Bioinspired dampers: Meniscus-inspired energy dissipation components

Nature provides examples of functionally graded porous structures that absorb energy effectively, such as the knee meniscus. The meniscus features a three-layered structure with varying porosity from the outer to inner layers. The tissue's porous spaces are fluid-saturated, facilitating energy dissipation and damping. Inspired by this architecture, two 3-layered porous geometries were designed, which consisted of thin outer layers and a thicker inner layer with higher porosity and permeability. They were created using image analysis (IA), computational fluid dynamics (CFD) simulations, and pore space segmentation (PSS). The PSS geometry shows a reduced peak pore diameter ( 88 μ m vs 111 μ m ) and an increased density of lower throat lengths but a slightly larger throat radius compared to the CFD geometry. These differences significantly impact permeability, with PSS samples showing a peak of 1522 D versus 151 D in CFD samples. Energy dissipation capabilities were evaluated through cyclic compression experiments at varying rates and with different fluid viscosities. The dissipation energy density of the CFD geometry ( 1.8 kPa ) was 2.5 times higher than that of the PSS geometry ( 0.7 kPa ). Scanning Electron Microscopy (SEM) compression tests revealed deformation patterns, including crease formation, bulging, and permanent deformation. • Mimicking biological gradation improves energy dissipation and damping in synthetic materials. • We developed 3-layered porous designs with thinner outer layers and a thicker inner layer. • Image analysis, CFD simulations, and PSS revealed significant design differences. • PSS design had smaller peak pore diameters and higher permeability than the CFD design. • CFD design outperformed in energy dissipation tests, especially at higher compression rates.