| 热声载荷下薄壁结构振动响应试验验证与疲劳分析 |
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| 引用本文： | 沙云东,王建,赵奉同,骆丽.热声载荷下薄壁结构振动响应试验验证与疲劳分析[J].航空动力学报,2017,32(11):2659-2671. |
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| 作者姓名： | 沙云东 王建 赵奉同 骆丽 |
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| 作者单位： | 沈阳航空航天大学 航空航天工程学部 辽宁省航空推进系统先进测试技术重点实验室，沈阳 110136 |
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| 基金项目： | 航空基础科学基金（20151554002） |
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| 摘 要： | 由于热声环境下金属薄壁结构表现出复杂的大挠度强非线性振动响应特性,影响结构的疲劳性能与寿命，结合有限元法与降阶模态法对四边固支高温合金矩形薄壁结构的热声响应进行计算。结果研究发现:屈曲后结构出现跳变运动且应力循环呈三角状分布,热声载荷的相对强弱决定了跳变形式。采用改进雨流计数法、Morrow平均应力模型、Miner线性损伤累积理论计算热声疲劳寿命,屈曲前到临界屈曲时应力循环损伤量级显著增大,由10-5增大到10-4,寿命随温度增加呈先减小后增加趋势。开展薄壁结构热声试验,并将仿真计算结果与试验结果进行对比,结果表明结构的模态频率偏差不超过1Hz,动态应变响应结果的量值相当,验证了薄壁结构热声响应计算方法与模型的有效性。
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| 关 键 词： | 热声载荷 非线性振动响应 疲劳寿命 屈曲 跳变 试验验证 |
| 收稿时间： | 2016/4/13 0:00:00 |
Vibration response experimental verification and fatigue analysis of thin walled structures to thermal acoustic loads |
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| Abstract: | Metallic thin walled structure under thermal acoustic environment shows complex nonlinear vibration response characteristics of large deflection, affecting fatigue performances and life of structure. Thermal acoustic responses of superalloy thin walled rectangular plates with four edges clamped were calculated by combining finite element method and reduced order modal method. Research showed that buckling structures could exhibit snap through motions which were decided by relative strength between thermal loads and acoustic loads, and stress cycle showed a triangular distribution. The Miner linear accumulative damage theory was employed in conjunction with improved rain flow counting method and Morrow mean stress model to calculate thermal acoustic fatigue life. From pre buckling to critical buckling, the damage level of stress cycle increased significantly from 10-5 to 10-4, and with the increase of temperature, the fatigue life showed a trend of decrease at first and then increase. The thermal acoustic experiment of thin walled structure was carried out to make a comparison between the results of simulation and experiment. Results showed that the deviation of structural modal frequencies was less than 1Hz, and strain responses of calculation and experiment results had a good alignment, validating the effectiveness of calculation method and model to thermal acoustic responses. |
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| Keywords: | thermal acoustic loads nonlinear vibration responses fatigue life buckling snap through experimental verification |
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