• 제목/요약/키워드: snapping

검색결과 92건 처리시간 0.027초

Flexural behaviour of GFRP reinforced concrete beams under cyclic loading

  • Murthy, A. Ramachandra;Gandhi, P.;Pukazhendhi, D.M.;Samuel, F. Giftson;Vishnuvardhan, S.
    • Structural Engineering and Mechanics
    • /
    • 제84권3호
    • /
    • pp.361-373
    • /
    • 2022
  • This paper examines the flexural performance of concrete beams reinforced with glass fibre-reinforced polymer (GFRP) bars under fatigue loading. Experiments were carried out on concrete beams of size 1500×200×100 mm reinforced with 10 mm and 13 mm diameter GFRP bars under fatigue loading. Experimental investigations revealed that fatigue loading affects both strength and serviceability properties of GFRP reinforced concrete. Experimental results indicated that (i) the concrete beams experienced increase in deflection with increase in number of cycles and failed suddenly due to snapping of rebars and (ii) the fatigue life of concrete beams drastically decreased with increase in stress level. Analytical model presented a procedure for predicting the deflection of concrete beams reinforced with GFRP bars under cyclic loading. Deflection of concrete beams was computed by considering the aspects such as stiffness degradation, force equilibrium equations and effective moment of inertia. Nonlinear finite element (FE) analysis was performed on concrete beams reinforced with GFRP bars. Appropriate constitutive relationships for concrete and GFRP bars were considered in the numerical modelling. Concrete non linearity has been accounted through concrete damage plasticity model available in ABAQUS. Deflection versus number of cycles obtained experimentally for various beams was compared with the analytical and numerical predictions. It was observed that the predicted values are comparable (less than 20% difference) with the corresponding experimental observations.

한국산 자라, Trionyx sinensis (1862)의 자연산란둥지에서 수거한 난들의 항온인공부화에 의해 출생한 새끼자라들의 성비 (Sex Ratios of Juveniles Hatched by Constant Temperatures Artificial Incubation From Eggs Collected in the Natural Nest of Soft-Shelled Turtle, Trionyx sinensis Strauch (1862))

  • 김성한
    • 수산해양교육연구
    • /
    • 제29권3호
    • /
    • pp.702-710
    • /
    • 2017
  • Recently, in many reptiles (14 genera of turtles in five families), common characteristics of incubation temperatures are known to determine the sexes of hatchlings in many species of turtles, including the map turtles, painted turtles and snapping turtles, emys turtle, etc. According to many researcher's reports, in general, incubation at $25^{\circ}C$ (cooler temperatures) produces all or mostly males, however, incubation at $31^{\circ}C$ (higher temperatures) or higher produces all or mostly females. Exceptionally, even cooler temperature ($20^{\circ}C$) produce females, they produced all or mostly females. Accordingly, it is well-known that incubation temperature is the sex determining agent in these turtles. However, this paper presents study of the sex ratio and nest ecology in natural spawning nest: Observations on hatching sex ratios of eggs collected from natural nests of T. sinensis are similar to a previous report of the same genus Trionyx in the soft-shelled turtles. However, this genus (or species) showed some different phenomena to other kinds of turtles such as various kinds turtles mentioned above. After collection of naturally spawned eggs (17 eggs of T. sisnensis) on the natural nests, a laboratory experiment by the constant incubation temperatures was conducted with natural fluctuating soil temperatures in the natural nest with the soft-shelled turtle, T. sinensis. And also laboratory experiments were conducted using constant incubation temperatures of $25^{\circ}C$ (cooler temp.) and $30^{\circ}C$ (higher temp.) with the turtle, T. sinensis. Exceptionally, it was confirmed that the first and second incubation temperatures can't control sex-determination in the freshwater soft-shelled turtle, T. sinensis. The sex ratio approximated 1:1 (${\chi}^2=0.06$, P>0.05 (the Ist experiment). And the sex ratio approximated 1:1 independently of incubation temperature (${\chi}^2=0.33$, P>0.05 (the 2nd experiment). Consequently, temperature has no effect on sex determination in the genus Trionyx in a soft-shelled turtle.

