• Title/Summary/Keyword: notch length

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Stress Intensity Factor Determination on the Crack Initiated from Notch Tip (노치에서 발생된 균열의 응력확대계수 해석)

  • 조용근;박종수;임창현;석창성;최용식
    • Journal of the Korean Society of Safety
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    • v.9 no.1
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    • pp.3-8
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    • 1994
  • This paper has described the analysis of the Stress Intensity Factor behaviour of a short crack Initiated from notch tip. The model for finite element analysis is a double edge notched specimen. The parameters used in this study are crack length and notch root curvature radius.

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Study of cracks in compressed concrete specimens with a notch and two neighboring holes

  • Vahab, Sarfarazi;Kaveh, Asgari;Shirin, Jahanmiri;Mohammad Fatehi, Marji;Alireza Mohammadi, Khachakini
    • Advances in concrete construction
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    • v.14 no.5
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    • pp.317-330
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    • 2022
  • This paper investigated computationally and experimentally the interaction here between a notch as well as a micropore under uniaxial compression. Brazilian tensile strength, uniaxial tensile strength, as well as biaxial tensile strength are used to calibrate PFC2d at first. Then, uniaxial compression test was conducted which they included internal notch and micro pore. Experimental and numerical building of 9 models including notch and micro pore were conducted. Model dimensions of models are 10 cm × 10 cm × 5 cm. Joint length was 2 cm. Joints angles were 30°, 45° and 60°. The position of micro pore for all joint angles was 2cm upper than top of the joint, 2 cm upper than middle of joint and 2 cm upper than the joint lower tip, discreetly. The numerical model's dimensions were 5.4 cm × 10.8 cm. The fractures were 2 cm in length and had angularities of 30, 45, and 60 degrees. The pore had a diameter of 1 cm and was located at the top of the notch, 2 cm above the top, 2 cm above the middle, and 2 cm above the bottom tip of the joint. The uniaxial compression strength of the model material was 10 MPa. The local damping ratio was 0.7. At 0.016 mm per second, it loaded. The results show that failure pattern affects uniaxial compressive strength whereas notch orientation and pore condition impact failure pattern. From the notch tips, a two-wing fracture spreads almost parallel to the usual load until it unites with the sample edge. Additionally, two wing fractures start at the hole. Both of these cracks join the sample edge and one of them joins the notch. The number of wing cracks increased as the joint angle rose. There aren't many AE effects in the early phases of loading, but they quickly build up until the applied stress reaches its maximum. Each stress decrease was also followed by several AE effects. By raising the joint angularities from 30° to 60°, uniaxial strength was reduced. The failure strengths in both the numerical simulation and the actual test are quite similar.

A Study on Notch Bit System for Controlling Blast Vibration and Over-break in Rock Mass (발파공해 해소 및 여굴 최소화를 위한 선균열 암굴착 노치장비 개발에 관한 연구)

  • Jeong, Dong-Ho;Moon, Sang-Jo;An, Dae-Jin;Jeong, Won-Joon;Kim, Eun-Kwan;Kim, Dong-Gyou
    • Tunnel and Underground Space
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    • v.17 no.3 s.68
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    • pp.216-224
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    • 2007
  • Blasting, using shock and dynamic energy of explosive, is very effective tunnel excavation method. But it had serious problem which is the blast vibration and over-break. In recent study, pre-cracked excavation method using notch hole reduced blast vibration and over-break in tunnel, so we performed study about developing notch bit system for making notch hole. In order to make notch hole effectively we had perform drilling experiments changing length and height of notch and in order to improve speed and precision of drilling we had developed notch bit system which consists of drilling bit, notch bit, adapter and notch guide.

