• Title/Summary/Keyword: mode of failure

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Experimental Static Strength Evaluation of a Passenger Car Aluminium Multi-link Suspension Corner Module (승용차 알루미늄 멀티링크 현가장치 코너모듈의 실험적 정강도 특성 평가)

  • Cho, Wonyong;Choi, Gyoojae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.4
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    • pp.166-173
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    • 2013
  • An aluminum suspension corner module is widely used in high class passenger cars to reduce vehicle weight and improve fuel economy. According to the change of material and suspension type, the evaluation of the static strength and failure mode of the corner module is important. In this study, static strength and failure mode analysis of aluminium multi-link suspension corner module is presented. Static strength test system is designed and static failure mode tests of the corner module are carried out in longitudinal, lateral, and vertical direction. From the resuls of the tests we found that the failure modes are different compare to those of the steel corner module. The static failure modes and load-displacement curves of this study will be used as a guidance in design of a passenger car aluminium multi-link suspension corner module.

Failure mechanisms in coupled soil-foundation systems

  • Hadzalic, Emina;Ibrahimbegovic, Adnan;Dolarevic, Samir
    • Coupled systems mechanics
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    • v.7 no.1
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    • pp.27-42
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    • 2018
  • Behavior of soil is usually described with continuum type of failure models such as Mohr-Coulomb or Drucker-Prager model. The main advantage of these models is in a relatively simple and efficient way of predicting the main tendencies and overall behavior of soil in failure analysis of interest for engineering practice. However, the main shortcoming of these models is that they are not able to capture post-peak behavior of soil nor the corresponding failure modes under extreme loading. In this paper we will significantly improve on this state-of-the-art. In particular, we propose the use of a discrete beam lattice model to provide a sharp prediction of inelastic response and failure mechanisms in coupled soil-foundation systems. In the discrete beam lattice model used in this paper, soil is meshed with one-dimensional Timoshenko beam finite elements with embedded strong discontinuities in axial and transverse direction capable of representing crack propagation in mode I and mode II. Mode I relates to crack opening, and mode II relates to crack sliding. To take into account material heterogeneities, we determine fracture limits for each Timoshenko beam with Gaussian random distribution. We compare the results obtained using the discrete beam lattice model against those obtained using the modified three-surface elasto-plastic cap model.

Analysis of Risk Priority Number for Grid-connected Energy Storage System (계통연계형 에너지저장시스템의 위험우선순위 분석)

  • Kim, Doo-Hyun;Kim, Sung-Chul;Park, Jeon-Su;Kim, Eun-Jin;Kim, Eui-Sik
    • Journal of the Korean Society of Safety
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    • v.31 no.2
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    • pp.10-17
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    • 2016
  • The purpose of this paper is to deduct components that are in the group of highest risk(top 10%). the group is conducted for classification into groups by values according to risk priority through risk priority number(RPN) of FMEA(Failure modes and effects analysis) sheet. Top 10% of failure mode among total potential failure modes(72 failure modes) of ESS included 5 BMS(battery included) failure modes, 1 invert failure mode, and 1 cable connectors failure mode in which BMS was highest. This is because ESS is connected to module, try, and lack in the battery part as an assembly of electronic information communication and is managed. BMS is mainly composed of the battery module and communication module. There is a junction box and numerous connectors that connect these two in which failure occurs most in the connector part and module itself. Finally, this paper proposes RPN by each step from the starting step of ESS design to installation and operation. Blackouts and electrical disasters can be prevented beforehand by managing and removing the deducted risk factors in prior.

Evaluation on Stiffness of Mortar-filled Sleeve Splice Using Estimation Method of Failure Mode (파괴모드 추정방법을 이용한 모르타르 충전식 슬리브 철근이음의 강성 평가)

  • Kim, Hyong Kee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.1
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    • pp.27-34
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    • 2012
  • The objective of this study is to evaluate the stiffness of mortar-filled sleeve bar splice using estimation method of failure mode in the sleeve reinforcement splice. To attain this goal, we analyzed the test results of 261 actual-sized mortar-filled sleeve splice specimens. The study results showed that the estimation method of the failure mode in mortar-filled sleeve bar splice made an effective estimate of the stiffness in this bar splice with the exception of specimens with SD500 bars and smooth pipe sleeve. Especially, of the specimens with cast sleeve or uneven pipe sleeve in the range of reinforcement fracture using the estimation method of the failure mode in mortar-filled sleeve splice, specimens over 98% with SD400 bars and all specimens with SD500 bars had the stiffness capacity of higher than "A" class of AIJ code in monotonic loading. In addition, of the specimens in the range of reinforcement fracture using the estimation method of the failure mode in mortar-filled sleeve splice, all specimens with SD400 bars and SD500 bars had the stiffness capacity of higher than "A" class of AIJ code in cyclic loading.

Optimum Design of a Simple Slope considering Multi Failure Mode (다중 파괴모드를 고려한 단순 사면의 최적 설계)

  • Kim, Hyun-Ki;Shin, Min-Ho;Choi, Chan-Yong
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.6
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    • pp.73-80
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    • 2010
  • Conventional slope stability analysis is focused on calculating minimum factor of safety or maximum probability of failure. To minimize inherent uncertainty of soil properties and analytical model and to reflect various analytical models and its failure shape in slope stability analysis, slope stability analysis method considering simultaneous failure probability for multi failure mode was proposed. Linear programming recently introduced in system reliability analysis was used for calculation of simultaneous failure probability. System reliability analysis for various analytical models could be executed by this method. Optimum design to determine angle of a simple slope is executed for multi failure mode using linear programming. Because of complex consideration for various failure shapes and modes, it is possible to secure advanced safety by using simultaneous failure probability.