하와이 목질의복(木質衣服)(Bark Cloth) KAPA에 대한 연구(硏究) (Study on the Hawaiian Bark Cloth Kapa)

  • 박민녀
    • 복식
    • /
    • 제17권
    • /
    • pp.137-148
    • /
    • 1991
  • The use of bark cloth, made of the inner bark of certain trees, was widespread along tropical zones from the Africa to the Hawaii encompassing the globe. They include Malaysia, Indonesia, New Guinea, Polynesian Islands and South America. Among them the Hawaiian bark cloth, named Kapa(pronounced as tapa) was rated as the best quality and most admired. It has variety in designs and colors as well as the most sophistcated production methods. The distinct processes of kapa making are composed of two stages. The first is called first beating and it is a preparatory stage to beat the sea-water soaked bast. It was done with a round beater on a stone anvil. The second beating process was carried out with the squared beater and wooden anvil. The strips from the first beating was soaked again in the water and then beaten lightly to break up fibers. The craftmen laid a bundle of strips over the anvil and beat it into pieces of kapa. The second beater of Hawaii was the most characteristic one among bark cloth producing countries. On their surfaces were the engraved patterns, which were creation of theirs. These distinguished designs enabled them to produce the kapa with the thinner and finer texture and an elaboration of impressed designs known as "watermaks". The Hawaiian culture was self-sufficient one : Everything they used was of their own creation until 19th century. Among their inventions of printing designs on kapa are three most important and distinguished processes. They are the overlaying, the cord snapping and the block printing techniques. Their inventiveness as well as self sufficient environment made it possible to develop their fine art of the kapa making. It is said that the mass producing and cheap western technology of loom forced them to gradually abandon their traditional art and as a result this fine and valuable legacy of Hawaiian traditional kapa making technique is all but disappeared. However it is encouraging and heart warming to find that some of the people as well as specialized researchers pined together to form a group to try to reproduce the old kapa and study the traditional art. They consider the kapa as an expression of the ethnic identity with Hawaii's heritage as well as valuable art of human history.

  • PDF

상지의 압박성 신경병증의 초음파 검사 (Ultrasonographic Examination of Compression Neuropathy in the Upper Extremity)

  • 정양국;김배균
    • 대한정형외과 초음파학회지
    • /
    • 제1권1호
    • /
    • pp.64-72
    • /
    • 2008
  • 주관절, 완관절 주변의 압박성 신경병증은 일상생활의 불편을 초래하는 상지에서의 흔한 신경병증의 하나로 이에 대한 초음파 검사 소견을 바르게 해석하는 데는 정상적인 신경의 구조와 압박성 신경병증의 병리적 변화를 이해하는 것이 중요하다. 압박성 신경병증에서는 특징적인 초음파 소견을 보이는데 압박부위의 신경은 눌려서 편평한 모양으로 나타나고 근위부에서는 고신호강도의 부종성 변화와 신경속 양상의 소실을 보인다. 기본적인 횡주사 및 종주사 영상 외에 관절이나 근육을 동적으로 움직이면서 시행한 초음파 검사는 척골신경이 주관절 굴곡시 삼두박건 내측두와 함께 내상과위로 아탈구 되는 탄발성 삼두박근 증후군이나 능동적 회내근의 수축시 신경압박이 일어나는 원형 회내근 증후군 등에서 신경의 아탈구나 압박소견을 보여준다. 수근관 증후군이나 주관 증후군 등에서는 신경 단면적의 정량적인 계측이나 압박비의 평가가 진단에 도움이 된다. 임상적 검사 및 전기생리적 검사와 병행하여 사용할 경우 초음파 영상은 상지에서의 압박성 신경병증을 진단하는데 있어 매우 유용한 검사방법의 하나이다.

