Abstract. Welding remains an attractive fabrication method for aero-engine assemblies, offering high production rates and reduced total cost, particularly for large complex assemblies. However, distortion generated during the welding process continues to provide a major challenge in terms of the control of geometric tolerances and residual stress. The welding distortion is influenced by the sequence and position of joints, the clamping configuration and the design of the assembly. For large complex assemblies the range of these options may be large. Hence the use of numerical simulation at an early stage of the product development process is valuable to enable a wide range of these factors to be explored with the aim of minimising welding distortions before production commences, and thereby reducing the product development time. In this paper, a new technique for simulation of welding distortions based on a shrinkage analysis is evaluated for an aero-engine assembly. The shrinkage simulations were built and solved using the ESI Group software Weld Planner. The rapid simulation speed enabled a wide range of welding plans to be explored, leading to recommendations for the fabrication process. The sensitivity of the model to mesh size and material properties is reported. The results of the shrinkage analysis were found to be similar to those of a transient analysis generated using ESI Group software SysWeld. The solution times were found to be significantly lower for the shrinkage analysis than the transient analysis. Hence it has been demonstrated that shrinkage analysis is a valuable tool for exploring the fabrication process of a welded assembly at an early stage of the product development process.

et al.2 demonstrated that, for approximately linear strain paths, the FLC predicted splitting failures adequately. Currently, the main feedstock of tubular blank However, the situation for a tube hydroformed commaterial for tube hydroforming is derived from slit ponent may be very different from that for a conventional steel coil, which has been roll formed and electric sheet metal stamping. This complexity is a consequence of resistance welded (ERW). From ERW tubular blank, the strains introduced by the various stages of processing, a number of intermediate processing stages such starting from the original parent coil through tube manuas prebending and preforming may be necessary to facture to the component. The series of strains involved achieve the final formed component. The end result may render the original sheet forming limit curve inaccurate is a component that may have experienced afor complete forming analysis. In the conventional electric complex strain path history. The traditional forming resistance welded (ERW) tube manufacturing process, the limit (strain) curve (FLC) is inherently affected by mechanical characteristics of the original strip may be non-linear strain paths; hence, a suitable alternative altered by a wide range of induced strains. The predominant forming limit criterion has been studied and is cold working effects, highlighted by Kato and Aoki,3 are: proposed for complex tube hydroforming processes.longitudinal bending, from uncoiling/levelling; transverse The criterion proposed is the forming limit stress plane strain bending, owing to roll forming; and compressive curve (FLSC), which is theoretically independent of strains caused by subsequent sizing of the tube to fix its strain path and prestrain history. The methods diameter. These straining effects mean that the original sheet used to generate the FLC and FLSC for tubular FLC cannot be used with confidence to predict splitting blanks are described, and prebending is used as an during any subsequent process. example to demonstrate how complex tubular Kergen and Lescart4 have suggested an experimental component forming operations, and subsequent method to obtain an FLC for ERW tubular blanks. This formability, may be evaluated through use of the involves applying internal pressure to a blank contained FLSC.I&S/1514 within die tooling that represents a double cone. The strain mode is varied by controlling the tube end constraint, andAt the time the work was carried out Mr Darlington and Professor this approach has been claimed to provide linear deformation Parker were at the EPSRC Engineering Doctorate Centre -Wales, paths. However, this technique has limitations in that biaxial

Very short manufacture cycle times are required if continuous carbon fibre and epoxy composite components are to be economically viable solutions for high volume composite production for the automotive industry. Here, a manufacturing process variant of resin transfer moulding (RTM), targets a reduction of in-mould manufacture time by reducing the time to inject and cure components. The process involves two stages; resin injection followed by compression. A flow simulation methodology using an RTM solver for the process has been developed. This paper compares the simulation prediction to experiments performed using industrial equipment. The issues encountered during the manufacturing are included in the simulation and their sensitivity to the process is explored.