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针对均匀升温热环境下夹芯梁的声振特性进行了研究。建立了考虑热应力、横向剪切效应、转动惯量影响的夹芯梁振动方程,获得了简支夹芯梁在热环境下振动响应的理论解;通过瑞利积分得到远场声压。结果表明,夹芯梁内存在热应力时,各阶固有频率均下降,速度、辐射声压级、声功率响应曲线均向低频方向漂移,声辐射效率变化不明显。通过与数值仿真结果对比,验证了本文的热预应力夹芯梁声振耦合响应理论分析方法的可行性。此外,本文还分析了不同芯材厚度和弹性模量对夹芯梁声振特性的影响。研究发现,芯层增厚或者软化均会降低整个结构的刚度。
The vocal-vibration characteristics of sandwich beam under uniform temperature rise were studied. The vibration equation of sandwich beam considering thermal stress, transverse shear effect and moment of inertia is established. The theoretical solution of vibration response of simply supported sandwich beam under thermal environment is obtained. The far-field sound pressure is obtained by Rayleigh integral. The results show that when the thermal stress exists in the sandwich beam, the natural frequency of each step decreases, and the response curves of velocity, radiation sound pressure level and acoustic power all drift to the low frequency, and the sound radiation efficiency does not change obviously. Through the comparison with the numerical simulation results, the feasibility of the theoretical analysis method of acoustic-mechanical coupling response of the thermal prestressed sandwich beam is verified. In addition, this paper also analyzes the different core material thickness and elastic modulus of the sandwich beam vibration characteristics. It has been found that thickening or softening of the core reduces the stiffness of the entire structure.