某燃气涡轮工作叶片裂纹分析

为阐明测试单元环境下加速任务试车(AMT)过程中叶片早期起裂的物理原因,对裂纹叶片断口进行了检查和分析,并采用LPTi's XactLIFETM系统对叶片进行了深入的分析.结果表明:叶片叶型发生了过量的蠕变损伤,此过量的蠕变损伤导致了叶片的过量延伸以及叶型特别是在尾缘区域的转扭,此行为可能造成AMT疲劳循环条件下缘板以下的叶片伸根部位疲劳裂纹的形核与生长.因此,过量的蠕变被认为是整个裂纹形核过程的主要驱动力.

Crack analysis of the first stage blade on a gas turbine

To clarify the physical cause of premature blade cracking during the accelerated mission test(AMT) in a test cell environment,initial fracture graphic investigation and analysis of the cracked blades was carried out and an in-depth analysis of the blade was undertaken using ansis system XactLIFE^TM of Life Prediction Technologies inc(LPTi's XactLIFE^TMM) system.Results show that the blades have suffered excessive airfoil creep damage,leading to excessive blade lengthening and airfoil untwisting particularly in the trailing edge region.It's believed that this uneven rubbing action might have contributed to the fatigue crack nucleation and growth process just below the platform in the shank region of the blade under AMT fatigue cycling conditions.Excessive creep deformation is therefore believed to be the significant contributor to the overall crack nucleation process.