• Title/Summary/Keyword: Effective stiffness

Search Result 1,076, Processing Time 0.042 seconds

The Outcome of the Treatment of Lesser toe Brachymetatarsia - focus on complications - (소 족지 단중족증의 치료결과 - 합병증을 중심으로 -)

  • Lee, Ho-Seung;Yoon, Joon-O;Park, Soo-Sung;Kim, Eu-Gene
    • Journal of Korean Foot and Ankle Society
    • /
    • v.7 no.1
    • /
    • pp.13-20
    • /
    • 2003
  • Purpose: We analysis the outcome and complications of treatment of lesser toe brachymetatarsia. Materials and Methods: We analysed 28 patients 35 cases of lesser toe brachymetatarsia. Mean post operative follow up period was 2 years 8 months. All of the patients were female and mean age at operation was 21 years old. 2 cases of third metatasal bone and 33 cases of fourth metatarsal bone were operated. 8 metatarsal bones were treated using one staged lengthening with tricortical bone graft and 27 metatarsal bones were treated using callotasis with monofixator. Results: The average amount of lengthening was 13.3mm(12mm-15mm) in one staged lengthening, while 14.4mm(4mm-23mm) in callotasis. Average percentile increase was 28.9%(26%-34%) in one staged lengthening and 32%(18%-46%) in callotasis. The average healing index of callotasis was 76 days/cm (41 days/cm-166 days/cm). Satisfied outcomes in 4 cases of 8 cases (50%) after one staged lengthening and 17 cases of 27 cases (63%) after callotasis. 6 complications in 4 cases were occurred after one staged lengthening; insufficient length gain in 3 cases, fracture on the junction of graft bone and metatarsal bone in 1 case, plantar bowing deformity in 1 case and bony fusion of metatarsophalangeal joint in 1 case. 17 complications in 10 patients were occurred after callotasis ; metatarsophalangeal joint stiffness in 8 cases, metatarsophalangeal joint subluxation in 2 cases, overlengthened metatarsal bone in 2 cases, tapering of callus in 1 case, fracture of callus in 1 case, premature consolidation of callus in 1 case, osteomyelitis of metataral head in 1 case and plantar bowing deformity in 1 case. Conclusion: Although one staged lengthening and gradual lengthening using callotasis are effective treatment for lesser toe brachymetatarsia, complications not rarely occured after lengthening. Insufficient lengthening are most common complication after one staged lengthening while metatarsophalangeal joint stiffness lire most common complication after callotasis.

  • PDF

Abnormal Response Analysis of a Cable-Stayed Bridge using Gradual Bilinear Method (Gradual Bilinear Method를 이용한 사장교의 케이블 손상응답 해석)

  • Kim, Byeong-Cheol;Park, Ki-Tae;Kim, Tae-Heon;Hwang, Ji-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.18 no.6
    • /
    • pp.60-71
    • /
    • 2014
  • Cable-stayed bridge, which is one of the representative long-spanned bridge, needs prompt maintenances when a stay cable is damaged because it may cause structural failure of the entire bridge. Many researches are being conducted to develop abnormal behavior detection algorithms for the purpose of shortening the reaction time after the occurrence of structural damage. To improve the accuracy of the damage detection algorithm, ample observation data from various kinds of damage responses is needed. However, it is difficult to measure an abnormal response by damaging an existing bridge, numerical simulation can be an effective alternative. In most previous studies, which simulate the damage responses of a cable-stayed bridge, the damages has been considered as a load variation without regard to its stiffness variation. The analyses of using these simplification could not calculate exact responses of damaged structure, though it may reserve a sufficient accuracy for the purpose of bridge design. This study suggests Gradual Bilinear Method (GBM) which simulate the damage responses of cable-stayed bridge considering the stiffness and mass variation, and develops an analysis program. The developed program is verified from the responses of a simple model. The responses of a existing cable-stayed bridge model are analyzed with respect to the fracture delay time and damage ratio. The results of this study can be used to develop and verify the highly accurate abnormal behavior detection algorithm for safety management of architecture/large structures.

