复合夹层梁瞬态响应的谱有限元法

采用谱有限元法进行复合夹层梁的瞬态响应分析．该方法基于复合夹层梁的六阶运动微分方程，以其波动解作为动力位移形函数，根据标准有限元策略来构建复合夹层梁的动刚度矩阵．在频域内，夹心粘弹性材料的频率相关性采用复模量模型来模拟，进而利用快速傅立叶变换技术(FFT)，得到时域内复合夹层梁的瞬态响应分析结果．最后以两端固支夹层梁为例，对其进行了矩形脉冲荷载下的动力响应分析，并与通用有限元程序NASTRAN的计算结果进行了对比，两者吻合良好．

TRANSIENT RESPONSE ANALYSIS OF SANDWICH BEAMS WITH SPECTRAL FINITE ELEMENT METHOD

The response of sandwich beams to transient excitations is studied using the spectral finite element method(SFEM). Based on the six-order motion equation of sandwich beams, SFEM is formulated by using the dynamic displacement shape function that is obtained from the exact wave solution. Following the procedure of conventional finite element method, the dynamic stiffness matrix of sandwich beams is formed. The complex modulus model that is convenient to integrate with SFEM in frequency domain is used to represent the frequency-dependent property of core viscoelastic materials. The response of sandwich beams in time domain is obtained using fast Fourier transform techniques. Two cases of core material property are considered, one is frequency-dependent store modulus and loss factor, the other is constant store modulus and loss factor. As an example, the dynamic response of clamped-clamped sandwich beams is analyzed using SFEM under rectangular impulse loadings. The results agree well with that obtained from NASTRAN.