• Title/Summary/Keyword: Physical model test

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A Study on the Model Updating Procedures Using Modal Frequencies (모드 주파수를 이용한 모델 개선 과정에 대한 연구)

  • Jang, In-Sik
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.2
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    • pp.109-116
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    • 2010
  • It is important to make a mechanical structure precisely and reasonably in predicting the dynamic characteristics, controlling the vibration, and designing the structure dynamics. In finite element analysis model updating is appropriate as the design parameter is used to analyze the dynamic system. The errors can be contained from the physical parameters and the element modeling. From the dynamic test, more precise dynamic characteristics can be obtained. In this paper, model updating algorithm is developed using frequency difference between experiment and calculation. Modal frequencies are obtained by experiment and finite element analysis for beams with various cross section and shapes which have added masses and holes in the middle. For plates with and without groove, experiment and analyses are carried out by applying free boundary conditions as well. Mass and stiffness matrices are updated by comparing test and analytical modal frequencies. The result shows that the updated frequencies become closer to the test frequencies in case that both matrices are updated. An improved analytical model is obtained by changing model parameters such that the discrepancy between test and finite element frequencies is minimized. For beam and plate models updating of mass and stiffness matrices can improve the dynamical behavior of the model by acting on the physical parameters such as masses and stiffness.

The Effects of Qigong training on the cardiopulmonary functions and catecholamine levels after physical traning stress in untrained college students (‘내경일지선(內徑一指禪)’ 기공수련이 대학생의 운동부하 스트레스 후의 심폐기능 및 Catecholamine 변화에 미치는 영향)

  • Kim Jong-Woo;Oh Jae-Keun;Whang Wei-Wan
    • Journal of Oriental Neuropsychiatry
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    • v.7 no.1
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    • pp.39-48
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    • 1996
  • This study was performed to investigate the effects of Qigong training after physical training stress in untrained college students For this study, 6 voluntary subjects(male 4, female 2) were chosen in untrained students of K University. they were trained by teachers during 6 weeks and tested just before Qingong training and after 6 weeks. Each subject was performed a treadmill exercise(model Q65, Quinton Co, U.S.A.) to the all-out state. During exercise stress test, electrocardiogram, heart rate were checked by stress test monitor(model Q4500, Quinton Co, U.S.A) and also oxygen uptake, maximal oxygen uptake analyzed continuously by automatic gas analysis(model QMC, Quinton Co, U.S.A). During physical training the serum were collected 3 times, pre-experimental rest time, and serum catecholamine were measured by HPLC.T-test of statistical analysis system was used in every experiment for statistical assessment. The results of T-test on these data were summarized as follow:1.Heart rate change during exercise stress test after Qigong training was shown more decreasing tendency than before training. Especially, heart rate change after Qigong training during resting periods was decreased significantly than before training.2. Oxygen uptake change during exercise stress test after Qigong training was shown more increasing tendency than before training, And also maximal oxygen uptake after Qigong training was shown more increasing tendency than before 6 weeks.3. Epinephrine level of after Qigong training was more decreased significantly than before training in all-out state. And norepinephrine level of after Qigong training was shown more decreasing tendency than before training in all-out state and after 30 minutes rest time. Above results indicate that Qigong training for 6 weeks could be effective to elevate the cardiopulmonary functions and diminish the stress responses of the physical stress.

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Development of Integrated Model for Accelerated Life Test Using Linkage Parameter (연계모수를 이용한 가속수명시험 통합모형의 개발)

  • Choi, Sung-Woon
    • Journal of the Korea Safety Management & Science
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    • v.9 no.5
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    • pp.43-48
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    • 2007
  • This paper is to present linkage parameter to integrate statistical models and physical models for accelerated life test. Statistical models represent the relationship of probability distribution and life. Physical models show the relationship of life and stress. Moreover, this study proposes the four steps for construction of integrated models for accelerated life test using linkage parameter. Finally, this paper develops new integrated models such as extreme value distribution-general Eyring, linearly increasing failure rate function-general Eyring, etc., and estimates various reliability measures.

Construction of Health-related Quality of Life Model in Acquired People with Physical Disabilities (후천성 지체장애인의 건강관련 삶의 질 모형구축)

  • Kim, Kye Ha
    • Korean Journal of Adult Nursing
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    • v.18 no.2
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    • pp.213-222
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    • 2006
  • Purpose: This study was designed to construct a structural model for explaining model health-related quality of life in acquired people with physical disabilities. Method: The hypothetical model of this study was consisted of 6 latent variables and 14 observed variables. Exogenous variables included in this model were physical status and economical level. Endogenous variables were social attitudes, family function, self-esteem, and health-related quality of life. Data were collected from 226 acquired people with physical disabilities residing in Seoul and Kyunggi-do from January to February, 2005. The collected data were analyzed using SAS 8.2 version and LISREL 8.32 version program. Results: The results of the fitness test of the modified model were follow as; ${\chi}^2=67.479$ (df=50, p=.05), GFI=.959, AGFI=.914, SRMR=.049, NFI=.961, NNFI=.979, CN=249.244. Health-related quality of life was influenced directly by physical status, economic level, and social attitudes and accounted for 88.8% of the variance by these factors. Conclusion: These results suggest that physical status is the most significant effect on health-related quality of life, and social attitudes and economic level are important factors having influences on health- related quality of life. Therefore improving physical status and economic level, and modifying negative attitudes are necessary to increase health-related quality of life of acquired people with acquired physical disabilities.

