The Configuration Library Of Plane Curved Beam With Desired Natural Frequency

Compliant mechanism is widely used in the frontier fields of precision engineering,bionic machinery,biomedical and aerospace because of its simple structure,free from friction and wear,easy energy storage and transformation,shock resistance and adapting to harsh environment.New application fields put forward higher requirements for the dynamic performance of compliant mechanism.Designers hope to design compliant mechanism with desired natural frequency.In this paper,a planar curved beam configuration library with desired natural frequencies is constructed based on IGA,which provides planar curved beams with desired degrees of freedom and performance for designers.In the design process of compliant mechanism,both degrees of freedom and natural frequencies are taken into account to improve the design level of compliant mechanism.In order to optimize the natural frequencies of curved beam elements,based on IGA and the principle of minimum potential energy,the dynamic analysis of general plane curved beam elements is completed.The expressions of stiffness matrix and mass matrix of curved beam elements with control points as parameters are derived,and the mapping relationship between control points and natural frequencies of curved beam elements is deduced.According to the fact that the mass of the curved beam element is small relative to that of the working platform of the compliant mechanism and can be neglected,the curved beam model is simplified.According to the mapping relationship between the control points of curved beams and their natural frequencies,combined with the determination method of degree of freedom,taking the degree of freedom as the constraint condition and the intermediate control points of curved beams as variables,and aiming at the desired natural frequencies,the natural frequencies of curved beams are optimized by the sweep optimization method and the particle swarm optimization algorithm respectively.The curved beam elements are classified according to degrees of freedom,and the planar curved beam configuration library with desired natural frequencies is established.The influence of relative position of curved beams on the natural frequencies of the compliant mechanism of parallel curved beams is studied through modal analysis of the compliant mechanism of parallel curved beams.Combining with the method of DOF determination,a planar curved beam compliant mechanism with desired DOF and natural frequency is designed by using the curved beam element in the configuration library,and the correctness of the theory and the feasibility of the design are verified by simulation.Combining with the theory of degree-of-freedom constraint topology,the curved beam elements with specific performance indexes are selected from the configuration library to design the Spatial Compliant mechanism.The correctness and feasibility of the theory are verified by simulation and experiment,which can provide a reference for the design,analysis and optimization of curved beam compliant mechanism.