• Title, Summary, Keyword: Bending Resistance

Search Result 604, Processing Time 0.033 seconds

Center Pillar Design for High Bending Collapse Performance (굽힘 붕괴 성능 향상을 위한 센터 필라 설계)

  • Kang, Sungjong;Park, Myeongjae
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.21 no.4
    • /
    • pp.128-134
    • /
    • 2013
  • High bending collapse performance (maximum resistance force and mean resistance force) of body center pillar is an important design target for vehicle safety against side impact. In this study, effect of the upper section shape and the thickness of outer reinforcement on bending collapse performance was investigated for the center pillar of a large passenger car. First, through bending collapse analyses using simple models with uniform section, an optimized center pillar upper section was chosen. Next, bending collapse performance for various models of the actual center pillar with changing the thickness of outer reinforcement were analyzed. The finally designed model showed distinctive enhancement in bending collapse performance nearly without weight increase.

An Experimental Study on Bending Performance of Hybrid Forming Composite Beam

  • Kim, Sung-Bae;Cho, Seong-Hyun;Choi, Young-Han;Kim, Sang-Seup
    • International journal of steel structures
    • /
    • v.17 no.4
    • /
    • pp.1641-1651
    • /
    • 2017
  • The new shape of Hybrid forming beam is a beam that two Z-shaped side plates and bottom plate are connected by high-strength bolt. By adjusting the height of Z-shaped side plate, it can be designed for required resistance and by adjusting the thickness of bottom plate and applying high-strength steel to it, nominal bending moment can be increased. In addition, if concrete is filled inside of the beam during the slab concrete installation process, it becomes the Hybrid forming composite beam which usability and fire resistance are increased. This study suggests the new shape of the Hybrid forming composite beam that applied high-strength steel to the bottom plate and this study acquired the conclusion as the following by the bending test. First, if the existing evaluating formula which evaluates the resistance of the couple moment by the compressive resistance and tensile resistance is applied to evaluating bending resistance of the Hybrid forming composite beam, the ratio of maximum load for the nominal load is more than 1.2 times on average, matches well with the experiment result. Second, if the bending stiffness of the Hybrid forming composite beam is calculated as the effective bending stiffness based on concrete that subjected to compression and steel that subjected to tension, it confirmed to reflect the experimental result well.

Effects of Patenting Temperature on the Bending Fatigue Resistance of the Steel Filaments used for Automotive Tire (열처리 조건에 따른 미세 강선의 굽힘 피로 특성 변화)

  • Yang, Y.S.;Bae, J.G.;Park, C.G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • /
    • pp.454-457
    • /
    • 2008
  • Effects of patenting temperature on bending fatigue resistance of pearlitic steel filaments were investigated experimentally. The fatigue resistance of steel filaments was carried out by using hunter machine, specially designed for ultra fine-sized steel wires, in the controlled conditions. The transmission electron microscopy (TEM) was used for observing the overall microstructure. It revealed that the fatigue resistance as well as tensile strength increased together with increase of patenting temperature from 510 to $600^{\circ}C$, while the endurance ratio ($\sigma_e/\sigma_{TS}$) of filaments decreased. It is believed that this variation of mechanical properties with change of patenting temperature should be strongly influenced by the change of microstructure. The bending fatigue properties of steel filaments were discussed based on microstructural parameters.

  • PDF

Experimental research on sagging bending resistance of steel sheeting-styrofoam-concrete composite sandwich slabs

  • Cao, P.Z.;Lu, Y.F.;Wu, Kai
    • Steel and Composite Structures
    • /
    • v.15 no.4
    • /
    • pp.425-438
    • /
    • 2013
  • A new-styrofoam-concrete composite sandwich slab with function of heat insulation is designed. Four full-scale simply supported composite sandwich slabs with different shear connectors are tested. Parameters under study are the thickness of the concrete, the height of profiled steel sheeting, the influence of shear connectors including the steel bars and self-drilling screws. Experimental results showing that four specimens mainly failed in bending failure mode; the shear connectors can limit the longitudinal slippery between the steel profiled sheeting and the concrete effectively and thus guarantee the good composite action and cooperative behavior of two materials. The ultimate sagging bending resistance can be determined based on plastic theory. This new composite sandwich slab has high sagging bending resistance and good ductility. Additionally, these test results help the design and application of this new type of composite sandwich slab.

