• 한국세라믹학회지
• /
• 제51권2호
• /
• pp.103-106
• /
• 2014

Nacre is an organic-inorganic composite material; it is composed of $CaCO_3$ platelet and protein. The microstructure of nacre is a matrix that is similar to bricks and mortar. Technology inspired by nature is called biomimetic technology. In this study, to make high thermal conducting ceramic composite materials using biomimetic technology, a porous green body was prepared with BN platelets. PMMA was infiltrated into the porous green body to make a composite. The microstructure of the composite was observed with FESEM, and the thermal properties were measured. The thermal conductivity of the prepared organic-inorganic composite was 4.19 $W/m{\cdot}K$.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.73-76
• /
• 2007

Electro-Active paper (EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, which result good correlation with each other.

• 한국소음진동공학회논문집
• /
• 제17권12호
• /
• pp.1179-1183
• /
• 2007

Electro-Active paper(EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, and which result in good correlation with each other.

• Tribology and Lubricants
• /
• 제26권2호
• /
• pp.129-135
• /
• 2010

Geckos have a unique ability to cling to ceilings and walls utilizing dry adhesion. Their foot pads are covered by a large number of small hairs (setae) that contain many branches per seta with a lower level of spatulae. Their fibrillar structure is the primary source of high adhesion. In this study, we construct the adhesion design database for biomimetic adhesive system. A simple idealized fibrillar structure consisting of single array of beams is modeled. The fibers are assumed as oriented cylindrical cantilever beams with spherical tip. We consider three necessary conditions; buckling, fracture and sticking of fiber structure, which constrain the allowed geometry. The adhesion analysis is performed for the attachment system in contact with rough surfaces with different s values for different main design variables-fiber radius, aspect ratio and material elastic modulus and so on. The developed adhesion design databases are useful for understanding biological systems and for guiding of fabrication of the biomimetic attachment system.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.1257-1258
• /
• 2006

Biomimetic apatite deposition behaviors and mechanical performance for as-rolled and annealed Ni-Ti plates were investigated . A good biomimetic apatite formation and excellent mechanical performance of Ni-Ti suggests that Ni-Ti can be an excellent candidate material as orthopedic implants.

• Smart Structures and Systems
• /
• 제2권3호
• /
• pp.225-235
• /
• 2006

With the discovery in plants of the proteinaceous forisome crystalloid (Knoblauch, et al. 2003), a novel, non-living, ATP-independent biological material became available to the designer of smart materials for advanced actuating and sensing. The in vitro studies of Knoblauch, et al. show that forisomes (2-4 micron wide and 10-40 micron long) can be repeatedly stimulated to contract and expand anisotropically by shifting either the ambient pH or the ambient calcium ion concentration. Because of their unique abilities to develop and reverse strains greater than 20% in time periods less than one second, forisomes have the potential to outperform current smart materials as advanced, biomimetic, multi-functional, smart sensors or actuators. Probing forisome material properties is an immediate need to lay the foundation for synthesizing forisomebased smart materials for health monitoring of structural integrity in civil infrastructure and for aerospace hardware. Microfluidics is a growing, vibrant technology with increasingly diverse applications. Here, we use microfluidics to study the surface interaction between forisome and substrate and the conformational dynamics of forisomes within a confined geometry to lay the foundation for forisome-based smart materials synthesis in controlled and repeatable environment.

