CAJ | 학술논문

使用谱有限元分析了自由阻尼梁中扩散波类型及其损耗因子，通过对其特征波形的分析探讨了各个频率下每种波的激励条件，然后使用有限元对自由阻尼长梁做谐响应分析得到各个单元的应变能，根据应变能法计算得到该长梁分别在垂直和水平激励下的结构损耗因子，对结构损耗因子同激励起的波类型之间的关系进行了讨论，最后分析了边界反射对结构损耗因子的影响。研究表明：垂直激励主要激励起最高阶弯曲波或者某些低阶纵波，水平激励主要激励起最高阶纵波；边界反射对结构损耗因子的影响随着梁长增大以及激励点远离边界而变小；不同边界条件的结构损耗因子一般情况下比较接近，但在一些频率点处会存在一定的差异；自由阻尼梁的结构损耗因子主要由激励所能激励起的波类型所决定，在一定程度上受到边界反射影响。
사용보유한원분석료자유조니량중확산파류형급기손모인자，통과대기특정파형적분석탐토료각개빈솔하매충파적격려조건，연후사용유한원대자유조니장량주해향응분석득도각개단원적응변능，근거응변능법계산득도해장량분별재수직화수평격려하적결구손모인자，대결구손모인자동격려기적파류형지간적관계진행료토론，최후분석료변계반사대결구손모인자적영향。연구표명：수직격려주요격려기최고계만곡파혹자모사저계종파，수평격려주요격려기최고계종파；변계반사대결구손모인자적영향수착량장증대이급격려점원리변계이변소；불동변계조건적결구손모인자일반정황하비교접근，단재일사빈솔점처회존재일정적차이；자유조니량적결구손모인자주요유격려소능격려기적파류형소결정，재일정정도상수도변계반사영향。
The spectral finite element method was used to analyze propagating wave types and their damping loss factor (DLF)in a beam with a non-constrained damping layer (NCDL).Every wave type's exciting condition was studied by analyzing characteristic wave shapes.The finite element method was used to compute the strain energy for every element of a long beam with a NCDL,the DLF was computed with the strain energy method and the relationship between structure DLF and load types was studied.In the end,the boundary reflected waves' effect on the DLF was studied.The study showed that the vertical excitation mainly excites the highest order bending wave or some lower order longitudinal waves whereas the longitudinal excitation mainly excites the highest order longitudinal wave;when the beam becomes longer and the distance between the exciting point and the boundary becomes farther,the effect of boundary reflection on the structural DLF becomes smaller;the DLFs under different boundary conditions are always the same except at some special frequencies;the structural DLF of a beam with a NCDL is decided mainly by the wave types and it is influenced a little by boundary reflection.