Evaluation on Sensitivity and Approximate Modeling of Fire-Resistance Performance for A60 Class Deck Penetration Piece Using Heat-Transfer Analysis and Fire Test

Woo Chang Park,Chang Yong Song 한국해양공학회 2021 韓國海洋工學會誌 Vol.35 No.2

The A60 class deck penetration piece is a fire-resistance apparatus installed on the deck compartment to protect lives and to prevent flame diffusion in the case of a fire accident in a ship or offshore plant. In this study, the sensitivity of the fire-resistance performance and approximation characteristics for the A60 class penetration piece was evaluated by conducting a transient heat-transfer analysis and fire test. The transient heat-transfer analysis was conducted to evaluate the fire-resistance design of the A60 class deck penetration piece, and the analysis results were verified via the fire test. The penetration-piece length, diameter, material type, and insulation density were used as the design factors (DFs), and the output responses were the weight, temperature, cost, and productivity. The quantitative effects of each DF on the output responses were evaluated using the design-of-experiments method. Additionally, an optimum design case was identified to minimize the weight of the A60 class deck penetration piece while satisfying the allowable limits of the output responses. According to the design-of-experiments results, various approximate models, e.g., a Kriging model, the response surface method, and a radial basis function-based neural network (RBFN), were generated. The design-of-experiments results were verified by the approximation results. It was concluded that among the approximate models, the RBFN was able to explore the design space of the A60 class deck penetration piece with the highest accuracy.

과도 열전달해석 및 화재시험 기반 A60 격벽 관통관의 방화성능 민감도해석과 메타 모델링

박우창 ( Woo-chang Park ),송창용 ( Chang Yong Song ) 한국산업융합학회 2021 한국산업융합학회 논문집 Vol.24 No.2

A60 class bulkhead penetration piece is a fire resistance system installed on bulkhead compartment to protect lives and to prevent flame diffusion in case of fire accident in ship and offshore plant. This study deals with evaluation on sensitivity of fire resistance performance and meta-modeling characteristics for A60 class bulkhead penetration piece using transient heat transfer analysis and fire test. The transient heat transfer analysis was carried out to evaluate the fire resistance design of the A60 class bulkhead penetration piece, and verified the analysis results via the fire test. In the sensitivity analysis, the bulkhead penetration piece length, diameter, material type and insulation density were applied to the design factors, and output responses were considered weight, temperature, cost and productivity. Quantitative effects on the output responses for each design factor were evaluated using design of experiment. Optimum design case was also identified to minimize the weight of A60 class bulkhead penetration piece while satisfying the allowable limits of output responses. From the design of experiment results, various meta-models such as Kriging, response surface method and radial basis function based neural network were generated. The design of experiment results were validated by the meta-modeling results. It was concluded that the radial basis function based neural network among the meta-models was able to explore the design space of the A60 class bulkhead penetration piece with the highest accuracy.

