Papers by Keyword: Aerospace Alloys

Abstract: The preforming stage in hydroforming of an aerospace generic shape was investigated using a combination of experimentation and numerical modeling. The preform die was manufactured using a rapid prototyping method, namely the selective laser sintering (SLS) process. The preforming experiments were conducted on 0.9 mm and 1.2 mm thick stainless steel 321 (SS321) tubes. To evaluate the preforming process, an automated deformation measurement system, ARGUS^®, was used to measure the 3-dimensional (3D) strains on the deformed tubes. Data collected from the experiments were used to validate the simulation of the preforming stage. The simulation and experimental results were found to be in good agreement, indicating that the preform model can be used as a starting point for simulating the tube hydroforming (THF) process. In addition, the SLS approach was found to be very promising, as it reduced greatly the lead time and cost of process development for THF.

Abstract: In the tube hydroforming (THF) process, a pressurized fluid is used to expand a thin walled tube inside a closed die in order to fill the die cavity. THF has many advantages that render this process interesting for different industries such as automotive and aerospace. In this work, to investigate the effect of different process parameters, such as the friction condition, tube thickness and end-feeding on the final product, THF experiments were performed on stainless steel 321 (SS 321) tubes using a round-to-square die. Experimental loading paths were obtained via the data acquisition system of the hydroforming press, which is fully instrumented. An automated deformation measurement system, Argus®, was used to measure the strains on the hydroformed tubes. The THF process was simulated using Ls-Dyna software. The variation in the strain and thickness measured from the experiments were compared to the simulation results at critical sections. Comparison of the results from the finite element (FE) simulations and experiments showed good agreement, indicating that the approach can be used for predicting the final shape and thickness variations of the hydroformed parts for more complex shapes in aerospace applications.

Abstract: A higher strength and heat resistance are increasingly demanded from the advanced engineering materials with high temperature applications in the aerospace industry. These properties make machining these materials very difficult because of the high cutting forces, cutting temperature and short tool life present. Laser assisted machining uses a laser beam to heat and soften the workpiece locally in front of the cutting tool. The temperature rise at the shear zone reduces the yield strength and work hardening of the workpiece, which make the plastic deformation of the hard-to-machine materials easier during machining. The state-of-the-art, benefits and challenges in laser assisted machining of metallic materials are summarized in this paper, and the improvement of tool life is discussed in relation to laser power, beam position and machining process parameters.