【作者】 张静；

【导师】 牛滨华；

【作者基本信息】 中国地质大学（北京） ， 地球探测与信息技术， 2006， 硕士

【摘要】 为了便于研究实际问题,通常将真实介质简单抽象成理想弹性介质,地震波在理想弹性介质中传播时,能量不会损失,振幅不存在衰减现象。实际的实验和地震勘探表明,地震波的能量在真实介质中会被消耗掉,其中的高频成分容易被吸收,振幅近似呈指数规律不断衰减。因此,真实介质并非理想弹性介质,在理论上更接近于弹性和黏滞性的结合体。黏弹性介质具有弹性和黏性。在物理学上,通常把介质的弹性和黏性抽象成弹簧和阻尼器,通过这两个理想力学模型不同方式的组合可表示成三种基本的黏弹性介质模型。通常用Kelvin固体模型和标准线性固体模型表示固体介质,Maxwell流体模型常被用来研究流体的性质。物质的不同本质上在于本构方程的表达式不同。本文将把这三种基本模型的本构方程,转化成与弹性介质本构方程相统一的数学表达形式,建立起弹性和黏弹性介质物性参数之间可以相互替换的对应关系,从而把黏弹性介质的求解问题转化成弹性介质的求解问题。频散和衰减是黏弹性介质中弹性波的两大主要特性,本文将先以Kelvin固体模型和Maxwell流体模型为例分析说明黏弹性介质中的频散现象,讨论弹性波的传播速度和振幅空间衰减系数随频率变化的规律。最后数值计算分析标准线性固体模型介质中弹性波振幅的衰减特征。更多还原

【Abstract】 Generally,actual medium can be abstract described for theoretical media which iseasily investigated simplify.Elastic seismic wave is not absorbed and weakened.Actual research and seismic exploration show that the high frequency of seismic waveis absorbed easily and amplitude attenuation is obviously deviated from theexponential character. So actual media is not theoretical elastic but elastic and viscous.The viscoelastic medium is elastic and viscous . In physics spring and dashpot areuaually defined representing elastic and viscous medium. Three kinds of basicviscoelastic models are composed of the two mixed mechanics models. Kelvin solidmodel and standard linear solid model are usurally reprented the character of the solidmedia. fluid character is discussed in Maxwell fluid model. The forms of constitutiverelation are different in natural .In this paper,three kinds of basic constitutiverelations are expressed the unified mathematics relations from which we can derivethe elastic-viscoelastic correnspondence principle. therefore the solution problems tothe viscoelastic are obtained by elastic methodsTwo of the most predominant characteristics of viscoelastic wave are dispersionand attenuation. In this paper. The first deal with viscoelastic frequency dispersion inKelvin solid model and Maxwell fluid model. The second discuss velocity andamplitude attenuation are changed with increasing frequency.Finally,the solutions forthe amplitude attenuation characteristics of elastic wave in viscoelastic media ofstandard linear solid model are computed and analyzed.更多还原