조각투자의 증권성에 대한 연구

성희활 한국경제법학회 2022 경제법연구 Vol.21 No.3

The recognition of Music Cow’s piece investment as securities under the Korean Capital Market Act marks the first time the “Howey test” has been applied in Korean history. This paper examines the significant decisions made by financial authorities in regards to Music Cow’s piece investment, as well as piece investments in “Korean native cattle” and “artwork”. In the case of Music Cow, it is difficult to classify the investment as securities due to its significant differences from traditional securities (such as stocks and bonds) in terms of “expectation of profits,” "business," and reliance on "mainly the efforts of others." Additionally, the original beneficiary rights held by the management trust between Music Cow Asset and the Copyright Association and the derivative claim rights held by the investor are virtually the same. Since the beneficiary right of the management trust is not a financial investment product, it is possible that the right to claim participation in copyright fees may not be a financial investment product either. While the issue of investor harm due to the secondary market and bankruptcy risk is a serious concern, and the authorities' conditional measures are appropriate, this should not be used as a factor in securities judgment simply for the purpose of investor protection. In the case of artwork piece investment, it is difficult to consider the investment as securities due to the close joint ownership of the investors and the lack of efforts or business properties on the part of the promoter to increase the value of the investment. In the case of piece investment in Korean cattle, securities properties can be relatively easily recognized due to the active business activities of the cattle farmers. In contrast, in the cases of Music Cow and artwork piece investments, it is difficult to say that there are significant efforts or business activities to increase the value of copyright and artworks. However, in the case of Korean cattle investment, the breeding farmers are responsible for raising the calf, so clear business properties exist. This type of business has been judged as an investment contract security in previous instances of the "Howey test" in the United States. While the financial authorities demanded a business reorganization as a condition of exemption from sanctions to protect investors, most of these requirements were unrelated to the judgment of securities properties. This suggests that the pressure to protect investors may have influenced the authorities’ judgment in applying the “Howey test.” However, the authorities' measures to protect investors should not be underestimated, and this issue should be addressed by expanding the scope of current investment contract securities. The “Howey test,” established in the United States in 1946, has not been effective in addressing new investment measures such as virtual assets like Bitcoin and recent joint ownership-based piece investments. It is desirable to redefine and expand the definition of financial investment products and investment contract securities in order to prepare for the future and to balance the risks of new investment tools based on new information technology with the benefits of creative innovation. 뮤직카우의 청구권에 대한 증권성 판단은 우리 자본시장법 역사상 처음으로 ‘Howey기준’이 적용된 사례다. 이 논문은 역사적 의의를 가진 뮤직카우 사례와 한우 및 미술품 조각투자에 대한 당국의 판단의 타당성을 검토하였다. 뮤직카우 청구권의 경우 “이익을 얻을 목적”, “사업성”, “주로 타인의 노력” 의존 등의 요건에서 전통적인 증권투자(주식ㆍ채권 등)와는 차이가 커서 증권성을 인정하기 어렵다고 하였다. 그리고 뮤직카우에셋과 저작권협회간 관리신탁에서 나오는 원본 수익권과 투자자가 보유하고 있는 파생 청구권은 사실상 동일하다고 볼 여지도 있고, 또한 관리신탁의 수익권은 금융투자상품이 아니므로 저작권료 참여청구권 또한 금융투자상품이 아닐 수 있다. 유통시장과 도산위험에 따른 투자자 피해 문제는 중대한 이슈로서 당국의 조건부 조치는 적절하다고 판단하지만, 투자자 보호에 중대하다고 해서 이를 증권성 판단 요소로 삼을 수는 없다. 미술품 조각투자의 경우 다른 조각투자에 비해 투자자들의 공동소유권이 투자자에게 보다 더 밀착되어 있고, 투자대상의 가치 상승을 위한 사업자의 노력 내지 사업성이 현저히 결여되어있어서 증권성을 인정하기 어렵다. 한우 조각투자의 경우는 위의 두 경우와 달리 상대적으로 증권성이 쉽게 인정될 수 있다고 하였는데 그 이유는 한우 사육농가의 적극적인 사업이 존재하기 때문이다. 뮤직카우 청구권과 미술품 조각투자의 경우 저작권과 미술품의 취득 이후 그 가치 상승을 위한 노력이나 사업이 중대하다고 보기 어렵지만 한우 조각투자의 경우 투자자들이 송아지에 투자하면 사육농가가 그 송아지의 사육을 위탁받아 지대한 노력을 하게 되므로 사업이 명확히 존재한다. 이런 유형의 사업은 미국에서 ‘Howey기준’의 적용 역사에서 여러 차례 출현하였고 모두 투자계약증권으로 판정되었다. 당국은 제재조치 면제 조건으로 투자자 보호를 위한 사업재편을 요구하였는데 대부분의 요구 사항이 증권성 판단과는 관계없는 조치들이었다. 이는 투자자 보호를 위한 압박감이 당국의 증권성 판단에 영향을 미칠 수도 있었음을 시사한다. 그렇다고 투자자 보호를 위한 당국의 조치가 잘못되었다고는 할 수 없으므로 결국 이 문제는 현행 투자계약증권의 범위를 확대하는 방향으로 나아가야 한다. 미국에서 1946년 확립된 ‘Howey기준’은 2008년 이후 등장한 가상자산과 최근의 공동소유권에 기반한 조각투자 등 신종 투자수단에 그다지 효과적인 대응 수단이 되지 못하였다. 새로운 정보기술과 금융기법을 바탕으로 등장하는 다양한 신종 투자수단의 위험성은 최대한 억제하면서 그 혁신성은 살려서 미래를 전향적으로 대비하기 위해 금융투자상품과 투자계약증권의 정의를 재정립하고 범위를 확장하는 것이 바람직하다.