  • PDF

26개월 여아에서 발생한 슬관절 외측 원판형 연골 파열의관절경적 치험례 -증례보고- (Arthroscopic treatment for symptomatic lateral discoid meniscus in a 26-month-old girl -A case report-)

  • 이병일;최형석;민경대;조영일
    • 대한관절경학회지
    • /
    • 제6권1호
    • /
    • pp.54-59
    • /
    • 2002
  • 소아에서의 슬관절 탄발음은 주로 원판형 연골에 의해서 발생되며 슬관절의 신전제한은 원판형연골의 파열을 강력히 시사하는 소견으로 알려져 있으며, 특히 3세미만 소아에서의 보고는 극히 적은 실정이다. 또한 3세 미만의 증상이 있는 원판형 연골의 치료방법에 있어서는 정설이 없고 기술적으로도 어려운 점이 있을 것으로 예상된다. 저자들은 신전제한을 주소로 내원한 25개월 여아에서 자기 공명영상검사상 외측 원판형 연골 파열을 확인하고 관절경하 부분 절제술 시행 후 2년 9개월간 추시 한 바 합병증이나 증상의 재발없이 임상적 및 기능적으로 만족할만한 결과를 보여 이에 대한 증례를 문헌 고찰과 함께 이를 보고하는 바이다.

  • PDF

증상을 유발하는 내측 반월상 연골 전각부의 비정상적 삽입 - 1예 보고 - (Symptomatic Abnormal Insertion of the Anterior Horn of Medial Meniscus - A Case Report -)

  • 유재두;신상진;김태호
    • 대한관절경학회지
    • /
    • 제11권1호
    • /
    • pp.45-49
    • /
    • 2007
  • 11세 여환의 증상을 유발하는 내측 반월상 연골판의 비정상적 소견을 보고하고자 한다. 환자는 내원 4개월 전부터 지속된 좌측 슬관절의 동통을 주소로 보존적 치료를 시행 받았으나, 치료에 반응이 없어 관절경 술식을 시행받았다. 관절경 소견상 환자의 내측 반월상 연골판 전각에서 기시하는 비정상적인 띠를 발견 할 수 있었으며, 이 띠는 전방십자인대 옆을 지나 대퇴골 과간 절흔으로 뻗어나가 대퇴골 내과의 외측면에 부착되는 비정상적인 소견을 보였다. 이 비정상적인 띠는 수술 전 시행한 슬관절 자기 공명 영상에서는 확인되지 않았으며, 관절경 시행시 발견되어 절제술을 시행하였다. 절제술 시행 후 술 전 호소하던 증상은 완전히 소실되었다.

  • PDF

제2형 상부관절와순파열로 진단받은 사회인 야구선수에 대한 보존적 치료 치험 1례 (A Case Report of Conservative Treatment for the Amatuer Baseball Player diagnosis with type 2 Superior labral anterior posterior lesion)

  • 진은석;염선규;김석;이진혁
    • 척추신경추나의학회지
    • /
    • 제5권2호
    • /
    • pp.151-158
    • /
    • 2010
  • Objective : SLAP is rupture of biceps brachii muscle tendon and it's origin, posterior side of superior labral to anterior glenoid fossa. Snapping and Pain, instability are its typical symptoms. SLAP is physical damage so surgeons use arthroscopy. In point of surgeons view, a conservative medicine is not effective for lesion of labrum. So In this article, we report a result of conservative treatment for the amatuer baseball player diagnosis with type 2 superior labral anterior posterior lesion. Methods : In this case, patient played amatuer baseball for 2 years, had diagnosis with type 2 Superior labral anterior posterior lesion by MRI after right shoulder Injury. OS recommened arthroscopy surgery. But he receive conservative Korean medicin treatment in Korean medicine hospital, including Atx, BV, herbal acupunture and rehabilitation excersise. Results : After 6 months, in the end of continuous conservative treatment and rehabilitation excersise, patient can play baseball normally, and felt a little pain. But In physical examination, he still has a some abnormal signs. Conclusion : A Conservative treatment for an amatuer baseball player diagnosis with SLAP type 2 was effective in restore of fuctional activities, but usefulness of this treatment needs more study.

