Ratcheting behavior of articular cartilage under cyclic unconfined compression.
The ratcheting deformation of articular cartilage can produce due to the repeated accumulations of compressive strain in cartilage. The aim of this study was to investigate the ratcheting behavior of articular cartilage under cyclic compression. A series of uniaxial cyclic compression tests were conducted for online soaked and unsoaked cartilage samples and the effects of stress variation and stress rate on ratcheting behavior of cartilage were investigated. It is found that the ratcheting strains of online soaked and unsoaked cartilage samples increase rapidly at initial stage and then show the slower increase with cyclic compression going on. On the contrary, the ratcheting strain rate decreases quickly at first and then exhibits a relatively stable and small value. Both the ratcheting strain and ratcheting strain rate increase with stress variation increasing or with stress rate decreasing. Simultaneously, the optimized digital image correlation (DIC) technique was applied to study the ratcheting behavior and Young's modulus of different layers for cartilage under cyclic compression. It is found that the ratcheting behavior of cartilage is dependent on its depth. The ratcheting strain and its rate decrease through the depth of cartilage from surface to deep, whereas the Young's modulus increases.
Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, PR China. Electronic address: gaolilan780921@163.com.
Li-Lan
LL
Gao
Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, PR China.
Xiao-Yi
XY
Qin
Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, PR China. Electronic address: zhang_chunqiu@126.com.
Chun-Qiu
CQ
Zhang
School of Chemical Engineering and Technology, Tianjin University, Tianjin, PR China.
Hong
H
Gao
Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, PR China.
Hong-Yu
HY
Ge
Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, PR China.
Xi-Zheng
XZ
Zhang
D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology* / Q000502:physiology*; D019245:Compressive Strength / Q000502:physiology; D003198:Computer Simulation; D055119:Elastic Modulus / Q000502:physiology; D066298:In Vitro Techniques; D008954:Models, Biological; D010812:Physical Stimulation / Q000379:methods*; D013314:Stress, Mechanical; D013552:Swine; D013718:Tensile Strength / Q000502:physiology
Articular cartilage; Cyclic compression; Different layers; Optimized DIC technique; Ratcheting behavior