1、 Evaluation of Material Design Limits for TBM Applications Abstract-The aim of the work presented is, firstly, an evaluation of existing design rules considered for austenitic steels exhibiting hardening cycle by cycle contrary to the reduced activation ferritic-martensitic steels (RAFM), which soft
2、en under cyclic loading. Secondly, it is a definition of the range of operation temperatures and loads for the current design of the test blanket module (TBM). Results of cycling tests of the EUROFER 97 performed by J. Aktaa & R. Schmitt Ill have been thereby used to adjust material parameters neede
3、d for an ABAQUS-own combined non-linear isotropic-kinematic hardening model. Furthermore, the visco-plastic material model considering material damage Ill implemented recently as an ABAQUS user material (UMAT) has been applied for simulations and the results have been compared with those obtained us
4、ing the material model mentioned above. Keywords-test blanket module, reduced activation ferritic-martensitic steel, EUROFER 97, structural design code, cyclic softening, stress categoriuation, ratcheting, high-temperature design rules TBM 材料 设计极限的评估 摘要，这项工作的目的提出的是，第一，对现有的参展硬化奥氏体钢和软化的马氏体钢的现有规则的评价。其次
5、，这是一个对工作温度和试验包层模块（隧道掘进机）目前的设计负荷范围的定义。对由 J. Aktaa河施密特表现欠佳的欧洲钢铁联盟 97 单车试验的结果已使使用 来调整有限元中结合自己的非线性各向同性运动强化模型所需的材料参数。此外，粘塑性材料模型考虑物质损害病患者实施的一种有限元中的用户材料（ UMAT）最近已申请模拟，结果也被使用的材料获得上述模型进行了比较。 关键词 试验包层模块，减少活化铁素体，马氏体钢，欧洲钢铁联盟 97，结构设计规范，循环软化，强调准则，棘轮，高温设计规则 I. INTRODUCTION This work is a part of the development ac
6、tivity of the ITER test blanket module (TBM).A determination of high-temperature design rules considering the creep/fatigue is the aim of the work. According to the present-day vision, the TBM should be manufactured from a reduced-activation ferritic-martensitic (RAFM) steel EUROFER 97, which exhibi
7、ts severe softening during cyclic loading contrary to usual austenitic steels. This abnormal behavior leads definitively to a necessity to revise a traditional formulation of some important design rules such as the well-known 3 Sm rule. Such a revision requests, firstly, a wide experimental data bas
8、e and, secondly, an advanced material model being able to describe a realistic behavior of a material. The fulfillment of both these requirements as well as acute needs of blanket designers in renewed rules forn thus positive initial conditions for the appearance of the work presented. 一，导言 这项工作是对 I
9、TER 试验包层模块的开发活动的一部分（隧道掘进机）。甲高温设计规则考虑蠕变 /疲劳是工作目标的决心。根据今天的理想，隧道掘进机制造的，应降低激活素体，马氏体（ RAFM）钢欧洲钢铁联盟 97，该展览在循环荷载违背一般奥氏体钢严重软化。这种不正常的行为导致最终以必要的修改等一些著名的 3 条重要钐传统的设计规则的制定。 这种修订的要求，首先，基础广泛的实验数据，其次是一种先进的材料模型能够描述一个现实的物质的行为。上述两项要求的实现，以及在新的规则毯福尔设计师紧迫需要为工作状态，从而提出了积极的初始条件。 II.ADJUSTMENT OF MATERIAL PARAMETERS To simu
10、late the actual behavior of the TBM under cyclic thermal and mechanical loading, experimental data of corresponding cyclic tests are needed. Such data stemming from a life time study of the EUROFER 97at 450 (723K),550 (823K) and 650 (923K) performed by J. Aktaa & R. Schmitt 1 as well as at the room
11、temperature (RT) provided by M. Weick 2 have been used to adjust material parameters required for an ABAQUS-own non-linear isotropic-kinematic hardening model 3. This model is able to account e.g. for the Bauschinger effect, a cyclic hardening with plastic shakedown as well as for a ratcheting. A de
12、scription of the material model is given in 3 and lies outside the paper. The determined values for the parameters C, y, Q and b specified also in 3 are collected in tabs. I and II. TABLE I. KINEMATIC HARDENING: THE FITTED PARAMETER C FOR DIFFERENT TEMPERATURES； THE 2ID PARAMETER r =1150 TABLE II. I
13、SOTROPIC HARDENING: THE FITTED PARAMETES Q AND b FOR DIFFERENT TEMPERATURES. II.ADJUSTMENT 材料参数 为 了模拟循环下热和机械载荷的隧道掘进机的实际行为，相应的循环测试的实验数据是必要的。从生命的时间研究产生的数据，欧洲钢铁联盟 97at 450（ 723K）， 550（ 823K）和650（ 923K）由 J. Aktaa R 的表现 施密特 1，以及在室内温度（ RT）由 M.韦克提供 2被用来调整一 Abaqus 中所需的非线性各向同性，运动强化模型 3 材料参数 。该模型能够考虑的包辛格效应，例如
14、，一个塑料循环硬化安定以及一步步。 甲材料模型的描述给出了 3和外部的文件所在。为参数 C， Y 和 Q 和规定也在 B 的测定值 3在标签收集。第一和第二。 表一 动硬化：拟合 C 的参数不同温度下的 2ID 参数 r = 1150 表二 各向同性硬化：拟合 PARAMETES Q 及同一的不同温度。 III. DETERMINATION OF THE ELASTIC LIMIT A. Finite Element Model To verify the material model described above, a 2D model of a quarter of the TBM ha
15、s been created according to the current design and meshed using PATRAN. The model is shown in fig. 1 together with mechanical constraints. The only external mechanical load in the non-accident operating mode is the hydrostatic pressure of 80 bar = 8 MPa in the cooling channels. For those simulations
16、 where thermal stresses occur, ABAQUS promotes a so called generalized plane strain element formulation, which accounts for an elongation in the out-of-plane direction and thus avoids enormously high non-physical out-of-plane stresses. The 8-noded generalized plane strain elements CPEG8 have been us
17、ed here. B. Thermal Simulation During the operating mode, it should be accounted for a heat flux of 250 up to 500 kW/m2 (peak) on the plasma-facing side as well as a heat flux of 60 kW/m2 and of 35 kW/m2 on the vertical and horizontal interior, respectively, due to breeder units, see fig. 2. For the
18、 reason of simplicity, boundary conditions depicted in fig. 2 have been considered in the simulations. C. Mechanical Simulations using various Plasma Heating and Pressure in Cooling Channels (no cycling) By variation of both the temperature in cooling channels and the plasma heating, a critical pressure has been determined. The critical pressure is defined as the minimum pressure causing an inelastic deformation after the 1st heating i.e. After the 1/2 of the 1st cycle.
