薄壁铝合金结构焊接应力变形数值模拟

WELDING RESIDUAL STRESS AND DISTORTION SIMULATION OF THIN ALUMINUM STRUCTURES

实际结构焊接过程的三维数值模拟因为计算量大而往往难以进行。为了采用三维热弹塑性有限元方法对薄 壁铝合金结构的焊接过程进行数值模拟,提出了粘贴单元和混和单元两种网格划分技术相结合的单元划分方案进 行有限元建模,通过薄板对接模型试验验证了此方案的可行性,并研究了不同建模方案对计算效率的影响。将这 种单元划分方案应用到实际薄壁筒体结构焊接过程的数值模拟中,对焊接过程产生的残余应力和变形进行了成功 地预测。结果表明:对于薄壁构件,采用粘贴单元和混合单元相结合的单元划分方案可以在保证一定精度的前提 下,可大大减少有限元网格划分工作量,同时可降低计算规模,提高计算效率。

The 3D welding numerical simulations of welded structure are hardly performed for the large computational requirements. A new mesh division technique is set up in order to use 3D thermal-elastic-plastic FEM (finite element method) to simulate the welding process of thin Al alloy structure. A butt weld of a thin plate by using the division technique is investigated. The two different element division schemes are carried out for achieving the calculation efficiency of different schemes. A cylinder product's welding process is also simulated. The welding residual stress and distortion are successfully obtained. All results indicate that using the new mesh division for thin structure is easier to perform and analysis time can be reduced greatly while high precision is still obtained.