| Beams with complex boundary conditions are the most common structures in the engineering field,such as aircraft wings and precision-machined tools.When such a structure vibrates,the boundary conditions often change with changes in temperature,clearance,contact deformation and other factors,and then affect the vibration characteristics of the structure.This is a process in which the system boundary and system motion are coupled.Since such structures contain non-linear boundaries,their vibration characteristics will become complicated.Therefore,it is of great significance to study the vibration characteristics of such complex boundary condition beams.The main research contents of this article are as follows:Firstly,according to the parameter relationship between temperature change,clearance and beam end displacement,the movement of boundary beams with gaps in temperature changing environment is divided into six categories: forced vibration of cantilever beams,shock vibration of beams with gaps at shaft ends,and shaft ends Non-linear vibration of contact deformation and friction cantilever beam,forced vibration of axially compressed cantilever beam with friction at the end,and forced vibration of fixed beam.The specific expressions of the relationship between the temperature change,the gap,and the end displacement of the beam when each type of situation occurs are given.Then based on the force at the beam end in each case,use Newton’s second law to establish a dynamic model of the beam in each case;analyze the effect of axial pressure on the natural frequency and natural mode of the system when the temperature changes;Scale method,incremental harmonic balance method,and numerical method are used to calculate the vibration response of the beam.The effects of parameters such as temperature variation,damping,friction coefficient,and amplitude of external excitation on the vibration response of the beam under different conditions are studied. |
PDF Full Text Request