通过对单自由度(SDOF)体系弹性和弹塑性地震能量反应的计算,提出了自抵耗能和自抵耗系数的概念,并计算了弹性SDOF体系在地震动作用下的地震总输入能、自抵耗能、地震输入能以及自抵耗系数与体系自振频率和阻尼比的关系。结果表明:当体系自振频率等于地震动卓越频率时,自抵耗系数最小,地震输入能最大,结构的自抵耗能力较弱,且阻尼比对地震输入能的幅值影响较大;当自振频率远离地震动卓越频率时,自抵耗系数增大,地震输入能减小,结构的自抵耗能力增强,且地震输入能受体系的自振频率影响较大,基本上不受阻尼比的影响。文中从能量的角度对汶川地震中的一些实际震害作了相关解释。
In this paper, based on the elastic and inelastic energy response analysis for SDOF system, the concepts for both self-dissipation energy and self-dissipation coefficient are proposed. Based on the elastic energy response analysis of an SDOF system subjected to the earthquake excitation, the relations among earthquake total input energy, self-dissipation energy, earthquake input energy, self-dissipation coefficient, natural frequency and damping ratio are calculated. The results indicate that when the natural frequency equals to or is close to earthquake dominant frequency, the self-dissipation coefficient is smaller, the earthquake input energy is larger, the capability of self-dissipation of the structure is weaker and the damping ratio has a bigger impact on the peak value of earthquake input energy. When the natural frequency is far away from the earthquake dominant frequency, the self-dissipation coefficient increases, the earthquake input energy decreases, the capability of self-dissipation becomes stronger, the natural frequency of the structure has a bigger impact on the earthquake input energy, and the damping ratio is unrelated with the earthquake input energy. Some seismic damage cases in Wenchuan earthquake are explained from the perspective of energy.