The International Thermonuclear Experimental Reactor (ITER) Toroidal Field (TF) coil case is made of austenitic stainless steel and is designed to operate at 4K. It is subject to fatigue due to pulsed loading cycles of a variety of magnitudes, along with less frequent TF charging loads, and periodic cool down cycles. Fatigue life estimation of such multiple lading becmes a critical issue in the TF structural design. The TF case stresses are computed in a large scale global model of the magnet system. Stress magnitudes vary in time and location around the case. ITER design critieria requires that a ful da/dN integral be carried out for a full simulation of all the charging and plasma shots. Paris Law integration and Miners's rule approaches are discussed in a companion paper by JUn Feng in this Conference. The Paris Law simulation is integrated into an ANSYS post process procedure that allows consideration of the spatial distribution of fatigue effects around the TF case. Peak stress, R values, life, and the factor of safety based on life (life divided by the required 100, 000 cycles) are output in a form that can be read back ANSYS and then contoured. Crack shape parameters, and crack position in the through thickness direction of the case wall may be considered. Results from the 1995-1996 evolution of the design show life estimates for the TF case side wall are near those set as a requirement for centered embedded cracks. Initial analyses of the present design (BDPA97) (4) show improved performance. Further work is needed in developing non destructive examination (NDE) procedures to reduce the size of the maximum un-detected near surface flaw.
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机译：国际热核实验堆（ITER）环形场（TF）线圈盒由奥氏体不锈钢制成，设计工作于4K。由于各种大小的脉冲加载循环，以及不那么频繁的TF加载负荷，以及周期性的冷却循环，它容易疲劳。这样的多层装货的疲劳寿命估计是TF结构设计中的一个关键问题。 TF壳体应力是在磁体系统的大规模全局模型中计算的。应力大小随时间和位置的不同而变化。 ITER设计标准要求对所有电荷和等离子发射进行完整的模拟，并进行充分的da / dN积分。冯俊（Jun Feng）在本次会议上的同伴论文中讨论了巴黎法律整合和矿工的规则方法。 Paris Law模拟已集成到ANSYS后处理程序中，该程序可以考虑TF案例周围疲劳效应的空间分布。峰值应力，R值，寿命以及基于寿命的安全系数（寿命除以所需的100、000个循环）以可读取的形式输出到ANSYS，然后绘制轮廓。可以考虑裂纹形状参数以及在壳体壁的贯穿厚度方向上的裂纹位置。 1995年至1996年设计演变的结果表明，TF箱侧壁的寿命估算值接近于定心嵌入裂纹的要求。本设计（BDPA97）的初步分析（4）显示了改进的性能。开发无损检测（NDE）程序需要进一步的工作，以减小最大的未检测到的近表面缺陷的大小。
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