CAJ | 학술논문

利用实验方法研究含非线性边界的梁结构频响特征。实验对象由一根矩形截面的主梁和二片与之垂直的片梁构成－T 字型结构，通过在片梁两端垫放不同厚度的钢尺，使主梁的一端形成不同的几何非线性约束边界，片梁不同程度的预变形改变了主梁静平衡点的位置。实验结果发现，预变形和外激励幅值对系统的非线性频响特征影响显著，随着预变形和外激励幅值的变化，主梁的频响特征呈现出软特性、硬特性和线性特性之间复杂的演变过程。进一步的理论分析表明，预变形的存在使得系统的动力学控制方程同时含有平方和立方非线性，数值计算的结果与上述实验现象相吻合。实验研究和数值计算的结果，宏观上揭示了几何非线性约束边界中的预变形对梁结构频响特征的影响规律。
이용실험방법연구함비선성변계적량결구빈향특정。실험대상유일근구형절면적주량화이편여지수직적편량구성－T 자형결구，통과재편량량단점방불동후도적강척，사주량적일단형성불동적궤하비선성약속변계，편량불동정도적예변형개변료주량정평형점적위치。실험결과발현，예변형화외격려폭치대계통적비선성빈향특정영향현저，수착예변형화외격려폭치적변화，주량적빈향특정정현출연특성、경특성화선성특성지간복잡적연변과정。진일보적이론분석표명，예변형적존재사득계통적동역학공제방정동시함유평방화립방비선성，수치계산적결과여상술실험현상상문합。실험연구화수치계산적결과，굉관상게시료궤하비선성약속변계중적예변형대량결구빈향특정적영향규률。
Tests for frequency response features of a beam structure under nonliear boundaries were conducted here.The test rig consisted of a linear cantilever main beam with a rectangular cross-section and two thin identical sheet beams connected at the main beamˊs free end and being perpendicular to the main beam to form a T-type structure.The different nonlinear supports at the one end of the main beam were formed by inserting steel rulers with different thicknesses into the ends of the sheet beams.The different pre-deformation levels of the sheet beams change the main beam's equilibrium position.The test results showed that with the variation of pre-deformation and external excitation amplitude, the frequency response features of the main beam reveal a complex evolution process among soft characteristic,hard one and linear one.The further theoretical analysis showed that the pre-deformation makes the beam's dynamic governing equations contain square and cubic nonliear terms.The results of numerical simulation agreed well with those of tests, they demonstrated that the pre-defoemation and external excitation amplitude have a significant effect on the beam's frequency response features.