Development of Multiaxial Creep Testing Machine Using Cruciform Specimen.
Development of Multiaxial Creep Testing Machine Using Cruciform Specimen.
复制标题
十字形试样多轴蠕变试验机的研制。
DOI：
10.2472/jsms.45.559
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
T. Tsurui
中科院分区：
文献类型：
--
作者：
S. Mukai;T. Takada;M. Sakane;M. Ohnami;T. Tsurui
本文介绍了十字形试件在0≤λ≤1的大范围双轴应力条件下的多轴蠕变试验机的研制，以及923K下的多轴蠕变破裂试验，其中λ为最小主应力与最大主应力之比。研制的试验机承载能力为98KN，最高温度为923K。通过三维有限元蠕变分析，确定了应力沿规长均匀分布的十字形试样的形状和尺寸。通过有限元分析确定的试样形状为32mm×32mm平行部分，厚度为5mm。在304型不锈钢十字形试件的双轴Mises应力恒蠕变试验中，蠕变破裂时间随λ的增大而增大，说明双轴应力对破裂时间有影响。当与基于裂纹张开位移的等效应力相关时，破裂数据不依赖于λ，而与Huddleston应力相关时则依赖于λ。Huddleston应力比Mises应力给出了更保守的等双轴拉伸蠕变破裂时间。在多轴蠕变试验中，Mises等效应变率随λ的增大而减小。
This paper describes the development of multiaxial creep testing machine using cruciform specimens in a wide range of biaxial stress conditions of 0≤λ≤1 and the multiaxial creep rupture tests at 923K, where λ denotes the ratio of the minimum principal stress to the maximum principal stress. The developed test machine has a loading capacity of 98KN and the maximum temperature is 923K. Three dimensional finite element (FE) creep analyses were made to determine the shape and dimensions of the cruciform specimen having uniform stress distribution along the gage length. The specimen shape determined by the FE analyses has a 32mm×32mm parallel part with 5mm thickness. In the biaxial Mises' stress constant creep tests using type 304 stainless steel cruciform specimens, creep rupture time increased with increasing λ, so that the biaxial stress has an effect on rupture time. The rupture data did not depend on λ when correlated with the equivalent stress based on crack opening displacement, but they depended on λ with Huddleston's stress. Huddleston's stress gave more conservative equi-biaxial tension creep rupture time than the Mises' stress. The Mises' equivalent strain rate decreased with increasing λ in multiaxial creep tests.