摘要
结构动力稳定性研究是工程力学领域的热门课题,其基本理论和分析方法尚不完善。因此,改进现有的动力稳定性分析方法——动态特征值法,提出基于Ansys平台的非线性动力稳定性分析方法。以一简谐载荷作用下的箱型截面长柱为研究对象,研究激励频率、动载荷幅值、阻尼比及初始弯曲对动态特征值的影响。研究表明,激励频率增大或动载荷幅值增大都会引起动态特征值的最大值增大、最小值减小,即越不利于结构的动力稳定;结构阻尼比增大,则引起动态特征值的最大值减小、最小值增大,即动态特征值变化更平稳,较高的阻尼有利于结构的动力稳定;柱初始弯曲增大,动态特征值的最小值略有增大,在一定范围内初始弯曲对动力稳定性的影响不一定是不利的。
Dynamic stability of a structure is a hot subject in the fields of engineering mechanics, and its basic theory and analytical method need to be further improved. The improved method to the current dynamic eigenvalue method for dynamic stability analysis by considering nonlinearity based on Ansys platform is proposed. A long column with box section under harmonic loads is taken as the research objective. Dynamic eigenvalues related with the load frequency, load amplitude, damping ratio and initial bending are studied. Results show that, the increasing of load frequency or dynamic load amplitude will lead to the increase of maximum dynamic eigenvalue and decrease of minimum dynamic eigenvalue, which is not beneficial to dynamic stability of a structure. The increasing of structural damping ratio will lead to the decrease of maximum dynamic eigenvalue and increase of minimum dynamic eigenvalue, and make the dynamic eigenvalue more stable. Therefore, the high damping is beneficial to dynamic stability of a structure. The increasing of initial bending will lead to slight increase of minimum dynamic eigenvalue. The effect of initial bending on the dynamic stability is unnecessarily negative with in a certain range.
出处
《机械强度》
CAS
CSCD
北大核心
2013年第2期142-147,共6页
Journal of Mechanical Strength
