• Title/Summary/Keyword: stress of the principal

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The Literatual Study on the Growth Disorder (성장장애(成長障碍)에 관(關)한 문헌적(文獻的) 고찰(考察))

  • Jung Yeon-Hee;Kim Yun-Hee;Yoo Dong-Yeol
    • The Journal of Pediatrics of Korean Medicine
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    • v.13 no.1
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    • pp.17-62
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    • 1999
  • Recently lots of books on the process of growing have been published on adolescence and their parents hope to grow tall but yet lacked the correct knowledge. Before helping the growth of body, the best way is to do away with the check factors of the human body. Therefore oriental and occidental medicine study on the inhibition of growth and the result of case study about life therapy, kinesiatrics, including medical therapy are as follows: The habits that help the process of growing are deep sleep, balanced diets, daily physical exercise, good posture. It is essential for people to relieve stress. The physical exercises that promote the process of growing are as follows: to stretch out, daily suitable exercise which stimulates the metabolism of human body to increase levels of growth hormone and excite growth plate, to hasten the process of growing, Oriental medicine causes on the inhibition of growth show many factors: kidney trouble is the inhibited cause, spleen ailment is the acquired ground. The lack of essence of the dual principal of the negative and the positive makes people the inhibition of growth. All these things including fire and dryness have close relations.

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An Analysis on Attitudes of University Students in the Prediction of Smoking Behavior (흡연행위 예측을 위한 대학생의 태도 분석)

  • Jung Hyang Mi
    • Child Health Nursing Research
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    • v.4 no.1
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    • pp.128-149
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    • 1998
  • Cigarette smoking has been identified as the single most important source of preventable morbidity and mortality. Smoking behavior varies each individual, so individuality & subjectivity of smoking behavior must be specially focused upon to understand smoking behavior. The purpose of this study was to find attitudes of university students in the prediction of smoking behavior. Q-Methodological method was used as a research design and data were collected during the period from Jan.1, 1997 to Feb. 28, 1998. As the research method, Q-statements were collected through in- depth interviews and a literature review. For the study 33 Q-statements were selected. There were 45 university students as subjects for the research. The 45 university students sorted the 33 statements using the principle of Forced Normal Distribution. The principle of Forced Normal Distribution, which has nine scales to measure the individual opinions, Pc Quanl program was used for analysis and Q-factors were analyzed by using principal component analysis. According to the results of this study, there were four categories of opinion about the smoking behavior in university students. The first type is seeking the habitual dependency. The second type is seeking the stress relief : The third type is seeking the active disapproval : The fourth type is seeking the self control. As a result, The meaning of the smoking behavior is affected by perceived subjective experience, so we need to understand each persons meaning of the smoking behavior and to develop appropriate nursing interventions based on the typology of smoking behavior. Finally, The result of the study will provide basic data for smoking prevention and cessation program.

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Study on Structure Design of High-Stiffness for Multi-Function Automatic Lathe Bed (다기능 자동 선반 베드의 고강성 구조설계에 관한 연구)

  • Jo, Eun-Jeong;Lee, Yun-Chul;An, Jong-Bok;Lee, Yeong-Sik;Lee, Jae-Kwon;Kim, Kwang-Sun
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.1
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    • pp.112-116
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    • 2019
  • This study was carried out by structural analysis using finite element method for designing high rigidity structure of multi - functional automatic lathe bed. As a result of comparison, it was confirmed that the weight was designed to be higher than the maximum deformation amount. The shape and dimensions of the main pillars and walls of the bed were changed to derive the most suitable design for the multifunction automatic lathe bed. A model of structural design was derived with the goal of minimizing the maximum deformation amount of $20{\mu}m$ or less and the weight of the bed. As a result of applying the derived design improvement proposal to the multifunctional automatic lathe bed, 57.4% weight reduction and maximum principal stress decreased by 45.0% than the initial design model. It is expected that the optimum design that meets these design conditions will reduce the weight of the structure as well as improve the safety of the structure and reduce the machining error in the operation of the machine tool.

