• Title/Summary/Keyword: Load types

Search Result 2,087, Processing Time 0.032 seconds

Broad and stage-based sensing function of HCFRP sensors

  • Wu, Z.S.;Yang, C.Q.
    • Smart Structures and Systems
    • /
    • v.3 no.2
    • /
    • pp.133-146
    • /
    • 2007
  • This paper addresses a new type of broad and stage-based hybrid carbon fiber reinforced polymer (HCFRP) sensor that is suitable for the sensing of infrastructures. The HCFRP sensors, a type of composite sensor, are fabricated with three types of carbon tows of different strength and moduli. For all of the specimens, the active materials are carbon tows by virtue of their electrical conductivity and piezoresistivity. The measurement principles are based on the micro- and macro-fractures of different types of carbon tows. A series of experiments are carried out to investigate the sensing performances of the HCFRP sensors. The main variables include the stack order and volume fractions of different types of carbon tows. It is shown that the change in electrical resistance is in direct proportion to the strain/load in low strain ranges. However, the fractional change in electrical resistance (${\Delta}R/R_0$) is smaller than 2% prior to the macrofractures of carbon tows. In order to improve the resistance changes, measures are taken that can enhance the values of ${\Delta}R/R_0$ by more than 2 times during low strain ranges. In high strain ranges, the electrical resistance changes markedly with strain/load in a step-wise manner due to the gradual ruptures of different types of carbon tows at different strain amplitudes. The values of ${\Delta}R/R_0$ due to the fracture of high modulus carbon tows are larger than 36%. Thus, it is demonstrated that the HCFRP sensors have a broad and stage-based sensing capability.

Verification Studies for Field Peformance of Micropiling (성능검증을 위한 마이크로파일 현장 시험시공 및 재하시험)

  • Goo, Jeong-Min;Lee, Ki-Hwan;Cho, Young-Jun;Choi, Chang-Ho
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2009.03a
    • /
    • pp.368-375
    • /
    • 2009
  • This paper describes field installation and load test results performed for three types of micropiles in the process of developing a new micropiling method. Field tests were performed for two conventional types(i.e., micropile reinforced with steel bar and gravity grouting, micropile reinforced with steel bar and steel casing and gravity grouting) and a proposed type(i.e., micropile reinforced with hollow steel pipe wrapped with geotextile-pack and pressurized grouting). The load test results subjected to axial compression and tension and lateral loading conditions are described in this paper. The micropiles were exposed in the air in order to verify the installation quality and curing condition of grouting material via ground excavation. Axial compression and tension test results indicate that the new micropile type provide at least 40% higher bearing capacity than that of conventional types. Based on the examination of exposed piles, it is induced that the proposed method, packed micropile, provides better interlocking between grouts and surrounding soils and increases higher frictional resistance comparing to conventional types.

  • PDF

Effect of Surface Profiles on Pavement Fatigue Life (포장 프로파일이 포장 피로수명에 미치는 영향 분석)

  • Park, Dae-Wook;An, Deok-Soon;Kwon, Soo-Ahn
    • International Journal of Highway Engineering
    • /
    • v.11 no.2
    • /
    • pp.167-174
    • /
    • 2009
  • The simulation of dynamic load was conducted based on surface profile on asphalt concrete pavement, vehicle speeds, and suspension types using a truck simulation program. The results of the simulated dynamic load based on different surface profile, vehicle speeds, and suspension types are analyzed. As pavement roughness and vehicle speed are increased, the dynamic load was increased. Walking beam suspension produces greater dynamic load than air spring suspension. Pavement damage index is calculated based on covariance of dynamic load and Paris-Erdogan fracture parameter, n which is based on creep compliance tests of asphalt mixtures used in Korea. The higher covariance of dynamic load, confidence level, and fracture parameter are used, the greater pavement damage index is obtained. Specification of pavement roughness can be developed in various vehicle speeds and asphalt mixtures, and pay factor can be determined after constructing asphalt concrete pavement using pavement damage concepts.

