• Title/Summary/Keyword: load-bearing structural element

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Light weight vehicle design by stick model (스틱모델에 의한 차체 경량화 설계)

  • 김천욱;김지홍
    • Journal of the korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.97-106
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    • 1990
  • A method of weight evaluation of the load-bearing structural elements of cars is presented and the weight ratio of the analysis model is investigated. Replacing the materials of floor elements of the car into the high-strength steel, a considerable weight-reduction of the model has been obtained. The 1500cc model is selected for the present study and the stick model analysis is employed for the structural analysis. The torsional stiffness of the weight-reduced model is also evaluated and it is shown it has a reasonable rigidity. The ratio of the weight of the load-bearing structural elements to the unladen vehicle weight of cars is about 0.12for the 1500cc model and the weight-reduction of this study can be obtained around 17% of the weight of the load-bearing structural elements.

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Structural response relationship between scaled and prototype concrete load bearing systems using similarity requirements

  • Altunisik, Ahmet C.;Kalkan, Ebru;Basaga, Hasan B.
    • Computers and Concrete
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    • v.21 no.4
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    • pp.385-397
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    • 2018
  • This study is focused on the investigation for similitude the requirements between prototype and scaled models to determine the structural behavior of concrete load bearing systems. The scaling concept has been utilized in many engineering branches, has been assisted to engineers and scientists for obtain the behavior of the prototype by using scaled model. The scaling can be done for two purposes, either scaling up or scaling down depending upon the application. Because, scaled down models are the experimentation on scaled models is cheaper than huge structures. These models also provide facilities for experimental work. Similarity relationships between systems are created either by field equations of the system or by dimensional analysis. Within this study, similarity relationships were obtained by both methods. The similarity relations obtained are applied to different load bearing systems and it is determined that the similarity relation is a general expression. In this study, as an example, column, frame, cantilever beam and simple beam are chosen and 1/2, 1/5 and 1/10 scales are applied. The results are compared with the analytical results which are obtained by creating of the finite element models with SAP2000 software of different scaled load bearing systems. The analysis results of all systems are examined and it is determined that the scale factors are constant depending on the scale types for different load bearing systems.

Structural Analysis on the Heavy Duty Diesel Engine and Optimization for Bearing Cap (대형 디젤엔진의 구조응력해석 및 베어링 캡의 최적설계)

  • Lee, Jae-Ok;Lee, Young-Shin;Lee, Hyun-Seung;Kim, Jae-Hoon;Jun, Joon-Tak;Kim, Chul-Goo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.5
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    • pp.402-410
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    • 2008
  • The heavy duty diesel engine must have a large output for maintaining excellent mobility. In this study, a three dimensional finite element model of a heavy-duty diesel engine was developed to conduct the stress analysis. The FE model of the heavy duty diesel engine main parts consisting with four half cylinder was selected. The heavy duty diesel engine parts includes with cylinder block, cylinder head, gasket, liner, bearing cap, bearing and bolts. The loading conditions of engine were pre-fit load, assembly load, and gas load. As the results of structural analysis, because the stress values of cylinder block and bearing cap did not exceed the basic design can be satisfied. But on the part which contacts with cylinder block and bearing cap the stress value exceeds the allowable strength of material. In order to decrease the stress at that part, it was optimized with parametric study.

Two-stage damage identification for bridge bearings based on sailfish optimization and element relative modal strain energy

