• Title/Summary/Keyword: Static analysis

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Improved Static Element Stiffness Matrix of Thin-Walled Beam-Column Elements (박벽보-기둥 요소의 개선된 정적 요소강성행렬)

  • Yun, Hee Taek;Kim, Nam Il;Kim, Moon Young;Gil, Heung Bae
    • Journal of Korean Society of Steel Construction
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    • v.14 no.4
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    • pp.509-518
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    • 2002
  • In order to perform the spatial buckling and static analysis of the nonsymmetric thin-walled beam-column element, improved exact static stiffness matrices were evaluated using equilibrium equation and force-deformation relationships. This numerical technique was obtained using a generalized linear eigenvalue problem, by introducing 14 displacement parameters and system of linear algebraic equations with complex matrices. Unlike the evaluation of dynamic stiffness matrices, some zero eigenvalues were included. Thus, displacement parameters related to these zero eigenvalues were assumed as polynomials, with their exact distributions determined using the identity condition. The exact displacement functions corresponding to three loadingcases for initial stress-resultants were then derived, by consistently combining zero and nonzero eigenvalues and corresponding eigenvectors. Finally, exact static stiffness matrices were determined by applying member force-displacement relationships to these displacement functions. The buckling loads and displacement of thin-walled beam were evaluated and compared with analytic solutions and results using ABAQUS' shell element or straight beam element.

The effects of patterns of proprioceptive neuromuscular facilitation & swiss ball exercise on static balance (고유수용성신경근촉진법 운동과 스위스 볼 운동을 적용 했을 때 정적 균형에 미치는 영향)

  • Choi, Won-Jye;Jeon, Jae-Keun;Lee, Woo-Young;Kim, Ki-Bum;Ju, Hye-Mi;Park, So-Hee;Byun, Ju-Hyung;Son, Kyung-Hyun;Kim, Bong-Hwan
    • PNF and Movement
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    • v.8 no.2
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    • pp.25-36
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    • 2010
  • Purpose : The purpose of study was to determine effects of Proprioceptive Neuromuscular Facilitation pattern exercise with Swiss ball exercise and Swiss ball exercise on balance in the 40 students from H university. Method : There were two experimental conditions. There were two difference groups in the experimental conditions, which had to perform different exercise tasks: Swiss ball exercise group (n=20) and Proprioceptive Neuromuscular Facilitation exercise with Swiss ball exercise group(n=20). The experimental group received Proprioceptive Neuromuscular Facilitation exercise for 20minutes and Swiss Ball exercise for 40minutes, 3 times a week for 4weeks. While another experimental group received Swiss Ball exercise for 40minutes, 3 times a week for 4weeks. In order to evaluation effects of the Proprioceptive Neuromuscular Facilitation pattern exercise with Swiss Ball exercise and Swiss Ball exercise in the two different experimental group, subjects was measured by static balance. Statistical analysis was the paired t-test to compare the differences within groups and the SPSS to analyze the differences between groups. Results : The result of this study were as follows: The static balance was higher for the two different experimental group in post-exercise than in pre-exercise(P<0.5). Proprioceptive Neuromuscular Facilitation pattern exercise with Swiss Ball exercise experimental group was significant difference better then another experimental group(P<0.5). Conclusion : The Proprioceptive Neuromuscular Facilitation pattern exercise with Swiss Ball exercise can result in improved static balance better then Swiss Ball exercise.

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A Study on Informediated code for Analyzing Bytecodes (바이트코드 분석을 위한 중간코드에 관한 연구)

  • Kim, Kyung-Soo;Yoo, Weon-Hee
    • Journal of the Korea Society of Computer and Information
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    • v.11 no.1 s.39
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    • pp.107-117
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    • 2006
  • Java language creates class files through Java compiler. Class files include informations involved with achievement of program. We can do analysis and optimization for efficient codes by analyzing class files. This paper analyzes bytecodes using informations of Java class files. We translate stack-based Java bytecodes into 3-address codes. Then we translate into static single assignment form using the 3-address codes. Static single assignment form provides a compact representation of a variable's definition-use information. Static single assignment form is often used as an intermediate representation during code optimization. Static sing1e assignment form renames each occurrence of a variable such that each variable is defined only once.

