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Flexure of cross-ply laminated plates using equivalent single layer trigonometric shear deformation theory

  • Sayyad, Atteshamuddin S.;Ghugal, Yuwaraj M.
    • Structural Engineering and Mechanics
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    • 제51권5호
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    • pp.867-891
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    • 2014
  • An equivalent single layer trigonometric shear deformation theory taking into account transverse shear deformation effect as well as transverse normal strain effect is presented for static flexure of cross-ply laminated composite and sandwich plates. The inplane displacement field uses sinusoidal function in terms of thickness coordinate to include the transverse shear deformation effect. The cosine function in thickness coordinate is used in transverse displacement to include the effect of transverse normal strain. The kinematics of the present theory is much richer than those of the other higher order shear deformation theories, because if the trigonometric term (involving thickness coordinate z) is expanded in power series, the kinematics of higher order theories (which are usually obtained by power series in thickness coordinate z) are implicitly taken into account to good deal of extent. Governing equations and boundary conditions of the theory are obtained using the principle of virtual work. The closed-form solutions of simply supported cross-ply laminated composite and sandwich plates have been obtained. The results of present theory are compared with those of the classical plate theory (CPT), first order shear deformation theory (FSDT), higher order shear deformation theory (HSDT) of Reddy and exact three dimensional elasticity theory wherever applicable. The results predicted by present theory are in good agreement with those of higher order shear deformation theory and the elasticity theory.

진도개의 고관절이형성에 대한 방사선학적 연구 (Radiographic Evaluation of Coxofemoral Joints in the Jindo (Canis familiaris))

  • 오석일;김상기
    • 한국임상수의학회지
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    • 제20권4호
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    • pp.467-473
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    • 2003
  • The pelvic radiographs of 47 clinically normal Jindoes (26 dogs and 21 bitches) were investigated to evaluate the coxofemoral joints, prospectively. The hip joints were graded according to the Orthopedic Foundation for Animals criteria of excellent, good, fair, borderline, mild canine hip dysplasia (CHD), moderate CHD, severe CHD. Of the 47 Jindoes evaluated, 8 (17%) were graded as dysplastic, 3 (6.4%) were mildly dysplastic, 3 (6.4%) were moderately dysplastic, and 2 (4.3%) were severly dysplastic. Of the 39 Jindoes graded as normal, 16 (34%) were classified as having excellent hip joint phenotype, 15 (31.9%) were classified as having fair, and 8 (17%) were classified as good. Each hip joint was scored based on the British Veterinary Association/The Kennel Club hip scoring system. The normal hip joint (excellent, fair, good) received score less than 5, while dysplastic hip joint (mild, moderate, severe CHD) received score form 5 to 29. Norberg angle (r=0.76) and femoral angle of inclination (r=0.6) were in inverse proportion to grade of the hip joint (P<0.01). The width of medial joint space was in proportion to grade of hip joint (r=0.7, P<0.01).

Elastic analysis of interfacial stress concentrations in CFRP-RC hybrid beams: Effect of creep and shrinkage

  • Abderezak, Rabahi;Daouadji, Tahar Hassaine;Abbes, Boussad;Rabia, Benferhat;Belkacem, Adim;Abbes, Fazilay
    • Advances in materials Research
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    • 제6권3호
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    • pp.257-278
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    • 2017
  • A simple closed-form solution to calculate the interfacial shear and normal stresses of retrofitted concrete beam strengthened with thin composite plate under mechanical loads including the creep and shrinkage effect has been presented in this paper. In such plated beams, tensile forces develop in the bonded plate, and these have to be transferred to the original beam via interfacial shear and normal stresses. Consequently, debonding failure may occur at the plate ends due to a combination of high shear and normal interfacial stresses. These stresses between a beam and a soffit plate, within the linear elastic range, have been addressed by numerous analytical investigations. Surprisingly, none of these investigations has examined interfacial stresses while taking the creep and shrinkage effect into account. In the present theoretical analysis for the interfacial stresses between reinforced concrete beam and a thin composite plate bonded to its soffit, the influence of creep and shrinkage effect relative to the time of the casting, and the time of the loading of the beams is taken into account. Numerical results from the present analysis are presented both to demonstrate the advantages of the present solution over existing ones and to illustrate the main characteristics of interfacial stress distributions.

