• Geotechnical Engineering
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• v.14 no.4
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• pp.129-140
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• 1998

Elasto-plastic finite element analysis of geotechnical boundary value problems necessitate the stress integration for the known strain increments. For the elasto-plastic constitutive model, the stress integration is generally achieved by numerical schemes, because analytical integration is impossible for general strain path. In this case, the accuracy of numerical stress integration has an important role on the overall accuracy of nonlinear finite element solution. In this study, the Sloan's substepping method which is one of explicit integration methods has been adopted and iris applicability has been checked. The unstability and inaccuracy of ifs results initiated from initial stress level were revealed. So. a new modified numerical integration method which employs the basic concept of modified Euler scheme for error control is proposed and accuracy and stability of the solutions are confirmed by triaxial test simulation.

• International Journal of Railway
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• v.3 no.4
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• pp.117-122
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• 2010

In transportation geotechnical engineering, stress-strain behavior of earth structures has been analyzed by numerical simulations with the implemented plasticity constitutive model. It is a fact that many advanced plasticity constitutive models on predicting the mechanical behavior of soils have been developed as well as experimental research works for geotechnical applications in the past decades. In this study, recently developed, a unified constitutive model for both clay and sand, which is referred to as CASM (clay and sand model), was compared with a classical constitutive model, Cam-Clay model. Moreover, integration methods of stress-strain rate equations using CASM were presented for simulation of undrained and drained triaxial compression tests. As a conclusion, it was observed that semi-implicit integration method has more improved accuracy of capturing strain rate response to applied stress than explicit integration by the multiple correction and iteration.

• East Asian Economic Review
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• v.19 no.4
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• pp.325-355
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• 2015

This paper looks at the integration of regions and nations through the prism of the merger of populations (societies). The paper employs a particular index of social stress. Stylized examples of the merging of two populations suggest that with integration, the social stress index will increase. The examples form the basis for the development of new formulas for calculating the social stress of an integrated population as a function of the levels of social stress of the constituent populations when apart. The formulas reveal that the social stress of an integrated population is higher than the sum of the levels of social stress of the constituent populations when apart. This raises the distinct possibility that the merging of populations may be a social liability: integration may fail to give the populace a sense of improved wellbeing.

• Structural Engineering and Mechanics
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• v.55 no.4
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• pp.885-900
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• 2015

This paper introduces Romberg-Richardson's method as one of the numerical integration tools for computation of stress intensity factor in a pre-cracked specimen subjected to a complex stress field across the crack faces. Also, the computation of stress intensity factor for various stress fields using existing three methods: average stress over interval method, piecewise linear stress method, piecewise quadratic method are modified by using Richardson extrapolation method. The direct integration method is used as reference for constant and linear stress distribution across the crack faces while Gauss-Chebyshev method is used as reference for nonlinear distribution of stress across the crack faces in order to obtain the stress intensity factor. It is found that modified methods (average stress over intervals-Richardson method, piecewise linear stress-Richardson method, piecewise quadratic-Richardson method) yield more accurate results after a few numbers of iterations than those obtained using these methods in their original form. Romberg-Richardson's method is proven to be more efficient and accurate than Gauss-Chebyshev method for complex stress field.

• Korean Journal of Materials Research
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• v.22 no.6
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• pp.292-297
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• 2012

In order to improve osseointegration of dental implants with bone we studied an implant with holes inside its body to deliver bioactive materials based on a proposed patent. Bioactive materials can be selectively applied through holes to a patient according to diagnosis and the integration progress. After the bioactive material is applied, bone can grow into the holes to increase implant bonding and also enhance surface integration. In order to improve the concept and study the effect of bioactive material injection on implant integration, design optimization and integration research were undertaken utilizing the finite element method. A 2-dimensional simulation study showed that when bone grew into the holes after the bioactive material was injected, stress vertically distributed in the upper part of the implant was relieved and mild stress appeared at the opening of the injection holes. This confirmed the effect of the bioactive material and the contribution of the injection holes, but the maximum stress increased ten-fold at the opening. In order to reduce the maximum stress, the size, location, and the number of holes were varied and the effects were studied. When bioactive materials formed an interface layer between the implant and the mandible and four holes were filled with cortical and cancellous bones all the stress concentrated opposite to the loading side without holes disappeared. The stresses at the four outlets of the holes was mildly elevated but the maximum stress value was ten-fold greater compared to the case without the bioactive material.