  • PDF

Comparative of Energy-Saving by Green Roof Type on Urban Office Building (도심 오피스건물의 옥상녹화 조성 유형별 건물에너지 절감 비교 연구)

  • Kim, Jeong-Ho;Kwon, Ki-Uk;Joo, Chang-Hun;Yoon, Yong-Han
    • Journal of Environmental Science International
    • /
    • v.23 no.8
    • /
    • pp.1437-1446
    • /
    • 2014
  • This study, the urban energy used office building green roof type composition of the target by analyze building energy reductions. Green roof is total 6 types(type A~F) were selected, EnergyPlus the energy simulation programs were used. Top floor of green roof types evaluation, the reduction of the cooling peak load type E(1.26%), type D(1.30%), type C(1.37%), type B(1.45%), type F(1.49%), and heating peak load is type D(1.32%), type E(1.40%), type C(1.47%), type F(1.69%), type B(2.13%) order. Annual cooling load of heating load is reduced more than about 1% effect. The heating load reduction ratio for a maximum of 9% respectively. Cooling peak load of the building energy performance evaluation of type F > type B > type C > type D > type E in the order and in the case of peak loads heating type B > type F > type D > type E>type C order. Annual total energy use reduction of 1.07 to 1.22% and earn, type B in the best good. In primary energy use reductions in the presence of a green roof were in the 4249~4876 kWh/yr. Annual $CO_2$ emissions reductions of unapplied type A were analyzed on average 469.78 kg.

THREE-DIMENSIONAL STRESS ANALYSIS OF IMPLANT SYSTEMS IN THE MANDIBULAR BONE WITH VARIOUS ABUTMENT TYPES AND LOADING CONDITIONS (임프란트의 상부구조물 형상과 하중조건에 따른 3차원 유한요소해석을 이용한 하악골의 응력분포에 관한 연구)

  • Shin Ha-Shik;Chun Heoung-Jae;Han Chong-Hyun;Lee Soo-Hong
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.41 no.5
    • /
    • pp.617-625
    • /
    • 2003
  • Statement of problem : There are many studies focused on the effect of shape of futures on stress distribution in the mandibular bone. However, there are no studies focused on the effect of the abutment types on stress distribution in mandibular bone. Purpose : The purpose of this study is to investigate the effect of three different abutment types on the stress distributions in the mandibular bone due to various loads by performing finite element analysis. Material and method : Three different implant systems produced by Warantec (Seoul, Korea), were modeled to study the effect of abutment types on the stress distribution in the mandibular bone. The three implant systems are classified into oneplant (Oneplant, OP-TH-S11.5). internal implant (Inplant, IO-S11.5) and external implant (Hexplant, EH-S11.5). All abutments were made of titanium grade ELI. and all fixtures were made of titanium grade IV. The mandibular bone used in this study is constituted of compact and spongeous bone assumed to be homogeneous, isotropic and linearly elastic. A comparative study of stress distributions in the mandibular bone with three different types of abutment was conducted. Results : It was found that the types of abutments have significant influence on the stress distribution in the mandibular bone. It was due to difference in the load transfer mechanism and the size of contact area between abutment and fixture. Also the maximum effective stress in the mandibular bone was increased with the increase of inclination angle of load. Conclusion : It was concluded that the maximum effective stress in the bone by the internal implant was the lowest among the maximum effective stresses by other two types.

