• 제목/요약/키워드: impact damages

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HOW TO DEFINE CLEAN VEHICLES\ulcorner ENVIRONMENTAL IMPACT RATING OF VEHICLES

  • Mierlo, J.-Van;Vereecken, L.;Maggetto, G.;Favrel, V.;Meyer, S.;Hecq, W.
    • International Journal of Automotive Technology
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    • v.4 no.2
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    • pp.77-86
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    • 2003
  • How to compare the environmental damage caused by vehicles with different foe]s and drive trains\ulcorner This paper describes a methodology to assess the environmental impact of vehicles, using different approaches, and evaluating their benefits and limitations. Rating systems are analysed as tools to compare the environmental impact of vehicles, allowing decision makers to dedicate their financial and non-financial policies and support measures in function of the ecological damage. The paper is based on the "Clean Vehicles" research project, commissioned by the Brussels Capital Region via the BIM-IBGE (Brussels Institute for the Conservation of the Environment) (Van Mierlo et at., 2001). The VriJe Universiteit Brussel (ETEC) and the universite Libre do Bruxelles (CEESE) have jointly carried out the workprogramme. The most important results of this project are illustrated in this paper. First an overview of environmental, economical and technical characteristics of the different alternative fuels and drive trains is given. Afterward the basic principles to identify the environmental impact of cars are described. An outline of the considered emissions and their environmental impact leads to the definition of the calculation method, named Ecoscore. A rather simple and pragmatic approach would be stating that all alternative fuelled vehicles (LPG, CNG, EV, HEV, etc.) can be considered as ′clean′. Another basic approach is considering as ′clean′ all vehicles satisfying a stringent omission regulation like EURO IV or EEV. Such approaches however don′t tell anything about the real environmental damage of the vehicles. In the paper we describe "how should the environmental impact of vehicles be defined\ulcorner", including parameters affecting the emissions of vehicles and their influence on human beings and on the environment and "how could it be defined \ulcorner", taking into account the availability of accurate and reliable data. We take into account different damages (acid rain, photochemical air pollution, global warming. noise, etc.) and their impacts on several receptors like human beings (e.g., cancer, respiratory diseases, etc), ecosystems, or buildings. The presented methodology is based on a kind of Life Cycle Assessment (LCA) in which the contribution of all emissions to a certain damage are considered (e.g. using Exposure-Response damage function). The emissions will include oil extraction, transportation refinery, electricity production, distribution, (Well-to-Wheel approach), as well as the emission due to the production, use and dismantling of the vehicle (Cradle-to-Grave approach). The different damages will be normalized to be able to make a comparison. Hence a reference value (determined by the reference vehicle chosen) will be defined as a target value (the normalized value will thus measure a kind of Distance to Target). The contribution of the different normalized damages to a single value "Ecoscore" will be based on a panel weighting method. Some examples of the calculation of the Ecoscore for different alternative fuels and drive trains will be calculated as an illustration of the methodology.

The effects of stacking sequence on the penetration-resistant behaviors of T800 carbon fiber composite plates under low-velocity impact loading

  • Ahmad, Furqan;Hong, Jung-Wuk;Choi, Heung Soap;Park, Soo-Jin;Park, Myung Kyun
    • Carbon letters
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    • v.16 no.2
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    • pp.107-115
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    • 2015
  • Impact damages induced by a low-velocity impact load on carbon fiber reinforced polymer (CFRP) composite plates fabricated with various stacking sequences were studied experimentally. The impact responses of the CFRP composite plates were significantly affected by the laminate stacking sequences. Three types of specimens, specifically quasi-isotropic, unidirectional, and cross-ply, were tested by a constant impact carrying the same impact energy level. An impact load of 3.44 kg, corresponding to 23.62 J, was applied to the center of each plate supported at the boundaries. The unidirectional composite plate showed the worst impact resistance and broke completely into two parts; this was followed by the quasi-isotropic lay-up plate that was perforated by the impact. The cross-ply composite plate exhibited the best resistance to the low-velocity impact load; in this case, the impactor bounced back. Impact parameters such as the peak impact force and absorbed energy were evaluated and compared for the impact resistant characterization of the composites made by different stacking sequences.

