【摘要】 利用一维波动方程对理想自由桩在桩顶受冲击力作用的动态过程进行数学仿真,用有限元法程序计算出桩顶处不考虑传感器的速度响应理论时程曲线,并由LTI系统卷积积分及傅立叶变换得出冲击力和速度响应的频域表示;根据LTI系统理论对考虑传感器特性的动态过程进行分析,得出速度响应的频域表示;将典型的传感器频率特性与不考虑传感器的理想自由桩的速度响应在频域进行数字合成,经傅立叶逆变换还原成含有传感器特性的速度响应时程曲线;调节冲击力脉宽,计算与同一传感器特性对应的速度响应,得出冲击力与传感器对速度响应的联合影响规律并举出实例进行验证;最后,提出一种新的变换域抑制法,使速度响应中的传感器特性影响有可能通过计算机程序来抑制。更多还原

【Abstract】 The dynamic procedure of an ideal free pile with a shock force impacting at its top is mathematically simulated by means of one-dimensional wave equation. The theoretic time history of velocity response without considering transducer at the top of pile is calculated with FEM program. The frequency-domain descriptions of the shock force and the velocity response are given out through convolution integral and Fourier transform of LTI system. According to the LTI system theory,an analysis is made on the dynamic procedure with considering transducer behavior and the frequency-domain description of velocity response is obtained. The digital frequency-domain combination of a typical transducer behavior with the velocity response of ideal free pile without considering transducer is turned back into a time history of velocity response,so that the transducer behavior can be considered through Fourier back transform. Calibrating shock duration and calculating the velocity responses from a certain transducer,the law of combination influence of shock force with transducer on the velocity response is developed and validated with examples. A new type of transform-domain suppressing method is put forward at last,so that the influence of transducer behavior within velocity response can be suppressed by means of a computation program possibly.更多还原