A60급 갑판 관통 관의 방화성능 평가를 위한 과도 열전달 해석과 화재시험

박우창(Woo Chang Park),송창용(Chang Yong Song) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.4

A60급 갑판 관통 관은 선박과 해양플랜트의 화재 발생 시 인명의 보호와 화염전파를 방지하기 위해 갑판 구획에 설치되는 방화 장치이다. A60급 갑판 관통 관이 새로 개발되거나 기존의 설계가 변경될 경우 국제해사기구의 화재시험절차 규정에 따라 A60급 갑판 관통 관의 방화성능을 검증하도록 요구하고 있다. 따라서, 본 논문에서는 신규 개발된 선박과 해양플랜트용 A60급 갑판 관통 관의 방화 설계의 적합성을 평가하기 위해 과도 열전달 해석을 수행하였고, 화재시험을 통해 해석결과의 타당성을 검증하였다. 또한 A60급 갑판 관통 관의 열전달 특성은 관의 직경, 내부형상 그리고 재질과 같은 설계 사양에 따라 비교하여 검토하였다. 과도 열전달 해석은 범용 유한요소법 소프트웨어인 ABAQUS/Implicit를 사용하여 수행하였으며, 해석결과의 검증을 위한 화재시험은 해사안전위원회에서 규정한 화재시험절차 코드에 따라 수행하였다. 본 연구에서 검토한 A60급 갑판 관통 관의 방화성능은 국제 해상안전규정을 만족하였고, 재질 사양의 설계가 중요한 것으로 나타났다. 최대 시험온도를 기준으로 SUS316L 재질의 측정온도는 S45C 재질보다 평균적으로 25% 낮게 나타났고, 이때 각 재질의 열전도계수와 비열의 차이는 각각 17%와 58%였다. A60 class deck penetration piece is a fire-resistance apparatus installed on the deck compartment to protect lives and prevent flame diffusion in fire accidents. In case that the A60 piece is newly developed or its initial design is revised, it is important to verify the fire resistance performance using a fire test procedure (FTP) code. In this paper, transient heat transfer analysis was carried out to evaluate the fire resistance design compatibility of the newly devised A60 piece. The analysis results were verified via a fire test. The heat transfer characteristics were also investigated by comparing design specifications, such as diameter, internal configuration, and material type. The analysis was performed using ABAQUS/Implicit, and the fire test was performed according to the FTP code. The fire resistance performance of the A60 pieces satisfied the safety of life at sea convention regulation. The material type was the most important design specification for the A60 piece. Based on the maximum test temperature, the measured temperature of SUS316L material was 25% lower than that of S45C on average. The differences between thermal conductivity and specific heat of each material were 17% and 58%, respectively.

조립식 경량 캠 샤프트 내구성 및 신뢰성 향상에 관한 연구

나완용(Wan Yong Na),이문석(Mun Seok Lee),최현규(Hyeon Gyu Choi),최연수(Yeon Soo Choi) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The aim of this study is to evaluate durability and reliance on lightweight assembled camshaft. The reliance valuation was performed by analyzing the cause of failure from field data and making improved tools through process Improvement. Durability and endurance test were implemented during the evaluation process. Solidity test, texture test by rubbing. cutting strength test. torque wrench test were all performed for test items and a valuation basis. The endurance test was performed in order to find out the volume of abrasion. The improvement items through the durability valuation guarantee more durability and decrease the rate of defects. This study is accomplished by the Ministry of Commerce Industry and Energy for the improvement of Reliance on Small Business.