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Factors Predicting the Physical Activity Behavior of Female Adolescents: A Test of the Health Promotion Model

  • Mohamadian, Hashem;Arani, Mohammad Ghannaee
    • Journal of Preventive Medicine and Public Health
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    • v.47 no.1
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    • pp.64-71
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    • 2014
  • Objectives: Physical activity behavior begins to decline during adolescence and continues to decrease throughout young adulthood. This study aims to explain factors that influence physical activity behavior in a sample of female adolescents using a health promotion model framework. Methods: This cross-sectional survey was used to explore physical activity behavior among a sample of female adolescents. Participants completed measures of physical activity, perceived self-efficacy, self-esteem, social support, perceived barriers, and perceived affect. Interactions among the variables were examined using path analysis within a covariance modeling framework. Results: The final model accounted for an $R^2$ value of 0.52 for physical activity and offered a good model-data fit. The results indicated that physical activity was predicted by self-esteem (${\beta}$=0.46, p<0.001), perceived self-efficacy (${\beta}$=0.40, p<0.001), social support (${\beta}$=0.24, p<0.001), perceived barriers (${\beta}$=-0.19, p<0.001), and perceived affect (${\beta}$=0.17, p<0.001). Conclusions: The findings of this study showed that the health promotion model was useful to predict physical activity behavior among the Iranian female adolescents. Information related to the predictors of physical activity behavior will help researchers plan more tailored culturally relevant health promotion interventions for this population.

The Study of Verification Bi-Digital O-Ring Test by gaugus (계측기(計測器)를 이용(利用)한 O-Ring Test법(法)의 검증(檢證)에 관(關)한 연구(硏究))

  • Kim, Jong-Ryol;Kim, Dal-Rae
    • Journal of Sasang Constitutional Medicine
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    • v.7 no.1
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    • pp.69-101
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    • 1995
  • Using Bi-Digital O-Ring Test which was developed by Ohmura Toshiaki, constitution classification by the vegetables' was measured by various muscle power measurement meters and the results are as follow : 1. Pinch guage (Model : pc5030HPG, Japan) is the guage to measure finger power between the thumb and second finger, Grip Strength Dynamometer (Model : T.K.K. 5101, Japan) is to measure the hand power (hand dynamometer), Back Strength dynamometer (Model : T.K.K. 5102, Japan)is to measue back muscle strength, Vertical Jump Meter (Model : T.K.K. 5106, Japan) is to measure the height of jump. The above guages were used and its result found that the radish, potato, carrot and cucumber can influence to the muscle strength was not true. 2. When the physical constitution is distinguished vy the O-Ring Test method, Taeyangin's rate appeared as average 21% although it was insistedthat there will be only 0.03-0.1%. This means that the influence power of vegetable doest not appear according to the physical constitution but it appears accidently according to the examinee's emotion about the material such as vegetable etc. as favor or unfavor. 3. It was found that the result of O-Ring Test is the same at any time and at any place was not true. there is no reemergence character. 4. The import of O-Ring Test method to the physical discriminatio disregarded that the mental facor influences absolutely to the physical heath in the ideological physical constitution medicla science. 5. 'O-Ring Test method is a objective judgement method'. is wrong judgement. As you see on the above result, Bi-Digital O-Ring Test set the changeable voluntary muscle as the standard of the judgement, that was first mistake logically, second in spite of leass influence of mental influence by the examiner and examinee than the vegetable discrimination influence, the test disregarded the influence. Thire, only grasp of some material on hand can influence to the voluntary was a wrong theory disregarding the physiology. Finally the misunderstaning his subjective view as an objective view in spite of examiner and examinee's strong influence. Therefore such kind of physical descrimination method must be sublated.

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Development of Finite Element Model of Hybrid III 5th Percentile Female Dummy (Hybrid III 5% 성인 여성 더미의 유한요소 모델 개발)

  • Yi, Sang-Il;Mohan, Pradeep K.;Kan, Cing-Dao Steve;Park, Gyung-Jin
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.4
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    • pp.18-30
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    • 2010
  • As the automobile industry is developing, the number of deaths and injuries has increased. To reduce the damages from automobile accidents, the government of each country proposes experimental conditions for reproducing the accident and establishes the vehicle safety regulations. Automotive manufacturers are trying to make safer vehicles by satisfying the requirements. The Hybrid III crash test dummy is a standard Anthropomorphic Test Device (ATD) used for measuring the occupant's injuries in a frontal impact test. Since a real crash test using a vehicle is fairly expensive, a computer simulation using the Finite Element Method (F.E.M.) is widely used. Therefore, a detailed and robust F.E. dummy model is needed to acquire more accurate occupant injury data and behavior during the crash test. To achieve this goal, a detailed F.E. model of the Hybrid III 5th percentile female dummy is constructed by using the reverse engineering technique in this research. A modeling process is proposed to construct the F.E. model. The proposed modeling process starts from disassembling the physical dummy. Computer Aided Design (CAD) geometry data is constructed by three-dimensional (3-D) scanning of the disassembled physical dummy model. Based on the geometry data, finite elements of each part are generated. After mesh generation, each part is assembled with other parts using the joints and rigid connection elements. The developed F.E. model of dummy is simulated based on the FMVSS 572 validation regulations. The results of simulation are compared with the results of physical tests.

