Laser-Gas Metal Arc (GMA) hybrid welding is fast making the transition from laboratory to production, in industries as diverse as shipbuilding to automobile manufacture. For the past 3 years, our team has striven to both develop a hybrid welding process for steel pipe, and to specify, build, and install a hybrid pipe welding system in a General Dynamics NASSCO shipyard. In March 2007, the syste...

Amodel based on a double-ellipsoidal volumeheat source to simulate the gasmetal arcwelding (GMAW) heat input and a cylindrical volume heat source to simulate the laser beam heat input was developed to predict the temperature field and thermally induced residual stress in the hybrid laser–gas metal arc (GMA) welding process. Numerical simulation shows that higher residual stress is distributed i...

*Corr. Author’s Address: University of Ljubljana, Faculty of Mechanical Engineering, Askerceva cesta 6, 1000 Ljubljana, Slovenia, [email protected] 267 Monitoring Gas Metal Arc Welding Process by Using Audible Sound Signal Horvat, J. Prezelj, J. Polajnar, I. Čudina, M. Jožef Horvat1 Jurij Prezelj2 Ivan Polajnar2 Mirko Čudina2,* 1 University of Ljubljana, College of Health Studies, Slove...

This paper presents a new method for measuring and classifying spatter in gas metal arc welding (GMAW) by optical monitoring of the weld pool and surrounding area via a high-frame-rate camera. Image processing and tracking algorithms are described that extract and classify individual spatter events from raw camera images. This new sensor is then used to investigate the relationship between work...

This paper addresses the problem of fault-tolerant robust supervisory control of discrete event systems (DES’s) with model uncertainty. Necessary and sufficient conditions for the existence of a fault-tolerant robust supervisor are derived. If the conditions are satisfied, then tolerable fault event sequences embedded in the system can be achieved. The results obtained are applied to design, mo...

-S 169 WELDING JOURNAL ABSTRACT. A 3-D transient numerical model was developed for simulation of gas metal arc (GMA) weld pools with free surface and droplet impact effects. This effort predicted a moving GMA weld pool by considering not only the heat transfer and fluid flow driven by surface tension gradient, electromagnetic force, buoyancy, and arc pressure, but also detailed information abou...

In this paper, stability and internal dynamics for a gas metal arc welding (GMAW) process will be studied. GMAW process is considered as a nonlinear MIMO system and input-output feedback linearization method will be applied for control purposes. Internal dynamics is the unobservable part of the system dynamics; its stability analysis is a vital step in the investigation of the system stability ...