테입 캐스팅 공정을 이용한 초경재료 박판재의 소결거동

심우영,김창삼,김영도,이욱성 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.12

Tape casting process was applied to the fabrication of cemented carbide thin plate with thickness below 1 mm, which is expected to reduce the production cost and to enable the mass production of thin plates. Using the tape casting process, thin plates of cemented carbide were fabricated in the various forms such as monolithic and laminated, perforated and non-perforated thin plate forms. The debinding and sintering behavior were investigated to define the related problems and the solutions were suggested. Through sequential application of sheet forming by tape casting, lamination, debinding and vacuum sintering, the flat cemented carbide thin plates of lateral dimension, the sintered thickness and its deviation of 45-75 mm, minimum 500μm and 50μm, respectively, could be fabricated. Cemented carbide thin plates of perforated forms as well as the laminated forms could also be fabricated with a similar specification. Abnormal grain growth was observed in the microstructure, which was attributed to the incorporation of the impurities during the tape casting process. It was found to be readily preventable. Sintering behavior was investigated for the laminated composite thin plates of TiC-Ni/WC-Ni, in the performance diversification perspectives. When the grain growth kinetics were different for the two layers, an asymmetric capillary force was generated to induce a different shrinkages of the layers. This induced a severe warping of the plates. When the grain growth kinetics of the two layers were made identical by addition of grain growth inhibitor, the shrinkage difference was prevented, which enabled warp-free, dense laminated plate. (Received February 13, 2004)

Ba$_{0.67}$Sr${0.33)2$TiO$_3$ 박편 및 박막의 유전 및 초전 특성

이문희,조성걸,이상기 한국세라믹학회 1998 한국세라믹학회지 Vol.35 No.7

Dielectricand pyroelectric properties of {{{{ { { {Ba }_{0.67 }Sr }_{0.33 } }`TiO_{3 } ^{ } }} (BST) thin plates and films were investigated. For BST thin plates maximum dielectric constant and pyrolelectric coefficient were observed at around 24$^{\circ}C$ and pyroelectric characteristics were improved as applied bias field was increased. When the electric field of 4kV/cm was applied to the thin plates sintered at 140$0^{\circ}C$ the pyroelectric coefficients over 4$\times$10-7C/{{{{ { cm}^{2 }K }} were obtained in the range of 0-4$0^{\circ}C$ BST thin films deposited using rf magnetron sputtering showed [001] preferred orientation at substrate temperatures above 50$0^{\circ}C$ On the contrary to the thin plates the dielectric constants of the thin films gradually increased above 15$^{\circ}C$ and decreased as applied bias field in-creased. The pyroelectric coefficients of thin films were lower than 1/10 those of thin plates.

Dynamic analysis of a transversely isotropic non-classical thin plate

Fadodun, Odunayo O.,Borokinni, Adebowale S.,Layeni, Olawanle P.,Akinola, Adegbola P. Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.25 No.1

This study investigates the dynamic analysis of a transversely isotropic thin plate. The plate is made of hyperelastic John's material and its constitutive law is obtained by taken the Frechect derivative of the highlighted energy function with respect to the geometry of deformation. The three-dimensional equation governing the motion of the plate is expressed in terms of first Piola-Kirchhoff's stress tensor. In the reduction to an equivalent two-dimensional plate equation, the obtained model generalizes the classical plate equation of motion. It is obtained that the plate under consideration exhibits harmonic force within its planes whereas this force varnishes in the classical plate model. The presence of harmonic forces within the planes of the considered plate increases the natural and resonance frequencies of the plate in free and forced vibrations respectively. Further, the parameter characterizing the transversely isotropic structure of the plate is observed to increase the plate flexural rigidity which in turn increases both the natural and resonance frequencies. Finally, this study reinforces the view that non-classical models of problems in elasticity provide ample opportunity to reveal important phenomena which classical models often fail to apprehend.

Dynamic analysis of a transversely isotropic non-classical thin plate

Odunayo O. Fadodun,Adebowale S. Borokinni,Olawanle P. Layeni,Adegbola P. Akinola 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.25 No.1

This study investigates the dynamic analysis of a transversely isotropic thin plate. The plate is made of hyperelastic John\'s material and its constitutive law is obtained by taken the Frechect derivative of the highlighted energy function with respect to the geometry of deformation. The three-dimensional equation governing the motion of the plate is expressed in terms of first Piola-Kirchhoff\'s stress tensor. In the reduction to an equivalent two-dimensional plate equation, the obtained model generalizes the classical plate equation of motion. It is obtained that the plate under consideration exhibits harmonic force within its planes whereas this force varnishes in the classical plate model. The presence of harmonic forces within the planes of the considered plate increases the natural and resonance frequencies of the plate in free and forced vibrations respectively. Further, the parameter characterizing the transversely isotropic structure of the plate is observed to increase the plate flexural rigidity which in turn increases both the natural and resonance frequencies. Finally, this study reinforces the view that non-classical models of problems in elasticity provide ample opportunity to reveal important phenomena which classical models often fail to apprehend.

장력법을 적용한 박판블록의 변형제어에 관한 연구

김철호,양종수,김호경,Kim, Cheol-Ho,Yang, Jong-Soo,Kim, Ho-Kyung 대한용접접합학회 2007 대한용접·접합학회지 Vol.25 No.6

The weld-induced deformation is more serious in thin plates than in thick plates because heat affect zone of thin plates is wider than that of thick plates and in addition internal and external constraints have much more influence upon weld-induced deformation of thin plates. This paper deals with the application of the mechanical tensioning method to butt weld of thin plates to reduce the transverse and longitudinal deformation. In order to investigate the quantitative effect of tensioning method upon the reduction of angular deformation and shrinkage in longitudinal and transverse direction of weld line, butt welding test has been carried out for several thin plate specimens with varying plate thickness and magnitude of tensile load. From the present experimental study, it has been found that the tensioning method is very effective in reducing the weld-induced residual stress as well as the weld-induced deformation.

