In this study a three-dimensional fnite element model is presented for precisely simulating laser cladding process with a focus on dilution control. Dilution is referred to as an important quality index in the laser cladding process, indicating the contamination level of the properties of clad layer by substrate metals. As regards a good quality of laser clad layer, low dilution as well as metallurgical bond of interface are prerequisite, so the dilution control is essential in the process. Unfortunately despite of its importance, to date, any practically usable computation techniques have not been reported, which is a motivation of this work. In the paper, proposing a simulation procedure, we develop and verify a code of !nite element method with Lagrangian view-point. Following the procedure, the dilution control is precisely estimated. The effects of process parameters on the dilution of clad layer are quantitatively discussed by the numerical and experimental means.

In this paper, response of stitched/unstitched woven fabric carbon/epoxy composite laminates subjected to high velocity impact loading is discussed. Aerospace grade plain and satin weave carbon fabrics were used to manufacture the laminate using a toughened SC-15 epoxy resin system with an affordable vacuum assisted resin infusion molding process. For fabrication of stitched laminates, a 3-cord Kevlar thread was used to stitch the fabric preform in lock stitch fashion in an orthogonal grid of size 12.7 and 25.4mm with 6mm stitch spacing. Unstitched laminates used in the study were made of 7, 17 and 37 layers whereas the stitched laminates were made of 7 and 17 layers. Four laminates of each type were subjected to high velocity impact loading at different velocity to determine the ballistic limit. The ensuing damage was characterized through ultrasonic NDE. Results of the study indicate that the damage was well contained within the stitch grid incase of stitched laminates. However, ballistic limit was higher for the unstitched laminates. Ballistic limit increased with the increase in the thickness of the laminate. Further, satin weave laminates exhibited higher ballistic limits in most of the cases.