• 대한물리의학회지
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• 제8권2호
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• pp.263-269
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• 2013

PURPOSE: The purpose of this study was to examine the effects of breathing retraining on asymmetry of diaphragm thickness in stroke patients. METHODS: This study was nonequivalent control group pre-post test design. Subjects were assigned to two different groups(intervention group=10, control group=12). Intervention group conducted breathing retraining program for six-week. Diaphragm thickness was assessed by ultrasound in B-mode with a 7.5 MHz linea probe. The collected data analyzed by Wilcoxon signed rank test and Mann-Whitney U test. RESULTS: The intervention group significantly increased diaphragm thickness ratio on paretic side but the control group showed no significant difference in diaphragm thickness ratio. The control group significantly increased asymmetry of diaphragm thickness, but intervention group showed no significant difference in asymmetry of diaphragm thickness. CONCLUSION: This study showed that breathing retraining increased diaphragm thickness ratio in stroke patients and prevent the increase of asymmetry in diaphragm thickness with stroke patients.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.153-154
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• 2022

When reinforcing an existing building with the Concrete Filled Tube(CFT) structure, it is impossible to form a diaphragm inside with the existing method. Therefore, in this study, a construction method was proposed so that the force could be transmitted using the friction force between the diaphragm and the concrete using a double diaphragm.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.551-554
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• 2005

This study uses a characteristic function to explain correlations between the objective function and design variables. Analysis of means and table of orthogonal array were carried out. The change of shape of diaphragm, thickness of diaphragm and voice coil weight based on the table of orthogonal array is made. Therefore this study carried to decide shape of diaphragm, voice coil weight and thickness of diaphragm for minimizing 1st natural frequency and maximizing 2nd natural frequency of diaphragm using design of experiments and characteristic function with constraints. we showed improved design factors that minimized 1st natural frequency and maximized 2nd natural frequency of diaphragm.

• 한국공작기계학회논문집
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• 제17권6호
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• pp.124-131
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• 2008

There are many factors which affect the acoustical properties of a micro-speaker. Among the factors, the shape of the diaphragm is considered in this study. As an investigating method, the finite element methods and measurement techniques applied to study the acoustical properties according to diaphragm shape. In order to vary the stiffness of the diaphragm, the some patterns of comb teeth, such as the angle and the number of comb teeth, are applied to diaphragm. We can confirm that the change of the stiffness by the changing diaphragm shape affects the vibration and sound properties of the speaker. As a result, the reduction of the angle of the comb teeth increases the diaphragm stiffness and shifts the resonance frequency to a higher frequency range. The number of the comb teeth is related to the stiffness of the edge part.

• 동력기계공학회지
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• 제14권6호
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• pp.35-40
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• 2010

This article deals with the numerical analysis results of stiffness of diaphragm spring used in the clutch of a manual transmission. In order to investigate the relationship of the force and displacement in a diaphragm spring, we have established a numerical model of diaphragm spring using a well-known analytic model of Belleville spring and a cantilever beam model for the finger part of diaphragm spring. Using the stress and strain relations of Belleville spring and cantilever beam, we propose the analytic equation of motion of diaphragm spring for the use of a clutch automated actuator in an automated manual transmission. The proposed analytic model represents the typical dynamic characteristics of diaphragm spring along with the release bearing travel. And it is characterized in a closed-form equation, therefore it can be used for the further study of development of actuator and control law of clutch automating mechanism.

• 한국전산구조공학회논문집
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• 제15권3호
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• pp.501-510
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• 2002

상자형의 중간격벽은 상자형의 단면변형을 구속하고 상부플랜지에서 발생되는 하중을 양측의 웨브에 분포시키는 역할을 한다. 그러나 상자형의 내부공간이 중간격벽으로 차단될 경우 내부공간을 활용할 수 없으며 유지관리에 많은 어려움을 격게 된다. 상자형의 격벽이 개구부를 갖는 경우 개구부가 없는 경우에 비하여 어떠한 영향을 갖는지를 실험을 통하여 중간격벽의 강성으로 표현하고자 하였다

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2961-2966
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• 2007

