T-Stresses Across Static Crack Kinking

2006 ◽  
Vol 74 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Xian-Fang Li ◽  
L. Roy Xu
Keyword(s):  
Open Crack ◽  
Elastic Solids ◽  
Crack Kinking ◽  
Growth Stability ◽  
Before And After ◽  
T Stress ◽  
Analytical Formulas ◽  
As Stress ◽  
Stress Function Method ◽  
Crack Growth Stability

This paper is concerned with the T-stress change before and after crack kinking in two-dimensional elastic solids. By using asymptotic analysis and the Westergaard stress function method, approximate analytical formulas for calculating the T-stress as well as stress intensify factors of an infinitesimal kink are given. Contributions from the T-stress before crack kinking, to the T-stress and the stress intensity factors of the kinked crack, are clearly described. It is noted that since the sign of the T-stress of a kinked open crack might be different from that of a main crack, simply using the sign of the T-stress before crack kinking is not sufficient to determine crack growth stability as observed in recent experiments.

Coupled EFGM and F2LFEM for Fracture Analysis of Cracks

2009 ◽  
Author(s):  
K. N. Rajesh ◽  
B. N. Rao
Keyword(s):  
Finite Element ◽  
Numerical Solutions ◽  
Consistency Condition ◽  
Shape Functions ◽  
Interface Elements ◽  
Element Free Galerkin ◽  
T Stress ◽  
Cracked Structures ◽  
As Stress ◽  
Element Free

This paper presents a coupling technique for integrating the element–free Galerkin method (EFGM) with fractal two-level finite element method (F2LFEM) for analyzing homogeneous, isotropic, and two dimensional linear–elastic cracked structures subjected to mixed–mode (modes I and II) loading conditions. F2LFEM is adopted for discretization of domain close to the crack tip and EFGM is adopted in the rest of the domain. In the transition region interface elements are employed. The shape functions within interface elements which comprises both the element–free Galerkin and the finite element shape functions, satisfies the consistency condition thus ensuring convergence of the proposed method. The proposed method combines the best features of EFGM and F2LFEM, in the sense that no structured mesh or special enriched basis functions are necessary and no post–processing (employing any path independent integrals) is needed to determine fracture parameters such as stress–intensity factors (SIFs) and T–stress. The numerical results show that SIFs and T–stress obtained using the proposed method are in excellent agreement with the reference solutions for the structural and crack geometries considered in this study. Also a parametric study is carried out to examine the effects of the similarity ratio, and the number of transformation terms on the quality of the numerical solutions.

Criterion for Crack Kinking out of the Interface of Two Orthotropic Layers Subjected to Thermal and Mechanical Loading

2013 ◽  
Vol 592-593 ◽  
pp. 169-172
Author(s):  
Petr Damborský ◽  
Oldřich Ševeček ◽  
Tomáš Profant ◽  
Michal Kotoul
Keyword(s):  
Residual Stresses ◽  
Mechanical Loading ◽  
Dissimilar Materials ◽  
Complex Stress ◽  
Crack Kinking ◽  
Thermal Residual Stresses ◽  
Complex Stress Intensity Factor ◽  
Finite Fracture Mechanics ◽  
T Stress ◽  
Path Stability

The problem of crack path stability along the interface between two orthotropic elastically dissimilar materials under the presence of in-plane residual stresses is analyzed using the concept of Finite Fracture Mechanics and matched asymptotic procedure. An energy based fracture criterion is introduced for this problem and it is investigated whether and how is the criterion for the prediction of crack kinking from the interface affected by residual stresses. The complex stress intensity factor and the T-stress characterizing the stress state at the crack tip are calculated both for the thermal (residual stresses) and mechanical loading using the two-state integral. The matched asymptotic procedure together with FEM is used to derive the change of the potential energy induced by the crack growth by crack increment of finite length.

scholarly journals Deep Breathing Relaxation for Decreasing Blood Pressure in People with Hypertension

Jurnal NERS ◽  
2019 ◽  
Vol 14 (3) ◽  
pp. 141
Author(s):  
Rahmatul Fitriyah ◽  
Gratsia Victoria Fernandez ◽  
Wahyu Sukma Samudera ◽  
Hidayat Arifin ◽  
Shenda Maulina Wulandari
Keyword(s):  
Blood Pressure ◽  
Blood Pressure Measurement ◽  
Measurement Data ◽  
Reduce Blood Pressure ◽  
Deep Breathing ◽  
Deep Breath ◽  
Before And After ◽  
Post Test ◽  
Data Collection Technique ◽  
As Stress

