Modeling of keyhole mode laser welding

小孔模式激光焊接建模

• 批准号: RGPIN-2019-06574
• 负责人: Pham, Tan
• 金额: $ 2.04万
• 依托单位: École de technologie supérieure
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754489
• 关键词: Modeling; keyhole; mode; laser; welding

High intensity keyhole mode laser welding, in which the laser makes a deep key-shape hole from the surface of the melting pool, is especially used to make thick welded joints. This capability of the laser welding is almost unique in this field. It makes laser welding very attractive. However, this laser welding mode is typically associated with keyhole instability that often creates imperfections.  The main objective of this research program is to develop numerical tools for the simulation of the laser welding in keyhole mode, especially the behavior of the keyhole. It includes the modeling of multiphysics phenomena occurring in the laser welding process, the application of advanced numerical methods and the development of the in-house object oriented code in C++. The research program includes also a significant amount of experimental investigation to characterize the behavior of laser sources, the behavior of materials and the heat transfer during process. To reach the main objective, the research program is split into three following steps. Firstly, the whole system of equations for the multiphysics modeling will be developed and implemented in COMSOL. It allows evaluating the capability and the limits of different available approaches for keyhole laser welding process simulation. In this stage, a series of laser welding tests on aluminium will be performed to characterize the laser heat source. It allows understanding the manner the laser hits and transfers the energy to materials. Also, a series of tests will be carried out to characterize the surface tension of aluminium liquid using pyrometer and high speed camera. Secondly, different approaches for modeling the interaction of laser heat source and the molten pool will be developed. This step is very important for simulating the behavior of the keyhole. Experimental results of pulsed laser will be used to validate these approaches. Finally, based on the knowledge from the two first steps, the proposed multiphysics modeling of the keyhole laser welding will be developed and implemented in the in-house code using advanced numerical methods. Experimental results of pulsed laser welding will be used to validate laser welding simulations in terms of temperature, keyhole behavior, weld cross-section and porosity. At the end of the research program, a better understanding of the keyhole formation in laser welding through experimental and modeling investigations will allow improving process control and development, avoiding defects and increasing weld quality. This knowledge will open the door for the industry to be able to transfer from conventional welding to laser welding which makes an important gain in productivity. Moreover, this research framework is generic and could be adapted for other material manufacturing processes such as cutting, forming and particularly additive manufacturing processes. Keywords: laser welding, keyhole, instability, defects, experimentation, modeling, simulation

高强度匙孔模式激光焊接，即激光从熔池表面形成深钥匙形孔，特别用于制造厚焊接接头，激光焊接的这种能力在该领域几乎是独一无二的。激光焊接非常有吸引力，然而，这种激光焊接模式通常与小孔不稳定性有关，常常会产生缺陷。​该研究计划的主要目标是开发用于模拟小孔模式激光焊接的数值工具，特别是小孔模式。它包括激光焊接过程中发生的多物理场现象的建模、先进数值方法的应用以及内部面向对象的 C++ 代码的开发。为了表征激光源的行为、材料的行为以及过程中的传热，为了实现主要目标，研究计划分为以下三个步骤：首先，将开发和分析整个多物理场建模方程组。实施于COMSOL。它可以评估小孔激光焊接工艺模拟的不同可用方法的能力和局限性。在此阶段，将对铝进行一系列激光焊接测试，以表征激光热源。此外，还将使用高温计和高速摄像机进行一系列测试来表征铝液的表面张力。其次，将采用不同的方法来模拟激光热源与熔池的相互作用。这一步对于模拟小孔激光焊接的实验结果非常重要，将用于验证这些方法。最后，基于前两个步骤的知识，提出了小孔激光焊接的多物理场建模。将使用先进的数值方法在内部代码中开发和实施。脉冲激光焊接的实验结果将用于验证激光焊接模拟的温度、小孔行为、焊缝横截面和孔隙率。在研究计划结束时，通过实验和建模研究更好地了解激光焊接中的小孔形成将有助于改进过程控制和开发，避免缺陷并提高焊接质量，这些知识将为行业打开大门。从传统焊接转移到激光焊接，这大大提高了生产率。此外，该研究框架是通用的，可以适用于其他材料制造工艺，例如切割、成型，特别是增材制造工艺。 , 缺陷,实验、建模、模拟