奥氏体钢四点弯曲疲劳行为的数值模拟与试验

发布时间：2019-07-08 11:13

【摘要】：采用有限元方法对奥氏体钢四点弯曲疲劳试验的加载过程进行了数值模拟,分析了疲劳试样的应力分布与疲劳寿命,确定了受力分布相对均匀的试样的合理尺寸范围,并对一种Cr-Mn奥氏体钢进行了四点弯曲疲劳试验研究,对比分析了有限元模拟与试验结果间的差别与原因。结果表明,试样尺寸不同,两加载辊之间的应力分布规律不同;当t/h(材料厚度/加载辊距)1.4时,最大应力出现在靠近加载辊的内侧,距加载辊0.4~0.5 mm;当t/h=1.2~1.4时,两加载辊之间的应力分布比较均匀,最大模拟应力与加载应力(理论值)的误差小于5%;当t/h1.2时,最大应力出现在两加载辊中间,其中t/h=0.7~0.8时,模拟值最大应力与加载应力比较接近,但应力分布均匀性较低;采用t/h≈1.3的试样进行疲劳试验研究,试验后的疲劳裂纹均产生在两加载辊中间,在加载辊外侧未发现疲劳裂纹,这与模拟结果相一致;模拟疲劳极限为498 MPa,循环4.0×10~6周次,试验测定疲劳极限为505MPa,循环3.6×106周次,模拟值略小于试验值,可见有限元方法可以较准确地预测材料的疲劳寿命。
[Abstract]:The loading process of the four-point bending fatigue test of the austenitic steel is simulated by the finite element method, the stress distribution and the fatigue life of the fatigue sample are analyzed, the reasonable size range of the sample with relatively uniform stress distribution is determined, In this paper, a four-point bending fatigue test of Cr-Mn austenitic steel is carried out, and the difference and reason between the finite element simulation and the test results are compared. The results show that the distribution of the stress between the two loading rolls is different when the size of the sample is different; when t/ h (the thickness of the material/ loading roller) is 1.4, the maximum stress occurs at the inner side of the loading roller and 0.4-0.5 mm from the loading roller; when t/ h = 1.2-1.4, the stress distribution between the two loading rollers is uniform. The error of the maximum simulated stress and the loading stress (theoretical value) is less than 5%; when t/ h1.2, the maximum stress occurs in the middle of the two loading rolls, where t/ h = 0.7-0.8, the maximum stress of the simulated value is close to the loading stress, but the stress distribution is less uniform; The fatigue test was carried out by the test of t/ h-1.3. The fatigue crack after the test was found in the middle of the two loading rolls, and no fatigue crack was found on the outside of the loading roll, which was consistent with the simulation results; the simulated fatigue limit was 498 MPa, the cycle was 4.0-6 weeks, and the fatigue limit of the test was 505 MPa. The simulation value is slightly less than the test value, and the fatigue life of the material can be predicted more accurately by the finite element method.
【作者单位】：燕山大学机械工程学院;
【基金】：河北省自然科学基金资助项目(钢铁联合基金E2016203163)
【分类号】：TG142.1

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