Thermal error analysis, modeling and compensation of five-axis machine tools

Zhi Huang,Yongchao Liu,Li Du,Han Yang 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.10

The role of five-axis CNC machine tools (FAMT) in the manufacturing industry is becoming more and more important, but due to the large number of heat sources of FAMT, the thermal error caused by them will be more complicated. To simplify the complicated thermal error model, this paper presents a new modelling method for compensation of the thermal errors on a cradle-type FAMT. This method uses artificial neural network (ANN) and shark smell optimization (SSO) algorithm to evaluate the performance of FAMT, and developing the thermal error compensation system, the compensation model is verified by machining experiments. Generally, the thermal sensitive point screening is performed by a method in which a large number of temperature sensors are arranged randomly, it increases the workload and may cause omission of the heat sensitive point. In this paper, the thermal imager is used to screen out the temperature sensitive points of the machine tool (MT), then the temperature sensor is placed at the position of the heat sensitive point of the FAMT, and the collected thermal characteristic data is used for thermal error modeling. The C-axis heating test, spindle heating test, and the combined movement test are applied in this work, and the results show that the shark smell optimization artificial neural network (SSO-ANN) model was compared to the other two models and verified better performance than back propagation artificial neural network (BP-ANN) model and particle swarm optimization neural network (PSO) model with the same training samples. Finally, a compensation experiment is carried out. The compensation values, which was calculated by the SSO-ANN model are sent to the real-time error compensation controller. The compensation effect of the model is then tested by machining the ‘S’-shaped test piece. Test results show that the 32 % reduction in machining error is achieved after compensation, which means this method improves the accuracy and robustness of the thermal error compensation system.

서중조건하에서의 콘크리트 충전 강관 기둥의 시공을 위한 실험적 연구

이장환,강용학,정근호,김진호,최문식,정상진 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)

The basic Physical properties, Slump, Slump flow, Air content, Bleeding, and Settlement of concrete was investigated to test Characteristic of Setting and to evaluate the relation between Model specimen and Heat of hydration for construction Over the High Temperature(CFT). The objective of this study is to take the partial core after the cementation of Model specimen, test the compression intensity and analyze the relation to Test piece.

가공 시편을 이용한 오축 머시닝센터 가공 시험 방법의 표준화

김주현 표준인증안전학회 2018 표준인증안전학회지 Vol.8 No.4

오축 머시닝센터는 한 번의 공정으로 제품을 가공할 수가 있어서 공정간 공작물 이동이 불필요하다. 이로 인하여 재공품 재고 감소, 준비시간 감소, 리드타임 감소등의 장점이 있다. 또한 한 번의 척킹으로 모든 가공이 가능하므로 가공 정밀도가 향상되고 공간 활용도가 개선된다. 이와 같은 머시닝센터의 정밀도 평가를 위해서는 새로운 기술이 필요한데, 특히 공작기계 기술이 지능화, 다축화, 복합화되어감에 따라 이에 따른 표준 제정의 필요성이 국내뿐만 아니라 세계적으로 증대되고 있다. 또한 고급 기종 및 대형 기종에 대한 수요가 큰 폭으로 증가하고 있기 때문에 오축 머시닝센터에 대한 수요 또한 큰 폭으로 증가하고 있다. 특히 최근에 널리 사용되고 있는 오축 머시닝센터에 대한 경우에는 국가간 이해관계가 첨예하게 대립하고 있기 때문에 이에 맞는 표준 제정의 필요성이 시급한 실정이다. 본 논문에서는 기존의 표준에서 취급하지 않았던 공작물 재료, 공작물 크기에 대응하여 오축 머시닝센터의 정밀도를 측정하는 시스템을 개발하였다. Cone frustrum test method, Truncated square pyramid test method 등을 기존 표준에 추가하면 기존 표준의 개정을 통하여 제안된 표준이 반영될 수 있을 것이다. 5-axis machine tools have been rapidly accepted in the world-wide machine tool market, and have been recognized as one of main forces for machine tool builders. By using 5-axis machine tools, it is possible to reduce setup time, fixturing and tooling costs, and finishing operations with increased accuracy. In the machining by using a 5-axis machine tool, various error sources in each of rotary and linear axes impose complex effect on the geometric accuracy of the machined workpiece. As a result, it is a common recognition in today's industry that the machining accuracy of a 5-axis machine tool cannot be as good as that of a conventional 3-axis machine tool. The results of the cutting test present comprehensive quality characteristics of a machine tool. A variety of combination of axes can be considered to different test piece shapes. Cutting test purposes the presentation of the comprehensive performance of machine tools in the form of physical object, accuracy evaluation based on real-cut surfaces, overall quality measures to machine tools, acceptance criteria for users, and trial for new cutting items. Cone frustum test method, truncated square pyramid test method, and sphere tes method are suggested. For these test methods, test setup, cutting conditions, cutting method, test purpose, and tolerances are determined.