Various non-pharmacological therapies can be used to reduce blood pressure. One of them is deep breathing relaxation. This study aimed to know the influence of deep breath relaxation to decrease the blood pressure of people with hypertension. The design of this study was an Pre-Experimental One Group Pretest-Post-test design which covered 30 respondents as the sample. They fulfilled the inclusion criteria and were chosen through purposive sampling. The independent variable in this study was deep breath relaxation and the dependent variable was blood pressure. The data collection technique was using the observation sheet of blood pressure measurement. Data were analyzed using the paired t test. The findings of this study majority there were decrease blood pressure after deep breath. Before doing the breath relaxation exercise, most of the respondents were hypertension level 1. Nonetheless, after the deep breath relaxation had been executed, most found that their blood pressure decreased although several respondents were at hypertension level 2 with stable blood pressure. The results showed that there were differences in the blood pressure patients with hypertension before and after the deep breath relaxation. There were several points which influenced the decrease in blood pressure after implementing the deep breath relaxation such as stress, cigarettes etc.

scholarly journals Probiotics in Psychosocial Stress and Anxiety. A Systematic Review

2020 ◽  
Vol 29 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Paola Vitellio ◽  
Alexandra Chira ◽  
Maria De Angelis ◽  
Dan L Dumitrascu ◽  
Piero Portincasa
Keyword(s):  
Systematic Review ◽  
Anxiety Disorders ◽  
Psychological Stress ◽  
Psychological Symptoms ◽  
Inclusion Criteria ◽  
Double Blind ◽  
Online Databases ◽  
Before And After ◽  
As Stress ◽  
Positive Effect

Background and Aims: Recent mounting evidence suggest that probiotics supplementation can have a positive effect on mood and psychological symptoms such as stress and anxiety disorders. The majority of studies, however, rely on animal models, while clinical data are still inconsistent. In this systematic review, we examined if and to which extent probiotics can influence psychological stress and anxiety disorders. Methods: The search of online databases Medline, PubMed, Scopus, Web of Science and clinical trials.gov provided relevant studies up to November 2019. We included double blind, randomized and placebo controlled or prospective studies, as well as studies measuring preclinical psychological symptoms of perceived stress and anxiety, before and after supplementation with a probiotic. Results: Twelve studies met the inclusion criteria (3 on stress, 4 on anxiety, and 5 both on stress and anxiety), accounting for 1,521 participants. The improvement of stress, anxiety, and stress-anxiety was reported in 1/3, 3/4, and 2/5 studies, respectively. Conclusions: Available studies suggest that probiotics may improve psychological symptoms associated particularly with anxiety. Further research needs to investigate whether probiotics also improve psychological stress disturbances.

Limits of crack growth stability in the double cleavage drilled compression specimen

2003 ◽  
Vol 70 (13) ◽  
pp. 1697-1719 ◽  
Author(s):  
Thomas A. Jenne ◽  
William D. Keat ◽  
Michael C. Larson
Keyword(s):  
Crack Growth ◽  
Growth Stability ◽  
Crack Growth Stability

scholarly journals Economic Stability and (or) Economic Growth

2021 ◽  
pp. 93-98
Author(s):  
A. Ya. Zaporozhan
Keyword(s):  
Economic Growth ◽  
Growth Potential ◽  
Financial Policy ◽  
Stabilization Policy ◽  
Economic Stability ◽  
Previous Period ◽  
Russian Economy ◽  
Growth Stability ◽  
Before And After ◽  
Macroeconomic Stability

The article is devoted to consideration of two directions of state economic policy — maintaining economic stability and ensuring economic growth. The coronavirus pandemic has divided the world into “before and after”. In the previous period, the financial policy in Russia was based on the principle of macroeconomic stability. It would seem that the macroeconomic stability that has existed for several years has created the basis for economic growth in the country, but it has not been possible to realize the growth potential of the Russian economy. Economic stability is an important criterion for the economy. Only economic stability can be different.The economic stability of the Russian economy in the previous period is the economic stability of stagnation, because the cornerstone of the economic stabilization policy was maintaining a low inflation rate by artificially slowing down demand. N ow this economic stability of stagnation was overturned by the coronavirus epidemic due to a decrease in budget revenues and an increase in budget spending, which results in the threat of inflation.The purpose of the article is to substantiate the necessity and possibility of transition to a new form of economic stability — economic growth stability

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