Residual stress constrained self-support topology optimization for metal additive manufacturing

2022 ◽  
Vol 389 ◽  
pp. 114380
Author(s):  
Shuzhi Xu ◽  
Jikai Liu ◽  
Yongsheng Ma
Keyword(s):  
Residual Stress ◽  
Topology Optimization ◽  
Additive Manufacturing ◽  
Metal Additive Manufacturing ◽  
Metal Additive

scholarly journals Study on Residual Stress Relief Technology Using Phase Transformation in Metal Additive Manufacturing

2020 ◽  
Vol 86 (2) ◽  
pp. 177-184
Author(s):  
Ichiro ARAIE ◽  
Hiroshi AMIOKA ◽  
Katsuya MATSUMURA ◽  
Atsushi HIROTA ◽  
Keiichi TANIGUCHI ◽  
...  
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Additive Manufacturing ◽  
Stress Relief ◽  
Metal Additive Manufacturing ◽  
Metal Additive

Utilizing Design for Metal Additive Manufacturing and Topology Optimization to Improve Product Designs

2019 ◽  
Author(s):  
Martin L. Tanaka ◽  
Jeremy J. Smith
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Yield Strength ◽  
Maximum Stress ◽  
Optimized Design ◽  
Original Design ◽  
Optimization Software ◽  
Metal Additive Manufacturing ◽  
Fea Model ◽  
Metal Additive

Abstract Metal additive manufacturing has transformed the product design process by enabling the fabrication of components with complex geometries that cannot be manufactured using conventional methods. Initial designs can be further enhanced by employing topology optimization software and Design for Metal Additive Manufacturing (DFMAM) guidelines. In this study, a commercially available bicycle spider-crank was optimized for three-dimensional (3D) metal manufacturing. The 3D surface geometry of the original spider-crank was acquired using a white light scanner and used to generate a 3D solid model of the part. Boundary conditions were obtained from cycling loads found in published literature and applied to an ANSYS Finite Element Analysis (FEA) model. The FEA model was analyzed to determine the von Mises stress throughout the part. ANSYS Topology Optimization software was applied to the model. The software uses an iterative process to remove low stress material and recalculate stress within the part until no more material can be removed without exceeding a target maximum stress value. Following topology optimization, DFMAM principles were applied to enable the part to be 3D printed. Results from the FEA showed the DFMAM optimized design to be 41.5% lighter than the original design. The maximum stress increased from 41.2% of the material yield strength to 61.5% in the DFMAM optimized design, which exceeded the target optimization value of 50% yield strength. Analysis results were verified experimentally. The original design and DFMAM optimized design were printed using an EOS M 290 metal additive manufacturing machine. Parts were separated from the support structure and tested on a universal testing machine. A custom testing apparatus was designed and built to conduct the testing. Testing was performed at 15 degrees intervals throughout the range of motion. Strain gages attached to the arm of the crank were used to obtain stress values at specific locations and dial indicators were used to measure the deflection of the crank arm under load. Experimental results closely matched results obtained from the FEA, validating the model. With the model validated at specific locations, it was assumed that the stress calculated by the FEA at the critical points were also accurate. The results showed the topology optimization software to be an effective and useful tool for optimizing the design of 3D metal printed parts. However, topology optimization alone was not enough to finalize a design prior to printing. The application of DFMAM principles were needed to ensure that the overhanging structures would not collapse during printing. Because the determination of what constitutes an overhang is determined by the part orientation when printed, some modification will generally be required prior to printing. In conclusion, using a bicycle spider-crank as an example, this research has shown that the use of topology optimization software and Design for Metal Additive Manufacturing principles is able to reduce the weight of a 3D metal printed part while simultaneously achieving a maximum stress near a target value.

scholarly journals Residual Stress Reduction Technology in Heterogeneous Metal Additive Manufacturing

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5516
Author(s):  
Myoung-Pyo Hong ◽  
Young-Suk Kim
Keyword(s):  
Residual Stress ◽  
Additive Manufacturing ◽  
Real Time ◽  
Stress Reduction ◽  
Room Temperature ◽  
High Hardness ◽  
Large Area ◽  
Metal Additive Manufacturing ◽  
Thermal Deviation ◽  
Metal Additive

Metal additive manufacturing (AM) is a low-cost, high-efficiency functional mold manufacturing technology. However, when the functional section of the mold or part is not a partial area, and large-area additive processing of high-hardness metal is required, cracks occur frequently in AM and substrate materials owing to thermal stress and the accumulation of residual stresses. Hence, research on residual stress reduction technologies is required. In this study, we investigated the effect of reducing residual stress due to thermal deviation reduction using a real-time heating device as well as changes in laser power in the AM process for both high-hardness cold and hot work mold steel. The residual stress was measured using an X-ray stress diffraction device before and after AM. Compared to the AM processing conditions at room temperature (25 °C), residual stress decreased by 57% when the thermal deviation was reduced. The microstructures and mechanical properties of AM specimens manufactured under room-temperature and real-time preheating and heating conditions were analyzed using an optical microscope. Qualitative evaluation of the effect of reducing residual stress, which was quantitatively verified in a small specimen, confirmed that the residual stress decreased for a large-area curved specimen in which concentrated stress was generated during AM processing.

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