Study on Topology Optimization Design, Manufacturability, and Performance Evaluation of Ti-6Al-4V Porous Structures Fabricated by Selective Laser Melting (SLM)
Abstract
:1. Introduction
2. Materials and Methods
2.1. Equipment and Materials
2.2. Design of Unit Cell and Porous Structures Using Topology Optimization
2.3. Compression Test
2.4. Calculation of Porosity and Measurement of Dynamic Elastic Modulus
3. Results and Discussion
3.1. Manufacturability of Topology Optimization Structure
3.1.1. Manufacturing Limits of Spiral Structure
3.1.2. Manufacturing Limit of the Arched Bridge Structure
3.1.3. Manufacturing Limit of Thin Walls and Small Holes
3.2. Compressive Properties of the Porous Structures
3.2.1. Static Elastic Modulus and Compressive Strength
3.2.2. Compressive Behavior of Porous Structure
3.3. Evaluations of the Porous Structures
3.3.1. Measurement of Dynamic Elastic Modulus
3.3.2. Evaluations for Stability of the Porous Structures
3.4. Evaluations of the Porous Structures
4. Conclusions
- The manufacturing limits of three typical structures abstracted from designed porous structures is given out: the rising angle of spiral structure >30°, the length of overhang from arched structure <1.04 mm, the diameter of hole >0.1 mm, and the thickness of wall >0.1 mm.
- Properties such as compression strength and dynamic elastic modulus of porous structures fabricated with SLM are measured. The compression test showed the compressive strength and elastic modulus of topology optimized structures can match the requirements of the trabecular and cortical bones of humans. The compressive strength of porous structures decreases with the increase of either unit cell size (porosity constant) or porosity (unit cell size constant). The compressive behavior of porous structures is evaluated and three failure models are proposed based on the Gibson-Ashby model, which can be attributed to that of elastic-brittle foam material.
- The Ashby-Gibson model was also used to evaluate the stability of porous structures, indicating better stability of the porous structure with smaller unit cell size, which is comparable with the evaluation of compressive strength.
- The numerical model for correlation among parameters of porous structural and elastic modulus was established, as well as a purple region which was further limited in the effective fitting surface for design implant, indicating the methods for parameter choice during design of porous structure.
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Thin Wall | Small Hole | |||
---|---|---|---|---|
Designed Value | Measured Value | Designed Value | Measured Value | |
1 | 0.05 | - | 0.05 | - |
2 | 0.1 | 0.16 | 0.1 | 0.07 |
3 | 0.2 | 0.24 | 0.2 | 0.16 |
4 | 0.3 | 0.33 | 0.3 | 0.27 |
5 | 0.4 | 0.42 | 0.4 | 0.38 |
6 | 0.6 | 0.61 | 0.6 | 0.58 |
7 | 0.8 | 0.81 | 0.8 | 0.78 |
8 | 1.0 | 1.06 | 1.0 | 0.99 |
Unit Cell Size = 1 mm | 2 mm | 3 mm | 4 mm | 6 mm | |||||
---|---|---|---|---|---|---|---|---|---|
P a (%) | E b (GPa) | P (%) | E (GPa) | P (%) | E (GPa) | P (%) | E (GPa) | P (%) | E (GPa) |
35.60 | 55.47 | 39.71 | 44.25 | 40.8 | 41.86 | 39.9 | 40.13 | 40.70 | 37.26 |
45.50 | 39.53 | 49.9 | 33.01 | 49.5 | 31.24 | 49.7 | 30.52 | 50.30 | 29.52 |
56.80 | 25.36 | 59.83 | 20.09 | 59.5 | 18.53 | 59.7 | 16.31 | 60.00 | 14.68 |
66.80 | 15.17 | 68.0 | 12.16 | 69.0 | 11.05 | 68.9 | 10.19 | 69.90 | 7.85 |
77.10 | 6.90 | 78.4 | 6.07 | 78.5 | 5.11 | 79.4 | 4.35 | 79.80 | 3.50 |
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Xu, Y.; Zhang, D.; Zhou, Y.; Wang, W.; Cao, X. Study on Topology Optimization Design, Manufacturability, and Performance Evaluation of Ti-6Al-4V Porous Structures Fabricated by Selective Laser Melting (SLM). Materials 2017, 10, 1048. https://doi.org/10.3390/ma10091048
Xu Y, Zhang D, Zhou Y, Wang W, Cao X. Study on Topology Optimization Design, Manufacturability, and Performance Evaluation of Ti-6Al-4V Porous Structures Fabricated by Selective Laser Melting (SLM). Materials. 2017; 10(9):1048. https://doi.org/10.3390/ma10091048
Chicago/Turabian StyleXu, Yangli, Dongyun Zhang, Yan Zhou, Weidong Wang, and Xuanyang Cao. 2017. "Study on Topology Optimization Design, Manufacturability, and Performance Evaluation of Ti-6Al-4V Porous Structures Fabricated by Selective Laser Melting (SLM)" Materials 10, no. 9: 1048. https://doi.org/10.3390/ma10091048
APA StyleXu, Y., Zhang, D., Zhou, Y., Wang, W., & Cao, X. (2017). Study on Topology Optimization Design, Manufacturability, and Performance Evaluation of Ti-6Al-4V Porous Structures Fabricated by Selective Laser Melting (SLM). Materials, 10(9), 1048. https://doi.org/10.3390/ma10091048