|Title||Kim Dong-chul-Moon Jun-hyuck professor team found metamaterial structure technology with mechanical characteristics that does not exist in natural world|
Kim Dong-chul-Moon Jun-hyuck professor team found metamaterial structure technology with mechanical characteristics that does not exist in natural world
- Announced in Scientific Report which is Nature’s sister magazine -
Sogang University Kim Dong-chul-Moon Jun-hyuck joint research team developed metamaterial structure technology with mechanical characteristics that does not exist in natural world by controlling the shape of 3 dimensional microstructure. This research result was published in Scientific Report which is Nature’s sister magazine on February 3. The title of article is called, “Controlled Unusual Stiffness of Mechanical Metamaterials (Corresponding author: Professor Kim Dong-chul, Moon Jun-hyuck, Lead author: Lee Woo-joo doctoral degree program at Sogang University).”
This research was developed in order to structure metamaterial with unique characteristics that does not exist in natural world and come up with a way of method to control triply periodic continuous structure, then in the future through development of concealment devices that are not detected from the sound detector, high-efficient shock absorption material which can be utilized in various fields such as defense industry, aerospace industry, car industry and so on therefore the research is more meaningful.
On the other hand, this research was proceeded with the support from junior executive researcher supporting project (core research) of Ministry of Science, ICT and Future Planning and the main contents of research and thesis are as follows.
1. Necessity of Research
Metamaterial is a material that is artificially designed to represent the characteristics that does not exist in the natural world. Recently imaginary tools are being actualized as the metamaterials are being developed in various fields beyond the characteristics of existing materials such as development of unique optical characteristics which can be used in invisibility cloaks. Especially development of metamaterials which contains unique mechanical characteristics that does not exist in natural world are expected to show high potentials to be utilized, but up to now, there has been no attempts of an in-depth study.
Developing metamaterials with new mechanical characteristics through experiments, takes high-degree of professionalism and technical skills which takes considerable time and cost. So in reality there will be considerable difficulty. Therefore there has to be efficient metamaterial design method to foresee technological characteristics of various structures.
With simple method, can change the complex internal objects of recent structures so triply periodic continuum which is receiving a lot of attention and expects to see various technological characters, however there has not been an offer as technological metamaterial yet.
* Triply Periodic Continuum : Mathematically defined structure where the same features of 3 dimensional space restraints are periodically repeated and all directions are continuously connected.
2. Fundamentals of Discovery
Through computer simulation that can predict technological characteristics of triply periodic continuum without any complex experiments, accurately and rapidly analyzed the mechanical characteristics in accordance to various conditions.
Through shape design of various types of triply periodic continuum structures, conducted a study on method to control the hardness of material that is significantly differed along with the directions of the force. Through this, it is possible to design a metamaterial that applies solid force on certain directions and are very weak on the other direction.
* Hardness : Hard characteristics that does not change its shape or volume when a force from outside is applied to an object.
Conducted a study to come up with method of the propagation velocity of elastic wave where the size of internal object of triply periodic continuum’s internal object that is significantly changed according to the direction of the progress. Through this, it is possible to design metamaterial where the propagation velocity of the wave in certain direction is very fast and the propagation velocity of the other direction is very slow.
* Elastic wave : Wave that is being transmitted as the vibration type of wave. Including sound wave, surface wave, seismic wave and so on.
Mechanical change of hardness according to the materials that forms triply periodic continuum is predicted as well.
3. Research Achievement
Through this study, the ratio of hardness is more than 130, according to the direction that is applied and suggested metamaterial that is 10 times higher than the materials that exist in natural world. This type of characteristics can diffuse certain force to the other directions which can be utilized to overcome the immediate force.
Also when making internal object of suggested proposal into micro size, can change the velocity propaganda up to 200 times more. When using this type of characteristics, for certain direction it can pass the wave as if the material does not exist so this can be utilized in concealment devices which are not detected in sound detector.
Developing new mechanical characteristics of metamaterial through experiment takes a lot of time and high-efficient professionalism and technical skills and needs considerable time and cost so realistically there are considerable difficulty. Therefore there has to be efficient metamaterial design method to predict mechanical characteristics.