A60급 구획 적용 격벽 관통용 관의 열전달 특성 II: 관 재질 및 단열재 종류에 따른 방화시험

박우창,송창용 한국해양공학회 2019 韓國海洋工學會誌 Vol.33 No.4

In the case of a fire accident on a ship or an offshore plant, the design of the bulkhead penetration piece must be verified via a fire test procedure (FTP), as specified by the Maritime Safety Committee (MSC). The purpose of this study is to verify both the numerical analysis results and the design specifications for penetration pieces that could be applied to the A60 class bulkhead division. In this study, the FTP was carried out in accordance with the test procedure prescribed in the MSC regulation. In order to review the fire resistance performance according to the material type, bulkhead penetration pieces for the FTP were made from brass, carbon steel for machine structures (S45C), and austenite stainless steel (SUS316). In addition, spray-type insulation and mechanical fastener-type insulation were applied to investigate the fire resistance performance according to the type of insulation. To verify the heat transfer numerical analysis results for the A60 class bulkhead penetrating piece from this test study, the design specifications of the penetrating piece material and the insulation type applicable to a ship and an offshore plant were identified.

복합 시험편을 이용한 다축 가공기의 정확도 검사 방법의 표준화

김주현(Kim, Joo Hyun) 표준인증안전학회 2021 표준인증안전학회지 Vol.11 No.4

다축 가공기를 사용하면 여러 공정이 필요한 생산 공정들을 한 번의 공정으로 제품을 생산할 수가 있기 때문에공정들 사이의 공작물 이동을 줄일 수가 있어서 생산성을 높일 수가 있다. 다시 말해서 공작물 준비시간, 재공품재고, 리드타임 등을 감소시킬 수 있다. 또한 생산성뿐만 아니라 한 번의 셋업으로 다양한 가공이 가능하고 가공정밀도를 향상시킬 수가 있다. 전통적인 공작기계로 가능하지 않은 다양하고 정밀한 가공을 다축 가공기를 적용하면 제품 생산성을 높일 수 있게 되는 장점이 있는 것이다. 하지만 전통적인 공작기계에 대한 성능 평가에 대해서는 많은 표준이 제시되고 있지만 최근에 개발되고 있는다축 가공기에 대한 성능 평가 표준은 아직 미흡한 면이 있다. 다축 가공기에 대한 기술이 지능화, 그리고 복합화되기 때문에 이에 대응하는 표준 제정이 필요하고, 이에 대한 필요성으로 국내뿐만 아니라 국제적으로 경쟁적으로 표준을 개발하고 있는 실정으로 이에 대한 측정 방법 개발이 활발하게 진행되어야 한다. 또한 다양한 크기의 공작물에 대응하는 공작기계가 개발됨에 따라 이에 대한 표준 개발에 대한 연구를 함께 하여야 한다. 본 논문에서는 기존의 공작기계 표준에서 취급하지 않았던 공작물 크기, 가공 방법 등을 제시하고, 다축 가공기에 대응하여 정확도를 측정할 수 있는 방법들을 연구하였다. 이를 통하여 복합 시험편을 사용하여 다양한 가공이 가능한 다축 가공기의 성능 측정을 위하여 실제 가공 시험편의 정확도를 측정하여 활용할 수 있는 더욱 신뢰성 있는 표준을 제시하고자 한다. When the movement of the workpieces between the manufacturing processes can be reduced, it is possible to save fixturing and tooling costs as well as the setup time. Therefore the finishing operations with increased accuracy by using multi-axis machine tools can be simplied. Multiaxis machine tools have been widely used in the inside and outside of country, and have been recognized as one of main machine tools. However compared with the machining accuracy of 3-axis machine tool, that of multi-axis machine tool cannot be good, due to the various error sources in each of rotary and linear axes. Therefore machining test method for multi-axis machine tools are necessary to present the comprehensive performance of machine tools by the accuracy evaluation based on real-cut surfaces. The machining test methods by using compound test pieces were studied and suggested as a standard. This standard is to measure the accuracy of the machine corresponding to the size of the specimen and test method. To measure the accuracy of the machine, machining test was performed and the geometric accuracy of the compound specimen was measured, and the corresponding tolerance was suggested.