• Geotechnical Engineering
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• v.12 no.4
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• pp.145-156
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• 1996

An implicit stress integration algorithm was formulated for implementing an aiusotorpic hardening constitutive model which has been based op the generalized isotropic hardening rule in nonlinear finite element analysis technique. the rate form of stress tensor was implicitly integrated using the generalized trapezoidal rule and the tangent stress-strain modulus was evaluated consistently with the nonlinear solution technique. As a result, it has been found that the nonlinear analysis with the anisotropic hardening constitutive model might be performed accurately and efficiently.

• Structural Engineering and Mechanics
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• v.59 no.5
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• pp.901-920
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• 2016

MeshFree methods have become popular owing to the ease with which high stress gradients can be identified and node density distribution can be reformulated to accomplish faster convergence. This paper presents a strategy for nodal density refinement with strain energy as basis in Element-Free Galerkin MeshFree technique. Two popular flat plate problems are considered for the demonstration of the proposed strategies. Issue of integration errors introduced during nodal density refinement have been addressed by suggesting integration cell refinement. High stress effects around two symmetrical semi-circular notches under in-plane axial load have been addressed in the first problem. The second considers crack propagation under mode I and mode II fracture loading by the way of introducing high stress intensity through line crack. The computational efficacy of the adaptive refinement strategies proposed has been highlighted.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.94-102
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• 2007

Applications of bonded dissimilar materials such as large scale integration (LSI) packages, ceramics/metal and resin/metal bonded joints, are very increasing in various industry fields. It is very important to analyze the thermal stress and stress singularity at interface edge in LSI. In order to investigate stress singularities on the bonded interface edges and delamination of die pad and resin in the IC package. In this paper, stress singularity factors(${\Gamma}_i$) and stress intensity factors($K_i$) considering thermal stress in the IC package were analyzed by using the 2-dimensional elastic boundary element method(BEM).

• Child Health Nursing Research
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• v.13 no.1
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• pp.73-80
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• 2007

Purpose: As a result of dramatic advances in the medical and surgical management of congenital heart disease (CHD), many babies born with cardiac anomalies today can expect to reach adulthood. The main purpose of this study was to examine the relationship between parenting stress and personal resources of mothers of children with CHD. Method: Fifty-one mothers of children with CHD were recruited at the pediatric cardiac outpatient clinic from July 14th to September 25th 2006. Abidin's parenting stress index/short form (PSI/SF) and Brandt and Weinert's personal resource questionnaire (PRQ) were used. PSI has 3 sub-concepts; parental role distress, dysfunctional parent-child interaction, and difficult child. PRQ has 4 sub-concepts; intimacy, social integration, worth, and assistance. Data were analyzed using SPSS 13.0 version. Results: Correlation analysis showed that parenting stress was significantly related to 'intimacy', 'social integration', and 'worth' of mothers. Multiple regression analysis showed that parenting stress was significantly related to personal resource of mother and information by internet. Conclusion: Mothers who felt they had supportive friends and family, high self esteem, and social integration reported lower parenting stress. Also, internet may be an effective method to provide information and share experience for mothers of children with CHD.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.543-551
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• 2022

The purpose of this study was to understand the integration and clinical practice stress of nursing students and to understand the relationship with department satisfaction. Data collection was from June to July 2021. Data were collected through questionnaires consisting of scales of integration, clinical practice stress, and departmental satisfaction, targeting 3rd and 4th grade nursing students who have had more than one clinical practice experience. A total of 394 copies were analyzed using the SPSS program to analyze the data. As a result of the study, integration showed a positive correlation with department satisfaction (r=.412, p<.01) and a negative correlation with clinical practice stress (r=-.193, p<.01). The predictive factors affecting the department satisfaction of nursing students were integration (β=.406, p<.001) and admission motivation (β=.166, p=.006), which accounted for 20% of the total variance. Integration Performance It was confirmed that the motivation for entering the nursing department affects department satisfaction. In order to increase the department satisfaction of nursing students, it is thought that it is necessary to operate an integration promotion program and department adaptation program from the early stage of admission.