Lhuillier P E, Chassignole B, Oudaa M, Kerhervé S O, Rupin F, Fouquet T
EDF R&D, EDF Lab Les Renardières, Materials and Mechanic of Components Department, 77818 Moret-sur-Loing, France.
EDF R&D, EDF Lab Les Renardières, Materials and Mechanic of Components Department, 77818 Moret-sur-Loing, France.
Ultrasonics. 2017 Jul;78:40-50. doi: 10.1016/j.ultras.2017.03.004. Epub 2017 Mar 8.
A finite element modeling approach of ultrasonic propagation combined with a description of the microstructure at the scale of the grains has been implemented. The simulations seek to determine the contribution of scattering to the ultrasonic attenuation in polycrystalline materials. The approach is applied to anisotropic microstructures exhibiting both elongated grains and transversely isotropic crystallographic texture which can be found in multipass welds. The ultrasonic propagation is computed with the 2D finite element code ATHENA 2D. The description of the propagation media accounts for the geometric, elastic and crystallographic properties of anisotropic welds. The study is focused on two types of welds made of austenitic 316L stainless steel and Ni-based alloy (182). The attenuation was computed from the decay of multiple backwall echoes. The contribution of the microstructure scattering was isolated by a correction of the attenuation data with the attenuation obtained in an equivalent homogenized material. The simulation investigates the attenuation as a function of several parameters: grain orientation and size, ultrasonic frequency, or anisotropy level. The attenuation level of elastic pressure waves was specifically examined as a function of the angle between the propagation direction and the grain orientation. The evolution of the attenuation is consistent with the theoretical models. Moreover the simulation results were compared to experimental data available from the literature in 316L stainless steel welds. The simulated and experimental values are in very good agreement.
已经实现了一种将超声波传播的有限元建模方法与晶粒尺度的微观结构描述相结合的方法。模拟旨在确定散射对多晶材料中超声衰减的贡献。该方法应用于具有拉长晶粒和横向各向同性晶体织构的各向异性微观结构，这种结构在多道焊缝中可以找到。使用二维有限元代码ATHENA 2D计算超声波传播。传播介质的描述考虑了各向异性焊缝的几何、弹性和晶体学特性。研究集中在由奥氏体316L不锈钢和镍基合金（182）制成的两种类型的焊缝上。衰减是根据多个后壁回波的衰减计算得出的。通过用等效均匀化材料中获得的衰减对衰减数据进行校正，分离出微观结构散射贡献。模拟研究了衰减作为几个参数的函数：晶粒取向和尺寸、超声频率或各向异性水平。特别研究了弹性压力波的衰减水平作为传播方向与晶粒取向之间角度的函数。衰减的演变与理论模型一致。此外，将模拟结果与文献中316L不锈钢焊缝的实验数据进行了比较。模拟值和实验值非常吻合。