• Computers and Concrete
• /
• 제23권5호
• /
• pp.351-359
• /
• 2019

In this study, the calcium hydroxide, an inherent product of cement hydration, was treated using biomimetic carbonation method of incorporating stearic acid to generate the hydrophobic calcium carbonate on concrete surface. Carbonation reaction was carried out at various $CO_2$ pressure and temperatures and utilizing the Scanning Electron Microscope (SEM), chloride-ion penetration test apparatus, and compression test machine to investigate the hydrophobicity, durability, and mechanical properties of the synthesized products. Experimental results indicate that the calcium stearate may change the surface property of concrete from hydrophilicity to hydrophobicity. Increasing reaction temperature can change the particles from irregular shapes to needle-rod structures with increased shear stress and thus favorable to hydrophobicity and microhardness. The contact angle against water for the concrete surface was found to increase with increasing $CO_2$ pressure and temperature, and reached to an optimum value at around $90^{\circ}C$. The maximum static water contact angle of 128.7 degree was obtained at the $CO_2$ pressure of 2 atm and temperature of $90^{\circ}C$. It was also found that biomimetic carbonation increased the permeability, acid resistance and chloride-ion permeability of the concrete material. These unique results demonstrate that the needle-rod structures of $CaCO_3$ synthetized on concrete surface could enhance hydrophobicity, durability, and mechanical properties of concrete.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.380-380
• /
• 2011

ZnO nanorod (NR) arrays prepared via simple ammonia hydrothermal method exhibiting superhydrophilicity, high transmittance and antireflection. These properties result from the unique surface structure and material property of ZnO NR arrays. Highly rough surface due to ZnO NRs enhanced hydrophobicity/hydrophilicity of the films and short NRs (about 300 nm) made ZnO arrays transparent. ZnO NR films were chemically modified by dipping the sample into 5mM stearic acid/ethanol solution for 3 hours. Then the ZnO NRs became superhydrophobic surfaces, whose contact angle reached 159.2$^{\circ}$ maintaining their high transmittance. These biomimetic ZnO NR arrays can be used in diverse field, such as antifogging/self-cleaning surfaces and optical devices.

• 한국전기전자재료학회논문지
• /
• 제33권5호
• /
• pp.380-385
• /
• 2020

Over the past decade, small robots have been of particular interest in the engineering field. Among the various types of small robots, biomimetic robots, which mimic animals and insects, have been developed for special activities in areas where humans cannot physically access. The optimal motion of a walking robot can be determined by the characteristics of the traversed surface (e.g., roughness, curvature, slope, materials, etc.). This study proposes three types of piezoelectric structures using different driving mechanisms, depending on the application range of the small walking robots. Dynamic modeling using computer-aided engineering optimized the shape of the robot to maximize its moving characteristics, and the results were also verified through its fabrication and experimentation. Three types of robots, named by their actuator shapes as I, π, & T-shape, were proposed regarding application for small scale ambulatory robots to different terrain conditions. Among these, the T-shaped robots were shown to have a wide range of speeds (from 2 mm/s up to 255 mm/s) and good carrying capacity (up to 10 g at 50 mm/s) through driving experiments. Based on this study, we proposed possible application areas for the three types of walking robot actuators.

• 대한기계학회논문집A
• /
• 제36권1호
• /
• pp.1-7
• /
• 2012

이 논문에서는 최소의 배터리를 소비하여 물고기 로봇을 구동하고, 물고기와 같은 유연한 운동을 할 수 있는 생체 모방(biomimetic) 물고기 로봇의 설계, 제작, 제어에 관하여 제안 하였다. 두 개 모터를 적용하여 물고기와 같이 유연하게 움직일 수 있는 방법을 제시 하였다. 중성 부력을 유지하는 방법과 빠르게 잠영하고, 방향을 전환 하기 위한 방법을 제시 하였다. 로봇 물고기의 꼬리는 유연한 움직임을 만들기 위하여 폴리머 재질을 사용하여 만들었다. 꼬리 내부는 관절과 강선으로 구성된다. 로봇 물고기에 척추에 해당하는 우레탄 골격과 관절을 이루는 핀에 연결된 강선을 당겨 꼬리에 정현파 명령을 주어 물고기와 비슷한 유영을 할 수 있도록 하였으며, 부력 조절 장치를 설치하였으며, 이 부력 조절 장치를 이용하여 물고기 로봇이 상승, 하강을 할 수 있도록 하였다.