材料期刊网

双剪切试样是设计用于研究镍基单晶超合金的蠕变问题.本文研究该试样详细的蠕变应力和应变分布以及边界条件的影响.计算结果表明,利用ABAQUS中的RIGID SURFACE作为边界的初步分析是保守的,因为它只能保证在10%蠕变应变内的精确性.利用更真实的边界条件(ABAQUS中的CONTACT PAIR),能给出更均匀和更高应变时的精确性.建立了材料蠕变性能参数(Norton律)和双剪切试样宏观响应的关系,使得能够利用双剪切试样试验来确定材料蠕变性能参数,并已给出了相应的公式.本文利用镍基单晶超合金的试验数据对镍基单晶超合金双剪切试样进行分析,并与试验结果进行对比,结果相当一致.

The double shear specimen was designed for the study of the creep behavior of nickel-base single crystal superalloys at high temperature. The creep stress and strain distributions and the influence of boundary conditions for the specimen are studied in the present paper. The results show that a preliminary analysis, by using the finite element code ABAQUS and RIGID SURFACE as a boundary condition for loading is conservative because a homogeneous state of shear stress is maintained only up to shear strains of the order of 10 0%0. Using a more realistic boundary condition for loading (ABAQUS-option: CONTACT PAIR), the homogeneous state of shear stress in the double shear specimen is maintained throughout creep up to much higher shear strains than that of the originally estimated.A macrorelationship has been built between the material creep properties (Norton law) and the macrobehavior of the double shear behavior, so that the material creep properties can be derived from the creep experiments of double shear specimens, and corresponding equations have been presented. Therefore, the further work on crystallographic anisotropic finite element creep stress analysis of our double shear creep specimen will be based on the more realistic loading condition which is represented by the ABAQUS-option CONTACT PAIR. A good agreement has been obtained between the creep behavior of the double shear damage specimen of the experiment and finite element analysis on nickel-base single crystal superalloys.