Effect of shear stresses on the deflection and optimal configuration of a rectangular FGM structure

  • Ayoub El Amrani;Hafid Mataich;Jaouad El-Mekkaoui;Bouchta El Amrani
    • Coupled systems mechanics
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    • 제12권4호
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    • pp.391-407
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    • 2023
  • This paper presents a static study of a rectangular functional graded material (FGM) plate, simply supported on its four edges, adopting a refined higher order theory that looks for, only,four unknowns,without taking into account any corrective factor of the deformation energy with the satisfaction of the zero shear stress conditions on the upper and lower faces of the plate. We will have determined the contribution of these stresses in the transverse deflection of the plate, as well as their effects on the axial stress within the interfaces between the layers(to avoid any problem of imperfections such as delamination) and on the top and bottom edges of the plate in order to take into account the fatigue phenomenon when choosing the distribution law of the properties used during the design of the plate. A numerical statement, in percentage, of the contribution of the shear effect is made in order to show the reliability of the adopted theory. We will also have demonstrated the need to add the shear effect when the aspect ratio is small or large. Code routines are programmed to obtain numerical results illustrating the validity of the model proposed in the theory compared to those available in the literature.

Analysis of the thermal instability of laminated composite plates

  • H. Mataich;A. El Amrani;B. El Amrani
    • Coupled systems mechanics
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    • 제13권2호
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    • pp.95-113
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    • 2024
  • In this paper, we will analyse the thermo-elastic behavior of the plate element of a structure arranged in a climatically aggressive environment (extreme temperature), we use a refined four-variable thick plate theory to take the shear effect into consideration, the proposed theory less computationally expensive and more accurate so that it incorporates the shear effect into the formulation. The plate is assumed to be simply supported on its four edges, so exact (closed-form) solutions are found according to the Navier expansion, and the governing stability equations and associated boundary conditions of the problem are obtained via the virtual works principle. The plate studied ismade of laminated composite materials, so a parametric study is needed to see the effect of different types of parameters and coupling on the critical temperature value causing thermo-elastic instability of the plate and also on the natural frequency of free vibration, as well as for other parameters such as anisotropy, slenderness and aspect ratio of the plate and finally the lamination angle. Numerical results are obtained for specially orthotropic and antisymmetrical plates and are compared with those obtained by othertheoriesin the literature to validate the analysis approach used.

Effect of flexure-extension coupling on the elastic instability of a composite laminate plate

  • H. Mataich;A. El Amrani;J. El Mekkaoui;B. El Amrani
    • Structural Engineering and Mechanics
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    • 제90권4호
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    • pp.391-401
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    • 2024
  • The present study focuses on the effect of extension-bending coupling on the elastic stability (buckling) of laminated composite plates. These plates will be loaded under uni-axial or bi-axial in-plane mechanical loads, especially in the orthotropic or anti-symmetric cross-angle cases. The main objective is to find a limit where we can approximate the elastic stability behavior of angularly crossed anti-symmetric plates by the simple behavior of specially orthotropic plates. The contribution of my present study is to predict the explicit effect of extension-flexion coupling on the elastic stability of this type of panel. Critically, a parametric study is carried out, involving the search for the critical buckling load as a function of deformation mode, aspect ratio, plate anisotropy ratio and finally the study of the effect of lamination angle and number of layers on the contribution of extension-flexure coupling in terms of plate buckling stability. We use first-order shear deformation theory (FSDT) with a correction factor of 5/6. Simply supported conditions along the four boundaries are adopted where we can develop closed-form analytical solutions obtained by a Navier development.

입체 재단법에 의한 Tight Fitting시 등폭 기준선의 설정에 관한여 (On the Fixing of the Shoulder Blade Level during Tight Fitting by the Draping Design)

  • 이순섭
    • 복식문화연구
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    • 제4권3호
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    • pp.373-381
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    • 1996
  • Draping design system organized by European about 13C has been developed greatly for a long while, but for the purpose of the practical use the Dress form similar to human body has been needed. In order to make three-dimensional effect as fitting Muslin ot the Dress form. the Basic lien has to be established in Muslin and Dress form each. At this time, Shoulder-blade level is indicated from various angles : measure down 10cm from the back neck point, a quarter of the back neck point to the waist lie, the half-way point between neckline and bust line, measure down 41 inches from the back neck line, measure down 3 inches from the top edge of the muslin at center back and cross mark for neck line, and so forth. This study established the Basic line through the two ways of them (B.N.P∼B.L/2, B.N.P∼W.L/4), did tight fitting to the 5 kinds of Dress forms which ar normal type in the drop value(the difference between hip circumference and bust circumference), and acquired Basic Pattern. After the experiment, fitness are throughly investigate by statistical analysis of measurements. As a result, this study finds out that fit is proper when shoulder blade level is situated on a fourth of the back neck point to the waist line and a quarter point between back neck point and waist line, and waist dart is situated on the back center line and princess line.

