Combining Variation Simulation With Welding Simulation for Prediction of Deformation and Variation of a Final Assembly

Abstract

<jats:p>In most variation simulations, i.e., simulations of geometric variations in assemblies, the influence from heating and cooling processes, generated when two parts are welded together, is not taken into consideration. In most welding simulations, the influence from geometric tolerances on parts is not taken into consideration, i.e., the simulations are based on nominal parts. In this paper, these two aspects, both crucial for predicting the final outcome of an assembly, are combined. Monte Carlo simulation is used to generate a number of different non-nominal parts in a software for variation simulation. The translation and rotation matrices, representing the deviations from the nominal geometry due to positioning error, are exported to a software for welding simulation, where the effects from welding are applied. The final results are then analyzed with respect to both deviation and variation. The method is applied on a simple case, a T-weld joint, with available measurements of residual stresses and deformations. The effect of the different sources of deviation on the final outcome is analyzed and the difference between welding simulations applied to nominal parts and to disturbed (non-nominal) parts is investigated. The study shows that, in order to achieve realistic results, variation simulations should be combined with welding simulations. It does also show that welding simulations should be applied to a set of non-nominal parts since the difference between deviation of a nominal part and deviation of a non-nominal part due to influence of welding can be quite large.</jats:p>

Mechanisms and coherences of robust design methodology: a robust design process proposal

“…Schleich et al (2012) use skin models to incorporate manufacturing data to increase the detail and accuracy of geometric variation simulation. Other studies seek to extent geometric variation simulations by for example including the influence of welding on the final assembly (Pahkamaa et al 2012) or by regarding deformable, slender parts like cables and hoses (Hermansson, Carlson, and Bjo 2013).…”

A Welding Capability Assessment Method (WCAM) to support multidisciplinary design of aircraft structures

“…Studies have also demonstrated that the distribution of residual stresses due to forming or tack welding operations must be considered in the estimation of residual stress due to welding [30,48]. In addition, studies have demonstrated that it is important to consider the input part variation, due to the fixturing or forming processes, when simulating the distortion due to welding [46,49].…”

“…In cases where the final assembly has not been reached, geometrical variation after welding can also influence the welding performance of the next subassembly [46].…”

“…In addition, due to the variation stack up, in order to ensure alignment conditions (gap, flush, parallelism) for the performance of the next welding operation, the edges that will conform to the joint in the next assembly require special form tolerances. Variation simulations are used to estimate the output result and set tolerances [39,46].…”

“…to study macro-level product deformation, and residual stresses [46]. However, not all phenomena related to welding can be virtually modelled.…”