【摘要】 岩石、混凝土等非线性介观弹性固体材料显示出与经典的非线性声学不同的非经典非线性声学现象,比如滞后现象、离散记忆等。本文实验研究了超声波在岩石材料中产生的基波、二次、三次谐波随声源幅度的依赖关系,研究了岩石的超声衰减,与金属材料的进行了对比;并且将浸水后的混凝土与浸水前的混凝土的超声谐波特性进行了对比,对此实验现象作出了定性的解释。此研究有利于岩石等非线性介观弹性固体材料的无损检测的研究。更多还原

【Abstract】 Nonclassical nonlinear acoustic phenomena such as hysteresis and discrete memory are shown in rock and concrete and other mesoscopic elastic material,which are different from classical nonlinear acoustics.In this paper,the transmission of fundamental,second and third harmonics changing with the source amplitude was experimentally studied in rock.The ultrasonic attenuation was also studied and compared with that in metal.The harmonic properties in concrete were compared with those in concrete after immersion in water.Qualitative explanation was given for the experimental results.This study is helpful for the study of non-destruction elevation in mesoscopic elastic material such as rock.更多还原