Ratcheting effect of reinforced graphite sheet with stainless steel insert (RGSWSSI) under cyclic compression at elevated temperature

Abstract

Ratcheting and creep of reinforced graphite sheet with stainless steel insert (RGSWSSI) are tested under cyclic stress‐controlled compression by a self‐designed clamp from 500°C to 600°C. The effects of insert type, temperature, stress amplitude, stress rate, creep, and loading sequence are considered. Results present that ratcheting deformations for RGSWSSI with 316‐L stainless steel tanged and bonded insert approach to each other and show little rate dependence, while they slightly increase with the increment of stress amplitude and temperature. Moreover, obvious ratcheting effect takes place under cyclic pulsating loads with the peak stress of 32 MPa at 500°C or higher. The accumulated deformations of RGSWSSI under small stress amplitude only increase during about the first 25 cycles and then always turn to shakedown. It can also be estimated by the corresponding static creep strain in practical engineering with good accuracy at high temperature. This work provides important data and understanding of RGSWSSI under harsh fluctuating loads.

Burst Pressures of High-Density Polyethylene Pipes Considering the Notch Effect: Testing and Prediction

“…This indicates that the proposed model can be well used to predict the damage behavior considering the notch effect. Taking into consideration the important effect of notch geometry on the degradation of HDPE pipes, the shakedown and low fatigue behavior of notched and virgin HDPE pipes will be further tested and evaluated in the following based on the approaches published in previous works [35,36,37,38,39] obviously. Moreover, the burst pressure remarkably decreases with the increment of the notch depth ratio.…”

A novel fatigue assessment approach by Direct Steady Cycle Analysis (DSCA) considering the temperature-dependent strain hardening effect

“…If a material is subjected to a cyclic stress with non-zero mean stress and the applied stress exceeds the yield surface, a cyclic accumulation of inelastic deformation, called material ratcheting, will take place [23]. The material ratcheting is usually tested by a homogeneous stress field and characterized by the evolution of back stress considering the kinematic hardening effect [24], [25], [26], [27]. However, the structural ratcheting is mainly caused by a inhomogeneously distributed stress field and the plasticity of material, which is usually described by EPP or RO models.…”

The ratchetting and retained austenite transformation of medium‐manganese transformation‐induced plasticity steel during asymmetrical cyclic stressing

“…Paul et al 28 also studied the microstructure change of DP steel under cyclic loading controlled by asymmetric stress, and found that grain orientation had little influence on the development of substructure compared with the test type. In addition, some scholars have studied the influence of stress ratio, 29 maximum stress, 30 temperature, 31 and other test parameters on ratchetting evolution. Sahu et al 32 investigated the effect of martensitic phase transformation on ratchetting behavior in austenitic stainless steel, but they only predicted that the volume fraction of martensitic would increase with the increase of deformation degree.…”