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박중구,Park, Jung-Gu 대한석유협회 2012 석유와 에너지 Vol.284 No.-
본 자료는 서울과학기술대학교 박중구 교수가 연구한 <한국석유산업의 산업연관효과분석>에서 일부 편집한 것임.
Thermal Elasto-Plastic Analysis of Large Steel Plate Cutting Using Layered Shell Elements
박중구 대한용접·접합학회 2022 대한용접·접합학회지 Vol.40 No.3
In this study, plasma cutting deformation of a large plate was simulated by applying a thermal elasto-plastic analy- sis technique using a layered shell elements. First, plasma cutting heat source model was proposed based on double Gaussian distribution model. And the proposed heat source model was compared with the experimental results through heat source parameter tuning. In addition, by applying the adaptive element division technique, we increase the heat flux input accuracy for the heat source concentration in a cutting area. And by applying the element de-acti- vating technique, it was possible to simulate the melted part extinguished by cutting. Thermal elasto-platsic analysis of cutting of large plates was performed using the developed heat source model. To this end, layered shell element was used, and heat flux was applied to each layer of the layered shell element to improve the accuracy of analysis. The analysis result was compared with the experimental result to confirm the analysis accuracy. Through the analy- sis results, the occurrence of rotational deformation and bending deformation that affect the dimensional quality of large plates was verified, and its validity was reviewed by comparing them with the experimental measurement results. In this study, plasma cutting deformation of a large plate was simulated by applying a thermal elasto-plastic analysis technique using a layered shell elements. First, plasma cutting heat source model was proposed based on double Gaussian distribution model. And the proposed heat source model was compared with the experimental results through heat source parameter tuning. In addition, by applying the adaptive element division technique, we increase the heat flux input accuracy for the heat source concentration in a cutting area. And by applying the element de-activating technique, it was possible to simulate the melted part extinguished by cutting. Thermal elasto-platsic analysis of cutting of large plates was performed using the developed heat source model. To this end, layered shell element was used, and heat flux was applied to each layer of the layered shell element to improve the accuracy of analysis. The analysis result was compared with the experimental result to confirm the analysis accuracy. Through the analysis results, the occurrence of rotational deformation and bending deformation that affect the dimensional quality of large plates was verified, and its validity was reviewed by comparing them with the experimental measurement results.
박중구 한국국제통상학회 2004 국제통상연구 Vol.9 No.1
본고는 한국에 진출한 외국인투자기업의 기술개발활동과 결정요인을 분석하였다. 한국에 진출한 외국인투자기업들의 기술개발활동은 매출액 대비 연구개발투자 비중과 국내기업과의 수직적 연계(vertical linkage)를 나타내는 실물자산 특정성 등에 의해 추진되고 있는 반면, 시장경쟁 심화와 종업원 수 대비 연구개발인력의 미흡에 따라서는 이루어지지 않는 것으로 분석되었다 그리고 기업규모나 해외 모기업으로부터의 기술이전, 국내기업과의 인적자산 특정성 등은 국내 외국인투자기업의 기술개발활동에 영향을 미치지 못하고 있는 것으로 분석 되었다. 이러한 분석의 결과는 한국에 진출한 외국인투자기업의 기술개발활동이 한국에 입지하고 있는 생산공장을 보조하거나 한국시장에 맞도록 제품을 개량하는 것을 목적으로 하는데 기인한다. 그러나 세계적으로 심화되고 있는 기술경쟁에 뒤지지 않고 최근 국정과제가 되어 있는 「동북아 R&D 허브(hub)」로 발전하기 위해서는 외국인투자기업의 기술개발활동을 활성화하고, 해외R&D활동을 추진하는 선진 다국적기업들의 글로벌 R&D전략에 편승할 필요가 있다. 이를 위해서는 외국인투자기업의 기술개발활동을 촉진하고 있는 연구개발투자를 확대할 수 있도록 조장하는 노력이 필요하다. 특히 첨단기술분야에 투자하고 있는 외국인투자기업과 선진 다국적기업들의 지역연구센터를 유치할 수 있도록 추가적인 연구개발투자 지원이 필요하다. 둘째, 외국인투자기업의 기술개발활동에 부정적 영향을 미치고 있는 연구개발인력의 부족을 보완하는 정책적 노력이 필요하다. 즉, 산업별 연구개발인력의 수급을 전망하고, 수급을 맞출 수 있는 교육·훈련제도의 확충과, 특히 현안이 되어 있는 이공계 기피현상의 극복 등에 대한 계획을 제시할 필요가 있다. 셋째, 외국인투자기업과 국내기업간 기술개발 협력을 강화하기 위해 국내기업과 부품조달계약을 맺고 있거나 공동연구개발 등을 통해 기술분업을 추진하고 있는 외국인투자기업에 대해 우선적으로 연구개발투자 및 연구개발인력 등을 지원할 필요가 있다. This study examines the R&D activities of foreign direct investment firms(FDIF) in Korean manufacturing industry by making multiple logistic regression on corresponding firms' endogenous technological efforts and cooperative relationship among Korean supplying firms. The R&D activities of FDIF in Korea are analyzed to have been positively influenced by R&D investment and cooperative relationship, but negatively by insufficient R&D manpower and pierce domestic market competition. And firm size and technology transfer from foreign parent company have no impact on the R&D activities of FDIF in Korea. The implications of this study are as follows: ⅰ) to activate the R&D activities of FDIF, Korean government and firms should make efforts intensifying R&D-related investment and particularly, manpowers; ⅱ) responded to the positive effect of cooperative relationship between FDIF and domestic suppliers, subcontracting and sourcing patterns should be changed to be amicable; ⅲ) vigorous efforts to induce and diffuse the technology transfer from foreign parent companies should be made.