Simulation and Experimental Comparison of Laser Impact Welding with a Plasma Pressure Model

Abstract

In this study, spatial and temporal profiles of an Nd-YAG laser beam pressure pulse are experimentally characterized and fully captured for use in numerical simulations of laser impact welding (LIW). Both axisymmetric, Arbitrary Lagrangian-Eulerian (ALE) and Eulerian dynamic explicit numerical simulations of the collision and deformation of the flyer and target foils are created. The effect of the standoff distance between the foils on impact angle, velocity distribution, springback, the overall shape of the deformed foils, and the weld strength in lap shear tests are investigated. In addition, the jetting phenomenon (separation and ejection of particles at very high velocities due to high-impact collision) and interlocking of the foils along the weld interface are simulated. Simulation results are compared to experiments, which exhibit very similar deformation and impact behaviors. In contrast to previous numerical studies that assume a pre-defined deformed flyer foil shape with uniform initial velocity, the research in this work shows that incorporation of the actual spatial and temporal profiles of the laser beam and modeling of the corresponding pressure pulse based on a laser shock peening approach provides a more realistic prediction of the LIW process mechanism.

Studies on Quality of Joints and Phenomena Therein for Welded Vehicle Components Made of Aluminium Alloy – a Review

“…Sadeh et al [232] experimentally characterized spatial and temporal profiles of an Nd-YAG laser beam pressure pulse focusing on laser impact welding (LIW) simulation. LIW tests were conducted using standoff distances of 0.12, 0.26, 0.40, and 0.54 mm, as well as laser fluence values of 31.08 and 37.30 J/cm 2 .…”

Modeling of multi-edge effects in the case of laser shock loadings applied on thin foils: Application for material characterization of aluminum alloys

“…spot irradiating the metal target is defined using experimental measurements of the spatial distribution of power density. A proportional scale law is directly applied between the power density distribution and the pressure distribution, as the maximum reached pressure (P max in GPa) is given by the following experimental law [expression (12)]:…”

“…This also gives C M,s % 11 000 m=s at I 0 . Furthermore, as the plasma is considered to be an ideal gas, we also assumed that the maximum temperature, similarly to the maximum pressure [see expression (12)], is proportional to the intensity: T M / ffiffi I p , so that…”

“…Another promising application is the laser adhesion test (LASAT), 10,11 where researchers evaluate the bonding strength in stack of laminates Carbon Fiber Reinforced Polymer (CFRP) by identifying the tensile stress areas due to highpower laser impact. We can also mention Laser Impact Welding (LIW) 12 and laser paint stripping. 13,14 During a laser shock, a shock wave is generated and propagates through the target.…”

Laser Shock Processing and Related Phenomena

“…In the second section (comprising nine full research papers), we aimed to compile as representative as possible coverage of the different key aspects leading the present-day research in LSP technology and related disciplines. The result has been a collection of articles ranging from the study of fundamental physics aspects (mostly laser-plasma interaction diagnosis and plasma pressure development, respectively represented by the articles of Colón et al [3] and Sadeh et al [4]); passing through the application of numerical modelling to the predictive assessment of the results of the application of LSP to the most relevant present-day materials (represented by the articles of Langer et al [5] and Angulo et al [6]); continuing on to the theoretical and experimental analysis of the parametric space of LSP in view of realistic applications (represented by the articles of Kallien et al [7], Troiani and Zavatta [8], and Petan et al [9]); and, finally, arriving at two of the most advanced developments at present day in the industrial application of LSP (i.e., the articles of Le Bras et al [10] and T. Sano et al [11]). In short, a collection of first-rank articles covering fundamental processes, numerical modelling, microstructural and material-related issues, materials and standard specimens testing, parametric applications design, advanced LSP applications, and implementation issues has been obtained.…”