  • Minshui Huang;Zhongzheng Ling;Chang Sun;Yongzhi Lei;Chunyan Xiang;Zihao Wan;Jianfeng Gu
    • Structural Engineering and Mechanics
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    • v.86 no.6
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    • pp.715-730
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    • 2023
  • Broad studies have addressed the issue of structural element damage identification, however, rubber bearing, as a key component of load transmission between the superstructure and substructure, is essential to the operational safety of a bridge, which should be paid more attention to its health condition. However, regarding the limitations of the traditional bearing damage detection methods as well as few studies have been conducted on this topic, in this paper, inspired by the model updating-based structural damage identification, a two-stage bearing damage identification method has been proposed. In the first stage, we deduce a novel bearing damage localization indicator, called element relative MSE, to accurately determine the bearing damage location. In the second one, the prior knowledge of bearing damage localization is combined with sailfish optimization (SFO) to perform the bearing damage estimation. In order to validate the feasibility, a numerical example of a 5-span continuous beam is introduced, also the noise robustness has been investigated. Meanwhile, the effectiveness and engineering applicability are further verified based on an experimental simply supported beam and actual engineering of the I-40 Bridge. The obtained results are good, which indicate that the proposed method is not only suitable for simple structures but also can accurately locate the bearing damage site and identify its severity for complex structure. To summarize, the proposed method provides a good guideline for the issue of bridge bearing detection, which could be used to reduce the difficulty of the traditional bearing failure detection approach, further saving labor costs and economic expenses.

Vehicular Impact Loading on with Laminated Rubber Bearing (탄성받침을 사용한 도로교의 충격하중특성 분석)

  • 김상효;허진영;신용준;이용선
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2000.04b
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    • pp.230-237
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    • 2000
  • The purpose of this study is to evaluate the dynamic behavior of highway bridge due to moving vehicle load, considering the effect of laminated rubber bearing. Dynamic behaviors of bridge considering the effect of bearings are studied with 3-dimensional bridge and vehicle models. To analyze the effect of bearings on the dynamic behaviors of superstructures of bridges, laminated rubber bearing is modeled as 3-dimensional frame element with equivalent stiffness and damping, and the models are included in the bridge analysis model. The results from the analytical models with laminated rubber bearing show a significant effects on dynamic responses and more complex vibration characteristics compared with the results from the bridge with pot bearings. Generally, larger dynamic amplification factors are obtained in the case of laminated rubber bearing, which is mainly due to the smaller torsional stiffness of the bridge with laminated rubber bearing. It can be recommended that were careful consideration on the vibration of bridges and dynamic load allowance in design are needed when adopting laminated rubber bearing.

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A load-bearing structural element with energy dissipation capability under harmonic excitation

  • Pontecorvo, Michael E.;Barbarino, Silvestro;Gandhi, Farhan S.;Bland, Scott;Snyder, Robert;Kudva, Jay;White, Edward V.
    • Advances in aircraft and spacecraft science
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    • v.2 no.3
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    • pp.345-365
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    • 2015
  • This paper focuses on the design, fabrication, testing and analysis of a novel load-bearing element with energy dissipation capability. A single element comprises two von-Mises trusses (VMTs), which are sandwiched between two plates and connected to dashpots that stroke as the VMTs cycle between stable equilibrium states. The elements can be assembled in-plane to form a large plate-like structure or stacked with different properties in each layer for improved load-adaptability. Also introduced in the elements are pre-loaded springs (PLSs) that provide high initial stiffness and allow the element to carry a static load even when the VMTs cannot under harmonic disturbance input. Simulations of the system behavior using the Simscape environment show good overall correlation with test data. Good energy dissipation capability is observed over a frequency range from 0.1 Hz to 2 Hz. The test and simulation results show that a two layer prototype, having one soft VMT layer and one stiff VMT layer, can provide good energy dissipation over a decade of variation in harmonic load amplitude, while retaining the ability to carry static load due to the PLSs. The paper discusses how system design parameter changes affect the static load capability and the hysteresis behavior.

Evaluation on Structural Safety for Bearing seat according to Replacement of Bridge Bearing (교량받침 교체에 따른 보자리 구조 안전성 평가)

  • Choi, Jung-Youl;Lee, Hee-Kwang;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.4
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    • pp.753-760
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    • 2020
  • In this study, the structural safety of the bearing support was analysed by applying the vertical load (bearing design load) and horizontal load (horizontal force generated during an earthquake) using a precise three-dimensional numerical model. The results of stress and displacement of newly-poured concrete and welded rebars were confirmed numerically. Numerical results show that the increase in the horizontal force and the height of the beam causes the concrete cracking and the stress increase of the rebar connections due to the increase of the stress at the new concrete interface. Therefore, it was analyzed that the increase in the height of bearing support is directly related to the horizontal force and it is necessary to apply the bearing support height appropriate for the bearing support capacity. It was proposed that a method of setting the height of the bearing support suitable for the bearing capacity and determining the reinforcement by presenting the guideline with the correlation between the horizontal force acting on the bearing support and its height.

