Development of a New Material That Becomes Stronger the More It Is Used Like Bone

Joint Research by KAIST, Johns Hopkins University, and Georgia Institute of Technology
Expected Applications in Artificial Bones, Implants, Aircraft, Ships, Automobiles, and Structures

A joint research team from Korea and the United States has succeeded in developing a new material that becomes harder the more it is used by utilizing human biomimicry technology.

Materials used in apartment buildings, vehicles, and other structures degrade in performance over time when subjected to repeated loads, leading to failure and breakage. However, this new material is based on the principle of human bones, which increase bone density by synthesizing minerals from the blood when load is applied to the bone.

Research schematic. Provided by Professor Kang Sung-hoon’s research team

The research team led by Professor Kang Seong-hoon of the Department of Materials Science and Engineering at the Korea Advanced Institute of Science and Technology (KAIST) announced on the 20th that they developed a new material that becomes stronger the more it is repeatedly used through joint research with Johns Hopkins University and Georgia Institute of Technology in the United States.

Professor Kang’s team synthesized a composite material by creating a porous piezoelectric (converting mechanical force into electricity) substrate that generates more charge as more force is applied to replace cellular functions, and embedding an electrolyte with mineral components similar to blood inside it.

When periodic forces were applied to this material and changes in its physical properties were measured, the results showed that the material’s stiffness and energy dissipation capacity improved proportionally to the frequency and magnitude of the stress.

Comparison of property changes between the newly developed material and other materials. Provided by Professor Kang Seonghun's research team.

Using micro-CT imaging to observe the internal structure, it was revealed that minerals form inside the porous material due to repeated stress, dissipate energy by breaking when large forces are applied, and then re-form when repeated stress is applied again.

Unlike conventional materials whose stiffness and shock absorption capabilities decrease with repeated use, this new material exhibited characteristics where both stiffness and shock absorption improve simultaneously with use. Additionally, its properties improve proportionally to the magnitude and frequency of the applied stress, allowing self-adjustment to have mechanical property distributions suitable for the intended use of structures, and it also possesses self-healing capabilities.

Professor Kang said, "This new material has characteristics of improved stiffness and shock absorption with repeated use compared to existing materials, and its principles are expected to be applied in various fields such as artificial joints, aircraft, ships, automobiles, and structures."

The research, with Professor Kang as the corresponding author, was published in the international journal Science Advances, Volume 11, Issue 6, in February.

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