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전이 직장암 환자의 FOLFIRI 유발 설사에 위령탕 가감방 치험 1례 (A Case Report of FOLFIRI-Induced Diarrhea in Patient with Metastatic Rectal Cancer Treated with Modified Wiryeong-tang)

  • 윤성수;김은혜;이지영;윤성우
    • 대한암한의학회지
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    • 제23권1호
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    • pp.15-21
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    • 2018
  • Objectives : This study was aimed to describe a case of a patient with FOLFIRI-induced diarrhea, which was improved by treatment with Korean herbal medicine, modified Wiryeong-tang. Methods : The patient with metastatic rectal cancer recieved FOLFIRI plus bevacizumab as a palliative chemotherapy and showed repetitive diarrhea despite administration of loperamide, which was treated with modified Wiryeong-tang. To evaluate the effect of the treatment, the Bristol Stool Form Scale and bowel movement frequency were checked. Results : During the treatment, the stool form using Bristol Stool Form Scale was improved from diarrhea to normal stool, and the bowel movement frequency was decreased. Conclusions : The result suggest that modified Wiryeong-tang may be an effective treatment for FOLFIRI-induced diarrhea.

Analysis of periodontal attachment loss in relation to root form abnormalities

  • Chung, Young-Mi;Jeong, Seong-Nyum
    • Journal of Periodontal and Implant Science
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    • 제43권6호
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    • pp.276-282
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    • 2013
  • Purpose: The aim of this study was to explore root shape abnormalities, to investigate the influence of root form abnormalities on periodontal attachment loss, and to gather basic data to assist in the diagnosis and treatment of aggressive periodontitis. Methods: From January 2010 to June 2012, a survey was conducted of all 3,284 periodontitis patients who visited the Department of Periodontology, Daejeon Dental Hospital, Wonkwang University School of Dentistry. Clinical parameters (probing depth, periodontal attachment loss, missing teeth) were measured and a radiographic examination was performed at the baseline. We classified the root shape abnormality of bicuspids and molars based on Meng classification. Results: The periodontal attachment loss was the highest at the maxillary first molar (6.03 mm). The loss of the second molar was prominent. Type V deformity was shown to be the most common in the second maxillary and mandibular molars (P<0.05). Type V root shape was associated with the highest attachment loss (P=0.01). Conclusions: Considering the small population and limited design of this study, definitive conclusions cannot be drawn. We suggest larger scale, methodologically more sophisticated studies that include normal controls and chronic periodontitis patients to clarify whether root form abnormalities are a potential risk factor for aggressive periodontitis.

남성 가성반음양 환자에서의 요도성형술 (Urethroplasty in Male Pseudohermaphroditism)

  • 김석권;하재성;이근철;박정민
    • Archives of Plastic Surgery
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    • 제32권1호
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    • pp.110-116
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    • 2005
  • Male pseudohermaphroditism is individuals with Y chromosome whose external appearances fail to develop as expected as a normal male. Cytogenetic form of male pseudohermaphroditism was 46XY but external genital forms were variable. We reviewed data from 7 patients with male pseudohermaphroditism operated in Dong-A University Hospital from January 1996 to August 2002. They all had severe form of hypospadias (pseudovaginal perineoscrotal type). Only 1 of 7 cases was operated urethroplasty by one stage method, and all others by two stage method. Patients with mild chordee were operated by one stage method and patients with severe chordee were operated by two stage method. Complete chordee release was done by Z-plasty or FTSG on the first stage and posterior urethroplasty was done at level of mid-dorsum of shaft at the same time. Anterior urethroplasty was done completely on the second stage. Results were good from the viewpoint of shape and urination. Urethral fistula occurred in two cases, but other complications (infection, urethral stricture, etc.) didn't occur. In conclusion, two stage method was compatible to correct hypospadias in male pseudohermaphroditism, because hypospadias in male pseudohermaphroditism is in severe form.