Numerical simulation of the flow in pipes with numerical models

  • Gao, Hongjie;Li, Xinyu;Nezhad, Abdolreza Hooshmandi;Behshad, Amir
    • Structural Engineering and Mechanics
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    • v.81 no.4
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    • pp.523-527
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    • 2022
  • The objective of this study is to simulate the flow in pipes with various boundary conditions. Free-pressure fluid model, is used in the pipe based on Navier-Stokes equation. The models are solved by using the numerical method. A problem called "stability of pipes" is used in order to compare frequency and critical fluid velocity. When the initial conditions of problem satisfied the instability conditions, the free-pressure model could accurately predict discontinuities in the solution field. Employing nonlinear strains-displacements, stress-strain energy method the governing equations were derived using Hamilton's principal. Differential quadrature method (DQM) is used for obtaining the frequency and critical fluid velocity. The results of this paper are analyzed by hyperbolic numerical method. Results show that the level of numerical diffusion in the solution field and the range of well-posedness are two important criteria for selecting the two-fluid models. The solutions for predicting the flow variables is approximately equal to the two-pressure model 2. Therefore, the predicted pressure changes profile in the two-pressure model is more consistent with actual physics. Therefore, in numerical modeling of gas-liquid two-phase flows in the vertical pipe, the present model can be applied.

The effect of arch geometry on the structural behavior of masonry bridges

  • Altunisik, Ahmet C.;Kanbur, Burcu;Genc, Ali F.
    • Smart Structures and Systems
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    • v.16 no.6
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    • pp.1069-1089
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    • 2015
  • Arch bridges consist of some important components for structural behavior such as arches, sidewalls, filling materials and foundations. But, arches are the most important part for this type of bridges. For this reason, investigation of arch is come into prominence. In this paper, it is aimed to investigate the arch thickness effect on the structural behavior of masonry arch bridges. For this purpose, Goderni historical arch bridge which was located in Kulp town, Diyarbakir, Turkey and the bridge restoration process has still continued is selected as an application. The construction year of the bridge is not fully known, but the date is estimated to be the second half of the 19th century. The bridge has two arches with the 0.52 cm and 0.69 cm arch thickness, respectively. Finite element model of the bridge is constructed with ANSYS software to reflect the current situation using relievo drawings. Then the arch thickness is changed by increasing and decreasing respectively and finite element models are reconstructed. The structural responses of the bridge are obtained for all arch thickness under dead load and live load. Maximum displacements, maximum-minimum principal stresses and maximum-minimum elastic strains are given with detail using contours diagrams and compared with each other to determine the arch thickness effect. At the end of the study, it is seen that the maximum displacements, tensile stresses and strains have a decreasing trend, but compressive stress and strain have an increasing trend by the increasing of arch thickness.

Concrete columns reinforced with Zinc Oxide nanoparticles subjected to electric field: buckling analysis

  • Arbabi, Amir;Kolahchi, Reza;Bidgoli, Mahmood Rabani
    • Wind and Structures
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    • v.24 no.5
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    • pp.431-446
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    • 2017
  • As concrete is most usable material in construction industry it's been required to improve its quality. Nowadays, nanotechnology offers the possibility of great advances in construction. In this study, buckling of horizontal concrete columns reinforced with Zinc Oxide (ZnO) nanoparticles is analyzed. Due to the presence of ZnO nanoparticles which have piezoelectric properties, the structure is subjected to electric field for intelligent control. The Column is located in foundation with vertical springs and shear modulus constants. Sinusoidal shear deformation beam theory (SSDBT) is applied to model the structure mathematically. Micro-electro-mechanic model is utilized for obtaining the equivalent properties of system. Using the nonlinear stress-strain relation, energy method and Hamilton's principal, the motion equations are derived. The buckling load of the column is calculated by Difference quadrature method (DQM). The aim of this study is presenting a mathematical model to obtain the buckling load of structure as well as investigating the effect of nanotechnology and electric filed on the buckling behavior of structure. The results indicate that the negative external voltage applied to the structure, increases the stiffness and the buckling load of column. In addition, reinforcing the structure by ZnO nanoparticles, the buckling load of column is increased.

Analysis of Deformation Behavior of Underground Caverns in a Discontinuous Rock Mass Using the Distinct Element Method (개별요소법을 이용한 불연속 암반내 지하공동의 변형 거동 해석)

