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Title: A damage mechanics based approach to structural deterioration and reliability

Technical Report ·
DOI:https://doi.org/10.2172/573315· OSTI ID:573315
;  [1]
  1. Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Civil Engineering

Structural deterioration often occurs without perceptible manifestation. Continuum damage mechanics defines structural damage in terms of the material microstructure, and relates the damage variable to the macroscopic strength or stiffness of the structure. This enables one to predict the state of damage prior to the initiation of a macroscopic flaw, and allows one to estimate residual strength/service life of an existing structure. The accumulation of damage is a dissipative process that is governed by the laws of thermodynamics. Partial differential equations for damage growth in terms of the Helmholtz free energy are derived from fundamental thermodynamical conditions. Closed-form solutions to the equations are obtained under uniaxial loading for ductile deformation damage as a function of plastic strain, for creep damage as a function of time, and for fatigue damage as function of number of cycles. The proposed damage growth model is extended into the stochastic domain by considering fluctuations in the free energy, and closed-form solutions of the resulting stochastic differential equation are obtained in each of the three cases mentioned above. A reliability analysis of a ring-stiffened cylindrical steel shell subjected to corrosion, accidental pressure, and temperature is performed.

Research Organization:
US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Engineering Technology; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Civil Engineering
Sponsoring Organization:
Nuclear Regulatory Commission, Washington, DC (United States)
DOE Contract Number:
AC05-96OR22464
OSTI ID:
573315
Report Number(s):
NUREG/CR-6546; ORNL/SUB-96-SP638; ON: TI98002846; TRN: 98:009260
Resource Relation:
Other Information: PBD: Feb 1998
Country of Publication:
United States
Language:
English