There are several applications, such as automotive, aeronautical, seismic protection, noise attenuation where energy dissipation devices, called dampers, are needed. For efficient and high performance operation these devices need to be designed such that they can respond quickly to disturbances that change rapidly and also range over a wide band of frequencies. This project derives its inspiration to design a new adaptive and lightweight damper from articular cartilage. Articular cartilage, the soft tissue at the ends of long bones, naturally provides efficient and sustained vibration attenuation across a broad range of frequencies. The state of the art design approaches are hampered by reliability, durability, and weight issues. This research will identify the main mechanisms that govern damping in cartilage, and then leverage those mechanisms to design engineered dampers. The results from this work will provide significant insights into natural mechanisms that exist in biological systems to provide dissipation at varying spatial and temporal scale. The work will also lead to synthetic materials with similar dissipative characteristics, and their application to create dampers. The results will be shared with the community, K-12, undergraduate and graduate students through interactive demonstrations.
Reliability and durability issues, cost, space and weight requirements prevent widespread use of existing broadband dampers. Conversely, articular cartilage, a thin, lightweight poroviscoelastic material, effectively dissipates energy over broadband dynamic loading experienced during daily life. This suggests that knowledge of the dissipative mechanisms in cartilage could be leveraged to design reliable, durable, thin and lightweight broadband dampers. Three different dissipative mechanisms play a role in porodynamics at different spatial and temporal scales: i) Flow-induced visco-inertial dissipation; ii) viscoelastic relaxation of porous matrix, and iii) microscopic squirt flow across micropores and openings. This research will first characterize how cartilage employs these three mechanisms to achieve efficient energy dissipation across wide frequency band (0.01to 1kHz). The mechanisms uncovered in cartilage will be used to design an adaptive and lightweight damper, which will then be built and tested. This new damper will address critical needs in structural and acoustic mechanics. If successful, this damper will replace the golden standard in the field by providing rate-independent damping across an unprecedented range of frequencies.