  • Jung, Wan-Kyo;Lim, Han-Uk
    • Journal of Industrial Technology
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    • v.23 no.A
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    • pp.69-81
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    • 2003
  • Numerical analysis is important for the design, construction and maintenance of large caverns. The rock mass contains generally discontinuities such as faults, joints and fissures. The mechanical behavior and geometric characteristics of these discontinuities would have a significant impact on the stability of the caverns. In this research the Distinct Element Method(DEM) was used to analyze the structural stability of the large cavern. The Barton-Bandis Joint Model (B-B J.M) was used as a constitutive model for the joint. In addition, two different cases 1) analysis with a support system and 2) analysis with no support system, were analyzed to optimize a support system and to investigate reinforcing effects of a support system. The most significant parameters of in-situ stress, JRC of in-situ natural joints, and spatial distribution characteristics of discontinuities were acquired through field investigation. Displacement (horizontal, joint shear), maximum joint opening, maximum and minimum principal stresses, range of relaxed zone, rockbolt axial forces and shotcrete stresses were calculated at each excavation stage. As a result of analysis the calculated values proved to be under the allowable value Rockbolts also proved to be an efficient support measure to control joint shear displacement which had significant effects on extending the relaxed zone. As a consequence, the structural stability of the cavern was assured with an appropriate support system.

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Large deflection analysis of orthotropic, elliptic membranes

  • Chucheepsakul, Somchai;Kaewunruen, Sakdirat;Suwanarat, Apiwat
    • Structural Engineering and Mechanics
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    • v.31 no.6
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    • pp.625-638
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    • 2009
  • Applications of membrane mechanisms are widely found in nano-devices and nano-sensor technologies nowadays. An alternative approach for large deflection analysis of the orthotropic, elliptic membranes - subject to gravitational, uniform pressures often found in nano-sensors - is described in this paper. The material properties of membranes are assumed to be orthogonally isotropic and linearly elastic, while the principal directions of elasticity are parallel to the coordinate axes. Formulating the potential energy functional of the orthotropic, elliptic membranes involves the strain energy that is attributed to inplane stress resultant and the potential energy due to applied pressures. In the solution method, Rayleigh-Ritz method can be used successfully to minimize the resulting total potential energy generated. The set of equilibrium equations was solved subsequently by Newton-Raphson. The unparalleled model formulation capable of analyzing the large deflections of both circular and elliptic membranes is verified by making numerical comparisons with existing results of circular membranes as well as finite element solutions. The results are found in excellent agreements at all cases. Then, the parametric investigations are given to delineate the impacts of the aspect ratios and orthotropic elasticity on large static tensions and deformations of the orthotropic, elliptic membranes.

Analysis and Optimization of Design Parameters in a Cold Cross Rolling Process using a Response Surface Method (반응표면법을 이용한 냉간전조압연공정 설계변수의 영향도 분석 밑 설계최적화)

  • Lee, H.W.;Lee, G.A;Choi, S.;Yoon, D.J.;Lim, S.J.;Lee, Y.S.
    • Transactions of Materials Processing
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    • v.15 no.8 s.89
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    • pp.550-555
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    • 2006
  • In this study, effects of forming angle and friction coefficient on a initiation of the Mannesmann hole defect were analyzed by using a response surface method. The maximum effective plastic strain at center point of specimen is utilized for the prediction of the starting point of crack occurrence, which is suggested by the comparison of integrals of four different ductile fracture models between the histories of the effective plastic strain at center point. It was revealed that the principal stress at the center is the dominant element to the increase of the effective plastic strain. It was also verified by the simulation results from the comparison of experiment and simulation. It is provided that the forming angle of 25 degrees and the spreading angle of 1 degree can be a proper design condition without an occurrence of internal hole defect and an excessive slip.

A Study on the Service Load State Behavior of Reinforced Concrete Plate Member

  • Bhang, Jee-Hwan;Kang, Won-Ho
    • KCI Concrete Journal
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    • v.12 no.2
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    • pp.55-72
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    • 2000
  • This paper proposes a mechanical model to describe the load-deformation responses of the reinforced concrete plate members under service load state. An Analytical method is introduced on the basis of the rotating crack model which considers equilibrium, compatibility conditions, load-strain relationship of cracked member, and constitutive law for materials. The tension stiffening effect in reinforced concrete structures is taken into account by the average tensile stress-strain relationship from the load-strain relationship for the cracked member and the constitutive law for material. The strain compatibility is used to find out the crack direction because the crack direction is an unknown variable in the equilibrium and compatibility conditions. The proposed theory is verified by the numerous experimental data such as the crack direction, moment-steel strain relationship, moment-crack width relationship. The present paper can provide some basis for the provision of the definition of serviceability for plate structures of which reinforcements are deviated from the principal stresses, because the present code defines the serviceability by the deflection, crack control, vibration and fatigue basically for the skeletal members. The proposed theory is applicable to predict the service load state behavior of a variety of reinforced concrete plate structures such as skew slab bridges, the deck of skew girder bridges.

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