Representation of Mechanical Behavior in the Presence of Changing Internal Structure

1988 ◽  
Vol 55 (1) ◽  
pp. 1-10 ◽  
Author(s):  
E. T. Onat ◽  
F. A. Leckie
Keyword(s):  
Mechanical Behavior ◽  
Internal Structure ◽  
Applied Stress ◽  
Constitutive Equations ◽  
Creep Damage ◽  
Main Ideas ◽  
The Relationship ◽  
Small Deformations

The paper is concerned with the representation of the relationship that exists, for a given material and temperature and for small deformations, between histories of applied stress and the observed strain and the accompanying changes in internal structure of the material. Emphasis is given to creep damage in metals as a vehicle for illustration of the main ideas introduced in the paper. In particular, the role played by irreducible even rank tensors in the representation of internal structure is discussed and clarified. The restrictions placed by thermodynamics on constitutive equations are considered and the use of potentials in these equations is examined and criticized.

Finite Element Simulation of the Creep Behavior of 2.25Cr-1Mo-0.25V Steel Based on Continuum Damage Mechanics

2015 ◽  
Vol 750 ◽  
pp. 266-271 ◽  
Author(s):  
Yu Zhou ◽  
Xue Dong Chen ◽  
Zhi Chao Fan ◽  
Yi Chun Han
Keyword(s):  
Genetic Algorithm ◽  
Finite Element ◽  
Creep Behavior ◽  
Constitutive Equations ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Creep Damage ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Element Simulation

The creep behavior of 2.25Cr-1Mo-0.25V ferritic steel was investigated using a set of physically-based creep damage constitutive equations. The material constants were determined according to the creep experimental data, using an efficient genetic algorithm. The user-defined subroutine for creep damage evolution was developed based on the commercial finite element software ANSYS and its user programmable features (UPFs), and the numerical simulation of the stress distribution and the damage evolution of the semi V-type notched specimen during creep were studied. The results showed that the genetic algorithm is a very efficient optimization approach for the parameter identification of the creep damage constitutive equations, and finite element simulation based on continuum damage mechanics can be used to analyze and predict the creep damage evolution under multi-axial stress states.

scholarly journals Review on the Current State of Developing of Advanced Creep Damage Constitutive Equations for High Chromium Alloy

2012 ◽  
Vol 510 ◽  
pp. 776-780 ◽  
Author(s):  
Li Li An ◽  
Qiang Xu ◽  
Dong Lai Xu ◽  
Zhong Yu Lu
Keyword(s):  
Constitutive Equations ◽  
Creep Damage ◽  
Chromium Alloy ◽  
High Chromium ◽  
Current State ◽  
Specific Material ◽  
Future Work

This paper presents a review of developing of creep damage constitutive equations for high chromium alloy (such as P91 alloy). Firstly, it briefly introduces the background of creep damage for P91 materials. Then, it summarizes the typical creep damage constitutive equations developed and applied for P91 alloy, and the main deficiencies of KRH (Kachanov-Robatnov-Hayhurst) type and Xus type constitutive equations. Finally it suggests the directions for future work. This paper contributes to the knowledge for the developing creep damage constitutive equations for the specific material.

Biblical theology and/or theological interpretation of scripture?

2008 ◽  
Vol 61 (1) ◽  
pp. 16-31 ◽  
Author(s):  
Daniel J. Treier
Keyword(s):  
Internal Structure ◽  
Biblical Theology ◽  
Theological Method ◽  
Theological Interpretation ◽  
Theological Hermeneutics ◽  
Disciplinary Boundaries ◽  
Organic Unity ◽  
The Bible ◽  
The Relationship ◽  
Biblical Teaching

Abstract‘Biblical theology’ has long influenced modern theological method, especially Protestant, as both boon and bane. Its role has been seen as either pivotal or problematic in the attempt to construe the Christian Bible as scripture with unified teaching for the contemporary church. The attempt to unfold biblical teaching as having organic unity, related to an internal structure of theological concepts, is frequently perceived as a failure, a has-been that leaves us only with fragmentation – between parts of the Bible, between academy and church, church and world, clergy and laity, and between various theological disciplines. Today a new movement is afoot, often labelled ‘theological interpretation of scripture’. Some of its adherents define this practice as distinct from, even opposed to, biblical theology. Others treat the two practices as virtually coterminous, while perhaps contesting what ‘biblical theology’ is typically taken to be in favour of new theological hermeneutics. Much of the difficulty in defining the relationship, then, stems from lingering debates about what biblical theology can or should be. The rest of the difficulty is perhaps rooted in the dilemma of any interdisciplinary efforts: how to breach unhelpful sections of disciplinary boundaries without redefining territory so nebulously that no one knows where they are.

scholarly journals Structure investigations of layered soil – varved clay

2016 ◽  
Vol 48 (4) ◽  
pp. 365-375 ◽  
Author(s):  
Matylda Tankiewicz
Keyword(s):  
Mechanical Behavior ◽  
Internal Structure ◽  
Strength Properties ◽  
Layered Soil ◽  
Radiographic Images ◽  
Composition And Structure ◽  
Computed Microtomography ◽  
Structure Investigations ◽  
Varved Clay

