A multilayer cartilage scaffold with a gradient pore size and directional arrangement structure was constructed using 3D bio-printing and template-freezing orientation technology to achieve a high degree of mimicry of the natural cartilage structure.

The dynamic distribution of contact stress of friction lining in the process of deep coal mine friction transmission was investigated in this study. Rope tensions during lifting and lowering were obtained using Simulink simulation models first. Then, correlation model of contact stress of friction lining was established. Subsequently, effects of the friction coefficient, lifting load, terminal mass ratio, maximum speed, maximum acceleration and acceleration rate on the dynamic distribution of contact stress were explored. The results show that the wrap angle of the friction pulley is divided into three, i.e. static, mixed, and friction angles, respectively. Furthermore, the friction angle decreases with the increasing coefficient of friction, and the increases of the terminal mass ratio induce expanding trends of overall ranges of the friction angle, which could result in rope skid accidents and unpredictable failure of friction lining.

In this paper, based on the real-time in-situ observation, aims to explore the effect of viscoelastic properties on the actual contact and friction. The dynamic viscoelastic contact characteristics and microscopic friction wear mechanisms for three linings were compared. The results show that the actual contact area increases linearly with the loss factor and the stick-slip displacement increases with the loss modulus. The friction coefficient of the GM-3 lining stabilized after approximately 1000 seconds and entered the stable friction stage. The actual contact area and friction coefficient of the G30 and K25 linings slowly increased and remained in the running-in friction stage. The best viscoelastic lining is more suitable for severe working conditions. The obtained results play an important theoretical role in enriching the friction transmission mechanism of the flexible body and have an important reference value for flexible body friction transmissions such as large high-speed elevators and belt conveyors.

This paper aims to investigate the microscopic friction mechanism based on in situ microscopic observation in order to record the deformation and contact situation of friction lining during the frictional process. The results show that friction coefficient increased with the shear deformation and energy loss of the surfacee, respectively. Furthermore, the friction mechanism mainly included adhesive friction in the high-pressure and high-speed conditions, whereas hysteresis friction was in the low-pressure and low-speed conditions. The mixed-friction mechanism was in the period when the working conditions varied from high pressure and speed to low pressure and speed.