Simplified equations for Vierendeel design calculations of composite beams with web openings

  • Panedpojaman, Pattamad
    • Steel and Composite Structures
    • /
    • v.27 no.4
    • /
    • pp.401-416
    • /
    • 2018
  • Composite beams with web openings are vulnerable to Vierendeel bending failure. The available methods provide quite conservative estimates of Vierendeel bending resistance. An alternative design method to compute the resistance was proposed in this study, based on quadratic nonlinear interactions of normalized shear force, axial force and Vierendeel bending moment. The interactions of the top and bottom Tee section must satisfy mutual conditions to prevent the Vierendeel failure. The normalized shear force and Vierendeel bending moment of the composite part were used instead in the top Tee interaction. The top Tee axial force was computed based on force equilibrium. Based on a rigid-plastic model, the composite resistance is estimated using an effective slab width of the vertical shear resistance. On using the proposed method, nonlinear reductions due to shear loads and axial forces are not required, in contrast to prior methods. The proposed method was validated against experiments from literature. The method limitations and accuracy as well as the Vierendeel behavior were investigated by finite element simulations, with varied composite beam parameters. The proposed design loads are less conservative than earlier estimates and deviate less from the simulations.

Bending Behavior of Nailed-Jointed Cross-Laminated Timber Loaded Perpendicular to Plane

  • Pang, Sung-Jun;Kim, Kwang-Mo;Park, Sun-Hyang;Lee, Sang-Joon
    • Journal of the Korean Wood Science and Technology
    • /
    • v.45 no.6
    • /
    • pp.728-736
    • /
    • 2017
  • In this study, the bending behavior of cross-laminated timber (CLT) connected by nails were investigated. Especially, the load-carrying capacity of the nail-jointed CLT under out-of-plane bending was predicted by the lateral resistance of the used nails. Three-layer nail-jointed CLT specimens and a nail connection were manufactured by 30 mm (thickness) ${\times}$ 100 mm (width) domestic species (Pinus koraiensis) laminas and Ø$3.15{\times}82mm$ nails using a nail-gun. Shear test for evaluating the nail lateral resistance and bending test for evaluating the load-carrying capacity of the nail-jointed CLT under out-of-plane bending were carried out. As a result, two lateral resistance of the used nail, the 5% fastener offset value and the maximum value, were 913 N and 1,534 N, respectively. The predicted load-carrying capacity of the nail-jointed CLT by the 5% offset nail lateral resistance was similar to the yield points on the actual load-displacement curve of the nail-jointed CLT specimens. Meanwhile, the nail-jointed CLT specimens were not failed until the tension failure of the bottom laminas occurred beyond the maximum lateral resistance of the nails. Thus, the measured maximum load carrying capacities of the nail-jointed CLT specimens, approximately 12,865 N, were higher than the predicted values, 7,986 N, by the maximum nail lateral resistance. This indicates that the predicted load-carrying capacity can be used for designing a structural unit such as floor, wall and roof able to support vertical loads in a viewpoint of predicting the actual capacities more safely.

Buckling resistance, bending stiffness, and torsional resistance of various instruments for canal exploration and glide path preparation

  • Kwak, Sang-Won;Ha, Jung-Hong;Lee, WooCheol;Kim, Sung-Kyo;Kim, Hyeon-Cheol
    • Restorative Dentistry and Endodontics
    • /
    • v.39 no.4
    • /
    • pp.270-275
    • /
    • 2014
  • Objectives: This study compared the mechanical properties of various instruments for canal exploration and glide-path preparations. Materials and Methods: The buckling resistance, bending stiffness, ultimate torsional strength, and fracture angle under torsional load were compared for C+ file (CP, Dentsply Maillefer), M access K-file (MA, Dentsply Maillefer), Mani K-file (MN, Mani), and NiTiFlex K-file (NT, Dentsply Maillefer). The files of ISO size #15 and a shaft length of 25 mm were selected. For measuring buckling resistance (n = 10), the files were loaded in the axial direction of the shaft, and the maximum load was measured during the files' deflection. The files (n = 10) were fixed at 3 mm from the tip and then bent $45^{\circ}$ with respect to their long axis, while the bending force was recorded by a load cell. For measuring the torsional properties, the files (n = 10) were also fixed at 3 mm, and clockwise rotations (2 rpm) were applied to the files in a straight state. The torsional load and the distortion angle were recorded until the files succumbed to the torque. Results: The CP was shown to require the highest load to buckle and bend the files, and the NT showed the least. While MA and MN showed similar buckling resistances, MN showed higher bending stiffness than MA. The NT had the lowest bending stiffness and ultimate torsional strength (p < 0.05). Conclusions: The tested instruments showed different mechanical properties depending on the evaluated parameters. CP and NT files were revealed to be the stiffest and the most flexible instruments, respectively.

