几何非线性假设下温度大范围变化瞬态热力耦合问题研究
发布时间：2019-01-04 13:11
【摘要】：传统的基于几何非线性假设的瞬态热力耦合计算方法由于忽略了几何非线性对耦合项的影响,在温度随时间剧烈变化的情况下结构传热与变形之间存在的耦合关系不能被真实的反映。针对上述问题,采用Galerkin和Newmark算法建立了一种能够在几何非线性假设下精确反映温度剧烈变化情况下结构传热与变形间耦合效应的瞬态热力耦合有限元方法。通过对各向正交异性材料薄板在热环境下的动力学问题的求解验证了该方法的准确性,并基于该方法对某型高超声速飞行器热防护系统的蜂窝结构进行了瞬态热力耦合计算。结果表明:热力耦合项使温度变化产生很小的波动,导致温度变化率发生震荡,其振动幅值与耦合项相关;热力耦合项对结构振动起到衰减作用,使结构形变速度趋于衰减,其衰减程度与结构温度成正比;几何非线性假设对增大结构温度变化率振幅作用显著,并且能够增大结构振动速度,影响热结构变形大小。
[Abstract]:Because the influence of geometric nonlinearity on the coupling term is neglected in the traditional calculation method of transient thermodynamic coupling based on geometric nonlinearity assumption, The coupling relationship between heat transfer and deformation of the structure can not be truly reflected when the temperature varies dramatically with time. In order to solve the above problems, a transient thermal-mechanical coupled finite element method is developed by using Galerkin and Newmark algorithms, which can accurately reflect the coupling effect between heat transfer and deformation of structure under the assumption of geometric nonlinearity. The accuracy of this method is verified by solving the dynamic problems of orthotropic thin plates in different directions in thermal environment. Based on this method, the transient thermodynamic coupling calculation of honeycomb structure of a hypersonic vehicle thermal protection system is carried out. The results show that the thermo-mechanical coupling term causes the temperature change to fluctuate very little, resulting in the oscillation of temperature change rate, and the amplitude of vibration is related to the coupling term. The thermal coupling term attenuates the vibration of the structure, which makes the velocity of deformation tend to attenuate, and the attenuation degree is proportional to the temperature of the structure. The geometric nonlinearity hypothesis plays a significant role in increasing the amplitude of the temperature change rate of the structure, and can increase the vibration velocity of the structure and influence the deformation of the thermal structure.
【作者单位】： 西北工业大学航天飞行动力学技术重点实验室;
【分类号】：O343.6
，
本文编号：2400335
[Abstract]:Because the influence of geometric nonlinearity on the coupling term is neglected in the traditional calculation method of transient thermodynamic coupling based on geometric nonlinearity assumption, The coupling relationship between heat transfer and deformation of the structure can not be truly reflected when the temperature varies dramatically with time. In order to solve the above problems, a transient thermal-mechanical coupled finite element method is developed by using Galerkin and Newmark algorithms, which can accurately reflect the coupling effect between heat transfer and deformation of structure under the assumption of geometric nonlinearity. The accuracy of this method is verified by solving the dynamic problems of orthotropic thin plates in different directions in thermal environment. Based on this method, the transient thermodynamic coupling calculation of honeycomb structure of a hypersonic vehicle thermal protection system is carried out. The results show that the thermo-mechanical coupling term causes the temperature change to fluctuate very little, resulting in the oscillation of temperature change rate, and the amplitude of vibration is related to the coupling term. The thermal coupling term attenuates the vibration of the structure, which makes the velocity of deformation tend to attenuate, and the attenuation degree is proportional to the temperature of the structure. The geometric nonlinearity hypothesis plays a significant role in increasing the amplitude of the temperature change rate of the structure, and can increase the vibration velocity of the structure and influence the deformation of the thermal structure.
【作者单位】： 西北工业大学航天飞行动力学技术重点实验室;
【分类号】：O343.6
，
本文编号：2400335
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