A Structures Perspective on the Challenges Associated with Analyzing a Reusable Hypersonic Platform
A Structures Perspective on the Challenges Associated with Analyzing a Reusable Hypersonic Platform
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DOI：
10.2514/6.2013-1747
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发表时间：
2013-04
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影响因子：
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通讯作者：
S. Spottswood
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文献类型：
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作者：
S. Spottswood
AFRL正在研究结构规模模拟的方法，以解决在分析极端环境结构方面的不足，这些结构在历史上一直阻碍着航空界的发展。这些缺陷的根源是无法准确量化高速流动环境和车辆结构之间的相互作用，无论是建模还是实验。高超声速飞行器要求结构承受复杂的非比例载荷，导致与路径相关的响应和相互作用的失效模式，迫使分析师考虑弹道上的裕度，而不是假设的最坏情况点。具体地说，这些结构将经历高的瞬时表面温度和梯度，包括流动压缩/粘性耗散、边界层湍流引起的宽带压力波动、变形引起的压力以及长期暴露在这些环境中[1，2]。挑战包括：气动热环境和结构变形之间的耦合；高超声速流动固有的局部效应的考虑；大型模型的计算成本；材料退化和非线性；材料和结构特性的空间变化；载荷、材料特性和边界条件的不确定性。使这些挑战进一步复杂化的是，无法考虑相互作用的失效模式，如气声和机械振动引起的高周疲劳、热机械载荷引起的低周疲劳以及极端热环境导致的材料降解或氧化[3]。
The AFRL is researching methods for structural-scale simulation to address deficiencies in the analysis of extreme-environment structures that have historically stymied the aerospace community. The root of these deficiencies is the inability to accurately quantify the interactions between the high-speed flow environment and the vehicle structure both modeling and experimentation. Hypersonic vehicles require structures to withstand complex non-proportional loading leading to path-dependant responses with interacting failure modes forcing the analyst to consider margins over a trajectory instead of assumed worst-case points. Specifically, these structures will experience high transient surface temperatures and gradients from flow compression/viscous dissipation, broadband pressure fluctuations due to boundary layer turbulence, deformation induced pressures, and long-duration exposure to these environments [1,2]. Challenges include coupling between the aero-thermal environment and the structural deflections; consideration of local effects inherent in hypersonic flows; the computational cost of large models; material degradation and nonlinearity; spatial variation of material and structural properties; uncertainty in loads, material properties, and boundary conditions. Further compounding these challenges is the inability to account for interacting failure modes such as high-cycle fatigue due to aeroacoustic and mechanical vibrations, low-cycle fatigue due to thermal-mechanical loading, and material degradation or oxidation due to the extreme thermal environment [3].