A Study on Compressive Strength of Aircraft Composite Specimens (항공기 복합재료 적용 시편의 압축 강도 연구)

  • Kong, Changduk;Park, Hyunbum;Kim, Sanghoon;Lee, Haseung
    • Journal of Aerospace System Engineering
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    • v.3 no.1
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    • pp.12-16
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    • 2009
  • The laminated sequence and thickness of a composite structure is an important design parameter which affect the strength and impact damage. In this study, it was investigated the residual strength of carbon fiber laminate after impact damage by the experimental investigation. The tensile strength test and compressive strength test were used to find the mechanical properties, previously. Impact test was performed using low-velocity drop-weight test equipment. The impact damages were finally assessed by the compressive strength test. The investigation results revealed the residual strength of the damaged specimens due to the impact damage.

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Damage identification using chaotic excitation

  • Wan, Chunfeng;Sato, Tadanobu;Wu, Zhishen;Zhang, Jian
    • Smart Structures and Systems
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    • v.11 no.1
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    • pp.87-102
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    • 2013
  • Vibration-based damage detection methods are popular for structural health monitoring. However, they can only detect fairly large damages. Usually impact pulse, ambient vibrations and sine-wave forces are applied as the excitations. In this paper, we propose the method to use the chaotic excitation to vibrate structures. The attractors built from the output responses are used for the minor damage detection. After the damage is detected, it is further quantified using the Kalman Filter. Simulations are conducted. A 5-story building is subjected to chaotic excitation. The structural responses and related attractors are analyzed. The results show that the attractor distances increase monotonously with the increase of the damage degree. Therefore, damages, including minor damages, can be effectively detected using the proposed approach. With the Kalman Filter, damage which has the stiffness decrease of about 5% or lower can be quantified. The proposed approach will be helpful for detecting and evaluating minor damages at the early stage.

Analysis on Damages of Carcass Disposal in Rural Area in Terms of Environmental Welfare Approach: A Questionnaire Based Survey (환경복지적 관점에서의 농촌지역 가축매몰지 피해 분석 - 설문조사를 중심으로 -)

  • Kim, Yoonjung;Hyun, Yunjung;Hwang, Sang-il
    • Journal of Soil and Groundwater Environment
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    • v.22 no.6
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    • pp.104-111
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    • 2017
  • As carcass disposal is increasing widely in Republic of Korea, there is a need to comprehensively analyze the impacts and subsequent damages of carcass disposal. Especially, since environmental policy aims to not only reduce environmental damages, but also enhance overall sustainability, we apply the concept of environmental welfare to assess the comprehensive impact of carcass disposal, especially focusing on the rural area. In specific, assessment criteria were suggested based on the four categories related to environmental welfare, which were 'environmental quality', 'level of environmental service', 'environmental safety', and 'participation, openness to public, and communication'. The results showed negative impacts of carcass disposal in environmental, social and economical elements. Overall decrease in environmental quality negatively impacts the other elements of environmental welfare. Furthermore, there were discrepancies of level of impacts and damages among stakeholder. In the end, we suggest critical elements that need to be applied in relevant policies and regulation to promote effective carcass disposal management.

Computation of the Bow Deck Design Pressure against the Green Water Impact (Green Water 충격에 대비한 선수갑판 설계압력의 산출)

  • Kim, Yong Jig;Shin, Ki-Seok;Lee, Seung-Chul;Ha, Youngrok;Hong, Sa Young
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.4
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    • pp.343-351
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    • 2019
  • Green water impact may sometimes cause some structure damages on ship's bow deck. Prediction of proper design pressure against the green water impact is an essential task to prevent the possible damages on bow deck. This paper presents a computational method of the bow deck's design pressure against the green water impact. Large heave and pitch motions of ship are calculated by the time domain nonlinear strip method. Green water flow and pressure on bow deck are simulated by the predictor-corrector second kind upstream finite difference method. This green water simulation method is based on the shallow water wave equations expanded for moving bottom conditions. For various kind of ships such as container ship, VLCC, oil tanker and bulk carrier, the green water design pressures on bow deck are computed and discussed. Also, the obtained results of design pressure on bow deck are compared with those of the classification society rules and discussed.

