“…The immense temperature gradient along with the edge constrains and circular track heating have the potential to cause large residual stress and deformation through coupled buckling and temperature gradient mechanisms. 33 –36 Figure 6. Deposition and vertical Z -displacement (in mm) profile of the aero-engine component with time.…”
The shape complexity of aerospace components is continuously increasing, which encourages researchers to further refine their manufacturing processes. Among such processes, blown powder direct laser deposition process is becoming an economical and energy efficient alternative to the conventional machining process. However, depending on their magnitudes, the distortion and residual stress generated during direct laser deposition process can affect the performance and geometric tolerances of manufactured components. This article reports an investigation carried out using the finite element analysis method to predict the distortion generated in an aero-engine component produced by the direct laser deposition process. The computation of the temperature induced during the direct laser deposition process and the corresponding distortion on the component was accomplished through a three-dimensional thermo-structural finite element analysis model. The model was validated against measured distortion values of the real component produced by direct laser deposition process using a Trumpf DMD505 CO2 laser. Various direct laser deposition fill patterns (orientation strategies/tool movement) were investigated in order to identify the best parameters that will result in minimum distortion.
“…The immense temperature gradient along with the edge constrains and circular track heating have the potential to cause large residual stress and deformation through coupled buckling and temperature gradient mechanisms. 33 –36 Figure 6. Deposition and vertical Z -displacement (in mm) profile of the aero-engine component with time.…”
The shape complexity of aerospace components is continuously increasing, which encourages researchers to further refine their manufacturing processes. Among such processes, blown powder direct laser deposition process is becoming an economical and energy efficient alternative to the conventional machining process. However, depending on their magnitudes, the distortion and residual stress generated during direct laser deposition process can affect the performance and geometric tolerances of manufactured components. This article reports an investigation carried out using the finite element analysis method to predict the distortion generated in an aero-engine component produced by the direct laser deposition process. The computation of the temperature induced during the direct laser deposition process and the corresponding distortion on the component was accomplished through a three-dimensional thermo-structural finite element analysis model. The model was validated against measured distortion values of the real component produced by direct laser deposition process using a Trumpf DMD505 CO2 laser. Various direct laser deposition fill patterns (orientation strategies/tool movement) were investigated in order to identify the best parameters that will result in minimum distortion.
“…By stress equilibrium, the surrounding region has compressive residual stress [1,2,3,4,5]. It has been well known that tensile residual stress affects brittle fracture, fatigue life, stress corrosion cracking, weld cracks, and buckling strength [6].…”
Section: Introductionmentioning
confidence: 99%
“…The angular distortion of one-pass welding is caused by non-uniform transverse shrinkage in the thickness direction [6]. The distortion is susceptible to the amount of weld deposition, temperature gradient through the thickness, and constraint.…”
Multi-layer welding involves the process of stacking many beads, so it requires much time and effort to predict the deformation through experimentation or numerical analysis. In this study, a systematic method for predicting transverse angular distortion in multi-layer butt welding has been proposed. First, the database was established through bead-on-plate welding experiments, which consisted of the relationship between welding conditions, the bead geometry, the material thickness, and the angular distortion. Then, when the arbitrary welding conditions and the shape of the butt joint were input, the method calculated the angular distortion per pass using the geometric principle and the database. The obtained prediction curves were verified with the V-groove welding experimental results. In addition, the characteristics of angular distortion in multi-layer butt welding were discussed. It was found that the angular distortion curve is a function of the number of passes and groove geometry. This algorithm is based on a numerical approach that saves computational time using databases and geometry, so it is suitable for industrial applications.
“…In order to reduce distortion, the appropriate distortion mode must be identified as first defined by Masubuchi. 1 The out-of-plane distortion modes include angular, buckling, and longitudinal bending distortion. Angular and buckling distortion are caused by similar mechanisms.…”
Distortion mitigation techniques for large parts constructed by additive manufacturing processes are investigated. Unwanted distortion accumulated during deposition is a common problem encountered in additive manufacturing processes. The proposed strategies include depositing equal material on each side of a substrate to balance the bending moment about the neutral axis of the workpiece and applying heat to straighten the substrate. Simple finite element models are used to predict the effectiveness of the mitigation strategies in order to reduce computation time and to avoid costly experiments. The strategy of adding sacrificial material is shown to be most effective and is then applied to the manufacture of a large electron beam deposited part consisting of several thousand deposition passes. The deposition strategy is shown to reduce the maximum longitudinal bending distortion in the large additive manufacturing part by 91%. It is shown that after the distortion mode of concern is identified, simple finite element models can be used to study distortion accumulation trends relevant to the large part. Experimental observations made here, as well as finite element model results, suggest that the order in which the balancing material is added significantly affects the success of the proposed distortion mitigation strategy.
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