• Title/Summary/Keyword: Effective stiffness

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A Retrospective Chart Review of 122 Inpatients with Knee Osteoarthritis Treated with Korean Medicine: An Analysis of the Effects of Treatment

  • Yoo, Dong-Hwi;Park, Han-Bin;Jang, Won-Suk;Kwon, Oh-Bin;Choi, Ki-Won;Lee, Yu-Jin;Lee, Sang-Gun;Choi, Jae-Yong;Kim, Ho;Jang, Seon-Woo
    • Journal of Acupuncture Research
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    • v.38 no.3
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    • pp.205-218
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    • 2021
  • Background: Korean medicine treatment was assessed in patients with knee osteoarthritis (OA) according to subgroups of: sex, age, cause of knee OA, body mass index, hospitalization period, history, OA compartment, phenotype, and comorbidity. Methods: A retrospective review was performed of 122 inpatients who were admitted to the Hospital of Korean Medicine for Korean medicine treatment of knee pain, and were diagnosed with knee OA based on magnetic resonance imaging findings. Analysis of patient subgroups (sex, age, cause of knee OA, body mass index, hospitalization period, history, OA compartment, phenotype, and comorbidity) was carried out and treatments including acupuncture, cupping, pharmacopuncture, herbal medicine, chuna therapy, medicinal steaming therapy, manual therapy, and extracorporeal shock wave therapy were listed. The numeric rating scale (NRS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 5-level EuroQol- 5 Dimension (EQ-5D-5L) scores were measured before and after treatment to assess the effects of treatment on pain and quality of life. Results: Seventeen males and 105 females were included in this study. Most patients were in their 60s. In the total study population, NRS, WOMAC, and EQ-5D-5L scores were improved statistically significant when comparing before and after treatment. The NRS and WOMAC scores improved statistically significant in the medial, patellofemoral, medial + patellofemoral, medial + lateral + patellofemoral compartment. Conclusion: Korean medicine treatment significantly reduced pain, stiffness, and physical dysfunction, and improved the quality of life of patients with knee OA, suggesting that it may be an effective alternative to the current conservative treatments.

A new method for infill equivalent strut width

  • Tabeshpour, Mohammad Reza;Arasteh, Arash Mahdipour
    • Structural Engineering and Mechanics
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    • v.69 no.3
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    • pp.257-268
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    • 2019
  • Infills are as important members in structural design as beams, columns and braces. They have significant effect on structural behavior. Because of lots of variables in infills like material non-linear behavior, the interaction between frames and infill, etc., the infills performance during an earthquake is complicated, so have led designers do not consider the effect of infills in designing the structure. However, the experimental studies revealed that the infills have the remarkable effect on structure behavior. As if these effects ignored, it might occur soft-story phenomena, torsion or short-column effects on the structures. One simple and appropriate method for considering the infills effects in analyzing, is replacing the infills with diagonal compression strut with the same performance of real infill, instead of designing the whole infill. Because of too many uncertainties, codes and researchers gave many expressions that were not as the same as the others. The major intent of this paper is calculation the width of this diagonal strut, which has the most characteristics of infill. This paper by comprehensive on different parameters like the modulus of young or moment of inertia of columns presents a new formula for achieving the equivalent strut width. In fact, this new formula is extracted from about 60 FEM analyses models. It can be said that this formula is very efficient and accurate in estimating the equivalent strut width, considering the large number of effective parameters relative to similar relationships provided by other researchers. In most cases, the results are so close to the values obtained by the FEM. In this formula, the effect of out of plane buckling is neglected and this formula is used just in steel structures. Also, the thickness of infill panel, and the lateral force applied to frame are constant. In addition, this new formula is just for modeling the lateral stiffness. Obtaining the nearest response in analyzing is important to the designers, so this new formula can help them to reach more accurate response among a lot of experimental equations proposed by researchers.