Delamination growth analysis in composite laminates subjected to low velocity impact

  • Kharazan, Masoud;Sadr, M.H.;Kiani, Morteza
    • Steel and Composite Structures
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    • v.17 no.4
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    • pp.387-403
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    • 2014
  • This paper presents a high accuracy Finite Element approach for delamination modelling in laminated composite structures. This approach uses multi-layered shell element and cohesive zone modelling to handle the mechanical properties and damages characteristics of a laminated composite plate under low velocity impact. Both intralaminar and interlaminar failure modes, which are usually observed in laminated composite materials under impact loading, were addressed. The detail of modelling, energy absorption mechanisms, and comparison of simulation results with experimental test data were discussed in detail. The presented approach was applied for various models and simulation time was found remarkably inexpensive. In addition, the results were found to be in good agreement with the corresponding results of experimental data. Considering simulation time and results accuracy, this approach addresses an efficient technique for delamination modelling, and it could be followed by other researchers for damage analysis of laminated composite material structures subjected to dynamic impact loading.

Influence of Stacking Composition on Fatigue Bending Strenght in CFRP Composite Laminates Subjected to Impact Loading (충격하중을 받은 CFRP적층판의 피로굽힘강도에 미치는 적층구성의 영향)

  • 임광희;강기광굉;양인영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.4
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    • pp.147-155
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    • 1996
  • The purpose of present paper is to estimate the static and fatigue bending strengths of CFRP(carbon fiber reinforced plastic) laminates having impact damage(FOD). The specimens which are formed with the different stacking composition, EPOXY and PEEK matirx and orthotropic and quasi-isotropic laminated plates, are prepared for this experiment. A steel ball is impacted on CFRP laminates, generating impact damages, and the three-point fatigue bending test is carried out by using the impacted laminates to investigate the influence of the stackin composition on the fatigue strength of CFRP laminates.

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Influence of Biaxial Loads on Impact Fracture of High-Strength Membrane Materials

  • Kumazawa, Hisashi;Susuki, Ippei;Hasegawa, Osamu;Kasano, Hideaki
    • Advanced Composite Materials
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    • v.18 no.4
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    • pp.395-413
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    • 2009
  • Impact tests on high-strength membrane materials under biaxial loads were experimentally conducted in order to evaluate influence of biaxial loads on impact fracture of the membrane materials for the inflated applications. Cruciform specimens of the membrane materials were fabricated for applying biaxial loadings during the impact test. A steel ball was shot using a compressed nitrogen gas gun, and struck the membrane specimen. Impact tests on uniaxial strip specimens were also conducted to obtain the effect of specimen configuration and boundary condition on the impact fracture. The results of the measured crack length and the ultra-high speed photographs indicate the impact fracture properties of the membrane fabrics under biaxial loadings. Crack length due to the impact increased with applied tensile load, and the impact damages of the cruciform membrane materials under biaxial loadings were smaller than those of under uniaxial loadings. Impact fracture of the strip specimen was more severe than that of the cruciform specimen due to the difference of boundary conditions.

Evaluation of Fatigue Life Characteristic of a Fiber-Reinforced Composites under the Repeated Impact Loading (반복충격에 의한 섬유강화 복합재료의 피로수명 특성 평가)

  • Choi J.H.;Kim H.I.;Huh Y.;Seok C.S.;Chang P.S.;Lee C.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.1025-1028
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    • 2005
  • Generally, fiber-reinforced composites have the highest possibilities of impact damages with external object collisions. Also, resulting in fatigue fracture considering the continued impact load. For the reasons mentioned above, the accurate understanding of interactions between the impact of composites and the fatigue load will be essential to understand the safety level of material structures. Furthermore, the composite materials and structures, due to the geometrical effect, vary the life in connection with the impact-fatigue. Therefore, I have reached the point that a focus of this study will be to evaluate fatigue fracture characteristics by the impacts-fatigue load of fiber-reinforced composites. Thus, in this paper, I have tried to work on impacts-fatigue load causing aspects and impact characteristics through impact-fatigue test on HTV-5Hl Black 9250 material made- structure, along with to evaluate the expected lift of real structures, the FEM analysis was carried out.

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