不同滞回模型下单自由度系统的位移和能量反应

为考察塑性耗能、阻尼耗能、延性以及刚度突变对于抗震和减振的意义,对冲击和简谐荷载作用下的不同滞回模型(理想弹塑性、双折线线性强化型、剪切滑移和非线性弹性模型)的单自由度(SDOF)系统振子进行了理论和数值的分析.通过研究得到了冲击荷载下,结构所能承受的荷载等于结构的最大静力承载力;并给出了结构的最大位移、振幅等计算式.在简谐荷载作用下,当荷载频率低于结构自振频率时,总体上振幅随后期刚度增大而减小;当荷载频率远大于结构自振频率时,结构的振幅几乎保持不变.结构的塑性耗能比阻尼耗能更有利于结构振动位移的控制,尤其在共振条件下更为显著.

Displacement and energy response of single degree freedom systems with different hysteretic models

The importance of ductility, abrupt change in stiffness and damping and the energy-dissipating capacity through plasticity in earthquake-resistance and vibration absorption were explored through analysis of single degree of freedom system (SDOF) with different hysteretic models under impact or harmonic loads. Study of ideal elasto-plastic model, bilinear hardening model, slip model and non-linear elastic model revealed that the maximum impact load is the static load the structure can endure during the maximum displacement. Under harmonic loads, when the load frequency is less than the basic frequency of the SDOF systems, the amplitude is reduced with the increase of the post-yield stiffness. While the frequency of loads greatly exceeded the frequency of the structures, the structure amplitude is almost independent of the post-yield stiffness. The energy dissipation capability of plasticity can reduce the structural displacement response more than damping, especially during resonance.