Physical modelling of sliding failure of concrete gravity dam under overloading condition

  • Zhu, Hong-Hu;Yin, Jian-Hua;Dong, Jian-Hua;Zhang, Lin
    • Geomechanics and Engineering
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    • v.2 no.2
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    • pp.89-106
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    • 2010
  • Sliding within the dam foundation is one of the key failure modes of a gravity dam. A two-dimensional (2-D) physical model test has been conducted to study the sliding failure of a concrete gravity dam under overloading conditions. This model dam was instrumented with strain rosettes, linear variable displacement transformers (LVDTs), and embedded fiber Bragg grating (FBG) sensing bars. The surface and internal displacements of the dam structure and the strain distributions on the dam body were measured with high accuracy. The setup of the model with instrumentation is described and the monitoring data are presented and analyzed in this paper. The deformation process and failure mechanism of dam sliding within the rock foundation are investigated based on the test results. It is found that the horizontal displacements at the toe and heel indicate the dam stability condition. During overloading, the cracking zone in the foundation can be simplified as a triangle with gradually increased height and vertex angle.

Effects of Repetitive Transcranial Magnetic Stimulation on Enhancement of Cognitive Function in Focal Ischemic Stroke Rat Model (국소 허혈성 뇌졸중 모델 흰쥐의 인지기능에 반복경두개자기자극이 미치는 효과)

  • Lee, Jung-In;Kim, Gye-Yeop;Nam, Ki-Won;Lee, Dong-Woo;Kim, Ki-Do;Kim, Kyung-Yoon
    • Journal of the Korean Society of Physical Medicine
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    • v.7 no.1
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    • pp.11-20
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    • 2012
  • Purpose : This study is intended to examine the repetitive transcranial magnetic stimulation on cognitive function in the focal ischemic stroke rat model. Methods : This study selected 30 Sprague-Dawley rats of 8 weeks. The groups were divided into two groups and assigned 15 rats to each group. Control group: Non-treatment after injured by focal ischemic stroke; Experimental group: application of repetitive transcranial magnetic stimulation(0.1 Tesla, 25 Hz, 20 min/time, 2 times/day, 5 days/2 week) after injured by focal ischemic stroke. To assess the effect of rTMS, the passive avoidance test, spatial learning and memory ability test were analyzed at the pre, 1 day, $7^{th}$ day, $14^{th}$ day and immunohistochemistric response of BDNF were analyzed in the hippocampal dentate gyrus at $7^{th}$ day, $14^{th}$ day. Results : In passive avoidance test, the outcome of experimental group was different significantly than the control group at the $7^{th}$ day, $14^{th}$ day. In spatial learning and memory ability test, the outcome of experimental group was different significantly than the control group at the $7^{th}$ day, $14^{th}$ day. In immunohistochemistric response of BDNF in the hippocampal dentate gyrus, experimental groups was more increased than control group. Conclusion : These result suggest that improved cognitive function by repetitive transcranial magnetic stimulation after focal ischemic stroke is associated with dynamically altered expression of BDNF in hippocampal dentate gyrus and that is related with synaptic plasticity.

Invention and Hydraulic Model Test of Combined Block System in River Bank Protection (일체형 하천호안블럭의 개발 및 모형실험 적용)

  • Jang, Suk-Hwan;Lee, Chang-Hae;Park, Sang-Woo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2008.05a
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    • pp.449-453
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    • 2008
  • This research focused on analyzing and comparing between the results of hydraulic physical modeling and the results of numerical modeling of Grass Concrete which is newly developed in-situ block system. The physical model was built as a scale of 1:50 by Froude similitude measuring the water levels and the water velocities for before and after vegetation and the effects were analyzed after reviewing the results. In consequence, the water velocities were observed to decrease meanly 19.1%, and the water depth were determined to increase meanly 27.8% in case of the of design flood, $Q=200m^3/sec$. Moreover, the velocities were produced reduction effects of 27.2%, and the water levels were derived from addition effects of the highest 31.3% in case of the probability maximum flood(PMF), $Q=600m^3/sec$. To verifying the hydraulic physical modeling, the numerical modeling was conducted for a close examination of before and after vegetation. HEC-RAS model was for 1 dimensional numerical analysis and RMA-2 was for 2 dimensional numerical analysis. The results of the numerical simulation, under the condition of roughness coefficient calibration, shows similar results of the physical modeling. These satisfactory results show that the accomplished results of hydraulic modeling and the predicted results of numerical modeling corresponded reasonably each others.

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