Microextrusion 3D bioprinting is a comparatively easy method to fabricate structures in tissue engineering. But high viscosity and wall shear stress in the tube and nozzle often lead to low cell survival rate of printed tissue. To reduce the viscosity and shear stress of materials in biological 3D printing, a multidimension microvibration assisted hydrogel 3D printing method was proposed. The compliant mechanism driven by piezoceramic was applied to 3D printing of hydrogels. The shear stress and viscosity of hydrogels could be effectively reduced by multidimension microvibration. Simulation analysis of the extrusion device was carried out to study the influence of vibration parameters on viscosity and shear stress, and optimized multidimension vibration forms and vibration parameters were selected for experiments. The experiment results show that multidimension microvibration can effectively reduce the viscosity of hydrogels and improve printing resolution and print speed.

Compliant mechanisms are widely used in cutting-edge scientific and technological fields such as precision engineering, micro-/nano-manipulation, or microelectronics. Hence, the demand for multi-degree-of-freedom compliant mechanisms has increased sharply. The structure of compliant mechanisms becomes increasingly complex with the increase of degrees of freedom. Here, a compliant mechanism with six degrees of freedom is proposed based on curved beams. The compliant mechanism has the advantages of simple structure and multi-degree-of-freedom. Using the isogeometric analysis method, a model of the mechanism is constructed. Static analysis show that six degrees of freedom can be generated. The prototype of the mechanism is developed by 3D printing. A loading test in six degrees of freedom is carried out. The output and input have high linear relations and the structure has low inter-directional coupling. We trust that this study provides a pioneering step towards the design of compliant mechanisms based on curved beam elements.

Aiming at the issue of the lack of the design theory for the three-dimensional elliptical vibration cutting device, a compliant mechanism with two rotations and one translation is synthesized based on the theory of freedom and constraint topologies. And a three-dimensional elliptical vibration cutting device is proposed on the basis of the compliant mechanism. The relationship between the critical speed and the length of the tool bar is analyzed. Simulation is conducted to analyze the influence of parameters on the output ellipse. Experiments are conducted to verify the validity of the elliptical vibration cutting device. The relationship between the roughness and the cutting speed is obtained. Experiments with different driving frequencies are conducted without the change of other parameters. Results show that the proposed compliant mechanism is feasible for the elliptical vibration cutting device. Compared with the common cutting, the new elliptical vibration cutting device has a better performance in the processing effect. This provides an important reference for design of the elliptical vibration cutting device.

Porous bone implants have been extensively studied, with gradient structures receiving increasing attention due to their superior compatibility with bone tissue. However, comparative studies between gradient and uniform structures remain relatively scarce. In this study, selective laser melting (SLM) technology was employed to fabricate a gradient composite Ti6Al4V humeral bone plate, utilizing rhombic dodecahedron and its derived structures as unit cells. By adjusting the porosity parameter range to 22.02–94.37% using the Ashby Gibson formula, the mechanical properties of the porous bone plate were analyzed by varying the porosity parameters and conducting compression tests. The experimental results show that after preparing and compressing the structure, the elastic modulus of the model is controlled between 0.09–5.43 GPa, and the maximum yield strength is 216.1 Mpa. The experimental results demonstrate that, under shear loading, the gradient structure generates stress from the center of mass, with the phenomenon becoming more pronounced as the number of struts aligned with the direction of the applied load increases. This results in the model exhibiting characteristics of good resilience on the outside and a certain degree of rigidity on the inside. Compared to non-gradient models, gradient structures are more effective in controlling the direction of force transmission. Moreover, the elastic modulus of the bone plate is closer to that of natural bone tissue. These findings provide valuable insights for further research into gradient structure models of other rod-shaped unit cells, highlighting the mechanical advantages of gradient structures over uniform ones.

A novel parallel compliant mechanism with one translation and two rotations is proposed. Its stiffness matrix and force/torque performance indices are derived. The influence of temperature on the output displacement of the compliant mechanism is deduced. Structure parameters of the compliant are optimized with the force and torque performance indices as objective and the equivalent nodal thermal load as constraint condition. The statics and dynamics experiments are conducted to verify the compliant mechanism rationality.

The tough space environment has a great influence on the reliability of the measurement results owing to the rapidly aging sensor. Also, the measurement uncertainty caused by the random factors seriously affects the accuracy of the sensor. Aiming at the multidimensional dynamic uncertainty problem of the six-axis force measurement, a six-axis force sensor for docking system is presented based on the piezoelectric force sensing element. The decoupling algorithm of the six-axis force sensor is proposed. Grey prediction model is employed to establish the dynamic uncertainty model in single channel. Residual test, correlation test and posterior error test are conducted to verify the reliability of the prediction model. The multidimensional dynamic uncertainty model of the six-axis force sensor is derived by combination of the decoupling algorithm and the dynamic uncertainty in single channel. The multidimensional dynamic uncertainty model of the six-axis force sensor can avoid the error signals for the force feedback control in the space environment, and the model can also be employed for the measurement of six-axis force in any other harsh conditions.