THE THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF THE PARTIALLY EDENTULOUS IMPLANT PROSTHESIS WITH VARYING TYPES OF NON-RIGID CONNECTION (부분 무치악 임플랜트 보철 수복시 자연치와의 비고정성 연결형태에 따른 3차원 유한요소법적 연구)

  • Lee, Seon-A;Chung, Chae-Heon
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.34 no.1
    • /
    • pp.101-124
    • /
    • 1996
  • In this study, we designed the finite element models of mandible with varying their connecting types between the prosthesis on implant fixture and 2nd premolar, which were free-standing case(Mf), precision attachment case(Mp), semiprecision attachment case(Ms) and telescopic case(Mt). The basic model of the designed finite element models, which contained a canine and the 1st & 2nd premolar, was implanted in the edentulous site of the 1st & 2nd molar by two implant fixtures. We applied the load in all models by two ways. A vertical load of 200N was applied at each central fossa of 2nd premolar and 1st implant. A tilting load of 20N with inclination of $45^{\circ}$ to lingual side was applied to buccal cusp tips of each 2nd premolar and 1st implant. And then we analyzed three-dimensional finite element models, making a comparative study of principal stress and displacement in four cases respectively. Three-dimensional finite element analysis was performed for the stress distribution and the displacement using commercial software(IDEAS program) for SUN-SPARC workstation. The results were as follows : 1 Under vertical load or tilting load, maximum displacement appeared at the 2nd premolar. Semiprecision case showed the largest maximum displacement, and maximum displacement reduced in the order of precision attachment, free-standing and telescopic case. 2. Under vertical load. the pattern of displacement of the 1st implant appeared mesio-inclined because of the 2nd implant splinted together. But displacement pattern of the 2nd premolar varied according to their connection type with prosthesis. The 2nd premolar showed a little mesio-inclined vertical displacement in case of free-standing and disto-inclined vertical displacement due to attachment in case of precision and semiprecision attachment. In telescopic case, the largest mesio-inclined vertical displacement has been shown, so, the 1st premolar leaned mesial side. 3. Under tilting load, The pattern of displacement was similar in all four cases which appeared displaced to lingual side. But, the maximum displacement of 2nd premolar appeared larger than that of the first implant. Therefore, there was large discrepancy in displacement between natural tooth and implant during tilting load. 4. Under vertical load, the maximum compressive stress appeared at the 1st implant's neck. Semiprecision attachment case showed the largest maximum compressive stress, and the maximum compressive stress reduced in the order of precision attachment, telescopic and free-standing case. 5 Under vertical load, the maximum tensile stress appeared at the 2nd implant's distal neck. Semiprecision attachment case showed the largest maximum tensile stress, and the maximum tensile stress reduced in the order of precision attachment, telescopic and free-standing case. 6. Under vertical load or tilting load, principal stress appeared little between natural tooth & implant in free-standing case, but large principal stress was distributed at upper crown and distal contact site of the 2nd premolar in telescopic case. Principal stress appeared large at keyway & around keyway of distal contact site of the 2nd premolar in precision and semiprecision attachment case, appearing more broad and homogeneous in precision attachment case than in semiprecision attachment case.

  • PDF

EFFECT OF RESTORATION TYPE ON THE STRESS DISTRIBUTION OF ENDODONTICALLY TREATED MAXILLARY PREMOLARS; THREE-DIMENSIONAL FINITE ELEMENT STUDY (수복물의 종류가 근관치료된 상악 제2소구치의 응력분포에 미치는 영향: 3차원 유한요소법적 연구)

  • Jung, Heun-Sook;Kim, Hyeon-Cheol;Hur, Bock;Kim, Kwang-Hoon;Son, Kwon;Park, Jeong-Kil
    • Restorative Dentistry and Endodontics
    • /
    • v.34 no.1
    • /
    • pp.8-19
    • /
    • 2009
  • The purpose of this study was to investigate the effects of four restorative materials under various occlusal loading conditions on the stress distribution at the CEJ of buccal. palatal surface and central groove of occlusal surface of endodontically treated maxillary second premolar, using a 3D finte element analysis. A 3D finite element model of human maxillary second premolar was endodontically treated. After endodontic treatment, access cavity was filled with Amalgam, resin, ceramic or gold of different mechanical properties. A static 500N forces were applied at the buccal (Load-1) and palatal cusp (Load-2) and a static 170N forces were applied at the mesial marginal ridge and palatal cusp simultaneously as centric occlusion (Load-3). Under 3-type Loading condition, the value of tensile stress was analyzed after 4-type restoration at the CEJ of buccal and palatal surface and central groove of occlusal surface Excessive high tensile stresses were observed along the palatal CEJ in Load-1 case and buccal CEJ in Load-2 in all of the restorations. There was no difference in magnitude of stress in relation to the type of restorations. Heavy tensile stress concentrations were observed around the loading point and along the central groove of occlusal surface in all of the restorations. There was slight difference in magnitude of stress between different types of restorations. High tensile stress concentrations around the loading points were observed and there was no difference in magnitude of stress between different types of restorations in Load-3.