Buckling Analysis of Laminated Composite Trapezoidal Corrugated Plates (적층 복합재료 사다리꼴 주름판의 좌굴해석)

  • Park, Kyung-Jo;Kim, Young-Wann
    • Composites Research
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    • v.32 no.4
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    • pp.185-190
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    • 2019
  • This work investigates the elastic buckling characteristics of laminated composite trapezoidal corrugated plates with simply supported edges using the analytical method. In the analysis, three types of in-plane loading conditions: uniaxial, biaxial and shear loads are considered. Because it is very difficult to determine the mechanical behavior of 3-dimensional corrugated structures analytically, the equivalent homogenization model is adapted to investigate the overall mechanical behavior of corrugated plates. The corrugated element is homogenized as an orthotropic material. The previous formulae for bending rigidities of corrugated plate are adapted in this paper. The comparisons of the proposed analytical results with those of FEA based on the shell element are made to verify the proposed analytical method. In the comparison study both the critical buckling loads and the buckling mode shapes are presented. Some numerical results are presented to check the effect of the geometric properties.

Simultaneous Optimization of Hybrid Mid-Story Isolation System and Building Structure (하이브리드 중간층 지진 격리 시스템과 빌딩 구조물의 동시 최적화)

  • Kim, Hyun-Su;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
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    • v.19 no.3
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    • pp.51-59
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    • 2019
  • A hybrid mid-story seismic isolation system with a smart damper has been proposed to mitigate seismic responses of tall buildings. Based on previous research, a hybrid mid-story seismic isolation system can provide effective control performance for reduction of seismic responses of tall buildings. Structural design of the hybrid mid-story seismic isolation system is generally performed after completion of structural design of a building structure. This design concept is called as an iterative design which is a general design process for structures and control devices. In the iterative design process, optimal design solution for the structure and control system is changed at each design stage. To solve this problem, the integrated optimal design method for the hybrid mid-story seismic isolation system and building structure was proposed in this study. An existing building with mid-story isolation system, i.e. Shiodome Sumitomo Building, was selected as an example structure for more realistic study. The hybrid mid-story isolation system in this study was composed of MR (magnetorheological) dampers. The stiffnessess and damping coefficients of the example building, maximum capacity of MR damper, and stiffness of isolation bearing were simultaneously optimized. Multi-objective genetic optimization method was employed for the simultaneous optimization of the example structure and the mid-story seismic isolation system. The optimization results show that the simultaneous optimization method can provide better control performance than the passive mid-story isolation system with reduction of structural materials.

Continuous force excited bridge dynamic test and structural flexibility identification theory

  • Zhou, Liming;Zhang, Jian
    • Structural Engineering and Mechanics
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    • v.71 no.4
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    • pp.391-405
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    • 2019
  • Compared to the ambient vibration test mainly identifying the structural modal parameters, such as frequency, damping and mode shapes, the impact testing, which benefits from measuring both impacting forces and structural responses, has the merit to identify not only the structural modal parameters but also more detailed structural parameters, in particular flexibility. However, in traditional impact tests, an impacting hammer or artificial excitation device is employed, which restricts the efficiency of tests on various bridge structures. To resolve this problem, we propose a new method whereby a moving vehicle is taken as a continuous exciter and develop a corresponding flexibility identification theory, in which the continuous wheel forces induced by the moving vehicle is considered as structural input and the acceleration response of the bridge as the output, thus a structural flexibility matrix can be identified and then structural deflections of the bridge under arbitrary static loads can be predicted. The proposed method is more convenient, time-saving and cost-effective compared with traditional impact tests. However, because the proposed test produces a spatially continuous force while classical impact forces are spatially discrete, a new flexibility identification theory is required, and a novel structural identification method involving with equivalent load distribution, the enhanced Frequency Response Function (eFRFs) construction and modal scaling factor identification is proposed to make use of the continuous excitation force to identify the basic modal parameters as well as the structural flexibility. Laboratory and numerical examples are given, which validate the effectiveness of the proposed method. Furthermore, parametric analysis including road roughness, vehicle speed, vehicle weight, vehicle's stiffness and damping are conducted and the results obtained demonstrate that the developed method has strong robustness except that the relative error increases with the increase of measurement noise.

