大结构模型中多裂纹种类并行疲劳试验方法研究

A study on parallel fatigue testing of multi cracks in a large structural model

大结构模型低周疲劳试验周期较长,成本高,一般情况只能通过一只或少量的模型研究裂纹的形成机理和扩展规律,确定裂纹的形成寿命和扩展寿命。文章通过开展裂纹尖端的应力场研究,提出了一种在大结构模型中预制多种裂纹类型同时进行低周疲劳试验的并行疲劳试验方法。利用该方法开展了锥柱结合壳结构模型疲劳试验,得到了该模型的多种裂纹类型的裂纹形成寿命和裂纹扩展寿命试验结果,验证了并行疲劳试验方法的可行性和可信性。

Because the periods of the low cycles fatigue test is very longer and the cost is very expensive for a large structural model, only one model or few models can be afforded to measure the crack initiation life and crack propagation life. Based on the study of the stress field at the crack tips, a parallel fatigue testing method is proposed in which several cracks can be pre-manufactured in the large structural model and their ignition life and propagation life can be measured in the same test. The test method is used to test a large structural model of the connection joint between cone and cylinder structure and the results are presented. From these measurements, the feasibility or creditability of the parallel fatigue test method is validated.