  • PDF

중량체 적용을 통한 계류선의 설계개선 방안 연구 (Improved design for mooring line with lumped weight at seabed)

  • 송제하;신승호;정동호;김현주
    • 한국해양공학회지
    • /
    • 제27권6호
    • /
    • pp.22-26
    • /
    • 2013
  • The purpose of this study was to improve the design of a mooring line by attaching a lumped mass to it on the seabed. A numerical analysis of the redesigned mooring system is performed to analyze the effect of the weight of the attached lumped mass using the commercial software Orcaflex. The ultimate tension of the mooring system with the lumped mass is compared with that of a bare mooring line in the original design. An appropriately designed weight for the lumped mass is found to induce a critical lifted point in the mooring line by floater motion in the ultimate condition to move toward the floater position from the anchor point, while maintaining a similar safety factor for the mooring line. On the other hand, it is shown that excess weight for the lumped mass induces snapping in a mooring line, resulting in low safety factor for the mooring system. The distance between lumped weights is shown to be a minor parameter affecting the safety of a mooring line, although a shorter line has an advantage from an economic point of view. Using the optimal weight for the lumped mass attached to the mooring line on a seabed reduces the mooring line length and installation area occupied by a mooring system under real sea conditions.

Understanding and Exercise of Gluteus Medius Weakness: A Systematic Review

  • Baik, Seung-min;Cynn, Heon-seock;Kim, Seok-hyun
    • 한국전문물리치료학회지
    • /
    • 제28권1호
    • /
    • pp.27-35
    • /
    • 2021
  • A weak or dysfunctional gluteus medius (Gmed) is related to several pathologies, and individuals with hip abductor weakness have Gmed weakness. This study aimed to systematically review the literature associated with the anatomy and function of the Gmed, and the prevalence, pathology, and exercise of Gmed weakness. Papers published between 2010 and 2020 were retrieved from MEDLINE, Google Academic Search, and Research Information Sharing Service. The database search used the following terms: (glut* OR medius OR hip abduct*) AND weak*. The Gmed plays an important role in several functional activities as a primary hip abductor by providing pelvic stabilization and controlling hip adduction and internal rotation. Weakness of the Gmed is associated with many disorders including balance deficit, gait and running disorders, femoroacetabular impingement, snapping hip, gluteal tendinopathy, patellofemoral pain syndrome, osteoarthritis, iliotibial band syndrome, anterior cruciate ligament injury, ankle joint injuries, low back pain, stroke, and nocturia. Overuse of the tensor fasciae latae (TFL) as a hip abductor due to Gmed weakness can also cause several pathologies such as pain in the lower back and hip and degenerative hip joint pathology, which are associated with dominant TFL. Similarly, lateral instability and impaired movements such as lumbar spine lateral flexion or lateral tilt of the pelvis can occur due to compensatory activation of the quadratus lumborum for a weakened Gmed while exercising. Therefore, the related activation of synergistic muscles or compensatory movement should be considered when prescribing Gmed strengthening exercises.

목재를 이용한 단층 지오데식 돔의 불안정 거동과 임계좌굴하중 (Unstable Behavior and Critical Buckling Load of a Single-Layer Dome using the Timber Elements)

  • 홍석호;하현주;손수덕;이승재
    • 한국공간구조학회논문집
    • /
    • 제23권2호
    • /
    • pp.19-28
    • /
    • 2023
  • Timber structures are susceptible to moisture, contamination, and pest infestation, which can compromise their integrity and pose a significant fire hazard. Despite these drawbacks, timber's lightweight properties, eco-friendliness, and alignment with current architectural trends emphasizing sustainability make it an attractive option for construction. Moreover, timber structures offer economic benefits and provide a natural aesthetic that regulates building temperature and humidity. In recent years, timber domes have gained popularity due to their high recyclability, lightness, and improved fire resistance. Researchers are exploring hybrid timber and steel domes to enhance stability and rigidity. However, shallow dome structures still face challenges related to structural instability. This study investigates stability problems associated with timber domes, the behavior of timber and steel hybrid domes, and the impact of timber member positioning on dome stability and critical load levels. The paper analyzes unstable buckling in single-layer lattice domes using an incremental analysis method. The critical buckling load of the domes is examined based on the arrangement of timber members in the inclined and horizontal directions. The analysis shows that nodal snapping is observed in the case of a concentrated load, whereas snap-back is also observed in the case of a uniform load. Furthermore, the use of inclined timber and horizontal steel members in the lattice dome design provides adequate stability.