Additive Manufacturing & Topology Optimization: Improving Aerospace Part Performance

Researchers from the Department of Mechanical Engineering of the National Institute of Technology in India willAdditive Manufacturing TechnologyandTopology Optimizationcombined, yesaerospaceThe bracket has been redesigned to reduce the weight of the part and improve the safety factor, thus proving that integrated topology optimization design and additive manufacturing can be an effective tool for designing and manufacturing lightweight parts.Additive Manufacturing (AM) Technologyis an advanced manufacturing process that can be used to manufacturebiologymedicine,carandaviationParts in aerospace and other fields. The main advantage of AM process is that any complex structure can be freely designed, reducing material waste and shortening production time, but in metal AM processmineral powderhigher cost. With the help of topology optimization, production costs can be minimized by reducing material usage.Topology OptimizationYesThe process of estimating optimal material distribution in a given product design space.

An overview of the research content:

In this study, the researchers used topology optimization to redesign the aerospace scaffold. The researchers considered not only material usage but also minimum residual stress during the design process (since residual stress is larger in AM processes due to higher temperature gradients). The researchers used CAD to redesign the aerospace support and completed the topology optimization through numerical simulation.based on
level set
The topology optimization method of the numerical simulation redesign and safety factor analysis of the part cloth was carried out. Through topology optimization, the weight of the part is reduced by 44.8%, and the safety factor reaches 2.3 (numerical analysis using AlSi12Mg alloy material data).The researchers carried out the printing process of the optimized parts
simulation
, so that the manufacturing time is minimized and the residual stress is minimized.simulated
SLM process
The parameters are 80W laser power, and the scanning speed is 1000 mm/s, and the simulation result is that the residual stress generated by the printing pitch of 90 μm is the smallest. The researchers validated the results using published research data on different types of parts.

Material

The aerospace mounts designed in this study are under static load conditions in aerospace applications. In order to ensure the lightweight of the parts, the AlSi12 Mg material with good corrosion resistance and light weight was selected in this study. Aluminum alloys are commonly used in the aerospace industry for their lightweight properties and excellent corrosion resistance. The physical and mechanical properties of AlSi12Mg are shown in the table below.

Design analysis

useSOLIDWORKSsoftwareParts are redesigned and modified. The part is subjected to static load conditions, the bracket will be fastened to the fixed base with four bolts and three loads will be applied to the bearings as shown in the diagram below.useANSYS 2020 R2The software performs the analysis, optimizes the part by selecting areas of material exclusion, and performs multiple iterations by varying the volume reduction percentage. For each iteration, the part is validated against the boundary conditions and the maximum reduction in volume for which the part meets the required boundary conditions is selected.

Simulation simulation

researchers useANSYS Additive SoftwareThe optimized part is simulated to find out the best parameters for the printed part. The researchers varied key process parameters, such as laser power, scan speed and print spacing, to find the best conditions for printing the part. The scanning speed is 900 mm/s~1000 mm/s, the spacing is 70 mm~9 mm, the interval is 10 mm, the laser power is 80~100W, and the interval is 10W.useMagics22.03The software optimizes the part printing orientation. By minimizing the support structure, printing time and material consumption can be reduced, and the parts were subjected to force analysis in different orientations to find the best orientation that produces less residual stress and less support structure.

Results and discussion

1. Force simulation analysis of unoptimized parts (original model)

The first stress loading diagram is as follows:

The red part in the figure is the area with the most stress

The third stress loading and safety factor are shown in the following table:

2. Optimize the analysis results of the part

The force simulation and safety factor simulation results of the optimized parts are as follows:

Force simulation results Safety factor simulation results

The results show that the optimized safety factor is increased from 1.54 to 2.23 during the first loading, and the safety factor during the second loading is increased from 1.61 to 2.25, and the weight is reduced by 44.8%. The increase in the safety factor is due to the increased overall thickness of the beam compared to the original beam. The ANSYS 2020 R2 software is used to simulate the safety factor of the bracket. The simulation results show that under the third loading condition, the bracket has a good safety factor because the stress is concentrated in the neck, indicating that material removal can be achieved in this part. The safety factors of the original stent model and the redesigned stent model were compared. The original model maintains a minimum safety factor of 1.5 under all loading conditions, and the optimized model maintains a minimum safety factor of 2.The use of topology optimization technology greatly changes the force transmission path of the structure, reduces the weight of the structure while optimizing the stress distribution, and improves the mechanical properties of the structure.

3. Direction optimization results

The model was simulated in five different directions using ANSYS Additive 2020 R2 software to estimate residual stresses in different directions. By observing the results of residual stress, it can be seen that,The residual stress in the 90° direction is smaller and the volume of the support structure is smaller.

4. Parameter optimization

The residual stress results under different process parameters are as follows:

At a scan speed of 1000 mm/s, a laser power of 80 W and a print pitch of 90 mm yielded an energy density of 29 J/mm3. Under the above process parameters printing, the residual stress developed in the part is much smaller compared to all other conditions. This may be because the size of the molten pool and the strength of the molten pool have a great influence on the residual stress.

in conclusion

1. In ANSYS2020 R2, the topology optimization algorithm based on level set is more suitable for this design than the algorithm based on density.

2. Topological optimization reduces 44% of the material weight required for aerospace brackets, and the safety factor is as high as 2-2.3 under all loading conditions.

3.Residual stresses in parts in SLM can be minimized by choosing the optimal process parameters with the correct print orientation.When the orientation angle is 90°, the residual stress is the smallest, and less support structure is used under this condition.

Note: The content of this article has been slightly adjusted, if necessary, you can view the original text.

Adapted from the original:Hanush SS, Manjaiah M. Topology optimization of aerospacepart to enhance the performance by additive manufacturing process[J]. MaterialsToday: Proceedings, 2022.

https://doi.org/10.1016/j.matpr.2022.02.074

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Additive Manufacturing & Topology Optimization: Improving Aerospace Part Performance

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