The Effect of Combined Suboccipitalis Release Exercise and Therapeutic Ultrasound on Mechanical Properties of Cervical Muscles and Neck Disability Index, Headache Impact Test in Tension-Type Headache Patients (초음파치료를 동반한 뒤통수밑근 이완운동이 긴장성 두통 환자의 근육의 기계적인 특성과 목 장애 지수, 두통 영향 검사에 미치는 영향)

  • Park, Seung-Kyu;Park, Sam-Heon
    • Journal of The Korean Society of Integrative Medicine
    • /
    • v.9 no.4
    • /
    • pp.271-281
    • /
    • 2021
  • Purpose : This study aimed to apply muscle relaxation exercise and ultrasound therapy as an effective treatment method for tension headache patients by comparatively analyzing the muscle mechanical properties, neck disorder index, and headache impact test. Method : The subjects were classified into three groups based on the intervention received: the therapeutic ultrasound (n=15, group I), placebo therapeutic ultrasound combined with the suboccipital release (n=15, group II), and therapeutic ultrasound combined with suboccipital release (n=15, group III) groups. The intragroup and intergroup differences in muscle mechanical properties, neck disability index, and headache impact test were compared and analyzed. Result : The comparison and analyses of the changes in muscle tone and post hoc analysis revealed statistically significant intragroup decreases in the suboccipitalis and upper trapezius in groups I and III. Furthermore, statistically significant intergroup differences in the upper trapezius with a greater change in group III than in group II and suboccipitalis with greater changes in group III than in groups I and II were observed. The comparison and analyses of the changes in muscle stiffness and post hoc analysis revealed statistically significant intragroup decreases in the upper trapezius in group I and suboccipitalis in group III. Moreover, statistically significant intergroup differences in both muscles with greater changes in group III than in group II for both cases were observed. The comparison and analyses of the changes in the neck disability index and post hoc analysis revealed statistically significant intragroup decreases in all three groups and statistically significant intergroup differences with greater changes in group III than in groups I and II. The comparison and analyses of the changes in the headache impact test and post hoc analysis revealed statistically significant intragroup decreases in all three groups and a statistically significant intergroup difference with greater changes in group III than in groups I and II. Conclusion : The therapeutic ultrasound and suboccipital muscle release exercise effectively increased the flexibility of the muscles around the cervical vertebrae and reduced muscle tension and stiffness in tension-type headache patients.

Efficacy and safety of HT008 and glucosamine sulfate in the treatment of knee osteoarthritis : a randomized double-blind trial (『퇴행성 관절염에 대한 HT008과 글루코사민의 유효성 및 안전성을 비교평가하기 위한 무작위 배정, 이중맹검 임상연구)

  • Park, Sangwoug;Kim, Young-Sik;Lee, Donghun;Kwon, Yongbeom;Park, Juyeon;Lee, Soh-Young;Nam, Dong Woo;Lee, Jae Dong;Kim, Hocheol
    • The Korea Journal of Herbology
    • /
    • v.29 no.4
    • /
    • pp.45-52
    • /
    • 2014
  • Objectives : The purpose of this study was to evaluate the efficacy of HT008 on pain relief and functional improvement in participants with mild knee osteoarthritis (OA) in comparison with that of glucosamine sulfate. Methods : This randomized double-blind trial was conducted at Kyung Hee University Medical Center in Seoul where participants with knee pain for more than 6 months and degenerative osteoarthritis were enrolled. The 100 participants were received either HT008 or glucosamine sulfate 750 mg twice daily for 8 weeks and evaluated at baseline, 4 and 8 weeks after the treatment. We primarily evaluated the differences between two groups with respect to changes in the visual analogue score (VAS) for pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score from baseline to week 8. Secondarily the difference between and within two groups with respect to changes in WOMAC stiffness and physical function score, and Lequesne Functional Severity Index (LFI) were also evaluated. Results : At week 8, treatment with HT008 resulted in a significant reduction of the VAS for pain and WOMAC pain scores compared to the glucosamine sulfate (both p=0.003). Patients receiving HT008 experienced statistically significantly greater improvements in WOMAC physical function scores and LFI (p = 0.014 and p=0.016, respectively) than glucosamine sulfate-treated group. The within-group change in WOMAC physical function and stiffness, and LFI during the 8-week intervention revealed significant improvements in HT008-treated group. Conclusions : HT008 treatment allows significant pain reduction and functional improvement compared with glucosamine sulfate. These data confirm HT008 as an effective and safe symptomatic drug for knee OA.