Research Trends on the Acupotomy Treatment for Knee Osteoarthritis : A Systematic Review (무릎 골관절염의 도침 치료에 대한 연구 동향 : 체계적 문헌 고찰)

  • Hong, Su Min;Yoon, Kwang Sik
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.34 no.6
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    • pp.285-298
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    • 2020
  • This study aimed to review clinical studies about Acupotomy used for Knee Osteoarthritis. We searched the following 12 online databases (KISS, NDSL, RISS, OASIS, Earticle, Kmbase, MEDLINE/Pubmed, Cochrane library, Ebscohost, Ovid, CNKI, Wanfang), to find randomized controlled trials that used Acupotomy for knee osteoarthritis. The methodological quality of randomized controlled trials were assessed by using the Cochrane risk of bias tool and meta-analyses were performed. 16 randomized controlled trials were included. Total number of patients was 1169. The average duration of treatment was 3.14 weeks and most of the patients were treated once a week. The major treatment sites were ligaments, muscles, and tender nodules and the most used evaluation tool was the efficiency. We selected 4 studies and meta-analyzed them. All of the studies performed Acupotomy+sodium hyaluronate injection as a treatment group, and sodium hyaluronate injection as a control group. Meta-analysis showed positive results for Acupotomy+sodium hyaluronate injection in terms of efficiency rate compared to sodium hyaluronate injection. Also Meta-analysis showed positive results for Acupotomy+sodium hyaluronate injection in terms of WOMAC (pain, stiffness, function) compared to sodium hyaluronate injection. In this study, we reviewed studies about Acupotomy used for knee osteoarthritis. The studies showed that Acupotomy can significantly effective on knee osteoarthritis. But according to Cochrane Risk of Bias (RoB) evaluation method, most of the study's risk of bias was unclear. Threrefore, more high-quality studies will be needed.

Characteristics of Static Buckling Load of the Hexagonal Spatial Truss Models using Timber (목재를 이용한 육각형 공간 트러스 모델의 정적좌굴하중 특성)

  • Ha, Hyeonju;Shon, Sudeok;Lee, Seungjae
    • Journal of Korean Association for Spatial Structures
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    • v.22 no.3
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    • pp.25-32
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    • 2022
  • In this paper, the instability of the domed spatial truss structure using wood and the characteristics of the buckling critical load were studied. Hexagonal space truss was adopted as the model to be analyzed, and two boundary conditions were considered. In the first case, the deformation of the inclined member is only considered, and in the second case, the deformation of the horizontal member is also considered. The materials of the model adopted in this paper are steel and timbers, and the considered timbers are spruce, pine, and larch. Here, the inelastic properties of the material are not considered. The instability of the target structure was observed through non-linear incremental analysis, and the buckling critical load was calculated through the singularities and eigenvalues of the tangential stiffness matrix at each incremental step. From the analysis results, in the example of the boundary condition considering only the inclined member, the critical buckling load was lower when using timber than when using steel, and the critical buckling load was determined according to the modulus of elasticity of timber. In the case of boundary conditions considering the effect of the horizontal member, using a mixture of steel and timber case had a lower buckling critical load than the steel case. But, the result showed that it was more effective in structural stability than only timber was used.

Muscle Elasticity Changes in the Presence or Absence of Elastic Band Resistance During Bridge Exercise Using Gymball (짐볼을 이용한 교각운동 시 탄성밴드 저항 유·무에 따른 근탄성도의 변화)

  • Kim, Myung-Chul;Huh, Jun;Kim, Hae-In
    • Journal of The Korean Society of Integrative Medicine
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    • v.9 no.3
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    • pp.145-153
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    • 2021
  • Purpose : The purpose of this study was to compare and analyze whether there are changes in muscle elasticity when resistance using an elastic band is present or absent during a bridge exercise on an unstable surface with a gymball. Methods : Eighteen healthy adult college students attending E University in Gyeonggi-do, who voluntarily agreed to participate were included in this study. The subjects were instructed to perform the bridge exercise using a gymball both without resistance and with resistance using an elastic band. Myoton was used during the exercise to measure the elasticity of the rectus abdominis and biceps femoris muscles. Results : There was a significant difference in the stiffness of the rectus abdominis muscle on both sides before and after using the elastic band (p<.05). however, no significant difference was observed in the biceps femoris on either side (p>.05). Based on the evaluation of the frequency before and after using the elastic band, no significant difference was observed between the rectus abdominis and biceps femoris muscles on both sides (p>.05). The logarithmic decrement was significantly different in the right rectus abdominis muscle (p<.05), and there was no significant difference in the left rectus abdominis and both biceps femoris (p>.05). Conclusion : Resistance exercise using an elastic band is more effective in improving elasticity of the rectus abdominis muscle than without a elastic band during bridge exercise with a gymball.