판형 부품의 밀링 가공에 의한 변형 최소화에 대한 연구

이민구,윤재웅,Lee, Min-Gu,Yun, Jae-Woong 한국금형공학회 2021 한국금형공학회지 Vol.15 No.3

Plate-shaped works are one of the materials that can be applied to the entire industry due to their various shapes and sizes. Plate-shaped parts workpieces are thin and wide, and when processing is completed, they are often bent or deformed in various directions, making it difficult to produce normal products. In particular, this study intends to study the processing deformation and distortion of plate-shaped parts fastened to the jig during milling processing. In this study, a method for preventing deformation occurring in plate-shaped parts was derived through jig element change and CAE analysis, and this was applied to actual processing to produce products with stable dimensions. Through a finite element analysis experiment, it was found that installing two supports on the back of the plate-shaped part results in minimal deformation and the optimal distance between the two supports is 150 mm. Through this experiment, when processing a thin plate product, a support was installed in a direction opposite to the cutting force applied to the thin plate to prevent deformation of the product, thereby improving defects.

초박판 사출성형특성 분석을 위한 금형제작에 관한 연구

이성희,고영배,이종원,김성규,양진석,허영무,Lee, Sung-Hee,Ko, Young-Bae,Lee, Jong-Won,Kim, Sung-Kyu,Yang, Jin-Suk,Heo, Young-Moo 한국금형공학회 2008 한국금형공학회지 Vol.2 No.5

A micro-injection mold for ultra-thin-walled plate was considered in this work. The proposed mold system is for the fabrication of ultra-thin walled plastic plate with micro features by injection molding. As the injection molding of thin-walled plastic, which has the thickness under $400{\mu}m$, itself is not easy, the injection molding of the micro-features in the thin-walled structure is more complicated and difficult. To investigate the basic phenomenon of the ultra-thin walled part during the injection molding process, design of the part and mold system were performed in the present study. The injection molding and structural analysis of the suggested part and mold system were also performed. Consequently, injection molding system for ultra-thin walled plate with micro features were manufactured and presented.

Analysis on nonlinear dynamics of a thin-plate workpiece in milling process with cutting force nonlinearities

Rui Zhou,Wei Zhang,Jean W. Zu 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.7

This paper aims to investigate the nonlinear dynamics of a thin-plate workpiece during milling process with cutting force nonlinearities. By modeling the thin-plate workpiece as a cantilevered thin plate and applying the Hamilton’s principle, the equations of motion of thethin-plate workpiece are derived based on the Kirchhoff-plate theory and the von Karman strain-displacement relations. Using the Galerkin’sapproach, the equations of motion are reduced to a two-degree-freedom nonlinear system. The method of Asymptotic Perturbationis utilized to obtain the averaged equations in the case of 1:1 internal resonance and foundational resonance. Numerical methods areused to find the periodic and chaotic oscillations of the cantilevered thin-plate workpiece. The results show that the cantilevered thin-plateworkpiece demonstrate complex dynamic behaviors under time-delay effects, the external and parametric excitations.

Fabrication of AA7075 Thin Plates for PEM Fuel Cells by Thixoforging

Amir Bolouri(아미르),Chang Hyun Jang(장창현),Chung Gil Kang(강충길) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.5

Aluminum 7075 alloy extrusion billets have been used as the feedstock for thixoforging of thin plates. Recrystallisation and remelting (RAP) route has been employed to prepare the semisolid slurries. A direct die-filling system was designed for thixoforging of thin plate. Thin plates were thixoforged at the temperatures of 610℃, 615℃ and 620℃ with application of 70 MPa forging pressure. The quality of thin plates was examined by X-ray radiography. Hot tearing defects were detected when thixoforging was conducted at higher temperatures. The elongated grains in the initial extrusion billets were transferred to the globular grains within the semisolid slurry. However, some interconnected grains were observed. The microstructure of thixoforged thin plates indicated that a disagglomeration effect was active during thixoforging.

Improved Quantum-Behaved Particle Swarm Method for Optimizing Complex Thin Plate Structure

Weitao Cheng,Yixiao Qin,Jinpeng Gu,Haibiao Gao,Yue Yan,Junle Yang,Yang Chen,Shen Su,Kaiyao Yang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.4

A large number of heavy-duty asymmetric thin-plate box girder structures exist in large equipment, and their optimization can reduce the amount of material used and increase their load-carrying capacity. A new optimization method based on the Improved Quantum-Behaved Particle Swarm Optimization method (IQBPSO) is proposed in order to efficiently solve the mathematical model for the rationalization and optimization design of structures. The penalty function and Lévy flight strategy are considered in the optimization design of the improved algorithm, thus transforming the constrained optimization problem into an unconstrained optimization problem and improving the diversity and local optimization search capability of the quantum particle swarm. A mathematical model for the optimal design of box girder section size is established with the reduction of beam cross-sectional area as the objective function and the thin plate strength, rigidity, and stability of the thin slab as the constraints. The rapid lightweight design of the thin plate box beam was achieved, resulting in a 9.6% reduction in the manufacturing cost of the thin plate box beam. The optimization results are compared with several solutions of the thin slab box beams to verify the reliability and validity of the proposed optimization method.