薄壁结构在热声载荷下的疲劳寿命分析与试验验证

Fatigue life analysis and experimental verification of thin-walled structures under thermal-acoustic loads

数值研究了热声载荷作用下薄壁结构的动态响应,并开展了薄壁结构的热声激振试验,获取了薄壁结构的热模态频率与不同热声载荷下的动态响应结果。采用热声疲劳寿命预估模型,仿真分析了薄壁结构疲劳寿命随声压级和温度的变化规律。试验与仿真结果对比表明,试验与仿真的模态频率具有一致性,应变响应量级相同。屈曲系数由0增加到1.8,GH188金属薄壁结构疲劳寿命呈先降低后增大趋势。验证了热声试验方法的合理性与可靠性,以及薄壁结构热声响应仿真方法与模型的有效性。薄壁结构在屈曲前/后过程中表现出稳定-失稳-再稳定的过程。

Dynamic response of thin-walled structures under thermal-acoustic loads was investigated, andthermal-acoustic excitation test was carried out to obtain the thermal modal frequencies and dynamic re-sponses under different thermal-acoustic loads combinations. Further, fatigue life prediction model was ad-opted to analyze the relationship between fatigue life of thin-walled structures and different temperaturesand SPL. The comparison between test and simulation indicated that the thermal modal frequencies wereconsistent and the magnitude of strain responses kept same. The fatigue life of GH188 metallic thin-walledstructures exhibited to be first decreased and then increased when buckling coefficient increased from 0 to1.8, validating the rationality and reliability of thermal-acoustic test methods, as well as the effectiveness ofthermal-acoustic calculation method for thin-walled structures. On the other hand, from pre-buckling re-gion to post-buckling region, thin-walled structures exhibited the stable, instable and stable processes.