Behaviour factor and displacement estimation of low-ductility precast wall system under seismic actions

  • Tiong, Patrick L.Y.;Adnan, Azlan;Hamid, Nor H.A.
    • Earthquakes and Structures
    • /
    • v.5 no.6
    • /
    • pp.625-655
    • /
    • 2013
  • This paper investigated the seismic behaviour of an innovated non-ductile precast concrete wall structural system; namely HC Precast System (HCPS). The system comprises load-bearing precast wall panels merely connected only to column at both ends. Such study is needed because there is limited research information available in design codes for such structure particularly in regions having low to moderate seismicity threats. Experimentally calibrated numerical model of the wall system was used to carry out nonlinear pushover analyses with various types of lateral loading patterns. Effects of laterally applied single point load (SPL), uniformly distributed load (UDL), modal distributed load (MDL) and triangular distributed load (TDL) onto global behaviour of HCPS were identified. Discussion was focused on structural performance such as ductility, deformability, and effective stiffness of the wall system. Thus, a new method for engineers to estimate the nonlinear deformation of HCPS through linear analysis was proposed.

Mechanical Behavior and Cracking Characteristics of Tunnel Lining by Model Experiment (모형 실험에 의한 터널 복공의 역학적 거동 및 균열 특성에 관한 연구)

  • 이대혁;김영근;이희근
    • Tunnel and Underground Space
    • /
    • v.8 no.1
    • /
    • pp.53-66
    • /
    • 1998
  • Considering the mechanical cracking in the concrete lining of tunnels occurring in relatively short period of time after the construction, there is a need for the study on the mechanical behavior and the cracking characteristics of double lining support system(shotcrete and concrete lining). For the proposed study, downscaled lining models of Kyung-Bu High Speed Railway tunnels were tested. Most longitudinal cracks at about 93 percentage developed within 30 arch degree from the vault. Cracking load was about 30 percentage of the failure load and the deflection under the cracking load was 10 percentage of the deflection under the failure load. The overbreak around the vault contributed to the reduction of the capacity for cracking and failure by the percentage greater than the reduced effective depth. Of several rock block types considered in this research, the triangular block was the most critical, and the right triangular block under eccentric load was secondly critical for the stability of the tunnel lining system. The dimensionless support reaction curves were derived from the experimental results for single and double lining. The general equation to compute the designed flexural moment was modified.

  • PDF

Simulation Analysis for Configuring Web Clusters (웹 클러스터 구성을 위한 시뮬레이션 분석)

  • Kang, Sung-Yeol;Song, Young-Hyo
    • Journal of Digital Convergence
    • /
    • v.6 no.2
    • /
    • pp.117-125
    • /
    • 2008
  • High-volume web sites often use clusters of servers with load balancing as a way to increase the performance, scalability, and availability of the sites. Load balancing, usually performed by load balancer in front of such clusters, is a technique to spread workload between several computers or resources, in order to get optimal resource utilization or response time. In this paper we examine the performance for several configurations of cluster-based web servers using a simulation approach. We investigate two types of buffering scheme (common and local) for web clusters and three load balancing policies (uniformly random, round robin, and least queue first), using response time as a performance measure. We also examine two basic approaches of scaling web clusters: adding more servers of same type or upgrading the capacity of the servers in the clusters.

  • PDF