• 제목/요약/키워드: Impact Energy Absorption

검색결과 265건 처리시간 0.023초

충돌에 의한 차체 박육구조부재의 에너지 흡수특성에 관한 연구 (An Energy Absorption Characteristic of Thin-Walled Structure Members by Crushing Load)

  • 양인영;심재기;김선규
    • 한국자동차공학회논문집
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    • 제3권5호
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    • pp.74-81
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    • 1995
  • In this paper, the crushing tests of circular tubes under axial impact loading are conducted to investigate the energy absorption abilities. A cross head with 18kg launched by the compressed air collides against circular tubes. Circular tubes used for this experiment are Al and CFRP laminates, which have 8 ply with $15^{\circ}$ and $45^{\circ}$. The absorbed energy unit mass and volume of the CFRP specimen with $15^{\circ}$ are higher than those of aluminum specimen. CFRP specimen having small stacking angle have better energy absorption abilities than that of large stacking angle.

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금속/폴리머 접합강의 충격 특성에 대한 실험적 연구 (Impact Energy Absorbing Capability of Metal/Polymer Hybrid Sheets)

  • 공경일;권오범;박형욱
    • 대한기계학회논문집A
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    • 제41권2호
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    • pp.137-142
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    • 2017
  • 최근 자동차 산업에서 경량화이면서 외부 충격에 민감한 시트 프레임은 안전성을 고려하여 꾸준히 연구개발되고 있다. 특히 본 연구에서는 고장력 강판과 폴리머의 이종 소재를 이용한 시트 프레임의 충격 특성에 대해 살펴보았다. 또한, 충격시 변위는 소재에 대해 굽힘 현상을 고려한 등가 굽힘강성식을 도입하여 살펴보았다. 층간 wire-web 구조물의 다양한 형상의 공학 디자인을 통해 충격시 변화가 적은 디자인을 설계하였으며, 육각형의 층간 wire-web 구조물이 외부 충격대비 안전계수가 높음으로 인해 흡수능력이 향상될 것으로 기대하고 있다. 이러한 연구 결과를 토대로 층간 wire-web 구조물의 설계를 통해 레진과의 함침을 높이고 이종 소재로써의 충격민감도에 유리한 제품을 개발할 수 있을 것으로 사료된다.

재활용 AC4A 알루미늄 합금의 충격 및 피로 특성에 미치는 (Ti-B), Sr 첨가제의 영향 (Effect of (Ti-B) and Sr Additives on Impact and Fatigue Properties of Recycled AC4A Aluminum Casting Alloy)

  • 오승환;김헌주
    • 한국주조공학회지
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    • 제39권4호
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    • pp.61-74
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    • 2019
  • The effects of Sr and (Ti-B) additives on the impact and fatigue properties of recycled (35% scrap content) AC4A aluminum alloy are investigated here. The acicular morphology of the eutectic Si phase of as-cast specimens was converted to the fibrous one with Sr additives. The grain size of the α-solid solution decreased by the addition of (Ti-B) additives. The crack initiation energy (Ei) of the impact absorption energy decreased due to the incorporation of an oxide film and inclusions depending on the scrap used. The modification of the eutectic Si morphology by Sr additives is considered as the main factor of the increase of the average impact absorption energy (Et). The addition of (Ti-B) additives contributed to an increase in the occurrence of crack deflections due to the refining of α-Al grains, resulting in improved fatigue properties.

Effect of length and content of steel fibers on the flexural and impact performance of self-compacting cementitious composite panels