Seismic progressive collapse mitigation of buildings using cylindrical friction damper

  • Mirtaheri, Masoud;Omidi, Zobeydeh;Salkhordeh, Mojtaba;Mirzaeefard, Hamid
    • Earthquakes and Structures
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    • v.20 no.1
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    • pp.1-12
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    • 2021
  • The occurrence of progressive collapse induced by the removal of the vertical load-bearing element in the structure, because of fire or earthquake, has been a significant challenge between structural engineers. Progressive collapse is defined as the complete failure or failure of a part of the structure, initiating with a local rupture in a part of the building and can threaten the stability of the structure. In the current study, the behavior of the structures equipped with a cylindrical friction damper, when the vertical load-bearing elements are eliminated, is considered in two cases: 1-The load-bearing element is removed under the gravity load, and 2-The load-bearing element is removed due to the earthquake lateral forces. In order to obtain a generalized result in the seismic case, 22 pair motions presented in FEMA p 695 are applied to the structures. The study has been conducted using the vertical push down analysis for the case (1), and the nonlinear time-history analysis for the second case using OpenSEES software for 5,10, and 15-story steel frames. Results indicate that, in the first case, the load coefficient, and accordingly the strength of the structure equipped with cylindrical friction dampers are increased considerably. Furthermore, the results from the second case demonstrate that the displacements, and consequently the forces imposed to the structure in the buildings equipped with the cylindrical friction damper substantially was reduced. An optimum slip load is defined in the friction dampers, which permits the damper to start its frictional damping from this threshold load. Therefore, the optimum slip load of the damper is calculated and discussed for both cases.

Evaluation of Boundary Conditions for Structural Analysis of Wheel Bearing Units (Wheel Bearing Unit의 구조해석을 위한 경계조건 설정에 관한 연구)

  • 김기훈;유영면;임종순;현준수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.6
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    • pp.230-237
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    • 2000
  • The wheel bearing in vehicles has been improved to unit module by joining a bearing to a hub in order to achieve weight reduction and easy assembly. Currently, the contact force between a raceway and balls of a bearing is applied as the external force in order to analyse the structure of the unit type bearings. In this paper, simplified boundary conditions are discussed for structure analysis of wheel bearing unit. From the procedure, the contact conditions of balls and race in wheel bearing unit are considered as equivalent non-linear spring elements. The end node of a spring element is constrained in displacement. And the external force of boundary conditions is applied at the contact point between tire and road. For the evaluation of this analysis, its results for the force of spring elements are compared with contact forces of calculated results. and also maximum equivalent stresses of analysis are compared with results of test at the flange of inner ring. The analysis results with proposed boundary conditions are more accurate than results from analysis which is generally used.

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Upgrading flexural performance of prefabricated sandwich panels under vertical loading

  • Kabir, M.Z.;Rezaifar, O.;Rahbar, M.R.
    • Structural Engineering and Mechanics
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    • v.26 no.3
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    • pp.277-295
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    • 2007
  • 3-D wall panels are used in construction of exterior and interior bearing and non-load bearing walls and floors of building of all types of construction. Fast construction, thermal insulation, reduced labor expense and weight saving are the most well pronounced advantage of such precast system. When the structural performance is concerned, the main disadvantage of 3D panel, when used as floor slab, is their brittleness in flexure. The current study focuses on upgrading ductility and load carrying capacity of 3D slabs in two different ways; using additional tension reinforcement, and inserting a longitudinal concentrated beam. The research is carried on both experimentally and numerically. The structural performance in terms of load carrying capacity and flexural ductility are discussed in details. The obtained results could give better understanding and design consideration of such prefabricated system.