High-Tc superconducting magnet properites with design conditions (설계조건에 따른 고온 초전도 마그넷의 특성변화)

  • Kim, Min-Ki;Ko, Yo;Han, Byoung-Sung
    • Electrical & Electronic Materials
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    • v.8 no.4
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    • pp.451-457
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    • 1995
  • Most important study on development of high-Tc superconducting magnet is magnetic properties with design conditions To study optimal design condition of high-Tc superconducting magnet, small size solenoid magnet was designed and simulated. Design conditions are radius of bobbin, radius of magnet, length of magnet, critical cur-rent and notch size. We know that intensity of magnetic fields was controled by critical current and uniformity of magnetic fields was controled by notch size. The optimal design conditions to get the high intensity and uniformity of magnetic field in this experiments were radius of bobbin=3[cm], radius of magnetic=12[cm], length of Z=10[cm], notch size=6[cm] and critical current=12[A].

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A STUDY OiM THE MORPHOLOGY OF CHIN IN RELATION TO VERTICAL DYSPLASIA OF CRANIOFACIAL COMPLEX (안모수직 부조화에 따른 하악이부 형태에 관한 연구)

  • Cha, Bong-Keun;Suhr, Cheong-Hoon
    • The korean journal of orthodontics
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    • v.20 no.1
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    • pp.135-156
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    • 1990
  • This study was undertaken to investigate the difference of chin morphology and mandibular form in relation to different mandibular growth direction. The subject was divided into three group i.e., control group, vertical group, and horizontal group, according to the criteria of $Bj{\ddot{o}}rk$ sum, and each group was composed of 15 females and 15 males. Medial axis analysis in addition to the routine cephalometric analysis using P.I.A.S. (personal image analysing system) was carried out to find out the differences of mandibular morphology on each group. The results were as follows: 1. The area of symphysis was larger in horizontal growth group than that of vertical growth group. 2. Protruding chin area was also larger in horizontal growth group than that of vertical growth group. 3. There was a close correlationship between protruding chin area and other form of mandible. 4. Antegonial notch depth and ramus posterior contour depth was deeper in vertical growth group than in horizontal growth group, and antegonial notch depth was more influenced by anterior part of notch than posterior part of notch. 5. Mental medial axis and incisal medial axis length, in relation to corpus medial axis length was larger in vertical growth group than in horizontal growth group.

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Bending Properties and Recommened Design Criteria for Domestic Softwood with Notch (파임을 가진 국산 침엽수재의 휨성능 및 구조설계기준에 관한 연구)

  • Oh, Sei-Chang
    • Journal of the Korean Wood Science and Technology
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    • v.26 no.4
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    • pp.6-12
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    • 1998
  • Test results of domestic softwood lumber were presented to examine the notch effect of beams and compare to present AIJ(Architecture Institute of Japan) formula in notched wood member especially positioned in bottom side (tension side) of a beam. Notched lumber was tested under following condition : each specimen supported simply, and subjected to third-point loading at points of 1/3 of the span length. Notch was located opposite side to loading direction and notch depth were 1/6, 1/4, 1/3 of beam depth. Deflection and load were measured by digital dial guage each in 25kgf increment. Bending test results were as follows; Mpro/Mmax range (proportional and maxium bending moment ratio in notched beam) was 0.5 - 0.65. It was considered that maxium bending moment was about 1.5 times to proportional bending moment in notched beam and showed same tendency in the test result of ordinary wood specimens. AU standard formula for the tension side notch, Mmat = 0.6 ${\times}$ (Zo $\sigma$), the constant 0.6 was suitble for notch ratio(notch depth to beam depth) 1/6, but this ratio for 1/4, and 1/3 was not. So it is preferable to accept smaller value than 0.6 for notch ratio more than 1/3. These experiment results showed critical effect in tension side notched wood beam especially in greater than notch ratio 1.3 of wood beam. From the above results, it is recommened to revise design formula adoptable to domestic wood constructon member with tension side notched member.