Fully Coupled Seismic Analysis of Stress-Flow According to Tunnel Drainage Type (터널 배수 형식에 따른 응력-침투 연계 내진해석)

  • Byoung-Il Choi;Myung-Ho Ha;Dong-Ha Lee;Eun-Cheol Noh;Si-Hyun Park
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.27 no.4
    • /
    • pp.94-103
    • /
    • 2023
  • Built in urban ares tunnels is necessary to accurately grasp not only the above-ground environment of the tunnel but also the below-ground environment of the tunnel for design and construct. However, fully coupled analysis of stress and flow is very difficult due to the limited function of the tunnel numerical analysis program and difficulty in using program. This can lead to excessive design that increases the construction cost or occur problems that can lead to accidents during construction. In particular, in the case of an urban tunnel has a low layer soil section above the tunnel and the groundwater level exists in the upper layer of the tunnel. Therefore, a reduction in the groundwater level during underground construction may increase the effective stress of the upper layer and cause the ground to subsidence. So It is necessary to design after accurately evaluating the change in the groundwater level. In this study, the tunnel's behavioral characteristics were analyzed through fully coupled analysis of stress and flow according to the drainage type for an urban underground tunnel.

Applications of Practical Analysis Scheme for Evaluating Effects of Over-Loads during Construction on Deflections of Flat Plate System (플랫 플레이트 시스템의 처짐에 대한 시공 중 과하중의 영향 평가를 위한 실용해석 기법의 적용)

  • Kim, Jae-Yo
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.22 no.1
    • /
    • pp.25-34
    • /
    • 2009
  • RC flat plate, which has no large flexural stiffness by boundary beams, may be governed by serviceability as well as strength condition. A construction sequence and its impact on distributions of construction loads among slabs tied by shores are decisive factors on immediate and long term performances of flat plate. The over-loading and tensile cracking in early-aged slabs significantly increase the deflection of flat plate system. In this study, for slab deflections, the practical analysis scheme using a linear analysis program is formulated with considering construction sequence and concrete cracking effects. The concept of the effective moment of inertia in calculating deflections of one-way bending member, that is presented in structural design codes, is extended to the finite element analysis of the two-way slab system of flat plates. Effects of over-loads during construction on deflections of flat plate system are analyzed by applying the proposed practical analysis scheme into the critical construction load conditions calculated from the simplified method.

An Improved Method for Initial Shape Analysis of Cable-Stayed Bridges (사장교의 개선된 초기형상 해석법)

  • Kim, Moon Young;Kyung, Yong Soo;Lee, Jun Sok
    • Journal of Korean Society of Steel Construction
    • /
    • v.15 no.2
    • /
    • pp.175-185
    • /
    • 2003
  • The extended tangent stiffness matrices and force-deformation relations of the elastic catenary element were initially derived through the addition of the unstrained length of cables to unknown nodal displacements. A beam-column element was then introduced to model the deck and pylon of cable-stayed bridges. The conventional geometric nonlinear analysis, initial force method, and TCUD method were summarized, with an effective method combining two methods presented to determine the initial shapes of cable-stayed bridges with dead loads. In this combined method, TCUD method was applied to eliminate vertical and horizontal displacements at cable-supported points of decks and on top of pylons, respectively. The initial force method was also adopted to eliminate horizontal and vertical displacements of decks and pylons, Finally, the accuracy and validity of the proposed combined method were demonstrated through numerical examples.

