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热环境下功能梯度梁力学特性分析

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为探究轴向功能梯度梁在热环境下部分力学特性,利用 Gauss-Lobatoo 节点与 Chebyshev 多项式建立功能梯度梁的轴向变形场,通过Chebyshev谱方法和 Lagrange方程推导其轴向变形场在热环境下的离散控制方程,结合投影矩阵法对模型施加边界条件,并利用均匀 Timoshenko 材料的对比结果进行辅助验证,分析得到系统固有频率在不同温度场、材料梯度指数、固支条件的变化情况,同时研究了结构的热屈曲温度。结果表明:在相同条件下,系统的各阶固有频率随着温度的升高呈下降趋势,且一阶频率的减小幅度最大。四阶固有频率减小幅度最小;悬臂梁的固有频率变化趋势与材料软化趋势相同,且三阶频率减小幅度较一二阶频率更明显;通过调节材料梯度指数可以优化结构的各阶固有频率;随着材料梯度指数的增大,材料的热屈曲温度不断提高,但对于不同的功能梯度材料,表现出不同的热屈曲温度变化趋势。本文研究可为功能梯度材料的研究与工程应用提供支撑。
Mechanical Characteristics Analysis of Functional Graded Beams in Thermal Environment
In order to explore the partial mechanical properties of functionally graded beams under ther-mal conditions,the axial deformation field of functionally graded beams was established by using Gauss-Lobatoo node and Chebyshev polynomial.The discrete governing equation of the axial deformation field under thermal conditions was derived by Chebyshev spectrum method and Lagrange equation.By apply-ing boundary conditions to the model with projection matrix method and using the comparison results of uniform Timoshenko materials for auxiliary verification,the changes of the natural frequency of the sys-tem under different temperature fields,material gradient index and anchorage conditions were analyzed.At the same time,the thermal buckling temperature of the structure was studied.The results show that under the same conditions,the natural frequencies of each order of the system decrease with the increase of temperature,and the first-order frequency decreases the most.The fourth order natural frequency de-creases the least.The variation trend of natural frequency of cantilever beam is the same as that of mate-rial softening,and the decrease of the third-order frequency is more obvious than that of the first-order frequency.The natural frequencies of each order of the structure can be optimized by adjusting the mate-rial gradient index.With the increase of material gradient index,the thermal buckling temperature of the material increases continuously,but for different functionally graded materials,the thermal buckling temperature changes show different trends.This study can provide support for the research and engi-neering application of functionally graded materials.

dynamic characteristicsmodel dispersionfunctionally gradient materialsthermal en-vironmentfinite element method

徐华栋、沈俊、李锋、孙云厚、梅勇、赵雨、黄李杰

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中国人民解放军军事科学院 国防工程研究院,北京 100850

动力学特性 模型离散 功能梯度材料 热环境 有限元

2024

动力学与控制学报
中国力学学会 湖南大学

动力学与控制学报

CSTPCD
影响因子:0.446
ISSN:1672-6553
年,卷(期):2024.22(9)