Abstract
Demand for orthopaedic implants is growing due to an increased aging population along with increasing numbers of traffic accidents and sport injuries. Among the existing choices of alloys, stainless steel 316L is commonly used for load-bearing implant applications due to its high mechanical strength, good corrosion resistance and biocompatibility as well as low cost.
Laser 3D metal printing is an additive manufacturing process based on selective laser sintering (SLS). It can directly print metal parts layer by layer with complex geometries and porous structures. Therefore, this technique is suitable to fabricate the implants specifically tailored to individual patient's anatomy. Comparing with the conventional manufacturing methods, it is environmentally friendly as the unused materials (i.e., metal powders) are totally recyclable.
For any load-bearing implants, good resistance to fatigue failure is often considered as essential in order to ensure the implants can provide sufficient mechanical support during their service life. Fatigue failure occurs under conditions of cyclic mechanical loading at stress levels well below the tensile strength. Such repetitive cyclic loading can result in formation of small cracks in the implant’s surface. Then, the small cracks will grow in size and propagate further until the implant completely fractures. Initiation of the small cracks due to fatigue is usually spontaneous and unexpected.
In this study, a customised real-time monitoring system was developed to capture the initiation and growth of small cracks during the 4-point bending fatigue test. A laser 3D-printed 316L plate was tested and the crack lengths at different loading cycles were measured. The results were compared with a wrought 316L plate cut in the same size.
Laser 3D metal printing is an additive manufacturing process based on selective laser sintering (SLS). It can directly print metal parts layer by layer with complex geometries and porous structures. Therefore, this technique is suitable to fabricate the implants specifically tailored to individual patient's anatomy. Comparing with the conventional manufacturing methods, it is environmentally friendly as the unused materials (i.e., metal powders) are totally recyclable.
For any load-bearing implants, good resistance to fatigue failure is often considered as essential in order to ensure the implants can provide sufficient mechanical support during their service life. Fatigue failure occurs under conditions of cyclic mechanical loading at stress levels well below the tensile strength. Such repetitive cyclic loading can result in formation of small cracks in the implant’s surface. Then, the small cracks will grow in size and propagate further until the implant completely fractures. Initiation of the small cracks due to fatigue is usually spontaneous and unexpected.
In this study, a customised real-time monitoring system was developed to capture the initiation and growth of small cracks during the 4-point bending fatigue test. A laser 3D-printed 316L plate was tested and the crack lengths at different loading cycles were measured. The results were compared with a wrought 316L plate cut in the same size.
| Original language | English |
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| Publication status | Published - 15 Sept 2022 |
| Event | The Northern Ireland Biomedical Engineering Society Symposium - University of Ulster, Belfast, United Kingdom Duration: 15 Sept 2022 → … |
Conference
| Conference | The Northern Ireland Biomedical Engineering Society Symposium |
|---|---|
| Country/Territory | United Kingdom |
| City | Belfast |
| Period | 15/09/2022 → … |
Access to Document
- Real-time monitoring of cracking behaviour for laser 3D-printed stainless steel under bending fatigue test
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