Abstract In the paper the results of laboratory investigations of structure of layered soil are presented. They focus on varved clay that is a soil composed of two alternately arranged varves with different texture and mechanical properties. An effect of such structure is an anisotropy of the material. Due to varying conditions during its formation process the soil exhibits some irregularities in composition and structure. Due to that modelling of mechanical behavior, like strength, may not provide satisfactory results. Main purpose of the examinations is an investigation of internal structure of layered soil – varved clay – in relation to its strength anisotropy and evaluation of the suitability of the use of two different techniques to assess the soil structure. Investigated material have been taken from area near city of Bełchatów in central Poland. The examinations included investigation of particle size distribution of soil and its components, identification of lamination with use of scanning electron microscope (SEM) and computed microtomography technique (μCT). First, the texture of each varve and varved clay as a composite have been estimated. Next, the investigation of surface perpendicular to the lamination have been carried out with SEM. Pictures of varves with different magnifications are presented. Also the varves arrangement and details of layers contact area are shown. Finally, investigation of internal structure of the soil have been performed by using microtomograph. The outcome is a series of radiographic images and reconstructed 3D model of tested soil. Presented results show complexity of the structure of varved clay that affect the mechanical behavior. Determination of the structure with use of presented techniques may be helpful in examination of strength properties and proper modeling of such soil.

Processing Relationships Between Language-Being-Spoken and Other Speech Dimensions in Monolingual and Bilingual Listeners

2016 ◽  
Vol 60 (4) ◽  
pp. 530-561
Author(s):  
Charlotte R. Vaughn ◽  
Ann R. Bradlow
Keyword(s):  
Internal Structure ◽  
Mandarin Chinese ◽  
Language Processing ◽  
The Other ◽  
Speech Features ◽  
The Relationship ◽  
Speeded Classification

While indexical information is implicated in many levels of language processing, little is known about the internal structure of the system of indexical dimensions, particularly in bilinguals. A series of three experiments using the speeded classification paradigm investigated the relationship between various indexical and non-linguistic dimensions of speech in processing. Namely, we compared the relationship between a lesser-studied indexical dimension relevant to bilinguals, which language is being spoken (in these experiments, either Mandarin Chinese or English), with: talker identity (Experiment 1), talker gender (Experiment 2), and amplitude of speech (Experiment 3). Results demonstrate that language-being-spoken is integrated in processing with each of the other dimensions tested, and that these processing dependencies seem to be independent of listeners’ bilingual status or experience with the languages tested. Moreover, the data reveal processing interference asymmetries, suggesting a processing hierarchy for indexical, non-linguistic speech features.

scholarly journals Investigation of a boundary simulation of continuity using the discrete solid element method

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882239
Author(s):  
Baochen Zhu ◽  
Ruoqiang Feng
Keyword(s):  
Mechanical Behavior ◽  
Thin Plate ◽  
Spring Stiffness ◽  
Conservation Of Energy ◽  
Solid Element ◽  
Strong Material ◽  
Spherical Elements ◽  
The Relationship ◽  
Method Model ◽  
Element Method

The discrete solid element method is an efficient numerical method that simulates the large deformation, strong material nonlinearity, fracture, and dynamic problems of continuity. In the discrete solid element method model, the spring stiffness of the spherical elements on the boundary is different from that inside the discrete solid element method model based on the principle of conservation of energy. The spring stiffness of the spherical elements on the boundary of the discrete solid element method model is shown to have a significant effect on the macroscopic properties. According to the position of the spherical elements on the boundary of the discrete solid element method model, the spherical elements on the boundary are divided into three types, which are spherical elements on the surface position, on the edge position, and on the corner position. To accurately reflect the mechanical behavior of the material, the principle of energy conservation is used to strictly deduce the spring stiffness of the three types of spherical elements on the boundary, and the relationship between the spring stiffness and elastic constants is established. The numerical example shows that the calculation accuracy of the discrete solid element method in modeling the mechanical behavior of continuity is improved after the spring stiffness of the spherical elements on the boundary is revised. In addition, the applications of the discrete solid element method to dynamic buckling of the thin plate and buckling of the cracked thin plate are also given.

Ultrasonic Nondestructive Evaluation of the Creep Damaged IN738LC Superalloy

2004 ◽  
Vol 449-452 ◽  
pp. 569-572 ◽  
Author(s):  
Jai Won Byeon ◽  
J.H. Song ◽  
S.I. Kwun
Keyword(s):  
Nondestructive Evaluation ◽  
Ultrasonic Wave ◽  
Linear Correlation ◽  
Ultrasonic Attenuation ◽  
Creep Damage ◽  
Ultrasonic Nondestructive Evaluation ◽  
Microstructural Parameters ◽  
Creep Time ◽  
The Mean ◽  
The Relationship

It was attempted to evaluate nondestructively the creep damaged IN738LC Ni based superalloys with different degree of rafting using ultrasonic wave. Microstructural parameters (length and width of γ' precipitates) and ultrasonic attenuation were measured in order to clarify the relationship between them. Both the mean length of γ' precipitates and the ultrasonic attenuation increased with creep time. Ultrasonic attenuation was found to have a linear correlation with the mean length of γ' precipitates. It is suggested that the ultrasonic attenuation can be used as a potential nondestructive parameter for assessing the degree of creep damage of IN738LC superalloy.

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