  • Denise-Penelope N. Kontoni;Behnaz Jahangiri;Ahmad Dalvand;Mozafar Shokri-Rad
    • Advances in concrete construction
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    • 제15권1호
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    • pp.23-39
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    • 2023
  • One of the important problems of concrete placing is the concrete compaction, which can affect the strength, durability and apparent quality of the hardened concrete. Therefore, vibrating operations might be accompanied by much noise and the need for training the involved workers, while inappropriate functioning can result in many problems. One of the most important methods to solve these problems is to utilize self-compacting cementitious composites instead of the normal concrete. Due to their benefits of these new materials, such as high tensile, compressive, and flexural strength, have drawn the researchers' attention to this type of cementitious composite more than ever. In this experimental investigation, six mixing designs were selected as a base to acquire the best mechanical properties. Moreover, forty-eight rectangular composite panels with dimensions of 300 mm × 400 mm and two thickness values of 30 mm and 50 mm were cast and tested to compare the flexural and impact energy absorption. Steel fibers with volume fractions of 0%, 0.5% and 1% and with lengths of 25 mm and 50 mm were imposed in order to prepare the required cement composites. In this research, the composite panels with two thicknesses of 30 mm and 50 mm, classified into 12 different groups, were cast and tested under three-point flexural bending and repeated drop weight impact test, respectively. Also, the examination and comparison of flexural energy absorption with impact energy absorption were one of the other aims of this research. The obtained results showed that the addition of fibers of longer length improved the mechanical properties of specimens. On the other hand, the findings of the flexural and impact test on the self-compacting composite panels indicated a stronger influence of the long-length fibers.

Design and analysis of low velocity impact on thermoplastic hat section with curvilinear profile

  • Gaur, Kumresh K;Dwivedi, Mayank;Bhatnagar, Naresh
    • Advances in materials Research
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    • 제6권1호
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    • pp.65-78
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    • 2017
  • A hat section was designed and developed for maximum impact energy absorption and/or transmission under low velocity impact. Towards this, different hat sections, having material properties of thermoplastic, were modeled and investigated numerically using finite element analysis (FEA) in the range of 20-50 J impact energy. In the study it was experienced that the design configuration of hat section with curvilinear profile (HSCP) was excellent in energy attenuation capacity and for even distribution of maximum impact force around and along the hat section under low velocity impact loading. To validate the numerical findings, polypropylene copolymer (Co-PP) HSCP and low density polyethylene (LDPE) HSCP were developed and evaluated experimentally in the said impact energy range. A correlation was established between FEA and experimental test results, thereby, validating a numerical model to predict results for other thermoplastic materials under given range of impact energy. The LDPE HSCP exhibited better performance as compared to Co-PP HSCP in the said range of impact energy. The findings of this study will enable the engineers and technologists to design and develop low velocity impact resistance devices for various applications including devices to protect bone joints.

전자선 가교된 PBT의 충격 특성 및 내마모 특성 연구 (The Impact Properties and Wear Resistance of Polybutylene terephthalate (PBT) Cross-linked by Electron Beam Irradiation)

  • 신범식;고금진;전준표;김현빈;오승환;강필현
    • 방사선산업학회지
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    • 제5권2호
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    • pp.145-149
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    • 2011
  • Poly(butylenes terephthalate) have made large strides in applications of injection, extrusion, and molding material due to their excellent thermal resistance and appropriate mechanical properties. However, PBT was not hard polymer but a soft polymer which caused low absorption of external energy and the defect of being easily broken with the strong impact. Thus, the electron beam irradiation was carried out over a range of irradiation doses from 100 to 1,000 kGy for enhancing the properties. The decreases of $T_m$, $T_c$, and enthalpy were observed as increasing the absorbed dose in the results of DSC analysis. The improvement in the impact strength of PBT was clearly observed as the absorbed dose was increased. This was probably due to the 3-dimensional network structures, resulting in increasing the absorption of impact energy. In addition, the wear properties had increased at higher than 300 kGy. The negative deviation of weight loss confirmed the improvement of the wear properties of PBT, as evidenced by SEM observation on the wear surfaces.

저속충돌조건에서 효과적인 충돌에너지흡수를 위한 알루미늄 크래쉬 박스의 비드형상 효과 (Effect of Bead Shape in Aluminum Crash Box for Effective Impact Energy Absorption Under Low- Velocity Impact Condition)