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Numerical Study on Estimation of Static Configuration of Steel Lazy Wave Riser Using Dynamic Relaxation Method (동적이완법을 이용한 Steel Lazy Wave Riser의 정적형상 추정에 관한 수치해석적 연구)

  • Oh, Seunghoon;Jung, Jae-Hwan;Park, Byeongwon;Kwon, Yong-Ju;Jung, Dongho
    • Journal of Ocean Engineering and Technology
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    • v.32 no.6
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    • pp.466-473
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    • 2018
  • This paper presents an estimation method for the static configuration of a steel lazy wave riser (SLWR) using the dynamic relaxation method applied to estimate the configuration of structures with strong geometric non-linearity. The lumped mass model is introduced to reflect the flexible structural characteristics of the riser. In the lumped mass model, the tensions, shear forces, buoyancy, self-weights, and seabed reaction forces at nodal points are considered in order to find the static configuration of the SLWR. The dynamic relaxation method using a viscous damping formulation is applied to the static configuration analysis. Fictitious masses are defined at nodal points using the sum of the largest direct stiffness values of nodal points to ensure the numerical stability. Various case studies were performed according to the bending stiffness and size of the buoyancy module using the dynamic relaxation method. OrcaFlex was employed to validate the accuracy of the developed numerical method.

Immediate Effects of Ankle Dorsiflexor Facilitation Dynamic Taping on Static and Dynamic Balance and Gait Speed in Stroke Patients With Foot Drop (발등굽힘근 촉진 다이나믹 테이핑이 발 처짐이 있는 뇌졸중 환자의 정적, 동적 균형과 보행 속도에 미치는 즉각적 효과)

  • Im, Jin-gu;Kim, Suhn-yeop
    • Physical Therapy Korea
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    • v.29 no.1
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    • pp.19-27
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    • 2022
  • Background: Foot drop is a common symptom in stroke patients. Tape applications are widely used to manage foot drop symptoms. Previous studies have evaluated the effects of static and dynamic balance and gait on foot drop using kinesiology tape; however, only few studies have used dynamic tape application in stroke patients with foot drop. Objects: The purpose of this study was to investigate the immediate effects of dynamic taping, which facilitates the dorsiflexor muscle, on static and dynamic balance and gait speed in stroke patients with foot drop. Methods: The study included 34 voluntary patients (17 men, 17 women) with stroke. The patients were randomly assigned to the experimental group (n = 17), wherein dynamic taping was used to facilitate the dorsiflexor muscle, or the control group (n = 17), wherein kinesiology taping was used. Before the taping application, velocity average, path-length average, Berg balance scale, and timed up and go test (TUG) were recorded to measure static and dynamic balance, whereas the 10-meter walk test (10MWT) was used to measure gait speed. After the taping application, these parameters were re-evaluated in both groups. Repeated measure analysis of variance was used. Statistical significance levels were set to α = 0.05. Results: Except for the 10MWT scores in the control group, significant differences were noted in all the parameters measured for static and dynamic balance and gait speed between the pre and post-test (p < 0.05). However, the parameters showed significant interaction effects between group and time in the TUG and 10MWT (p < 0.01). Conclusion: These results indicate that compared with kinesiology taping, dynamic taping used in chronic stroke patients with foot drop had a more significant effect on dynamic balance and gait speed.

Fatigue Life Prediction for the Skin Structures of Aircraft Sensor Pod Under Acoustic Load with Mean Stress (평균 응력을 고려한 음향 하중을 받는 항공기 센서 포드 외피 구조의 내구 수명 분석)

  • Min-Hyeok Jeon;Yeon-Ju Kim;Hyun-Jun Cho;Mi-Yeon Lee;In-Gul Kim;Hansol Lee;Jae Myung Cho;Jong In Bae;Ki-Young Park
    • Journal of the Korea Institute of Military Science and Technology
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    • v.26 no.1
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    • pp.1-9
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    • 2023
  • The skin structure of sensor pod mounted on the exterior of aircraft can be exposed to the acoustic dynamic load and static load such as aerodynamic pressure and inertial load during flight. Fatigue life prediction of structural model under acoustic load should be performed and also differential stiffness of model modified by static load should be considered. The acoustic noise test spectrum of MIL-STD-810G was applied to the structural model and the stress response power spectral density (PSD) was calculated. The frequency response analysis was performed with or without prestress induced by inplane static load, and the response spectrum was compared. Time series data was generated using the calculated PSD, and the time and frequency domain fatigue life were predicted and compared. The variation of stress response spectrum due to static load and predicted fatigue life according to the different structural model considering mean stress were examined and decreasing fatigue life was observed in the model with prestress of compressive static load.

