boundaries were discussed through methods developed on the basis of Melan's theorem over last few decades. Ratcheting response of materials was reviewed through descriptions of parametric models and kinematic hardening rules involving various variables and parameters. Interaction of ratcheting with creep and low‐cycle fatigue has promoted progressive damage in materials. Pressurized pipes subjected to thermal cycles and external bending cycles were evaluated by numerical solutions along with kinematic hardening rules to assess ratcheting over stress cycles.

Concurrent ratcheting and stress relaxation at the notch root of steel samples undergoing asymmetric tensile loading cycles

“…Ahmadzadeh and Varvani developed a kinematic hardening rule by introducing an internal variable, , into the dynamic recovery term to control the evolution of backstress increments over loading process. The dynamic recovery in the A‐V model was formulated through involvement of to enable evolution of yield surface on the deviatoric stress space accumulating for the ratcheting strain with a gradual decreasing rate. The framework of the hardening rule consisted of relatively less number of coefficients empowering the model to assess ratcheting with less CPU/computation time.…”

Ratcheting‐fatigue behaviour of bainite 2.25Cr1MoV steel with tensile and compressed hold loading at 455°C

“…Interactions between thermal gradient and cyclic thermal load create thermal ratcheting deformation . Therefore, ratcheting is an important concern for pressure component design . Design rules limiting inelastic strain have been established, such as ASME B&PV Code, RCC, and R5 .…”

Prediction of asymmetric cyclic‐plastic behaviour for cyclically stable non‐ferrous materials

“…The phenomenon of ratcheting severely influences the fatigue life of engineering components, especially for structures subjected to low cycle fatigue . Experimental studies on cyclic‐plastic behaviour of ferrous and non‐ferrous materials by numerous investigators have revealed the influence of mean stress, stress amplitude, and nature of loading on ratcheting behaviour of materials, and there exists several reports on modelling the cyclic‐plastic behaviour of materials. The existing constitutive models are popularly focused towards predicting the ratcheting behaviour of ferrous materials.…”

“…Simulation of the shakedown phenomenon considering combined hardening models typically demands the use of linear hardening rule in the KH component . But the earlier investigators have dealt with this problem by incorporating a small amount of nonlinearity in the third backstress of the KH component in the original Chaboche model to achieve simulations for the stabilized rate of ratcheting.…”