• 한국정밀공학회지
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• 제28권7호
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• pp.834-850
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• 2011

In this paper, a novel tissue engineering scaffold design method based on triply periodic minimal surface (TPMS) is proposed. After generating the hexahedral elements for a 3D anatomical shape using the distance field algorithm, the unit cell libraries composed of triply periodic minimal surfaces are mapped into the subdivided hexahedral elements using the shape function widely used in the finite element method. In addition, a heterogeneous implicit solid representation method is introduced to design a 3D (Three-dimensional) bio-mimetic scaffold for tissue engineering from a sequence of computed tomography (CT) medical image data. CT image of a human spine bone is used as the case study for designing a 3D bio-mimetic scaffold model from CT image data.

• 대한기계학회논문집A
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• 제41권8호
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• pp.737-744
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• 2017

최근 Shellular라는 새로운 극저밀도 재료가 소개되었다. Shellular는 주기적 구조를 가지면서도 한장의 부드러운 곡면의 쉘로 구성되어 있다. 최초의 Shellular는 리쏘그래피를 이용하여 제조되며 3주기최소곡면의 일종인 P-곡면과 유사한 형태를 갖는다. 본 연구에서는 와이어 직조에 기반하여 D-곡면과 유사한 Shellular를 제작하는 새로운 방법을 제시한다. 실험과 유한요소해석을 통하여 압축하중 하의 재료물성을 평가하고 종래의 극저밀도 재료와 비교하였다.

• 대한수학회지
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• 제61권4호
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• pp.761-778
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• 2024

A separable minimal surface is represented by the form of f(x) + g(y) + h(z) = 0, where f, g and h are real-valued functions of x, y and z, respectively. We provide exact equations for separable minimal surfaces with elliptic functions that are singly, doubly and triply periodic minimal surfaces and completely classify all them. In particular, parameters in the separable minimal surfaces change the shape of the surfaces, such as fundamental periods and its limit behavior, within the form f(x) + g(y) + h(z) = 0.

• 소성∙가공
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• 제33권4호
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• pp.248-254
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• 2024

The triply periodic minimal surface (TPMS) structure is characterized by a high surface-to-volume (S/V) ratio and the separated internal structure for flow. Combining the different TPMS structures can provide unique flow and strength characteristics. This paper investigates the effects of dimension, density and arrangement of the unit cell of the TPMS on contact and flow areas of combined TPMS structures. Several representative TPMS structures, including primitive, gyroid and diamond structures, are adopted to design gradient and heterogeneous types TPMS structures. The estimation method of contact and flow areas using an image processing technique is proposed. Python software is used to predict contact and flow area. The influence of the combination method of TPMS on contact and flow areas in the contact surface of combined TPMS structures with different shapes is investigated. Based on the results of the investigation, an appropriate combination method of TPMS structures is discussed.

• 소성∙가공
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• 제33권4호
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• pp.241-247
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• 2024

The triply periodic minimum surface (TPMS) shape with a complex geometry can easily manufactured from additive manufacturing processes. The TPMS shape has a high surface-to-volume ratio. In addition, the TPMS shape increases the possibility of the self-circulation when the fluid flows inside the TPMS structure. Due to these reason, the performance of the fluid flow filter can be greatly improved when the TPMS structure is applied to the filter. The aim of this paper is to investigate the influence of the design of the unit cell for TPMS on self-circulation characteristics of air using computational fluid dynamics (CFD). From the results of the CFD, the effects of the shape and the dimension of the unit cell for TPMS on the self-circulation pattern and the pressure difference are examined. Finally, a proper design of the TPMS is discussed from the viewpoint of self-circulation of air.

• 소성∙가공
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• 제33권4호
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• pp.270-276
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• 2024

In order to improve the performance of the PM (Particulate Matter) filter, the TPMS structure was used as a flow controller to control the flow entering the filter. Among various TPMS structures, a primitive structure that is easy to utilize 3D printing technique was selected and the effect of unit cell size was analyzed. In addition, numerical analysis was performed and swirl ratio was analyzed to confirm changes in filter inlet flow characteristics that affect changes in filter performance. Unit cell size is closely related to filter performance, and both PM collection efficiency and pressure drop increase as unit cell size decreases. Through quality factor (QF) comparison, which comprehensively evaluate collection efficiency and pressure drop, it was confirmed that when the unit cell size is 5 mm, PM collection efficiency increases, but the flow controller actually reduces filter performance. QF values are similar for unit cell sizes of 10 and 20 mm, and it is advantageous to select the unit cell size among these two considering collection efficiency and operating costs. The filter's collection performance increases due to the increase in swirl flow caused by the primitive structure, and the filter's collection efficiency increases due to the swirl flow that increases throughout the flow field as the unit cell size becomes smaller.