Report on FY15 Two-Bar Thermal Ratcheting Test Results

Abstract

Helpful discussion with Peter Carter of Stress Engineering Services, Inc. is gratefully acknowledged. The contribution of Shane Hawkins of the Oak Ridge National Laboratory (ORNL) in this testing program by setting up and running some of the experiments is greatly appreciated. David Thomas of ORNL configured the hardware for coupling two servo-hydraulic machines and Donald Erdman of ORNL programmed the controls and established the initial experimental setup. The time spent by Hong Wang of ORNL in reviewing this report is also greatly appreciated. We would also like to acknowledge Richard Wright of INL for supplying the Alloy 617 materials to support the testing task of this work.

FY16 Progress Report on Test Results In Support Of Integrated EPP and SMT Design Methods Development

“…Consistent with the preceding work by Wang et al (2013Wang et al ( , 2014Wang et al ( , 2015Wang et al ( , 2016, the ratcheting strain is defined as the difference in the mechanical strain at a time point in a cycle and that at the same time point in the reference cycle. The mechanical strain is the sum of the elastic strain and inelastic strain, and it can be extracted from the test data by subtracting the thermal expansion from the total strain.…”

Support of the Development of EPP Plus SMT Design Method (FY2020 Test Results)

“…The SMT method requires testing of a specimen with accurate end displacement control for the control length. Wang et al (2014Wang et al ( , 2015Wang et al ( , 2016aWang et al ( , 2016b explained the details of the testing procedure. Testing was performed by cyclically applying an end-displacement to the control length while maintaining a constant internal pressure load.…”

“…In the original SMT key feature testing methods, the elastic follow-up factor was achieved by sizing the length and area ratios of the driver section to the test section. Achievement of the requisite representation of creep damage characteristics using key featured SMT, particularly at very high temperatures, involves specimen configurations that are both costly and beyond the limits of test control and stability (Wang et al, 2013(Wang et al, , 2014(Wang et al, , 2015(Wang et al, , 2016a(Wang et al, , 2017b(Wang et al, , 2017c. Although key featured SMT testing is crucial in the verification of the SMT-based design methodology, it is not practical to be used for generating SMT-based design curves.…”

Report on FY17 testing in support of integrated EPP-SMT design methods development

“…5. The experimental control logic used is similar to what was previously reported by Swindeman et al (1982) and is explained in detail in Wang et al (2013aWang et al ( , 2015Wang et al ( , 2016. In this method, two coupled servocontrolled machines are used to implement two bars in a parallel testing condition and the control system forces equal strains in the two specimens, yet allows the applied total load to be constant.…”

“…The changing of loading conditions was performed at 405 o C without unloading the specimens to zero load from the previous condition. Wang et al (2013aWang et al ( , 2014Wang et al ( , 2015Wang et al ( , 2016, the ratcheting strain is defined as the difference in the mechanical strain at a time point in a thermal cycle and that at the same time point in the reference cycle. When the same reference point in the thermal cycle is selected, the amount of ratcheting strain calculated based total strain is the same as that calculated based on mechanical strain.…”