The hybrid CMC and superalloy bolted joints have exhibited great potential to be used as thermostructural components of reusable space transportation systems, given the respective strengths of these two materials. In the high temperature excursion of the hybrid joints with the aircrafts and space vehicles, the substantial difference in thermal expansion coefficients of CMC and superalloy materials will induce complex superposition of initial assembly stress, thermal stress, and tensile stress around fastening area, which might lead to unknown failure behavior of joint structure. To address this concern, a finite element model embedded with progressive damage analysis was established to simulate the thermostructural behavior and high-temperature tensile performance of single-lap, single-bolt C/SiC composite and superalloy joint, by using the ABAQUS software. It was found that the initial stiffness of the CMC/superalloy hybrid bolted joints decreases with the rise of applied temperature under all bolt-hole clearance levels. However, the load-bearing capacity varies significantly with the initial clearance level and exposed temperature for the studied joint. The thermal expansion mismatch generated between the CMC and superalloy materials led to significant changes in the assembly preload and bolt-hole clearance as the high-temperature load is applied to the joint. The evolution in the thermostructural behavior upon temperature was then correlated with the variations in stiffness and failure load of the joints. The provided new findings are valuable for structural design and practical application of the hybrid CMC/superalloy bolted joints at high temperatures in next-generation aircrafts.

中文翻译：

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基于渐进式损伤分析的混合CMC与超合金螺栓连接的热失配效应及高温拉伸性能模拟

考虑到这两种材料各自的优势，混合CMC和超合金螺栓连接接头具有巨大的潜力，可用作可重复使用的空间运输系统的热结构部件。在飞机和航天器混合接头的高温偏移中，CMC和超合金材料的热膨胀系数的显着差异将导致初始装配应力，热应力和紧固区域周围的拉应力的复杂叠加，这可能导致未知的关节结构破坏行为。为了解决这一问题，建立了带有渐进式损伤分析的有限元模型，以模拟单搭接，单螺栓C / SiC复合材料和高温合金接头的热结构行为和高温拉伸性能，通过使用ABAQUS软件。结果发现，在所有螺栓孔间隙水平下，CMC /高温合金混合螺栓连接的初始刚度均随施加温度的升高而降低。但是，对于所研究的接头，承重能力随初始间隙水平和暴露温度而显着变化。CMC和超合金材料之间产生的热膨胀失配会导致组件预紧力和螺栓孔间隙发生明显变化，因为高温载荷会施加到接头上。然后，热结构行为随温度的变化与接头的刚度和破坏载荷的变化相关。