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为了解释试验结果,并把缩比模型试件的性能与发射前加载状态下的壳体性能相对照,进行了综合分析工作。建立了全尺寸壳体和缩比试件的有限元模型,用确认的轴对称模型作壳体分析。除一些三维有限元模型用于研究三维效应对试件性能的重要影响外,大多数情况下用广义平面应力有限元模型作试件模型。由于所用的试件层数多且结构复杂,因此把整个试件厚度离散化的网格元素限制到每层一个。螺旋梯层区域观察到的层裂用无摩擦的滑板模拟。预计的应力和位移值与壳体及试件试验数据相比较的结果说明,使用有限元模型是合理的。根据对试验结果和有限元预计值的观察,提出了试件和壳体的断裂准则,并通过预计值和试验结果的比较得到确认。最后,又用这一标准预计首批飞行的两个壳体在发射前加载下的性能。
In order to explain the test results and compare the performance of the shrinkage model specimen with that of the shell before loading, a comprehensive analysis was carried out. The finite element model of full-scale shell and shrinkage test specimen is established, and the shell model is analyzed with the confirmed axisymmetric model. Except for some three-dimensional finite element models, which are used to study the important effect of three-dimensional effects on the properties of the specimens, the generalized plane stress finite element model is used as the specimen model in most cases. Due to the large number of layers and complex structures used, the mesh elements that discretize the entire specimen thickness are limited to one per layer. The observed splits in the helical step region are simulated with a frictionless skateboard. The results of the predicted stress and displacement values compared with the shell and specimen test data indicate that it is reasonable to use a finite element model. According to the test results and the predicted value of the finite element, the fracture criterion of the specimen and the shell is proposed and confirmed by the comparison between the predicted value and the test result. Finally, this standard is used again to predict the performance of the first two shells flying prior to launch.