When the pressure at the weak spot established at a certain part of a high pressure vessel or piping system exceeds a design pressure, this weak spot is burst, and the pressurized gas emitted through the weak spot will cause a compression wave system. In this connection, in the present study, an experimental study by using a conventional shock tube facility is performed to estimate the effects of the material of diaphragm, curvature radius and thickness of materials on the valve opening time in diaphragm. Pressure sensor having 500kHz in natural frequency is installed at 35mm downstream of the rupture diaphragm to measure the static pressure history of propagating and being accumulated compression wave. 4 kinds of materials are used as diaphragm that is aluminium, copper, stainless steel and zinc. The diaphragm radii of curvature R are ${\infty}$, 120mm and 60, respectively. And the depth for $90^{\circ}$ groove is 0.04mm. It is found that the smaller the tensile strength and elongation of the rupture diaphragm is, the smaller the radius of curvature of the rupture diaphragm is, and for the same conditions the thinner the thickness of the rupture diaphragm is, the shorter the valve opening time becomes. Also, the tensile strength, elongation and the radius of curvature of the rupture diaphragm for the same conditions are smaller, the maximum pressure rise caused by the coalescences of the compression wave is smaller. Finally the pressure ratio is higher, the valve opening time is shortened and gradient of pressure increment is more steepen.

• Structural Engineering and Mechanics
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• 제77권4호
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• pp.463-472
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• 2021

Fully rigid floor diaphragm is one of the main assumptions that are widely used in common practices due to its simple application. However, determining the exact degree of diaphragms flexibility cannot be easily accomplished without finite element modeling, which is an expensive and time-consuming procedure. Therefore, it is always possible that apparently rigid diaphragms, based on prescriptive limitations of seismic codes, experience some degrees of flexibility during the earthquakes. Since diaphragm flexibility has more uncertainties in asymmetric-plan structures, this study focuses on errors resulting from probable floor diaphragm flexibility of torsionally restrained structures. The analytical models used in this study were single-story buildings with asymmetric plan and RC shear walls. Although floor system is not considered explicitly, a wide range of considered diaphragm flexibility, from fully rigid to quite flexible, allows the results to be generalizable to a lot of lateral load resisting systems as well as floor systems. It has been shown that in addition to previously known effects of diaphragm flexibility, presence of orthogonal side elements during design procedure with rigid diaphragm assumption and rapid reduction in their absorbed forces can also be an important source to increase errors due to flexibility. Accordingly, from the obtained results the authors suggest designers to consider the possibility of diaphragm flexibility and its adverse effects, especially in torsionally restrained systems in their common designs.

• 한국강구조학회 논문집
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• 제18권2호
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• pp.123-135
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• 2006

이 연구에서는 원형기둥-상자형보 접합부의 다이아프램 형상에 따른 거동특성과 다이아프램 설계방법에 관한 것이다. 강재 원형기둥-상자형보 접합부의 다이아프램은 상자형보 하부플랜지로부터 전달되는 집중력을 지지하게 되며, 보와 기둥의 강도 뿐만아니라 접합부의 거동에 큰 영향을 미치게 된다. 기존의 연구에서는 부정정 곡선보 모델로부터 유도된 다이아프램의 응력계산식이 제시되어 있으나, 설계식으로 활용되기에는 계산과정이 난해하고 유도과정이 비합리적이다. 또한 접합부 강도에 대한 다이 아프램의 역할을 고려하지 않음으로써 다이아프램의 합리적인 설계가 이루어 지지 못하고 있다. 따라서 이 연구에서는 접합부 다이아프램의 설계변수에 대한 비선형 유한요소 해석을 수행하여, 다이아프램의 형상에 따른 강도특성을 검토하였다. 또한 원형기둥-상자형보, 접합부 다이아프램의 이론식이 접합부의 실제 거동과 큰 차이를 나타냄을 확인하였고, 보와 기둥 및 다이아프램 강성을 고려한 강재 원형기둥 접합부 다이아프램의 설계방법을 제안하였다.

• Computers and Concrete
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• 제33권2호
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• pp.195-204
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• 2024

Floor inertial forces are transferred to lateral force resisting systems through a diaphragm action during earthquakes. The diaphragm action requires floor slabs to carry in-plane forces. In precast concrete diaphragms, these forces must be carried across the joints between precast floor units as they represent planes of weakness. Therefore, diaphragm reinforcement with sufficient strength and deformability is necessary to ensure the diaphragm action for the floor inertial force transfer. In a shake table test for a three-story precast concrete structure, an unexpected local failure in the diaphragm flexural reinforcement occurred. This failure caused loss of the diaphragm action but did not trigger collapse of the structure due to a possible alternative path for the floor inertial force transfer. This paper investigates this failure event and its impact on structural seismic responses based on the shake table test and simulation results. The simulations were conducted on a structural model with discrete diaphragm elements. The structural model was also validated from the test results. The investigation indicates that additional floor inertial force will be transferred into the gravity columns after loss of the diaphragm action which can further result in the increase of seismic demands in the gravity column and diaphragms in adjacent floors.