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

高强度钥匙孔模式激光焊接，其中激光从熔融池的表面形成一个深键形孔，特别用于制造较厚的焊接接头。激光焊接的这种能力在该领域几乎是独一无二的。它使激光焊接非常吸引人。但是，这种激光焊接模式通常与钥匙孔不稳定性相关联，而钥匙孔不稳定性通常会产生不完美。该研究计划的主要目的是开发数值工具，以模拟钥匙孔模式，尤其是钥匙孔的行为。它包括在激光焊接过程中发生的多物理现象的建模，高级数值方法的应用以及C ++中面向对象的代码的开发。该研究计划还包括大量的实验投资，以表征激光源的行为，材料的行为和过程中的传热。为了达到主要目标，研究计划分为以下三个步骤。首先，将在comsol中开发和实现多物理建模的整个方程式。它允许评估钥匙孔激光焊接过程模拟的不同可用方法的能力和限制。在此阶段，将进行一系列铝的激光焊接测试，以表征激光热源。它允许了解激光击中并将能量转移到材料的方式。此外，将进行一系列测试，以表征使用高速摄像机和高速相机的铝液体表面张力。其次，将开发用于建模激光源和熔融池相互作用的不同方法。此步骤对于模拟钥匙孔的行为非常重要。脉冲激光的实验结果将用于验证这些方法。最后，基于两个第一步的知识，将使用高级数值方法在内部代码中开发和实现钥匙孔激光焊接的拟议多物理建模。脉冲激光焊接的实验结果将用于在温度，钥匙孔行为，焊接横截面和孔隙率方面验证激光焊接模拟。在研究计划的结尾，通过实验和建模研究对激光焊接中的钥匙孔形成有了更好的了解，将允许改善过程控制和开发，避免缺陷并提高焊接质量。这些知识将为业界从传统焊接转移到激光焊接打开大门，从而使生产力具有重要提高。此外，该研究框架是通用的，可以适用于其他材料制造过程，例如切割，形成，尤其是成瘾性的制造过程。关键字：激光焊接，钥匙孔，不稳定性，缺陷，实验，建模，仿真