A Study on Assessment Method of Crack Resistance and Thermal Shock Resistance in Hardfacing for Hot Forging Die (열간단조 금형 육성용접부 내균열성 및 내열충격성 평가방법에 관한 연구)

  • Cho, Sang-Myung;Kim, Sung-Ho;Jung, Yun-Ho;Baek, Seung-Hui;Jang, Jong-Hun;Park, Chul-Gyu;Woo, Hee-Chul;Jung, Byong-Ho
    • Journal of Welding and Joining
    • /
    • v.28 no.3
    • /
    • pp.79-85
    • /
    • 2010
  • Hardfacing is one of the frequently applying method to increase surface hardness in hot forging die. Recently, hardfacing receives great attention due to it's repair availability and low cost. In hot forging die, crack resistance and thermal shock resistance have been considered as major properties, However there are few studies for the assessment of these properties. So, it is necessary to establish the assessment method for crack resistance and thermal shock resistance in hardfacing for hot forging die. In this study, flux cored arc welding was applied to make hardfacing welds. Three point bending test was carried out to assess hardfacing weld's crack resistance, and high temperature bending test using salt bath was developed for thermal shock resistance. Consequently, it was possible to assess crack resistance and thermal shock resistance of hardfacing welds for hot forging die quantitatively.

Bending Characteristics of Ag Micro Circuits using Electrohydrodynamics Printing Technology (전기수력학적 프린팅 기술을 이용한 Ag 미세회로의 굽힘 특성)

  • Lee, Yong-Chan;Ahn, Ju-Hun;Lee, Chang-Yull
    • Journal of Aerospace System Engineering
    • /
    • v.13 no.4
    • /
    • pp.37-42
    • /
    • 2019
  • The objective of this study was to study the bending characteristics of Ag nano ink using EHD (Electrohydrodynamics) inkjet printing technology for flexibility and miniaturization of devices. The optimal conditions for the technology were derived, and bending characteristics of the Ag nano circuit obtained. For the EHD printing, it is essential to find the optimal point for each parameter such as material characteristics, density, flow rate, voltage, discharge height etc. Therefore, it was derived as the point from the working height and the applied voltage. Also, bending characteristics are confirmed by measuring resistance with each radius of curvature using a fabricated bending module. It was confirmed that rate of resistance change increases rapidly as the radius of curvature increases.

Steel fibre reinforced concrete for elements failing in bending and in shear

  • Barros, Joaquim A.O.;Lourenco, Lucio A.P.;Soltanzadeh, Fatemeh;Taheri, Mahsa
    • Advances in concrete construction
    • /
    • v.1 no.1
    • /
    • pp.1-27
    • /
    • 2013
  • Discrete steel fibres can increase significantly the bending and the shear resistance of concrete structural elements when Steel Fibre Reinforced Concrete (SFRC) is designed in such a way that fibre reinforcing mechanisms are optimized. To assess the fibre reinforcement effectiveness in shallow structural elements failing in bending and in shear, experimental and numerical research were performed. Uniaxial compression and bending tests were executed to derive the constitutive laws of the developed SFRC. Using a cross-section layered model and the material constitutive laws, the deformational behaviour of structural elements failing in bending was predicted from the moment-curvature relationship of the representative cross sections. To evaluate the influence of the percentage of fibres on the shear resistance of shallow structures, three point bending tests with shallow beams were performed. The applicability of the formulation proposed by RILEM TC 162-TDF for the prediction of the shear resistance of SFRC elements was evaluated. Inverse analysis was adopted to determine indirectly the values of the fracture mode I parameters of the developed SFRC. With these values, and using a softening diagram for modelling the crack shear softening behaviour, the response of the SFRC beams failing in shear was predicted.