  • 이찬주;이선봉;고대철;김병민
    • 대한기계학회논문집A
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    • 제36권10호
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    • pp.1155-1162
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    • 2012
  • 알루미늄 크래쉬 박스는 저속충돌조건에서 프론트 사이드 멤버를 변형을 방지하기 위한 부품이다. 본 연구에서는 저속충돌조건에서 비드형상이 알루미늄 크래쉬 박스의 충돌성능에 미치는 영향을 분석하였다. Edge concave, surface convex 와 surface concave 타입의 비드형상들에 대한 충돌해석 및 실험을 수행하여 비드가 없는 normal 타입의 알루미늄 크래쉬 박스의 충돌성능과 비교분석하였다. 충돌성능은 저속충돌조건에서 크래쉬 박스의 초기 최대하중 및 충돌에너지 흡수능으로 평가하였다. 이를 검증하기 위해 알루미늄 크래쉬 박스와 결합된 프론트 사이드 멤버에 대해 저속충돌실험 수행하고, 이를 분석하였다. Surface concave 타입의 비드가 삽입된 알루미늄 크래쉬 박스 경우, 프론트 사이드 멤버의 변형을 방지할 수 있음을 확인하였다.

FE 해석을 통한 충격흡수시설의 개발 (Development for Shock Absorption System by Using FE Analysis)

  • 강영호;김홍주;박동화;김계수;강범수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집A
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    • pp.224-229
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    • 2000
  • This paper describe a (mite element computer simulation of a absorption system using full scale car crash test. The full scale test selected for this study is a 80kmh frontal, side and 25% offset impact of a 1993 Ford Taurus vehicle into a absorption system. This absorption system has external rubber and internal steel pannel. This simulation has completed for decision of these components energy absorption performance. Dynamical performance of this system and movement are obtained from this simulation. and then We can appreciate the safety of passenger from measure the vehicle C.G's acceleration.

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순철분말과 인(P)이 피복된 철분말 소결강의 기계적 성질 (Mechanical Properties of Sintered Steel of Pure Iron Powder and Iron Powder Coated with Phosphorus)

  • 정재우
    • 한국분말재료학회지
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    • 제1권2호
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    • pp.181-189
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    • 1994
  • The compacts of pure and phosphorus-coated iron powder with 0~0.8%C were sintered at $1100^{\circ}C$ for 40 min. in cracked ammonia gas atmosphere. The tensile and impact strengths were measured and the relationship of the results with carbon content, phosphorus, quenching and tempering was investigated. The results obtained can be summarized as follows : (1) The tensile strength of sintered compacts increased slowly with carbon content. Increase in tensile strength by heat treatment was evident especially in the low carbon specimen. The specimen with phosphorus showed higher strength compared to pure iron compacts value. (2) No inflection point of elasticplastic deformation on stress-strain curve was observed in sintered steel. The elastic modulus of sintered steel had the same tendency as tensile strength. But the elongation showed the opposite tendency. (3) The impact absorption energy of sintered steel without addition of phosphorus decreased successively with carbon content and by quenching and tempering. On the contrary, addition of phosphorus resulted in an increase of the impact absorption energy. Quenching and tempering did not affect the impact energy especially in high carbon content. (4) The main fracture source was pore in specimen and the propagation of crack occured mostly along the grain boundaries. But the intragranular fracture was also observed in high carbon, quenched and tempered specimen, and especially in the specimen with phosphorus.

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피라미드형 내부구조체를 가진 ISB 판넬의 접합형태에 따른 충격 특성 변화 (Variation of Impact Characteristics of ISB Panels with a Pyramidal Inner Structure According to Joining Technologies)

  • 안동규;문경제;정창균;양동열
    • 한국정밀공학회지
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    • 제24권9호
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    • pp.110-118
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    • 2007
  • ISB (Inner structured and bonded) panel with a pyramidal inner structure is actively developing to reduce the weight and to improve the crashworthiness of the material. The objective of this paper is to investigate into the variation of impact characteristics of ISB panels with a pyramidal inner structure according to joining types between skin sheets and inner structures. Several drop impact tests have been performed. In order to examine the impact characteristics at a drawing condition, drawing type of experimental set-up has been proposed. From the results of the experiments, the influence of joining types between skin sheets and the inner structures on the characteristics of the deformation, the energy absorption and the failure has been quantitatively examined. In addition, it has been shown that maximum load decreased and the maximum displacement increases as the joining type changes from the bonding to the welding. The results of the observation of the specimen have been shown that major wrinkles form in the minor crimping direction irrespective of the joining types. Through the comparison of the experimental results for bonding and welding specimens, it has been shown that the absorption energy of the bonded specimen is nearly 1.3-1.5 times of the welded specimen at the same displacement.