Experimental and analytical study on prestressed concrete hollow slabs with asymmetric boundary conditions

  • Ma, Haiying;Lai, Minghui;Xia, Ye
    • Structural Engineering and Mechanics
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    • v.81 no.1
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    • pp.59-68
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    • 2022
  • Prestressed prefabricated hollow core concrete slabs with spans of 5 m and 10 m are commonly used since last century and still in service due to the advantage of construction convenience and durability. However, the end slabs are regularly subjected to cracks at the top and fail with brittleness due to the asymmetric boundary conditions. To better maintain such widely used type of hollow core slabs, the effect of asymmetric constraint in the end slabs are systematically studied through detailed nonlinear finite element analyses and experimental data. Experimental tests of slabs with four prestressed tendons and seven prestressed tendons with different boundary conditions were conducted. Results observe three failure modes of the slabs: the bending failure mode, shear and torsion failure mode, and transverse failure mode. Detailed nonlinear finite element models are developed to well match the failure modes and to reveal potential damage scenarios with asymmetric boundary conditions. Recommendations regarding ultimate capacity of the slabs with asymmetric boundary conditions are made to ensure a safe and rational design of prestressed concrete hollow slabs for short span bridges.

Development of a Web-based Analysis Program for Reliability Assessment of Machine Tools (공작 기계의 신뢰성 평가를 위한 웹 기반 해석 프로그램 개발)

  • 강태한;김봉석;이수훈;송준엽;강재훈
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.10a
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    • pp.369-374
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    • 2004
  • Web-based analysis programs for reliability assessment of machine tools were developed in this study. First, the reliability data analysis program was developed to search for failure rate using failure data and reliability test data of mechanical part. Second, failure mode analysis was developed through performance tests like circular movement test vibration test for machine tools. This analysis program shows correlation between failure mode and performance test result. Third, tool life was predicted by correlation between flank wear and cutting time, using the extended Taylor tool life equation in turning data and the equivalently converted equation in order to apply ball endmill data to Taylor tool life equation in milling data. All the information related to input and result data can be stored in theses programs.

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The effect of compression load and rock bridge geometry on the shear mechanism of weak plane

  • Sarfarazi, Vahab;Haeri, Hadi;Shemirani, Alireza Bagher
    • Geomechanics and Engineering
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    • v.13 no.3
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    • pp.431-446
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    • 2017
  • Rock bridges in rock masses would increase the bearing capacity of Non-persistent discontinuities. In this paper the effect of ratio of rock bridge surface to joint surface, rock bridge shape and normal load on failure behaviour of intermittent rock joint were investigated. A total of 42 various models with dimensions of $15cm{\times}15cm{\times}15cm$ of plaster specimens were fabricated simulating the open joints possessing rock bridge. The introduced rock bridges have various continuities in shear surface. The area of the rock bridge was $45cm^2$ and $90cm^2$ out of the total fixed area of $225cm^2$ respectively. The fabricated specimens were subjected to shear tests under normal loads of 0.5 MPa, 2 MPa and 4 MPa in order to investigate the shear mechanism of rock bridge. The results indicated that the failure pattern and the failure mechanism were affected by two parameters; i.e., the ratio of joint surface to rock bridge surface and normal load. So that increasing in joint area in front of the rock bridge changes the shear failure mode to tensile failure mode. Also the tensile failure change to shear failure by increasing the normal load.

Failure-Proof Design of the PCB of a Monitor Using Deformed Mode Shape (변형 모드를 이용한 모니터용 회로 기판의 파손 저감 설계에 관한 연구)

  • Park, Sang-Hu;Lee, Bu-Yun
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.1
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    • pp.111-116
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    • 2001
  • A practical scheme to reduce failure of the PCB(Printed Circuit Board) of a monitor is introduced using deformed mode shape under mechanical shock. When the monitor is given critical shock loads, cracks are commonly initiated at the tip of a hole on the PCB. Accordingly, a deformed mode shape of the PCB is obtained using a FEM code to define a weak point on the PCB under mechanical shock, and then the position and direction of the hole is determined to prevent the failure at the critical mode shape. Also, the stress intensity factor around the weak point on the PCB is calculated to check the possibility of fracture by normal tensile stress. In conclusion, present research is useful to assist the practical design of components-layout on the PCB.

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Bond properties of steel and sand-coated GFRP bars in Alkali activated cement concrete

  • Tekle, Biruk Hailu;Cui, Yifei;Khennane, Amar
    • Structural Engineering and Mechanics
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    • v.75 no.1
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    • pp.123-131
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    • 2020
  • The bond performance of glass fibre reinforced polymer (GFRP) bars and that of steel bars embedded in Alkali Activated Cement (AAC) concrete are analysed and compared using pull-out specimens. The bond failure modes, the average bond strength and the free end bond stress-slip curves are used for comparison. Tepfers' concrete ring model is used to further analyse the splitting failure in ribbed steel bar and GFRP bar specimens. The angle the bond forces make with the bar axis was calculated and used for comparing bond behaviour of ribbed steel bar and GFRP bars in AAC concrete. The results showed that bond failure mode plays a significant role in the comparison of the average bond stress of the specimens at failure. In case of pull-out failure mode, specimens with ribbed steel bars showed a higher bond strength while specimens with GFRP bars showed a higher bond stress in case of splitting failure mode. Comparison of the bond stress-slip curves of ribbed steel bars and GFRP bars depicted that the constant bond stress region at the peak is much smaller in case of GFRP bars than ribbed steel bars indicating a basic bond mechanism difference in GFRP and ribbed steel bars.