The effects of two different visual feedback exercise tools based on rehabilitative ultrasound imaging in the elderly

  • Shin, Jang-Hoon;Lee, Wan-Hee
    • Physical Therapy Rehabilitation Science
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    • v.9 no.4
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    • pp.287-294
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    • 2020
  • Objective: This study aimed to investigate the effects of an ultrasound-based bar graph proportional to the quadriceps muscle thickness as a real-time visual feedback training tool in the elderly. Design: Cross-sectional study. Methods: Twenty-four elderly persons participated in this study and were randomly divided into three groups: oral training group (n=8, group 1), ultrasound imaging group (n=8, group 2), and graph group (n=8, group 3). In the pre condition, all participants performed maximal voluntary isometric contraction (MVIC) of the quadriceps with knee extension three times with oral training. In the post condition, group 1 performed MVIC of the quadriceps with oral training, group 2 performed MVIC of the quadriceps with real-time visual feedback using ultrasound imaging, and group 3 performed MVIC of the quadriceps with real-time visual feedback using a bar graph proportional to the quadriceps muscle thickness, three times for all groups. Muscle thickness, activity (mean, peak), tone, stiffness, logarithmic decrement, relaxation, and creep were measured in both conditions in all participants. Results: Visual feedback with a bar graph showed significant effects on muscle thickness, mean muscle activity, and peak muscle activity compared with oral training and visual feedback with ultrasound imaging (p<0.05). Conclusions: Isometric training of the quadriceps with real-time visual feedback using a bar graph proportional to the quadriceps muscle thickness may be more effective than other methods in improving muscle thickness and muscle activity. This study presented a tool that can help increase muscle thickness in the elderly.

Experimental assessment of post-earthquake retrofitted reinforced concrete frame partially infilled with fly-ash brick

  • Kumawat, Sanjay R.;Mondal, Goutam;Dash, Suresh R.
    • Earthquakes and Structures
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    • v.22 no.2
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    • pp.121-135
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    • 2022
  • Many public buildings such as schools, hospitals, etc., where partial infill walls are present in reinforced concrete (RC) structures, have undergone undesirable damage/failure attributed to captive column effect during a moderate to severe earthquake shaking. Often, the situation gets worsened when these RC frames are non-ductile in nature, thus reducing the deformable capability of the frame. Also, in many parts of the Indian subcontinent, it is mandatory to use fly-ash bricks for construction so as to reduce the burden on the disposal of fly-ash produced at thermal power plants. In some scenario, when the non-ductile RC frame, partially infilled by fly-ash bricks, suffers major structural damage, the challenge remains on how to retrofit and restore it. Thus, in this study, two full-scale one-bay, one-story non-ductile RC frame models, namely, bare frame and RC partially infilled frame with fly-ash bricks in 50% of its opening area are considered. In the previous experiments, these models were subjected to slow-cyclic displacement-controlled loading to replicate damage due to a moderate earthquake. Now, in this study these damaged frames were retrofitted and an experimental investigation was performed on the retrofitted specimens to examine the effectiveness of the proposed retrofitting scheme. A hybrid retrofitting technique combining epoxy injection grouting with an innovative and easy-to-implement steel jacketing technique was proposed. This proposed retrofitting method has ensured proper confinement of damaged concrete. The retrofitted models were subjected to the same slow cyclic displacement-controlled loading which was used to damage the frames. The experimental study concluded that the hybrid retrofitting technique was quite effective in enhancing and regaining various seismic performance parameters such as, lateral strength and lateral stiffness of partially fly-ash brick infilled RC frame. Thus, the steel jacketing retrofitting scheme along with the epoxy injection grouting can be relied on for possible repair of the structural members which are damaged due to the captive column effect during the seismic shaking.