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A Compact UWB Planar Antenna with WLAN Band-Notch Characteristic

  • Park, Dong-Kook;Kwak, Byung-Haw
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.7
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    • pp.857-862
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    • 2007
  • A novel compact ultra wideband(UWB) antenna for UWB application is proposed in this paper. The proposed antenna with $22mm{\times}26mm{\times}1.6mm$ covers the entire UWB bandwidth and has band notch characteristic for the frequency band of $5.15{\sim}5.825GHz$ limited by WLAN. The antenna has a concaved ground plane and staircase shape patch to achieve the wide bandwidth, and has an U shape slot with $\lambda/4$ length to notch the band. The return loss and group delay of the proposed antenna are measured.

A Planar Folded Monopole Antenna with Inverted T-Shape Notch in Ground Plane for 4G Mobile Communication (역 T형 노치를 가진 4세대 이동통신용 평면형 폴디드 모노폴 안테나)

  • Shin, Ho-Sub;Choi, In-Tae
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.10a
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    • pp.893-895
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    • 2013
  • In this paper, we propose the planar folded monopole antenna with an inverted T-shape notch in ground plane. The proposed antenna is not only varied to a width of inner and outer patch lines to broaden bandwidth, but also it is inserted to a modified inverted T-shape notch with the same length of horizontal and vertical slit, difference of its width is about twice in the ground plane to broaden bandwidth. It is designed and simulated.

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Numerical simulation of wedge splitting test method for evaluating fracture behaviour of self compacting concrete

  • Raja Rajeshwari B.;Sivakumar, M.V.N.;Sai Asrith P.
    • Computers and Concrete
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    • v.33 no.3
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    • pp.265-273
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    • 2024
  • Predicting fracture properties requires an understanding of structural failure behaviour in relation to specimen type, dimension, and notch length. Facture properties are evaluated using various testing methods, wedge splitting test being one of them. The wedge splitting test was numerically modelled three dimensionally using the finite element method on self compacting concrete specimens with varied specimen and notch depths in the current work. The load - Crack mouth opening displacement curves and the angle of rotation with respect to notch opening till failure are used to assess the fracture properties. Furthermore, based on the simulation results, failure curve was built to forecast the fracture behaviour of self-compacting concrete. The fracture failure curve revealed that the failure was quasi-brittle in character, conforming to non-linear elastic properties for all specimen depth and notch depth combinations.

Evaluation of the antegonial notch related to the mandibular morphology and the curve of Spee in anteroposterior relation (전후방적 분류에 따른 하악 형태 및 Spee 만곡에 대한 antegonial notch의 관계 평가)

  • Son, J-H;Kim, Y-H;Kook, Y-A
    • The Journal of the Korean dental association
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    • v.45 no.8 s.459
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    • pp.483-490
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    • 2007
  • The aim of this study was to investigate the relationship between the mandibular antegonial notch and the mandibular morphology, and the curve of Spee in anteroposterior skeletal relationship. Pre-treatment lateral cephalograms were obtained from 80(male 34, female 46) adult orthodontic patients and the samples were classified into 3 categories by ANB angle($0^{\circ}$$\leq$ANB< $4^{\circ}$ Class I, $4^{\circ}$$\leq$ANB Class II, ANB< $0^{\circ}$ Class III). The curve of Spee was measured directly from the pre-treatment mandibular study cast of each patient included in this study. Pearson correlation coefficient test and multiple regression analysis in each group revealed the following results; 1. Antegonial notch depth was positively correlated with hoth lower anterior facial height(ANS-Me) in skeletal Class I, II and III groups and Id-Me height in skeletal Class I and II groups. 2. A statistically significant negative correlation was found between the depth of the antegonial notch and the curve of Spee in the Class III group. 3. Significant relationship was not found between the antegonial notch depth and any of the other cephalometric variables such as mandibular body length(Go-Gn) and ramus height(Co-Go). As antegonial notch depth increased, more vertical growth of the mandible was observed. Antegonial notch can be used as a predictor of vertical mandibular growth in the diagnosis and treatment planning of malocclusion.

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