Session: DA-01-03 Design & Analysis of Heat Exchangers & Components

Paper Number: 62952

Start Time: Wednesday, July 14, 2021, 08:00 PM

62952 - A Unified Constitutive Model for Diffusion Bonded Alloy 800H To Perform Full Inelastic Analysis of Components in High Temperature Nuclear Service 

Development of the next generation nuclear plants needed elevated temperature component design. A typical power plant experiences thermomechanical transients, which impose a challenge on the component designs. Current elastic and inelastic analysis design methodology in Section III, Division 5 captures the inelastic nature through a simplified approach. However, existing design codes do not provide any guidelines for full inelastic analysis using finite element methods. Gap analysis of the current Section III, Division 5 design code indicated a need of the viscoplastic constitutive model and respective optimized parameters for the full inelastic analysis. This paper presents a viscoplastic constitutive model with two back stress equations for wrought base metal (BM) Alloy 800H and diffusion bonded (DB) 800H. BM data collected from literature and DB data developed in this study are used for constitutive model parameter optimization. This model captures the fatigue, creep, and creep-fatigue simulation features such as hysteresis loop, stress relaxation, rate effects, and cyclic hardening observed in BM and DB Alloy 800H. A comparative study between constitutive model with and without isotropic damage term is presented. A detailed description of the UCM model and the optimized BM and DB parameters with and without damage and their simulations are presented.

Presenting Author: Heramb Mahajan North Carolina State University

Authors:

Heramb Mahajan North Carolina State University
Tasnim Hassan North Carolina State Univeristy