An Improved Method for Initial Shape Analysis of Subpension Bridges (현수교의 개선된 초기형상 해석법)

  • Kim, Moon Young;Kyung, Yong Soo;Lee, Jun Sok
    • Journal of Korean Society of Steel Construction
    • /
    • v.15 no.2
    • /
    • pp.219-229
    • /
    • 2003
  • The extended tangent stiffness matrices and force-deformation relations of the elastic catenary element were initially derived through the addition of the unstrained length of cables to unknown nodal 'displacements. A beam-column element was then introduced to model the deck and pylon of cable-stayed bridges. The conventional geometric nonlinear analysis, initial force method, and TCUD method were summarized, with an effective method combining two methods presented to determine the initial shapes of cable-stayed bridges with dead loads. In this combined method, TCUD method was applied to eliminate vertical and horizontal displacements at cable-supported points of decks and on top of pylons, respectively. The initial force method was also adopted to eliminate horizontal and vertical displacements of decks and pylons. Finally, the accuracy and validity of the proposed combined method were demonstrated through numerical examples.

An Experimental Study on Uniaxial Compressive Behavior of RC Circular Columns Laterally Confined with Prestressing Aramid Fiber Strap (아라미드 스트랩으로 프리스트레싱 횡구속된 RC 원형기둥의 일축압축거동에 관한 실험적 연구)

  • Han, Sang-Hoon;Hong, Ki-Nam;Lee, Jae-Bum
    • Journal of the Korea Concrete Institute
    • /
    • v.21 no.2
    • /
    • pp.159-168
    • /
    • 2009
  • In this study, strength, stiffness and confinement effect with stress-strain and stress-volumetric strain curves for improved uniaxial compressive behavior of RC circular columns laterally confined with prestressing aramid fiber strap were experimentally investigated. The test variables were the specimens with or without axial reinforcing bar and the number and spacing of strap, prestressing level, the types of reinforcing fiber (CFS, GFS). As a result, the failure type of the columns was very stable and strength increase rate was about 73% comparison with the general RC columns. Moreover, the strain increase rate is very small and the axial displacement confinement effect was very effective compared with existry methods (CFS, GFS), the initial and final lateral confinement effect was excellent.

Seismic and vibration tests for assessing the effectiveness of GFRP for retrofitting masonry structures

  • Michelis, Paul;Papadimitriou, Costas;Karaiskos, Grigoris K.;Papadioti, Dimitra-Christina;Fuggini, Clemente
    • Smart Structures and Systems
    • /
    • v.9 no.3
    • /
    • pp.207-230
    • /
    • 2012
  • Full-scale shake table seismic experiments and low-amplitude vibration tests on a masonry building are carried out to assess its seismic performance as well as study the effectiveness of a new multifunctional textile material for retrofitting masonry structures against earthquakes. The un-reinforced and the retrofitted with glass fiber reinforced polymer (GFRP) strips masonry building was subjected to a series of earthquake excitations of increasing magnitude in order to progressively induce various small, moderate and severe levels of damage to the masonry walls. The performance of the original and retrofitted building states is evaluated. Changes in the dynamic characteristics (lowest four modal frequencies and damping ratios) of the building are used to assess and quantify the damage states of the masonry walls. For this, the dynamic modal characteristics of the structure states after each earthquake event were estimated by performing low-amplitude impulse hammer and sine-sweep forced vibration tests. Comparisons between the modal results calculated using traditional accelerometers and those using Fiber Bragg Grating (FBG) sensors embedded in the reinforcing textile were carried on to investigate the reliability and accuracy of FBG sensors in tracking the dynamic behaviour of the building. The retrofitting actions restored the stiffness characteristics of the reinforced masonry structure to the levels of the original undamaged un-reinforced structure. The results show that despite a similar dynamic behavior identified, corresponding to reduction of the modal frequencies, the un-reinforced masonry building was severely damaged, while the reinforced masonry building was able to withstand, without visual damage, the induced strong seismic excitations. The applied GFRP reinforcement architecture for one storey buildings was experimentally proven reliable for the most severe earthquake accelerations. It was easily placed in a short time and it is a cost effective solution (covering only 20% of the external wall surfaces) when compared to the cost for full wall coverage by GFRPs.