Evaluation of the Resistance Bias Factors to Develop LRFD for Driven Steel Pipe Piles (LRFD 설계를 위한 항타강관말뚝의 저항편향계수 산정)

  • Kwak, Kiseok;Park, Jaehyun;Choi, Yongkyu;Huh, Jungwon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.5C
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    • pp.343-350
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    • 2006
  • The resistance bias factors for driven steel pipe piles are evaluated as a part of study to develop the LRFD(Load and Resistance Factor Design) for foundation structures in Korea. The 43 data sets of static load tests and soil property tests performed in the whole domestic area were collected and analyzed to determine the representative bearing capacities of the piles using various methods. Based on the statistical analysis of the data, the Davisson's criterion is proved to be the most reasonable method for estimation of pile bearing capacity among the methods used. The static bearing capacity formulas and the Meyerhof method using N values are applied to calculate the design bearing capacity of the piles. The resistance bias factors of the driven steel pipe piles are evaluated respectively as 0.98 and 1.46 by comparison of the bearing capacities for both of the static bearing capacity formulas and the Meyerhof method. It is also shown that uncertainty of the static bearing capacity formulas is relatively less than that of the Meyerhof method.

A Novel Stator Hybrid Excited Doubly Salient Permanent Magnet Brushless Machine for Electric Vehicles

  • Zhu Xiaoyong;Cheng Ming
    • Journal of Electrical Engineering and Technology
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    • v.1 no.2
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    • pp.185-191
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    • 2006
  • In this paper, a novel stator hybrid excited doubly salient permanent magnet (SHEDS-PM) brushless machine with a special magnetic bridge is proposed for the first time. The originality of this machine is purposely to add a magnetic bridge in shunt with each PM pole, which not only maintains the stator lamination in its entireness, but also amplifies the effect of DC field flux on PM flux. An equivalent magnetic circuit is presented to clarify the novelty. Based on the 2-D finite element analysis, the static characteristics of the SHEDS-PM machine, namely phase flux linkage, back-EMF, cogging torque, winding inductance and static torque are deduced. The corresponding results on a prototype machine illustrate that the proposed machine is promising for application to electric vehicles.

Seismic Performance Evaluation of Building Structures Using Modified Capacity Spectrum (수정된 능력스펙트럼을 이용한 건축구조물의 내진성능평가)

  • 최원호
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2000.04a
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    • pp.267-274
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    • 2000
  • Current seismic design codes for building structures are based on the method which can provide enough capacity to satisfy objected performance level and exactly evaluate the seismic performance of buildings. The capacity spectrum method using the nonlinear static(pushover) analysis is becoming a popular tool for evaluating the seismic performance of existing and new building structures. By means of a graphical procedure capacity spectrum method esimates the performance level of structure by comparing the capacity of structure with the demand of earthquake ground motion on the structure. In the method the relation between base shear estimated by a nonlinear static analysis and horizontal displacement is used. Capacity spectrum is usually expressed as what represent the responses of the equivalent single degree of freedom (ESDOF) system for the building structures. However there are some problems in converting procedures into ESDOF system which include not considering the effect of higher modes of structures. The objective of this paper is to compare and verify existing methods and suggest the modified capacity spectrum for seismic performance evaluation of building structures.

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A Study on the Energy Absorption Capacity of Collision and Corner Posts of EMU according to APTA SS-C&S-034-99 Standard (미국 규격에 따른 전두부 충돌에너지 흡수 요구조건의 해석적 평가)

  • Jeong, Ji-Ho;Lee, Jan-Wook;Park, Gun-Soo;Woo, Kwan-Je
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.289-294
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    • 2011
  • The purpose of this paper is to validate energy absorbing capacity that satisfies APTA SS-C&S-034-99, REV.2 with North America type Electric Multiple Units. The FE models for collision and corner post simulation were developed. Two type of simulation were conducted. One is quasi-static analysis for collision post and the other is quasi-static analysis for corner post. And the energy absorption capacity of the analytical model was verified.

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